Mach3 Settings for the Rotary Axis

Almost ready!

With the rotary axis assembled and ready to go, it’s time to set up Mach3 to work with it. Rather than go through the entire process here, I’ll give you some of the highlights and refer you to the video on my YouTube channel, linked below. Read More

I will, however, include screen shots of all of the relevant Mach3 windows that I went through in the video. If you right-click the pictures, then select “Open in New Tab, a full-sized picture will open in a new tab on your browser. Feel free to download and save these pictures for future reference, but please don’t post them online without talking to me BEFORE you do it. I would appreciate it.

Initial Steps

The first step is to create a separate Mach3 profile for it. We can clone the profile we use now and modify that clone, or we can clone one of the factory profiles and modify that clone. No matter which way we go, we’re going to have to enter and change a bunch of settings, so I chose to clone the factory Mach3 Mill profile. You don’t want to use Mach3 Turn, because that’s designed for a CNC lathe. A rotary axis is not a CNC lathe – there are some major differences. The rotary axis is just an accessory to the CNC router, so I cloned the Mach3 Mill profile.

The Settings

The second step is to Select Native Units.

Right click, and select "Open in New Tab."
Select Native Units

Third is to activate the Motor Outputs one by one.

Right-Click, then select "Open in New Tab."
The Motor Output settings

Next is to make sure the A, B, and C axes are configured as ANGULAR axes, and there is no checkmark next to Home Slave with Master Axis box in the General Configuration window.

Right-Click and select "Open In New Tab"
General Configuration Settings

The Really Important Bits

Fifth is the motor setup, which we’ll do by going to the CONFIG menu and selecting Motor Tuning. The A axis is the axis that may cause the most confusion. The thing to remember is that the other axes are LINEAR, and they’re based on Steps Per Inch. The A axis is ANGULAR, and it’s based on Steps Per Degree. So we’ll need to get some info and do a little bit of math before we can enter the Steps Per for this axis.

Right-Click and select "Open in New Tab"
Motor Tuning Settings for X axis
Right-Click and select "Open in New Tab"
Motor Tuning Settings for Z axis

First, we’ll need to find out how many steps our motor takes to turn one complete revolution. In the case of the Xylotex motor, that number is 3200 steps. So we have our 3200 steps to turn the stepper motor 1 complete revolution. Now we need to know the drive ratio of the rotary axis. In the case of my Sunwin unit, that ratio is 6:1 – meaning it takes 6 revolutions of the stepper motor to turn the chuck 1 complete revolution. So to find out how many steps per degree to enter in the Steps Per box in the Motor Tuning window, the math looks like this:

3200 steps X 6:1 drive ratio = 19,200 steps to turn the chuck 360 degrees, or 1 complete revolution.

(3200 X 6 = 19,200)

19,200 steps divided by 360 degrees in a circle = 53.33333 recurring.

(19,200/360 = 53.33333 recurring.)

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Motor Tuning settings for A axis

So, I now know that the Steps Per for the A axis is 53.33333. I entered 5 places to the right of the decimal only because I don’t know how many Mach3 will let me enter, and I really don’t know if going any further than 5 places to the right of the decimal will matter. If it turns out that it does matter, I can come back and add more.

For the velocity, I entered 2500. Remember that we’re not working in inches per minute in this case – we’re working in DEGREES per minute. For instance, if I set the velocity at 360, that means it will take 1 minute for the axis to make one complete 360 degree revolution. That’s way too slow. At 2500, it should take less than 10 seconds to make 1 complete revolution, which is not very fast at all. Next I’ll set the acceleration to 485 degrees per second. That’s not how fast the axis will turn – that’s how fast it will accelerate to the speed of 2500 degrees per second. Also remember that the speeds we’re setting in this window are the rapid movement rates – NOT the normal feed rates.

Just a Few More To Go

The next step is to make sure there are no axes slaved together. Whether you make any changes in the Slave Axis window or not, it’s time to restart Mach3. Before you do, however, go back to the CONFIG menu, and click Save Settings so that all of these changes will be written to the hard drive and saved.

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Slave Axis settings

With the profile made and the settings entered, we’re ready to test the rotary axis. Pay attention to the direction of the chuck’s rotation. Positive Rotation should be counter-clockwise. So if I stand in front of the machine, the top of the chuck should appear to be turning toward me. If it’s not, I’ll have to reverse the direction of that stepper motor by going up to the CONFIG menu, selecting Homing/Limits, and putting a checkmark in the Reversed column, next to A Axis.

Next comes programming some hot keys for the rotary axis. If you use a pendant or video game controller, now is the time to program that as well.

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Mach3 System Hotkeys screen

The next 2 settings are used to make sure the toolpath display in Mach3 will display correctly, and the feedrate will be calculated correctly.

First we’ll enter the correct settings in the Toolpath window. Don’t forget to go to CONFIG, and click Save Settings again.

Right-Click and select "Open in New Tab"
Toolpath Configuration settings

Next click the Settings tab at the top of the screen, and look at the top, right corner for Rotation Radius. Each time I chuck something into the A axis, I’ll want to enter the RADIUS of the piece of material in that DRO in the A Axis row. So if I have a piece that’s 1.5” square, the rotation radius will be .75. So I’ll click the DRO next to A, type in .75, then hit the ENTER key. Now when I go back to the Program Run tab, to the right of the 4 DRO, I can see that the Radius Correct LED is lit up. That lets me know that I remembered to enter the rotation radius into the Settings screen, so my toolpath display should actually display the toolpath correctly. It also means that Mach3 will now calculate the feedrate called for in the g-code correctly. Again, this will have to be done each time we put a piece of material into the chuck of the rotary axis.

