hey all!
i have a cnc x3 and have a lot of parts that i can do on my x3, but would be easier to do on a cnc lathe. I'm a unemployed high school student, so i can't justify spending $1,100 on a 10x22 then converting that. But i had the thought to build a lathe with the x3. I want it to be quite rigid, but not too big(not physical size as much as travel). I had the thought that for now, i will not be running both machines at the same time so just transferring the x and y steppers and my 1hp 3phase motor over to the lathe will be fine. Then using a different(lathe) profile for the lathe(mach3). The only question i have about this as i would want this lathe to thread is the indexing situation might get a little complicated won't it? maybe not. This literally takes out more then half the cost of the lathe which makes it so practical. my budget for the whole thing is quite low, since i would rather put more money into my main horse(x3). I was thinking around $500. I have already ordered some parts, 19" long linear ways(they arn't too bulky, the blocks are thk rsr20's i believe) for the z and will buy some 15" linear ways for the x. Thats about $175. I was going to do roton's for the x and y axis with double nuts on each. i have double nuts on my x3(x,z) and like it. I ordered a 8x12 lathe with bearings for $50 from harborfreight, it will take ~ 2 months to get here though. I will probably replace the bearings.
Something i would like some feedback on is size. the max y travel on my x3 is ~ 6.5", so parts can't really be wider then 6" without it being a pain in the arse and sacrificing a tiny bit of straightness (the machine is going to be more accurate then my setting up i would imagine). If anyone thinks that having the z axis rails ~ 6" apart is going to really hurt my rigidity over say 8", i will just do that. The overall length will probably be about 30" long, but i can't design the headstock until i have the spindle on hand so don't know the overall length. I also thought i would have flat bottom, this would save tons of work and $ in steel. If anyone thinks this is going to be an issue or hurt rigidity i will change it to a raised/boxed bed. The material is going to be hot/cold roll steel and will be bolted together (stepper mounts, ballnut mounts will probably be alu). The x axis is so large because i will be using gang tooling. i have no plans to make a tailstock at this point because im turning mostly 1.5" aluminum that is fairly short.
If i could get the granite drilled and tapped for not too much id be really interested in using a surface plate as the base.
http://cgi.ebay.com/18-X-24-GRANITE-...#ht_3059wt_939
Here are the sketchup designs. Its all pretty accurate exactly how i was thinking i wanted it, except i didn't bother with the details like fasteners and motor mounts because i know ill change it.
cheers