[montreal333]

I got a wild hair up my butt to build a machine and thought I'd post a few pics of the progress so far. It's about a 4' x 4' foot print, all aluminum build. I'm stuck on the Z axis mount right now but when I get some time this weekend I'll figure it out. The gantry is heavy so I may need to beef up the motor to something stronger. I'm going to use steppers that are approximately 300oz and use 1/2-10 acme. It's my first build so I'm not too worried about ipm right now. Let me know what you think.

[Jkountz]

Looks like you're off to a great start! Keep it up. Ill be following your build as Im doing a 4x5 all aluminum build right now myself.

[montreal333]

Here's a little tidbit about this build. I have a few odds and ends when it comes to tools. I have an assortment of bolt tighteners, wrenches, sockets, and such. and I also have about a dozen tape measures and three times as many screwdrivers. I have a drill press, a hand drill, a sawzall, a dremel and about 500 hours of music on my phone. That's pretty much it for tools. I also have a bunch of aluminum, which is why I decided to make this out it, and not wood. Cutting the aluminum is easy with the sawzall, but not exactly square. I do have a hand me down tap set, but its metric. I have about three coffee cans full of nuts and bolts...none of which are metric.
The side rails are 5" aluminum rails with a hardened steel 'v' rail molded in, and the rails are held in place by five cross pieces which will have 1/4 inch all thread running from one side, through the cross piece and bolted on the opposite side. Two pieces of all thread per cross piece. Same thing with the Y axis rail, except its 5/8...if I remember correctly. I'll also add some corner brackets from the Y axis rail and the gantry. The four corner brackets on the main frame in the photos (which, btw, are seat brackets for a HUMVEE) will either be replaced by something more substantial or eliminated all together depending on how well the all thread cross member idea woks out. The cross members will also be the cutting table supports and should give me about 4" of travel for the z axis.
The X axis bearings are 1 1/2in PBC Vee bearings with set screws for alignment adjustment. The bearings were on two different sized 1/2in plates that I had to cut in half and bolt to the gantry uprights to fit the rails. Looks rather sloppy but their right, tight and work perfect. The Y axis have four v-groove bearings from eBay.
The Z axis.... This is proving to be a problem. I want to use the one in the photos with the v-groove bearings but how to mount it is proving to be elusive. I have some closed bearing blocks on rails (20mm, I think) and could probably use that set up rather easily.
I have yet to buy the acme rod from Enco, 1/2-10 1 start but would much rather have 1/2-8 2 start. I need to decide on a router as well. I was going to take a shot at making the antibacklash nuts but will most likely just buy them and be done with it.
I do have a great ballscrew that's 3/4in X 42 or 43 inches long, but it has a slight bend in it. Any ideas how to straighten it out?
All told, I didn't get anything done today except stare at the parts and scratch my head.
I've attached a few more pics of the different interesting parts and of some measurements. Total cost so far for everything in the pics, plus 6 steppers, 6 drivers (I got 6 in case I fried any or wanted a 4th axis or a 2nd machine, or a dual motor X axis) and a power supply, $165.00 The rails were given to me and I only paid $5 for the PBC bearings. Cost for acme rods, nuts, and a router will be approximately $170.00. I'll be pretty happy if I can get this built for under $500!
If you happen to have acme rods, a router, a spindle, or anything else you might want to sell, send me an email.
A quick question for anyone who actually read this far: would a two motor X axis setup give me more power then a single or will it only, possibly, eliminate racking? Rack and pinion...there's an idea I wish I could afford.
Hopefully I actually get something done tomorrow after work...like finishing the z axis.
-Mike

[CarveOne]

You will be disappointed with the speed you get with the one start ACME. This is one critical performance thing that you really need to spend some money on. It will get the machine running, but that's about it. Two start will be better, but five start or eight start will give you much better results. One common mistake is to think that 30 inches per minute is fast enough to get started with. That's about all you will get with one start ACME screws. For cutting wood it is woefully slow. Aim for a reliable 200 ipm cutting speed as a minimum. Don't even consider all-thread rods. The drive system mechanics, motors, and drivers you buy will make or break your interest in this effort. There are homebrew designs on CNC Zone for anti-backlash nuts. DumpsterCNC and CNC Router Parts sell reliable ones if you don't want to try making something.

24 vdc power supply, cheap poorly designed drivers, and high inductance motors all contribute to frustration and problems getting the machine fast enough and reliable enough to be useful. Been there and done all of that myself. As many others in these forums have also done. We eventually cough up the money to build better machines if we stay in the hobby. It's part of the learning curve.

[ger21]

To add to what CarveOne said, 1/2-8 2 start will only give you a maximum of about 200ipm. I'd recommend 1/2-8 4 start or 1/2-10 5 start.
Two motors on X might give you a little more speed ,but it will make the machine much more rigid, especially when cutting near the ends of the gantry. Racking near the ends of the gantry will be an issue with a single center mounted screw.
The speed will be more a factor of the maximium rpm of the steppers, and the screws you're using. Using two motors will allow you to move more weight, but won't really add much speed.