Right-Click and select "Open in New Tab"
Settings Tab

Made it!

That’s a lot of information, I know. It made for a very long video, I know. There’s nothing inherently difficult in setting it up – there are just a lot of things to remember to do. The single hardest part for me was in remembering to think in terms of degrees, rather than inches. I’m working on that, and it is getting easier.

Summing Up

If you’ve stuck with me this far, I’d like to say thank you very much. I know that videos and articles like this are as boring as watching paint dry, but it’s impossible to put this much info into a short presentation.

In my next article, I’ll talk about how I mounted the axis on my Gatton CNC, future mounting plans, and hopefully I’ll get to do some cutting on it! Thanks for stopping by!

Here’s a list of all of the parts I bought to get a rotary axis for my Gatton CNC, with links so you can check them out.

Xylotex Stepper Motor

Sunwin Hollow Shaft Rotary Axis

POWGE 10 Teeth HTD 5M Synchronous Pulley

(Make sure to select 6.35mm bore diameter, for 15mm wide pulley, and choose the number of pieces you want.)

LUPULLEY HTD 5M Timing Belt

(Be sure to select 15mm belt width and 355mm belt length.)

As usual, if you have a question or comment, leave it in the comments section below. Or, if you’d prefer, go over to the Contact Us page and submit it to me there.

If you’d like more info on a Gatton CNC kit of your own, check out Dave Gatton’s home page here.

Until next time, take care and have fun! 

Introducing the Rotary Axis for my Gatton CNC

I’ve wanted to add a rotary axis to my CNC since I built my first Shoestring Budget CNC back in 2015, but they were just too pricey. I looked into a couple of options for a home-built unit, but never found one that I really liked. I downloaded a few sets of free plans, and eventually bought the plans being offered by Dave Gatton, here on his website.   Read More

I got Dave’s plans and started looking into them, getting more and more excited as I did so. I even went ahead and bought a Xylotex stepper motor to use in the build. Then I immediately got slammed with work, and it had to go on the back burner. When I started my Gatton CNC build back in June of 2017, the rotary axis project got pushed even further back. Finally, in December of 2017, with my Gatton CNC build finished, I decided that I had waited long enough, and that I was going to have a rotary axis for my CNC by the end of 2018.

The Search

The problem was that by the time I got back into the plans to build the Gatton Rotary Axis, prices had gone up quite a bit. As I started adding up the cost of all the parts, I wondered if I had waited too long to get going on it. I then decided to price a few rotary axis kits being offered online and do some comparison shopping. I was surprised by what I found.

I found complete kits ranging from $150 to $375. Some of those kits came with a tailstock, and others did not. I did a little bit of looking around, comparing the pros and cons of each kit I was looking at, and decided that I would purchase a rotary axis kit, rather than build one. My thinking was that the major part of the building was done for me, for the same amount of money (or less in some cases,) as a pre-assembled kit. Also, by this time, I was getting a little tired of building CNCs, and wanted to focus on actually USING the CNC I had worked so hard to build.

With that decision made, I then set out to choose a rotary axis that would work with my Xylotex drive box. That proved to be harder than I thought it would be. You see, the Xylotex drive box I have is a 4.0 amp system. The only rotary axis kits I could find were 3.0 or 3.5 amp kits. Now I’m not an electronics guy. My electronic knowledge is rudimentary at best – downright barbaric at worst. I do know enough to try to match a motor’s voltage and amperage to that of the power supply, however. I just wondered if one of the 3.5 amp motors could be used with the 4.0 amp Xylotex drive box.

I emailed Jeff at Xylotex, and asked him if one of these motors would work with the drive box (I sent him the spec sheet on the motor in that email.) He warned me that while the motor would physically turn, it would tend to shudder, stutter, and jump as it did. It would also tend to overheat in a short amount of time. He recommended that I didn’t use it, but rather to swap it out for one of the Xylotex motors. (I had reminded him in my initial email that I already had a spare Xylotex motor, which I had purchased to build a rotary axis with, so there was no opportunity for another sale here – he knew I had the spare motor on hand. I have dealt with Jeff many times in the past, and I just don’t think he’s the type to tell someone a flat-out lie for a $40 sale.)

So, I finally decided on which rotary axis I wanted, then ordered it. I chose this Sunwin CNC hollow shaft rotary axis with100mm 4-jaw Chuck and 65mm tailstock through Amazon.com. 

The Sunwin Hollow Shaft Rotary Axis Kit as purchased.

I chose this kit for two major reasons. First, when I ordered this kit, they were offering free shipping. Second was Amazon’s return policy. I knew that if I received a defective unit, I’d have an easier time returning or exchanging it through Amazon than I would through someone on eBay or Ali-Express. I did find several other rotary axis kits that were less expensive, but those two factors were what decided it for me. For example, I found a solid shaft rotary axis kit, without the tail stock, that was $150. However, reading the fine print, the shipping from China to the US was $195! More than the cost of the unit! And I’d still need to buy a tailstock! The Sunwin kit was only $24 more, and had the tailstock, plus the hollow shaft. I decided to go with that unit.

Sunwin hollow shaft headstock

I received the kit about 10 days after ordering it, and was chuffed to bits when I got the boxes open. I got the Sunwin motor off with no problem. I got the Xylotex motor mounted with no problem. I took the timing belt pulley off the Sunwin motor with no problem. I went to put it on the Xylotex motor, and had a problem.

The Parts Chase

The motor shaft on the Xylotex motor is 1/4” diameter. The motor shaft, and therefore the bore on the pulley, is 8mm. Yup – that’s too big. If I were a machinist with a metal lathe, I could have made a sleeve to adapt the Sunwin pulley to the Xylotex motor. Well, I’m not a machinist, and I don’t have a metal lathe. So, I went online and searched for the proper pulley to fit the belt and my stepper motor.

