80/20 mill build

[LeeWay]

It's time I started a build log on this I think.
I had originally intended to convert an X2 to cnc, but have decided to forgo that and just build one from scratch. This way, I can not only use the mill during the build, but I can build it a little bigger and heavier actually. Heavy? I thought I saw 80/20 in the thread title?
It's no mistake. I will be using the big 80/20 extrusions. 3060 with is 3" x 6". They are fairly heavy for aluminum. I will add to that as this log progresses. There are several different aspects to this design that have sparked not only controversy in some threads, but my curiosity as well. Firstly the stiffening up or filling of the extrusions with hydraulic cement. Not just filling with cement, but also adding threaded rod as well as small rebar and #8 bird shot that I have been hoarding for years, Really just trying to get rid of it, but I think the extra weight they might provide to the mix will help. The rebar to take up space. The threaded rod to actually tension the cement in each extrusion.

I intend to use the same mill head that is on the X2, but with some modifications eventually. I know this mill cannot turn out any worse than converting an X2, although that would be much cheaper. I intend to document and weigh all the parts as well so I can get an idea just what the finished machine weighs. Ultimately, it will have a mister and be caged in.

I have a few pics to show now and more will follow as it progresses. This will take some time. I finished my router in around a month, but I expect this to take longer.

I have most all the parts needed and will list those out later with photos.

These pics show why its good to over build sometimes. I originally intended for my router to just cut mostly plastic, but it does a fine job on aluminum as well.

I don't have a grinder or access to one. The 80/20 extrusions are somewhat flat, but not good enough for this. The absolute flattest thing I have in the shop is my cnc router table. I used a 1/2" carbide end mill to face both big extrusions. I took off about .0075". Then I scraped the fuzz off with a jointer blade in a hand scraper. That left the surface as flat as I'll ever get it. Good enough to start this show at any rate.

[digits]

I really look forward to seeing how you get on as I am hoping to build something pretty similar.

Best of luck!

[LeeWay]

Thanks Digits.
Here are a few of the parts I have already. A couple nice ground ball screws for X and Y.
The Z axis will get this cast iron IKO slide. It's a ready made unit and is pretty heavy itself. It has 9" of travel. I think that will be enough, but since this is going to be mounted to a plate that is also mounted to the 80/20, I should be able to raise it up when needed on the 80/20 column. That part is 24". The base is 25.5".
I bought a cast iron angle plate on sale from Enco to go on the back of the column. That should help keep the column vertical and in the right spot. I should have bought one with now holes in it. I am having to modify the holes to mount this to the 80/20, but that part of the fun.
I will work up a drawing showing my intentions soon.

[digits]

I like the idea of angle plates for fixing the column too - they are stiff as hell and properly square, and IMHO pretty reasonably priced.

[LeeWay]

Here are a couple more pics with some of the parts laid out.
I have three of these motors. Just the standard 470 oz steppers. I have three of the 201 Gecko's. A lab power supply. I have a 50 caliber ammo box that I want to use for the control box. I want to use these gecko's and the control box on both this mill and a plasma cutter that will come after this build. I have plug in receptacles from Ebay. I should be able to just plug the motors into this box to make it swappable.
I did buy a few of the 80/20 t-nuts, but that really isn't needed. 5/16-18 carriage bolts fit in there perfectly and will work very well where applicable.

The small holes in this extrusion accepts 1/4" threaded rod so putting caps on both ends will be easy. I will cap all four ends. The largest cavities in the extrusions line up with the t-slots underneath. I plan on using 2" 5/16-18 bolts in the bottom of the column. I will add some threaded rod connecting nuts there and then run a rod out the top. Then when the filling is dry, I can start to tension the cement using these rods. The coupling nut should put pressure on the cement to tension it. The 1/4" rods will simply hold the caps in place. If I get any resonance, I should be able to adjust the tension to change that.
Kinda into uncharted waters here. I have no number crunching or degrees to back this.
I do know when I was forming up the floor pour for an MRI machine, we tensioned the concrete in the way to make the concrete structurally stronger and more resilient. There has to be something to that.
At any rate, that will be a test and we'll see just how well that works.


The Y axis bearings are THK HRW27 and the are 18 3/8" long.
The X axis laying beside are THK HSR25 and are 24" long.
That's all for now.

[LeeWay]

Here is another image that shows a needed tool to align the second rail once the master rail is set. I got this gauge and mag base from Grizzly a few years back when they were on sale. I have seen some at HF, but can't speak to how they work. This one will do what I need. Not a tool maker's instrument, but that isn't where I am aiming for this. If I were, it would all be cast iron.

I will use 1/4" aluminum plate to cap the bottom of the column since it will also be bolted through the t-tracks. 1/2" plate on the top and both ends of the base. The base will also have 1/4" plate gussets on both sides. The base will of course have steel feet on the sides for anchoring. I have rounded up some stainless steel panels as well for the enclosure.

It will be going slow for awhile. I'll post more when I can. feel free to leave any comments especially on the filling.

[LeeWay]

Just a little more and some observations and questions.

When buying the ways, I had no real plan as to how to attach them to what would be the saddle. I bought most everything off Ebay and got killer deals on all except the last rail for the HSR25's. I had to get it from THK.
The bottom wide rails have threaded mounts for the bearings. The top bearings have through holes. I had considered making the X like Arie's build in this forum. With the bearing on top. I was more curious than anything. I'll have t make this the more conventional way with bearings on bottom for the X. It seems that the layout and type of bearings I wound up with will allow me to stack build the table from the bottom up. Screws will go into the bottom bearings through the saddle and down through the top bearings into threaded holes in the saddle. The saddle will be some 1" plate I had left from my router. This should make the distance from base extrusion to the top of the table around 5". That should all go together pretty well.

The screws I have on all three axes look to be around 1 cm per rev. I haven't measured them yet, and expect a lot of trial and error when setting steps in Mach, but does anyone have any experience with screws designed with such a pitch? I think they are built for speed, but I should be able to get a happy medium with torque/speed relationship. I hope that is.

Some of this is uncharted design wise. One thing about it is that nothing will be wasted by attempting this build but time an possible two extrusions. I can always sell it as anchors. It should be rather interesting to see how it works. I know I'm already having fun.

[LeeWay]

I did a little research on the screws and they appear to be 15 mm shafts with a 10 mm pitch. Anyone have any experience with these?
Thanks.

[LeeWay]

Here are a couple other items.

I got a few of these to use so I can unhook the motors when I want. I used trailer wiring plugs on my router and they are fine, but a little difficult to unplug and also don't seat as well as these. They were more costly also.

This is a signal control center. Is this similar to what a Grex does? I haven't really studied those. They were still in progress when I bought my Gecko's.

I also got three of these PPP's with the one I bought but these seem to only come with two now. You can still order those separately though.
I have bought several items from this Ebayer and have always been satisfied.


Here is the lab power supply I bought.
I wanted one that was easy plug and play and one that I could use for other things and this one seemed to be okay. I should be able to get 60v @ 10 amps or 30 v @ 20 amps. I am hoping that will do okay for the gecko's.

[ger21]

Originally Posted by LeeWay This is a signal control center. Is this similar to what a Grex does?

No, it looks like it's just a basic breakout board. That's why it's $29 vs the Grex $399

[LeeWay]

Thanks Gerry. Caused me to go see what a Grex does. I guess it's kinda like comparing a pogo stick with a Ferrari.

[txcowdog]

Are all your screws the same diameter and pitch?