D I Y power drawbar for PCNC 440

burtonbr

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I spent more than I should have on my initial 440 CNC package a few months ago, and I'm very glad I bought it rather than a manual mill, but I need to get it paid off before I can justify spending more money on more accessories, but seeing Tormach release the power drawbar for the 440 made me want it even more. $700 for the factory kit isn't bad but I thought if I could get a few components cheaper I could make one that suited my needs just fine it didn't look that difficult and I saw a few others had made their own versions so I had a little bit of a template to follow. I ended up about $240 in everything I needed even had twice as much 6061 just in case i needed a do over, but I was surprised the first version worked very well. I didn't take pictures of each stage which it really wasn't a lot, the base plate, 3 standoffs threaded at each end, hardware and air cylinder. I got a 100mm x 15mm cylinder from ebay for less than $50 and a cheap foot pedal for $27, the hose and fittings was about another 50. I probably had less than 2 hrs machining everything. I have my air set at 90PSI and it operates well at that air pressure. If your even thinking about adding a PDB just do it, it is very simple, inexpensive and makes running the Tormach so much nicer.



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This is the cheap foot pedal I used, it is ok but might get a better one later.
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Nicely done! Made some major savings there. How do you like your 440 so far?
 
I absolutely love it. I am impressed by the accuracy of it every time I use it and it did not take long at all to learn how to use it and be comfortable milling manually or running a cnc program on it. I was shopping for a mill bigger than a g0704 and really wanted things like DRO, power feed, and power down feed, & what's available from grizzly or PM I felt like I would be in over 5k and still have a manual mill. I did pay a lot more than that for the 440 initial Cost with tooling was 8500 & but includesd enough to start making parts ,nothing more needed & I think it's a better machine for me at the end of the day. Just like all small mills the work envelope can limit you some but it is easy to work around & Ive done projects double the work area size twice now and both came out perfect.
For me there were 2 things that me look at Tormach and think I might be able to use a cnc mill were that Path-pilot looked really good and had good reviews from users over Mach 3 and Fusion360, having a full blown CAD-CAM software without additional cost and I was able to get familiar with it before ordering & I could see that the would be useful.
The PDB is a luxury but it sure is nice and glad I was able do it, though eventually I probably would have saved enough to buy the factory kit.
I use the probe a lot, checking set ups and measuring parts and things, it is amazing how accurate it is once set up, it's the most used tool I've got and with the PDB, it's not so tedious changing in and out.
 
Awesome to hear you're happy with the 440, I'm considering one too. I'd prefer the bigger envelope and grunt of the 1100 but right now I don't have the budget and space. When you say you're pleased with the accuracy, what kind of tolerance can you hold... is 0.001" doable on a consistent basis? Have you machined much steel on it? Just wondering how it copes being a smaller lighter mill and possibly not as rigid as it's bigger brothers.

Looks like you're having fun which is the best part!
 
I don't do much that needs .001" accuracy and thinking about it, there's probably a lot that would need to go into preparation and set up to hold that consistently. Thinking tool wear compensation and such but I'm sure it could be done.
This week I just ran 4 identical pieces, one at a time, spinners for the kids from 6061. I hadn't measured them since only the bearing pocket size matters, I programmed it a few thou shy and dial it in to press fit using conversational boring, only takes 1 pass to get it perfect. Your question had me wondering how close they were to each other since I really don't take a lot of time setting them up, Just clamp a piece in the vice on parallels and hit go. They are cut from 1/2" stock and programmed to be 3/8" thick, I machine both sides and all 4 measure .375" -.3765" thick everywhere I check them. That only with a digital caliper so its not really accurate anyway but I wasn't even trying, so I think with a little effort tight tolerances could be held, I just think so many factors can effect that tight of a tolerance & someone would have to monitor all variables consistently to hold it under a thou all the time.
My Tormach is on a wood floor that bounces with rapid movements and just roughly leveled. I know the tram in the x axis is out a half a thousand at least but I don't think there's any point of tramming it closer on this floor.
I have done a few things in mild steel, 1018, bored several 1" holes in 1/2" bars with a cobalt roughing endmill and milled out a 24mm wrench with same tool, the right feeds and speeds, was no problem I actually like milling steel much more, I just need to get more tooling to do more.
Only thing I've got to compare this to is the G0794 I had and this 440 seems so much more rigid and I started out doing a lot of manual machining to start with I remember thinking the passes I was able to make were much heavier cuts than I ever could do on the G0704 I used to stall it regularly trying to take too deep or wide a cut and I've stalled the Tormach too but it's easy to find the sweet spot once I got used to it and getting the right tooling for the job has made a big difference in being able to push the feed rate up, but I see videos of others running their 440 harder than I'm able to but I keep pushing it up..
I have had a lot of fun with the 440 and feel like I have learned much more than I ever thought I would in a very short time.

Good luck with whatever you choose.


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Those fidget spinners look great! Must be awesome to have the machinery to be able to do those sorts of projects now. Thanks for the info and feedback, appreciate it. Hopefully I'll be able to get in on the fun too pretty soon!
 
Wanted to try a spinner out of mild steel, so I modeled this one up yesterday and milled it out of 1018, came out pretty good. I need some more cutters for steel, only have a few and not the right ones for this.

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I spent more than I should have on my initial 440 CNC package a few months ago, and I'm very glad I bought it rather than a manual mill, but I need to get it paid off before I can justify spending more money on more accessories, but seeing Tormach release the power drawbar for the 440 made me want it even more. $700 for the factory kit isn't bad but I thought if I could get a few components cheaper I could make one that suited my needs just fine it didn't look that difficult and I saw a few others had made their own versions so I had a little bit of a template to follow. I ended up about $240 in everything I needed even had twice as much 6061 just in case i needed a do over, but I was surprised the first version worked very well. I didn't take pictures of each stage which it really wasn't a lot, the base plate, 3 standoffs threaded at each end, hardware and air cylinder. I got a 100mm x 15mm cylinder from ebay for less than $50 and a cheap foot pedal for $27, the hose and fittings was about another 50. I probably had less than 2 hrs machining everything. I have my air set at 90PSI and it operates well at that air pressure. If your even thinking about adding a PDB just do it, it is very simple, inexpensive and makes running the Tormach so much nicer.



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Thats a sweet setup I read that you only used 1 air cylinder? Most that I see have 3 stacked . How many bellville washers did you use 8?
 
I have a 440 and about the only material I don't do is aluminum. Tool steel, stainless, Titanium...it's all I've ever done on mine. I guess I avoided anything that said not to and ignorance is bliss. Its one of those things where you need to take healthy bites but you have a small machine. I have work hardened and had to restart. GOOD cutters are a must...YG-1 is the one I have the best results with.
As far as my dislike, the doors. So I made up some sliding doors, other than that, I'm happy as hell.
 
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