It was harder to find than I thought it would be. I checked all of the usual websites (McMaster-Carr, etc…,) but came up empty. I finally found it on Ali-Express, here.

A word of warning here. If you ever need to order something from China, make certain it can be shipped before February 1st. Most of the manufacturing in China closes down for 2-3 weeks for the Chinese New Year celebration. I didn’t know that, and ordered my pulley on February 7th. It shipped Feb 28th, and I received it March 9th.

With the timing pulley finally in hand, I was excited again. It fit the Xylotex motor perfectly, and tightened securely. Then I ran into a second problem. See, the Xylotex motor is not only higher amperage, it’s also physically longer than the Sunwin motor – by about 1/2”. That put the end of the motor right in line to interfere with the bolts that mount to eh chuck to the faceplate. Awwwww, crumb… I needed a longer timing belt.

Thankfully, I didn’t need a much longer belt. I got online (again) looked for 15mm wide high torque timing belts with a 5mm pitch, and found them in short order. I decided to order 2 different sizes. I ordered one that was 5mm bigger, and one 10mm bigger. I know my luck – if I had ordered the 5mm longer belt, it would have been too short. If I had ordered the 10mm longer belt, it would have been too big. I ordered both, and that basically confounded the CNC gods enough that the 5mm longer belt fit perfectly. With all of the parts finally in one place, I assembled everything perfectly, and got it ready to take outside to test it.

The completely assembled headstock, after modifications

Well, actually, I did have to do one last thing to the headstock, but… well… This article is getting pretty long. Check out the YouTube video I posted below, and you’ll get all of the details.

The Bottom Line

So, in summing up, yes I now have a rotary axis for my Gatton CNC. So far, yes, I do like it. Would I do it again? Well, knowing now what I didn’t know then, yes I would. I would time things a little differently, but yes I would.

Here’s a list of all of the parts I bought to get a rotary axis for my Gatton CNC, with links so you can check them out.

Xylotex Stepper Motor

Sunwin Hollow Shaft Rotary Axis

POWGE 10 Teeth HTD 5M Synchronous Pulley

(Make sure to select 6.35mm bore diameter, for 15mm wide pulley, and choose the number of pieces you want.)

LUPULLEY HTD 5M Timing Belt

(Be sure to select 15mm belt width and 355mm belt length.)

In my next article and video, I’ll get into Mach3, and show you how I created a new rotary axis profile, and what settings I used to get my rotary axis working with my Xylotex drive box.

As usual, if you have a question or comment, leave it in the comments section below. Or, if you’d prefer, go over to the Contact Us page and submit it to me there.

If you’d like more info on a Gatton CNC kit of your own, check out Dave Gatton’s home page here.

Until next time, take care and have fun! 

Creating a Spoilboard Surfacing Toolpath in VCarve

Surfacing a spoilboard is the final necessary step, after laying one down on the CNC table. Creating the surfacing toolpath sounds intimidating, but it’s actually pretty simple. You just have to remember a couple of things. Read More

Why Surface a Spoilboard?

The simple answer is that we surface the spoilboard to make sure that it’s flat and smooth. Material to be cut on the CNC is mounted to the spoilboard. We want that material to be as flat as possible to ensure smooth cuts of equal depth along every part of its surface.

This is especially important when it comes to v-carving or engraving. If the work piece isn’t sitting flat, a v-bit will cut deeper in areas that are sitting on a high spot, and shallower in areas that are sitting in a low spot.

Assuming you have trammed your router or spindle, and have your spoilboard mounted, we can start gathering the info we need to create a toolpath we can use to surface the spoilboard. If you haven’t trammed your router or spindle, I highly recommend you do so before you attempt to surface a spoilboard. I covered the process in my website article “Tramming the Router on my Gatton CNC,” which you can read here.

Things to Note and Remember

There are a couple of things we need to know before we get on the computer. Chief among them is the physical size of your spoilboard, and its proximity to your limits. We need to be sure that the toolpath we create will allow you to run the surfacing bit over the entire spoilboard without hitting a limit switch or crashing an axis.

When I made my spoilboard, I used a felt pen chucked into my router to draw a line on the table, from one side of my X axis to the other. I purposely triggered the limit switches at both ends of the X axis when I drew that line. I did that for several reasons, but one reason was to learn exactly where those limits were in relation to the centerline of the router bit over the table. It turns out that limit was roughly 1/4” away from the aluminum angle along each side of the table.

I put a piece of t-track right next to that aluminum angle, and it’s just shy of 3/4” wide. My spoilboard actually starts right next to that t-track. That means the left and right edges of my spoilboard are roughly 1/2” inboard of the limits of my X axis. This means I can safely machine the surface of the spoilboard without triggering a limit switch in X.

Along the Y axis, my CNC will run past the front edge of the table by a couple of inches without hitting the forward limit switch. I used that line I drew on the table to aid in placement of the spoilboard pieces, and trimmed the back edge of the spoilboard flush, using a 1/4” straight bit in my router. I know that the router will miss the rear Y axis limit switch by at least 3/8” – probably more.

With the measurements of the spoilboard in X and Y and the distance from each edge of the spoil board to each limit written down, I can get into VCarve Pro and start creating the toolpath.

Creating the Toolpath

Follow along in the video below as I go through the steps needed to create a toolpath for surfacing the spoilboard. I’m using VCarve Pro version 8.5, so some of the screens may differ from yours slightly, depending on which version you’re using.

