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turning on a vmc

  • Thread starter c'drill
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c'drill

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Has anyone done any turning on a vmc ( stock in the spindle)? any pointers or things to look out for?
 
I saw a device at IMTS 2000 just for this purpose but haven't heard a peep out of them since...wonder if they are still in business ? I seem to recall it was device for holding gang tooling on the vmc table to emulate lathe functions with stock held in mill spindle.
 
There was a company from Austrailia that was building an attachment for CNC turning on a 2 axis knee or bedmill. It had a right angle head that used 5C collets, and an Aloris-type tool post. Pretty slick. Wish I could remember their name.
 
I've done it many times. Even used Smartcam to program it. I put a tool holder in the vise and the material in a collet tool holder. When programming it's little tricky to remember your moving the material past the tool, not tool accross material. Otherwise no big deal, it works great to get you out of jam. I threaded some parts once using the rigid tapping cycle. Just programmed a series of holes a few thou. apart so the stock kept getting closer to the tool.
 
Yes, I have also used a mill to do turning.
A couple of points;

I took a block of steel 3 x4 x4 and tapped a hole in it to mount my Aloris tool post.
Then I clamped it in the vise so the tool post was horizontal towards me. The tool holders then slide in on top, and it makes a very sturdy setup, with complete freedom to change tools !

Review your program carefully with this in mind...turning in this style, means a lot of repeative steps .
On a .75 diameter x 3" long piece, I did about 35 passes at .005 depth to achieve the profile/finish I wanted without chatter (no tailstocK.
I used a 3/4 endmill holder, so the bottom of the part was about 6 inches out of the spindle...no problem !
You have to be concerned about crashes, or stopping the program and the results in YOUR particular machine. Mine, like most will immediately retract the spindle....CRASH
If I had a problem and want to abort, I hit feed hold, then grabbed the tool holder and slid it out of the way (Aloris post mounted, remember?), then aborted with the normal retract (no tool in the way)
After correcting the program etc, I popped the tool back in ...and go !
To get the "steps" in the passes, I used X axis offset,with 35 steps for example
And of course all work is done in X and Z planes only

It is a trip to see it run !
 
I meant to say that I was ready to make a collor to go around the quill bottom , that would have a arm going down to the stock bottom and mount a center in it.
Think of a Mortising attachmant for a drill press, and you get the idea.
I only have 3/8 of an inch sticking out at full retrack, so it was going to be tight for a clamping collar,but it ran so well , I didn't need it.

A clarification on the ALoris mounting.
The bolt holding the post was aimed at me when in the Horizontal position. that meant the clamp handle was also close to the operator(raise to clamp) and the work piece is on the right of the post.
Also no special tooling used on lathe bits !
 
Works great for making saw arbors too. We buy CAt 40 blanks and turn them into saw arbors for running saw blades. This works the best because you get the best possible run out by turning the arbor right in the spindle. It makes cutting the tread on the end for the retaining nut easy too.
It is also a handy way to make complex single use form cutters from tool steel.
Rich's idea about the aloris is great also. Along those same lines you could make up a gang tool block like you might find in a slide type lathe to hold all your cutting tools for repetative work.

"Machining is only limmited by imagination"


ARB
 








 
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