diy Mini lathe test bed

[miljnor]

well here is the "throw it together as fast as I can" mini lathe..

Had to do something to fill all those voids in my schedual.

its all low buck.. a test be for all the cam systems out there So far Mach3 is the winner.

first picture is of the somewhat finsihed controler box.

second is Enco lathe. just a slightly higher quality HF lathe

third is the x limit switch

forth is the z limit switch

fifth is a slightly blurry pic of the encoder for spindle timing. (would make another but am at work.)

[JavaDog]

Nice looking little set-up you have there!

What do those lathes run, cost wise?

[Chris D]

What size steppers are those (in. Oz.)? and what ball screws are you using?

Java Dog, the harbor freight version run around $400.

Chris

[DieGuy]

I see you have the Ford fine adjustment tool out!

[miljnor]

Originally Posted by DieGuy I see you have the Ford fine adjustment tool out!

ya that tool holds about .0002" tolerance all day long

the stepper motors are Hobbycnc (as well as the kit) 200oz/in. which I originaly thought were quite punny, but I soft crashed last night (took a .100 cut radius ) and tripped getting to the e-stop and the motors were making a hell of a raquet. But after re-zeroing the machine. Turns out the only thing I overloaded was the underpowered spindle motor. Didn't even miss a step!

The lathes are the same prices as HF but IMO are a little better quality, and you know the yellow goes better with hair.

I paid 399.00 +sh

The Motor mounts I was too busy/lazy to make so I bought them from http://cnc.wc101.com/ They work great! and saved me Lots of time. Ask Paul I think he's got them on his lathe as well

[RotarySMP]

I think the Mini Lathes with 200 OzIn make a very forgiving CNC trainer, The only thing way to damage the machine is running into the running chuck, otherwise either the spindle stalls or the steppers stall. I have 2A fuses in mine (240V here) and the fuses blow just as the spindle stalls. Never had a problems with the spindle mosfets.
I only did home switches as +X stalls on the bearing mount, - X stalls on the back of the enclosure. +Z stalls on either the leadscrew bearing block or the tailstock, and -Z could be dangerous, but is not a defined position as it depends on whether collets, faceplate, three Jaw or four is in use at the time.

Did you copy the X axis home/end switch from my machine?
http://www.wrathall.com/Interests/CN...e_Switches.htm
I am not happy with it here. Gets completely covered in swarf. I'd love to find a better location for this, or come up with effective shielding.

[JFettig]

I ended up putting my X+ home switch on the motor mount and my Z switch on the back side way at the end, couldng really get a good picture of it way back there but I tried

miljnor: if you want a little more reliability, take the handwheel and gears out of the carrage, or at least protect it from chips. I had some large chips get into mine and it would stall if it couldnt make it over them.


Jon

[miljnor]

good point on the hand wheel I've only used it twice and both times ended up cutting my hand because of the closeness of the motor mount. (its always something)

Did you copy the X axis home/end switch from my machine? http://www.wrathall.com/Interests/C...me_Switches.htm I am not happy with it here. Gets completely covered in swarf. I'd love to find a better location for this, or come up with effective shielding.

No I didn't copy you but I might as well. thats exactly where I thought would would be easyist. Great minds think alike!

The swarf issue will be my next tackle after cleaning up the controler box. (its goto look good, even if it dosn't run, its goto look good)

[RotarySMP]

Jon, I guess you must be just making small stuff on your lathe, as you must have very limited X travel. I really should have a bigger lathe. The job I just finished was 100mm diameter pulley. Unfortunately I don't have any more space, so the poor little 7x just has to make do.

Mike, I guess none of us has come up with a really good solution for the home switches. If great minds think alike, maybe we mediocre minds do also

I have been thinking about making up a set of sheet metal sliding swarf guards like the real CNC's have, but the relationship between min space between X slide and motor bearing mount, and travel would mean I'd need 5 or 6 panels.

http://www.wrathall.com/Images/107_0708.jpg

My cross slide is longer, and the travel increase by about an inch more than stock.

I am just in the process of retrofitting to ball screws, and have designed in a swarf guard for Z.

We I get all the bits made, the whole machine needs a going over to fix a bunch of stupid things I did in cable routing witch now make maintenance a real PITA.

The enclosure made a huge difference to the machine.

[JFettig]

Mark, yes, mostly I have been making stuff less than 3" but I could cut a part from center out to 5.2" in diameter with my setup. I have the tooling plate that I made that extends back over the mount and I offset my tool post back.

My next thing i want to do is convert over to ballscrews or at least the Z-axis, I have a ballscrew all made up but havent made the skirt for it yet, I have seen some ballscrews on ebay that appear to be small enough to work in the cross slide.

The swarf gards your considering, what parts would they cover? before I put the z-axis screw in, I will make a cover that bolts on where the rack bolted on, I might make some way wipers as those are not looking the greatest anymore.

Jon

[Bloy2004]

Is this partly of what you want to cover ? I left the hand crank in for easy traversing during setup and whatnot. Maybe I won't need it if I can accomplish everything with CNC.....

[miljnor]

The plus side for you making your own way covers is you can do them right. (which means they will actually keep chips out of the screw area) there isnt a commercial machine on the market that does a good job of this.. Sure they work when you get them for a couple months up to a couple years but after that they suck.. and replacement covers never seam to do the trick. So what would be prohibitively expensive for the factory (hand making and fitting) you can do fairly cheaply..

Of course now you have to come up with something better..

I of course go for the practical route knowing the chips will get everywhere i opt for the simple rubber covers maybe a bellows or something to prevent direct chip assault! And lots of cleaning.