We’ll be using some of the calculators built into the VCarve software to create the toolpath boundary. Then we’ll calculate a pocket toolpath, preview it, and make any adjustments needed. Finally, we’ll save the g-code.

As usual, if you have a question or comment, leave it in the comments section below. Or, if you’d prefer, go over to the Contact Us page and submit it to me there.

Until next time, take care and have fun!

Adding a Spoilboard to my Gatton CNC

One of the final steps I needed to take before putting my Gatton CNC into service was laying down a spoilboard. Read More

What is a Spoilboard?

A spoilboard is a sacrificial piece of material that’s mounted to the table. Material to be cut on the CNC is mounted to the spoilboard, rather than to the table itself, in order to keep from cutting into the table.

A spoilboard can be as simple or as complex as you want to make it. It can be as simple as a sheet of material clamped or screwed down to the CNC table. It can be made more complex by adding t-track, threaded inserts, holes for registration pins, indexing straight edges, and more.

At it’s most basic level, it’s simply there to raise the work material so that when a bit or end mill cuts through it, the CNC table doesn’t get damaged.

Designing A Spoilboard

There are several things to take into consideration when designing a spoilboard. Chief among them is how you’re going to use your CNC. If you’re only doing laser engraving, you may not need to add a spoilboard at all. If you’re running a router or spindle, however, you’ll want to add one.

Most spoilboards incorporate a method of mounting a piece of work material to it. Threaded inserts or t-track are the most common methods used, however there are some who include provisions for adding offset clamps, wedges, and other means of fastening work material to it.

Another factor in the design process is the size of your table, and the limits of your machine. You should measure not only the physical size of the table, you should also measure and mark out the cutting capacity of both your X and Y axes to get a clear idea of just how large of a spoilboard you’ll need to make. Once you have those dimensions, record them so you can refer to them when it comes time to start building.

When I started designing my spoilboard, I knew that I wanted versatility. I went back and forth over whether to use t-track or threaded inserts for several weeks. I plan on making and using several jigs and fixtures, and I wanted to be able to mount them easily and accurately. For that reason, I opted to go with t-track, as it seems to offer more mounting locations than threaded inserts will. I then got online and did some comparison shopping. I decided to go with 36” long sections of t-track from Orange Aluminum. I’ve placed a link to Orange Aluminum at the end of this article.

Thirteen pieces of T-track, ready to go onto my Gatton CNC table.
Creating My Spoilboard

I decided to mount the t-track straight to the table’s surface, and fill in the areas between the pieces of t-track with 3/4” thick MDF. MDF is reasonably priced, readily available, and machines smoothly. Most folks opt for MDF, however I have seen some spoilboards made out of plywood. The choice is 100% yours.

I then needed to know what size of spoilboard to make. In the video linked below, I show how I mounted a felt tip pen in my router, and used it to mark a line on the CNC table from one side to the other along my X axis. I moved the Y axis back until it was 1/8” away from triggering the rear limit switch, then put the pen in my router, using the 1/2” collet. I moved the X axis to the right until it triggered the limit switch, then I ran the X axis to the left until it triggered that limit switch. That drew a line across my table, parallel to the X axis.

The length of the line the felt pen drew gave me my absolute max limits in X. It also showed me exactly where the center of a bit or end mill would be, in relation to the aluminum angle, when the limit switches were triggered. In my case, the center of the bit or end mill would be approximately 1/4” away from the aluminum angle at the edge of the table when the limit switch was triggered.

The t-track I ordered is just under 3/4” wide. I wanted to place a piece of t-track right up against the aluminum angle at the edge of the table on each side, and butt a strip of MDF right up against it. With the limit switch being triggered 1/4” away from the aluminum angle, that would put the right edge of that strip of MDF 1/2” to the inside of my max X axis limit. I knew then that I could surface the entire width of my spoilboard without hitting an X axis limit switch.

With those measurements taken, I went back to the model of my CNC table in SketchUp.

The Design Drawing

My table features a large cutout in the front edge that will eventually allow me to clamp work pieces to the front of the machine vertically. I knew that I wanted a piece of t-track that ran from the front edge of the table, along the side edge of the cutout, at both ends of the cutout. I also knew that I wanted a piece of t-track butted up against the left and right Y axis linear rail.

Orange Aluminum has a measured drawing of its t-track on their web page, so I jotted down the measurements, and drew several sections of it into SketchUp. I didn’t put a lot of detail into the t-track drawing, but I did get the critical measurements.

With the t-track drawn in and located at the edge of the cutout and beside the linear rail, I measured from the centerline of one to the centerline of the other, divided that measurement by 2, then added a third piece, centering it between the first two. See the photo below.

An illustration of how I arranged the t-track on my Gatton CNC table.

I then added a few more pieces of t-track in the area behind the cutout, and arranged them so that I’d have enough to be able to mount just about any fixture or jig within that cutout. I finally settled on mounting 7 pieces of t-track in that area, then drew MDF strips to fill in the spaces in between the t-tracks. With the design finalized, I went out to the shop and started work.

Building the Spoilboard

I know that the way I mounted the spoilboard will freak a few people out. I’ve anticipated some of the questions I’m sure to get, and I’ll answer them right now.

Q. Why did you glue the MDF down? What are you going to do when it’s time to replace one?

A. I’ll answer that question with a question: Why would I want to replace one? When the surface gets too scarred up or full of holes, I’ll surface it. When it gets surfaced down to the point that I’m close to hitting the t-track with the bit, I’ll glue a strip of 1/2” MDF on top of each strip, then surface them.

