CNC'd mini 3 in 1 lathe/mill

[Bloy2004]

Here's a mini 3in1 that has servos mounted to the three axes.
It is an evalutaion model for a company (Shoptask)to possibly market it.

The mill assembly ,although it looks nice, is full of problems. Each one of those aluminum collars that are used as guides for vertical movement are drilled differently so reassembly was a puzzle to get them right side up and in the correct location to align with the holes in the mill cross arm (or whatever it is called).

[RotarySMP]

Nice work. Pretty radical mod to a 7x12. How do you have the milling column legs anchored?

[Bloy2004]

Mostly what I did to this was just true everything up and get the motors from ebay, make the mounts and cover, and build a reinforcement frame that supports the base and mill....and of course...paint it. The vertical mill glide rods are bolted into an aluminum "stamped" angle plate that is secured to the lathe bed and back frame. I'll be posting more pics...am working now but have this online in the background.

[jimbo]

looks nice and spiffy. Could be a factory made item.

I have some question about the mill. what is the spindle for the mill? Is this custom made?

Made anything with it yet?

[Bloy2004]

more pics....
..for more info you can go here:
http://forums.delphiforums.com/threeinone/start
This is being reviewed to see if it would be an acceptable combo to market.

At that forum I have pointed out some of its shortcomings...one, the mill assembly is using simple collars for the glides tightened only enough to remove slop. They are secured with oversized holes for alignment and I am sure when stressed with side loads would shift and, as has happened to me, bind the vertical movement while losing (if slightly,but enough) position.
...So, the glide system on this is going to be worked on.
The lathe? It works great and because the servos have a lot of OOOmph, I can tighten up the ways snugly for good tolerances.

The pictures show it upon delivery by UPS..(that was the first test) it failed but with clever packing this can be avoided
other pics are apparent...I added the angle/tube frame to add rigidity to the whole thing as the heavy sheet metal flexed somewhat affecting accuracy.

Note the deliverey picture....the enclosure with the sliding plexiglass doors was realy an obstruction....difficult to get access to the controls and cleanout would have been very laborious. I'm working on "swing away" type door system that opens up for complete machine access.....OR. a housing that just lifts off.

[Bloy2004]

Mill spindle...not very good.. it is basically a three jaw chuck, and although the controls allow reverse, the chuck immediately spins off. It's mount was also iffy (note two holes for attachment? I've since put four mounting screws at the four corners.

There is much to be done to this machine to make it a good sturdy 3 in 1.
For now only light cuts with the mill.

Oh! the mill spindle motor is also under powered and has too low RPM. It doesn't respond to the speed control when load is applied... but the lathe motor holds it's speed under load rather well...
This model uses a 240VAC input.....will be changed to 120VAC if the machine's problems can be eliminated.

[Bloy2004]

With the two servos on the lathe, Mach2 and some education, I should be able to turn threads of any reasonable size nicely.

[Bloy2004]

I was thinking that these mounted in place of the mill's vertical glides with the pillow blocks secured to the mill head/bracket on each end would be a step in the positive direction.
http://cgi.ebay.com/ws/eBayISAPI.dll...848855337&rd=1

Maybe a similar set with larger diameter shafts....

anybody see on ebay a 180VDC motor with 2-3 thousand rpm? could be more. At present the diameter of the motor can't exceed 3".
I would also like to extend the mill head out more and move the whole works-lathe and all-out away from the back an inch or two. This would allow a larger diameter spindle motor or at least more room for adjustment.
As it is now, the frame is pretty solid (relative to the machine's size) and just the mill's vertical linear bearings(collars ) are the really weak link.

[Bloy2004]

Here's the back enclosure which adds a lot of strength to the little bugger..along with those gussets on the sides.
...included ...another shot of the angle/tube iron "cradle" I added with adjustable feet.


The whole idea here with this machine is to keep it compact and the weight down so it can be shipped within UPS's constraints.
I think with that extra angle and tube iron I went over the limits. But it could be shipped separately....as the extra fourjaw and tools were.

[Bloy2004]

some closeups of the servo mounts.
also note in the background the black plastic cover installed behind the carriage to protect the gears.....this should be standard on ALL mini lathes shipped from any supplier.
That aluminum "crank" on the Y-axis came with the unit....its more in the way but can't be removed as the pulley was press-fit tightly onto it.
Mounts were made with pieces of aluminum found in my scrap box. My Shoptask Bridgemill big 3in1 did a nice job with the small slots and other parts.

That cover over the X -axis was made from a discarded Sears garage door opener housing.

[RotarySMP]

From my experience with a converted 7X12, you really need to have the X axis drive belt enclosed, as swarf will cause problems here over time (mine isn't yet, and it is a pain).

Does this use the apron split nuts for the Z axis drive? Isn't backlash a bit problem? I replaced both leadscrews with acme (ISO) when I converted mine, but will get some ballscrews next time I come to the states and do the job properly.

[Bloy2004]

You're right... it should have proper drive screws.
Yes, the split/half nut is driving the carriage....I increased the little ball and spring that engages it and while making the ball a little bigger, moved the detent in the shaft so it applies more pressure to the acme screw...
This seems to work well....for now.