[montreal333]

I'm going to be using three 5 phase Oriental Motor PK564AN-TG10 with matching drivers and a 30v power supply.

I'm all for using 1/2-10 (or 8) 5 start acme rods but, not to sound cheap, the jump in price from single start to five start isn't something I can do right now. We've started a remodel of our upstairs and every time I think of forking out a couple of hundred bucks for something, I can't help thinking about what I could buy for the house instead. I've already planned on upgrading the rods somewhere down the road, after the remodel, but for now the single start will have to do. Unless someone here knows of a place to get 2 or 5 start at a decent price. I'd need two four foot pieces, three of them if I go with two motors on the X.

As for the two motors on the X, I'm was concerned about the weight of the gantry but if having two motors will improve stability, and I already have the motors, it may be worth doing regardless. Other then I now need a third piece of acme rod.

I plan on doing aluminum with this at some point, I have access to a fair amount of it, but wood and maybe limestone will go under it as well. Living in Indiana, just down the road from a stone mill, I can get end cuts all day long. Piles of it everywhere.

[Bl@ckrat]

Then IMO I'd put the machine aside for a while and save a bit/ put some cash aside.... Get proper screws , or you going to be more frustrated than anything . I used to cut at 1500 to 2000mm /min and thought damn it's slow!

[montreal333]

For some reason I thought 5 start rod was up in the $180 range, per rod. While there is some that's north of $200, I went looking and found some that's about $80 for a 6' length. I didn't come across any 4' lengths though. I'm in the 46/48" range on the X and 43/45" on the Y and a couple of 4' lengths would be perfect. Less waste.

So, with that in mind I'm going to plan to go with a dual motor X axis. I need another power supply though cos' the one I have only has 3 outputs.

High winds put a hold on any garage time building today.

[Jkountz]

This is all starting to sound on old familiar tune in my head. If you look at the year I joined this forum you will see it was 2009. That's when I started planning the machine I am currently building for the first time. It has taken on many many forms and about everything has changed many times before deciding on the final design I have now. I even built a smaller more affordable machine first just to get my feet wet and learn the basics of this hobby before tackling the much larger machine I am building now. My point to all of this is not to tell you you should wait five years before building your machine of course, but that the planning stage can often take a lot longer than the actual build if you are trying to cover all your bases and do things the correct way. In short go big where you have to, cut some corners when you can, but never ever sacrifice quality if at all possible. In the end you want a usable machine not something that just simply "works". You actually have some good material and parts there that you are already using, now just add the key ingredients stir well, and serve! LOL good luck with your build and keep us all posted on your progress very interesting to say the least!


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[montreal333]

This build of mine has been about 6 months making it in my mind and about a week now actually building something. I'm winging it as I go but it seems to be jelling pretty good so far. Now I need some screws.
I was going to order three 6' pieces of 1/2-10 5 start acme rod today but I can't find the site that I swear I saw it for $64 each. Did I imagine it at that price or am I a little loopy? If someone knows where to find it, let me know...please. The other site I found was cadcamcadcam and I think it was something like $84 ea plus FedEx shipping. Enco is $118 ea.
The temps here fell through the floor last night so the garage will be just a bit too chilly to do any working for a few days. That'll give me time to order the rods and anything else I can think if that I might need.
I can feel impatience creeping up on me.

[CarveOne]

McMaster-Carr.com - Fast-Travel Precision Threaded ACME Rods

Look at 1/2-10 5:1 99030A304 (3') and 99030A704 (6')

3' rods are $33.25
6' rods are $66.50

[montreal333]

Thanks to everyone who's pointed me in the right direction, I truly appreciate it.

Today's free score are 5 V rails, approximately 14 inches long. 2 are bent a bit but will straighten up nicley when bolted to something. I don't know what I'll use them for but I can't complain about something I got for free. They may have a future appearance on eBay.

I also have a bunch (50+) Pacific bearing company closed bearings (bushings?). Not the ball bearing kind but the ones that have some smooth something or another lining the inside. Teflon maybe?? Approximate size is one inch, though I fo have some that are bigger and a few smaller ones. Red, blue, and green. One size (colour) is metric. I also have a few short rails for the 1" sized bearings, approximate length is 14 inches. If anyone has a use for these, shoot me an email.
-Michael

[montreal333]

Here are a couple of pics of the Z axis I built. Kind of ugly but solid and straight.

I haven't ordered the rod yet because I want to see if I can get the ball screw I have straightened out. If it can be used then I only need 1 acme rod and anti backlash nut OR maybe just buy a 40" ball screw off eBay.

Still need to find a router or spindle and I need to put some legs on it. I have some 3" 8020 that I'm going to use for the legs but just haven't gotten around to cutting and mounting it.

Sorry about the pics being sideways.


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[montreal333]

I have a quick question. My Vexta steppers have a gear box attached to them. Is that a good thing or a bad thing? I've also been looking at 3 Chinese ball screws with ball nut (pitch 5) for about $80 each shipped. 2x 1100mm and 1x 1200mm. Pros, cons compared to acme 1/2-10 5 start?