Q. Why did you screw the MDF down from the top? Why not screw up from the bottom?

A. It’s a simple matter of access. It was easier to drive screws on top of the spoilboard than to crawl under the table.

Q. But now you have a bunch of holes in the spoilboard!

A. So? It’s a spoilboard. It’s sacrificial. It will get cut up, drilled into, have screws driven into it, and basically get messed up. That’s its job.

If that doesn’t cover the questions, feel free to add yours in the comment section below.

Summing Up

In the video below, I show some of my design considerations, how I made the cutout in the table, then how I mounted and surfaced the spoilboard.

My next video will go over how I created the toolpath in VCarve Pro to surface my spoilboard. It looks intimidating, but it’s not as difficult as you think.

https://www.youtube.com/watch?v=ddyGvHG6cwo

 

Here are some links to some of the supplies I used to mount the spoilboard to my Gatton CNC:

T-Track – http://bit.ly/2zDPR6w

Freud 1.25″ x 1/4″ Straight Mortising Bit:

http://amzn.to/2lBW7FD

Titebond III Ultimate Wood Glue:

http://amzn.to/2zG5Q1b

Additionally, I made the spoilboard out of 3/4″ thick MDF and fastened the t-track down with 1″ long, #8 exterior grade woodscrews. I used Titebond 3 to glue the MDF strips to the CNC table, and temporarily screwed down the MDF with 1 1/4″ exterior grade woodscrews.

As usual, if you have a question or comment, leave it in the comments section below. Or, if you’d prefer, go over to the Contact Us page and submit it to me there.

Until next time, take care and have fun!

Tramming the Router on my Gatton CNC

Trammign the Router on my Gatton CNC

What Is Tramming and Why Would You Do It?

 

Tramming the router means adjusting the router mount to get the router as close to perfectly perpendicular to the spoilboard in the X and Y direction as possible. A router that’s not adjusted properly will cut deeper on one edge than it does on the other, leaving ridges and grooves on flat surfaces. This phenomenon is less noticeable when using smaller diameter bits. When you get into using larger diameter bits, however, it can become very apparent. Read More

In the picture below, you can see an exaggerated demonstration of what I’m talking about. The bit on the left is tilted clockwise, so the cutting edge of the bit is cutting deeper into the material on the right side than it is on the left. This is known as shingling, because when you look at it from above, the ridges and grooves look like rows of shingles on a roof. The bit on the right is running straight and true, leaving a smooth cut.

A gross exaggeration of what shingling looks like.
A demonstration of Shingling due to a tilted router.

Tramming the router eliminates that shingling problem.

Let me say right here that you may or may not need to tram your router. If you’ve been using it for a while and you haven’t noticed a problem, you probably don’t have one. If you mainly use bits and end mills smaller than about 1/4” in diameter, you may never notice a thing. I didn’t notice any problems on my Shoestring Budget CNC until I went to surface a pine slab with a 1 1/4” diameter bit. It was then that I discovered just how badly I needed to tram my router.

If, on the other hand, you plan on surfacing materials like slabs or rough milled lumber on your CNC, you might want to look into tramming your router. In my opinion, I think a person should tram their router even if they just plan on adding a spoilboard and surfacing it. If you’re going to go to all of the trouble of adding a spoilboard, you’ll want it as flat, smooth and level as you can get it, right?

So What Tools Do You Need to Tram Your Router?

 

When it came to tramming the router on my Gatton CNC, there were a lot of options. Edge Technology offers a Mini Pro Tramming System, which consists of an anodized aluminum beam that has 2 dial indicators on it. Basically, you chuck it into your router, and use the dial indicators to get very precise measurements. They run right around $125.00, however, and that just isn’t in the cards for me right now. I may get one further down the road, but for the moment, I need to focus on a cheaper alternative. Instead, I went with a Triton dial indicator, which I ordered online for less than $20.

Link to this dial indicator in the main body of the article.
The inexpensive dial indicator used for tramming.

We’ll also need a piece of glass, some small blocks of wood to hold the glass stationary, and something to use as shim stock.

Why do we need a piece of glass? Well, in order to adjust the router, we’ll need a flat, level plane to measure it against. The piece of glass is going to provide that level plane. You don’t need any special kind of glass. I used a piece of glass from a cheap picture frame I picked up at the big box store for less than $2. I would suggest, however, that you don’t use a piece of glass larger than 8” x 10”. The reason for that is because even though the dial indicator isn’t putting very much downward pressure on the glass, it can be enough to make the glass flex. That will throw off your measurements, and your tramming won’t be very accurate at all.

You’ll also need a way to mount the dial indicator in to the router. In the video posted below, I show you the mounts I made out of scrap. They both worked like a charm.

Tramming Isn’t Difficult

While tramming the router isn’t the most exciting thing in the world, it wasn’t hard to do at all. All in all, it took me about 2 hours to do, but it has taken some other folks I’ve talked to up to 6 hours or more, depending on how far they needed to adjust it. With that in mind, let me offer a few tips that can make things go a lot smoother for you.

First and foremost, don’t lean on the table while you’re taking measurements. In fact, you should completely clear the table of everything other than the glass and shims. You’d be surprised at how much your dial indicator will move if you even rest your hand on the table. Try it and see for yourself.

Adjust the nod of the router first. If you adjust the tilt first, when it comes time to adjust the nod, you’ll undo all of the work you did when you adjusted the tilt.

When measuring the nod of the router, take the reading you get and divide it by two, then use a shim of that thickness if possible. In other words, if you find that your router is off by .012, divide that by 2 and use a shim that’s .006.

For shimming the router mount to adjust the nod, I sacrificed an old blade type feeler gauge. The blades are clearly marked, and you should be able to find one at an auto parts store if you don’t have one. The blades I used tucked under the router mount horizontally like they had been made for that job, and it made shimming the mount really easy.

Other than that, relax, take your time, and take breaks when you need to. Tramming could potentially get frustrating. It’s easy to move the mount too far, then move it back too far. The tramming plates I made and installed on my Z box helped me out a lot when it came time to adjust the tilt. Just remember to take your time. It’s not a race. The point is accuracy, so walk away from it for a while if you need to.

Follow along in the video to see the steps I took to tram the router on my Gatton CNC.

Here are some links to the tools I used to tram the router in my Gatton CNC:

Triton 1″ Face Dial Indicator 

GearWrench Feeler Gauge

As usual, if you have a question or comment, leave it in the comments section below. Or, if you’d prefer, go over to the Contact Us page and submit it to me there.

Until next time, take care and have fun!

Adding Homing and Limit Switches to My Gatton CNC

Adding homing and limit switches to my Gatton CNC wasn’t as difficult as I thought it would be, but there are some things to watch out for. Read More

Let me explain the sentence above. I’m not an electronics person – I’m a wood guy. My interests run toward the mechanical – not the electronic. It’s not that I don’t think I could learn electronics. I just don’t have any desire to learn it. That’s worked to my disadvantage a few times, and it’s been a limiting factor on occasion, but I’m fine with that. I’m not a total dunce to all things electrical or electronic. I can run wire and hook up devices. I just don’t get into sensors, relays, and automating simple tasks that I can do manually. That sounds weird coming from a guy who is building a CNC, I know, but it works for me.

As I type this on November 6th, 2017, my Gatton CNC is basically finished. About all I have left to do is add a dust collection system, then mount and surface a spoilboard. On my old Shoestring Budget CNC, I felt no need to use homing or limit switches. I knew the size of my table and the size of the cutting area, so I worked within those boundaries with no problems. I could see the extents of my CNCs cutting area quite plainly, and it was easy to position a piece of material in an area where all of the toolpaths fit inside the limits of the machine. That worked fine for me for over 2 years.

The Gatton CNC is much bigger than the Shoestring Budget CNC was, and the gantry is oriented so that it moves along the Y axis, rather than the X axis like the Shoestring Budget CNC did. That in itself is taking some getting used to, but it also means that it would be easier for me to mount a piece of work material in such a place that I could potentially crash an axis. On the Gatton CNC, I can’t physically see the rearmost limits of the gantry travel, and I can’t physically see the left and right limits of the X axis’ travel. Knowing that, I decided early in the build process that I was going to have to seriously consider adding limit switches to the build to help me avoid damaging it.

In my case, I lucked out. A gentleman by the name of Andrew Hague, of The Old English Workshop, has been building a Gatton CNC of his own. He’s heavily into 3D printing, and he’s been gracious enough to send me some limit switch mounts he’s come up with for his Gatton CNC build. Andrew has posted the files for the limit switch mounts and the bumpers on his Thingiverse page, and they’re free for you to download and 3D print, or have printed for you. You can access Andrew’s Thingiverse page here. 

With these mounts in hand, I decided that I should move forward with mounting them.

Here are a few links to the supplies I used in this modification to my Gatton CNC:

Limit Switches:

Pack of 5 Switches

Pack of 10 Switches

Pack of 20 Switches

15mm X 30mm Drag Chain

18/2 Shielded Stranded Cable

In the first video posted below, I talk about the importance of using stranded, shielded cable. It basically comes down to 2 factors – stress fractures and blocking RF interference. It’s important to use stranded wire in any area where there will be movement, and a CNC is loaded with things that move. Using stranded wire reduces the possibility of breaking a wire through repetitive bending of the wires. Using a shielded cable is important because it will reduce the number of false limit triggers by absorbing RF interference created by the router or spindle motor and other sources. Hooking up the shielding wires is crucial – without doing that, the shielding has no effect whatsoever. I mention this here because it was completely left out of the first video. I discussed it in the second video.

There are a couple of different schools of thought on connecting the shielding wires. Some will say that they should be run to an earth ground, which consists of a grounding rod driven into the ground at least 6 feet, and the appropriately sized cable run from the shielding wires to that grounding rod. The people who think this way are in the minority, however. The general consensus is that connecting the shielding wires to the same ground that the switches themselves are connected to is fine.

The thing to remember about this is that we’re not talking about huge current levels. We’re talking about dissipating RF interference as it is created. It’s a bit like static electricity. If you shuffle your feet on some carpet, then reach out and touch a door knob, there will be an arc, and you’ll get zapped. If you hold onto that door knob and shuffle your feet, there’s no arc and you won’t get zapped – even if you let go of the door knob, then reach to touch it again. The static was dissipated as it was created. It’s the same thing with this RF interference. Any interference is absorbed by the shielding wire and dissipated through the ground before it can build to the point that it is absorbed by the limit switch wires. It’s a passive system that is constantly working.

Mounting the limit switches themselves was pretty straight forward. I put the mount and bumper where it was supposed to go, mounted the switches to the mount, and ran the wire through the drag chain I had previously mounted on the axes. At the other end, I connected positive wire to the breakout board, the negative wire to the grounding terminal strip I mounted under my table, and the cable’s shielding wire to that same strip. That’s all there is to it.

The main thing to remember is to connect the shielding wires to ground on one end only. DO NOT connect both ends! If you do, you’ll create a ground loop that will cause you problems almost immediately. So remember – connect one end of the shielding wires to ground, and don’t connect the other end to anything. Trim them back flush with the cable’s outer insulation and leave them be.

With everything hooked up, I then got into Mach3 and configured the switches to work as both homing and limit switches. That was straight forward enough as well. There are just a number of steps to take to make sure you have them configured correctly. The most important step is to remember to set the general configuration so that the slave axis homes with the master axis. I explain this in detail in the video below that accompanies this blog post. The second most important step is to remember to go back into the CONFIG menu in Mach3 and click Save Settings after you finish configuring the homing and limit switches, before you exit Mach3.

While the process wasn’t difficult, it was pretty involved. There’s a lot to do, a bit to remember, and quite a bit to explain. So much, in fact, that I broke it up into 2 separate videos, which I’ve posted below.

So where do I stand right now? As I said earlier, the major construction is finished. I have the spoilboard mounted and it’s looking good (video on the way!) Right now I’m putting together a dust collection system, then I can surface the spoilboard, then fire this puppy up!

Have a question or comment? Leave it in the comments below. If you’d prefer, go over to the Contact Us page and submit it to me there.

Until the next update, take care and have fun!

Gatton CNC Build Part 10 – Router Mount and Tramming Plates

In this installment of my Gatton CNC build, I modified, drilled, and assembled the router mount assembly, then added two plates to the sides of the Z box that will allow me to adjust the router mount when it comes time to tram the router. Read More

So what is tramming? Well, without getting too deeply into it here, tram is the squareness of your router or spindle to the table. Adjusting that squareness, whether it be along the X axis or Y axis, is known as tramming. The two plates I made will help me to more precisely adjust that squareness, then lock it into position while I tighten the mount, securing it to the Z box.

The first modification I made to the router mount was to take it over to the table saw and cut about a blade’s width off of each side of the mount plate. The router mount plate needs to be slightly narrower than the Z box front panel to give the mount room to move when it comes time to adjust it.

In deciding on what type of nut to use in the router clamp, I used 1/4” 20tpi weld nuts. I think square 1/4” 20tpi nuts would work just fine for this as well. I wouldn’t use standard hex nuts, as they could easily break loose and spin inside the hole, where a square nut wouldn’t be able to. Follow along with the video to see further details of the assembly of the router mount.

The tramming plates are very simple to make out of 3/4” plywood left over from the construction of the gantry. In fact, I made mine out of the leftover scrap from the gantry bottom panel. Using the measurements in the picture below, I first used a 3/4” forstner bit to drill a recess into the back side of each plate. One thing to keep in mind when making the plates is that you are making one for the left side and another for the right side. These two plates mirror each other, so make sure you drill these recesses on the correct side of each plate.

With the recesses cut deep enough that a #10 – 24 T-nut will sit below the surface of the plywood, I then used the correct size twist drill bit to drill the rest of the required holes. The size of the bit needed will depend on the outside diameter of the shank of the T-nuts you use.

Outside faces of tramming plates. Click to enlarge.
Inside faces of tramming plates. Click to enlarge.

With everything stained and finished, I assembled the router mount, then loosely attached it to the Z box using standard 1/4” – 20tpi hex head nuts (after first trying socket head cap screws and deciding against them.) I then aligned the bottom edge of the tramming plates with the bottom edge of the Z box, and clamped them into place, keeping the back edge of the tramming plates held tight against the edge of the aluminum angle on the Z box.

Once clamped into place, I drilled pilot holes, and secured the plates with #10 – 1 1/4” long exterior grade woodscrews. I used my impact driver to drive the screws most of the way in, then finished tightening the screws by hand to prevent the screws from going all the way through the sides of the Z box.

I then let the glue on the router mount cure overnight before mounting my Porter Cable 890 router motor.

That’s all there is to it!

As usual, thanks for stopping by, and remember that if you have any questions or comments for me, feel free to leave them here, or you can email me through the Contact Us link up at the top of the page.

Good luck with your build!

Have a question or comment? Leave it in the comments below. If you’d prefer, go over to the Contact Us page and submit it to me there.

Until the next update, take care and have fun!

Gatton CNC Build – Progress Report 1

 

As I type this on September 12th, 2017, my Gatton CNC is basically finished. I can plug in the drive box and use it at any time. I’m struggling to refrain from doing so, however, because there are still a few things to be done. Chief among them is cable management.Read More

On my old Shoestring Budget CNC, my cable management system boiled down to an, “It looks good hanging right about there,” approach. On the Gatton CNC, however, that’s just not going to cut it. Or maybe it will. Let me explain.

The Shoestring Budget CNC was pretty small, as I explained in Episode 2 of my Gatton CNC build series. Also, the gantry moved along the X axis. All of the power outlets that I used for it were located at the rear end of the CNC, so that meant that all of the cables could be draped over the back of the gantry and left to hang there, without worry of them being damaged by anything. As the gantry moved toward the other end, the cables simply moved along with it. When the gantry moved back, there was enough weight in the cables that they slid back with the movement. Well, this is not the case with the Gatton CNC.

First, the Gatton CNC is much bigger than the Shoestring Budget CNC was. That meant that I had to get extension cables for the stepper motors. Second, the gantry is oriented so that it moves along the Y axis, rather than the X. That in itself is taking some getting used to, but it also means that the power outlets I’ve been using are located to the left of the gantry now. So I have much longer cables that have to be guided in a certain direction over a much larger area. So, yes, that means I need to dig deeper into cable management so I didn’t run over a cable with the gantry, or cut into it with a bit spinning at 16k RPM.

In my case, I lucked out. A gentleman by the name of Andrew Hague, of The Old English Workshop, has been building a Gatton CNC of his own. He’s heavily into 3D printing, and he’s been gracious enough to send me some prototype drag chain mounts he’s come up with for his Gatton CNC build. I hadn’t considered mounting drag chain before, but with these mounts in hand, I decided that I should give them a try.

Andrew was nice enough to also send me an alignment jig that he designed for aligning the X axis lead nut block to the stepper motor hole on the gantry upright, and another jig for aligning the Z box lead nut block to the stepper motor mount and support bearing. Both of those jigs worked brilliantly, and I’ve since passed those on to another Gatton CNC builder so that they can use them, then pass them on to another builder, who can use them, then pass them on to another builder, and so on. You’ll find complete info on the alignment jigs in the video description of Episodes 7 and 8 of my build series (the link to the playlist is below,) including links to the Thingiverse pages, where you can download the files to 3D print the jigs, or have them printed for you.

I’ve also added a couple of modifications to my Gatton CNC. One modification is the recessed under-gantry lighting that I featured in Episode 6 of my build series. So far it really works a treat, and it’s a modification I should have made to my Shoestring Budget CNC when I recut the gantry in 2016.

Under Gantry Lighting

Second are a pair of plates I’ve created that will help me when it comes time to tram the router. There will be much, much more on those tramming plates in Episode 10 of the build series.

 

Tramming Plates on Z box, with router mount installed.

So where do I stand right now? As I said earlier, the major construction is finished. I’m waiting on the drag chain to arrive, then I can rout the cables, hook up the drive box, then fire this puppy up! There will still be more work to do after that… but that’s for another update, down the road.

For now, here’s a link to the YouTube play list that includes all of the episodes of my Gatton CNC build.

Have a question or comment? Leave it in the comments below. If you’d prefer, go over to the Contact Us page and submit it to me there.

Until the next update, take care and have fun!

My Gatton CNC Build!

After keeping it under wraps for over 6 months, I finally revealed the secret lurking in The Magic Box on the final episode of The CNC with Dave Show at the end of July, 2017. That secret was that I’m building a Gatton CNC.Read More

The project was kept under wraps for a couple of reasons. One reason was because a lot of work had to be done before I could even start the build. I’ve made it no secret that I basically work out of an over-glorified garden shed. My shop/shed is 8’ wide and 12’ long on the outside. Every tool I owned was piled up in the shed, and to do anything at all meant that I had to move a lot of “stuff” out into my driveway. That meant that I was at the mercy of the weather. I’m in southern Oregon, so it’s wet and rainy most of the year, and that means I can’t just move things outside and leave it there. I had to get another shed to store all of that “stuff” in so I could work in the shop/shed. I got my new shed in March of 2017 and was able to get everything moved rather quickly.

The other reason I waited to talk about the build was because I intended to video the build and post it on my YouTube channel. I wanted to make sure I could get it done fairly quickly. It’s still taking longer than I had hoped, but progress is being made. There are a lot of unfinished projects on YouTube, and I didn’t want this build to be one of them. I needed to get far enough ahead in the building process that I could release a video, and have at least one video in reserve to post should I encounter a problem. So far that seems to be working out for me. I’m able to post a video, release it on Wednesday, then immediately start editing the footage for the next video, while simultaneously shooting the video to be posted after that. It sounds like a confusing mess, but it isn’t. Part 5 was just released yesterday, as I type this. Right now I’m editing Part 6, and shooting Part 7. When I get Part 6 edited, I’ll upload it, schedule it to go public at the appropriate time, then concentrate on the build. I’ll be filming Part 7 as I do. After Part 7 is finished, I’ll take a break, then get everything ready to go to start filming Part 8. Then, when Part 6 goes public, I’ll start editing the footage for Part 7 and start building and filming Part 8. You get the idea.

Okay, enough chit-chat. Here’s a link to my YouTube video, where I announce the project, unbox the Gatton CNC kit, and tell you about my plans for the build.

Enjoy!

Have a question or comment? Leave it in the comments below. If you’d prefer, go over to the Contact Us page and submit it to me there.

Until the next update, take care and have fun!

Joining Problem Vectors using Layers in VCarve and Aspire

There are times when you need to join vectors to create a profile toolpath, but in doing so, you’ll also have to trim away vectors or sections of vectors that you can’t eliminate. What I mean by that is that if you trim a vector, you lose that vector’s shape, or you lose some detail you’re trying to save. Take the picture below for example.Read More

This is a preview of the completed project from VCarve Pro.

 

Obviously, it’s a representation of the state of Michigan. The author of the file* wanted to join the Upper Peninsula to the main body of the state using two arcs to connect them. To compound the issue, he also added the banner and text down in the bottom quarter of Lower Peninsula. It’s a great looking design, but the problem is, how do you join the arcs to the Upper Peninsula without deleting that entire section of coastline? How do you join the outline of the state to the banner without getting rid of the banner detail?

How do we trim the vectors where the arcs join the Upper Peninsula?

The answer is to use layers to your advantage. Follow along in the video as I explain how I copy the vectors to a new layer and edit them to create a new outside profile. Along the way I’ll fix a couple of other problems with the file and show you an alternate method of associating a toolpath with a vector.

*Occasionally people having problems will send me files to look at for them. I ask that you please reach out to me before you send me anything. I may be able to answer your question without the need for you to send it to me. If you do send me a file, please understand that I will NOT fix it for you. I simply don’t have the time to do that. Instead, I will help you to fix it yourself, and guide you through it step-by-step if necessary. I believe that we all can learn from one another, but we don’t learn anything if someone else does the work for us. If I think that the problem with the file may be of interest to others, as in the case with the file used in this article, I may ask your permission to use the file in a video and website article as an example of how to fix the problem. Permission to use the file is NOT mandatory, and you’re under no obligation to let me use it.

Bottom line: I am more than willing to help you if I can, but please get in touch with me before you send me anything. I’ll do what I can to help you out.