Uni-Vertical mill

[blockmanjohn]

I have a Uni-Vertical mill with a Bridgeport C type head that takes 2VB collets. I want to mount a Tormach super fly cutter that has a 3/4 inch shank. The largest collet this head will take is 1/2 inch. Does it sound reasonable to try and find an ER collet chuck with a 1/2 inch straight shank and a 3/4 inch collet? Might this be a bit much for the 1/2 horsepower motor my mill has?

Maybe I should try and find a decent fly cutter with a 1/2 inch shank? Any suggestions?

Thanks in advance, John.

 

[Wizard69]

I have a Uni-Vertical mill with a Bridgeport C type head that takes 2VB collets. I want to mount a Tormach super fly cutter that has a 3/4 inch shank. The largest collet this head will take is 1/2 inch. Does it sound reasonable to try and find an ER collet chuck with a 1/2 inch straight shank and a 3/4 inch collet?

Not to me! You might consider making an ER Coler holder with an integrated 2VB shank. This should help maintain rigidity.

My main concerns with what you suggest are rigidity and tolerance stack up. You might end up with a lot of run out which maybe isn't a big deal for a single point cutter.

Might this be a bit much for the 1/2 horsepower motor my mill has?

You match the cutting load to the motor power you have. The problem you might run into is creating enough of a cut to get the carbide to work correctly.

Maybe I should try and find a decent fly cutter with a 1/2 inch shank? Any suggestions?

That would make sense.

Thanks in advance, John.

Personally for a machine with an odd sized collet I would strongly consider making an integral shank ER collet holder. Such a holder is far easier to find collets for. However don't expect to suddenly be able to use massive tooling beyond 1/2". The spindle itself still needs to be able to support whatever it is turning.

 

[blockmanjohn]

Now I'm wondering if it would be possible to just turn the shank on the cutter down from 3/4 to 1/2 inch? I only plan on taking light cuts. John

 

[Dalee]

Hi,

Been there done that. It works. And for the amount of power available to us HSM, it will never be a problem.

Though honestly, I'd just make a cutter body with a 1/2" shank and then a holder for my insert of choice, (I prefer APTK style myself). There is nothing special about the cutter body and any cheap 1/2" shank body could be used. The insert holder is a simple square bar with a simple milled seat and one single screw to hold the insert.

Dalee

 

[blockmanjohn]

Tormach says that the shaft on the super fly is Rc 45-50 hardness. Where can I find an explanation of what this number means? Also, I would like to find out what type of tool I would need to turn the shaft down on my lathe-if it is possible at all.
Thanks, John.

 

[Swifty]

Tormach says that the shaft on the super fly is Rc 45-50 hardness. Where can I find an explanation of what this number means? Also, I would like to find out what type of tool I would need to turn the shaft down on my lathe-if it is possible at all.
Thanks, John.

Hi John, Rc 45-50 means that the part has a hardness on the Rockwell C scale between 45 and 50. In my years as a toolmaker the maximum hardness of a soft piece of tool steel was around 35Rc, this was tough but could be machined using high speed steel tooling. The piece you mention has definately been heat treated, but not to a hardness where you can't readily machine it. You will have to use carbide tips and machine at a lower speed, you should have no problem and achieve a good surface finish. Parts harder than this can be readily machined using ceramic inserts, but this is another ballgame all together.

Paul.

 

[hanermo3]

I cut-off and ER40 collet body with inserts.
Hardened ballscrews machine easily with ccmt 21.51 inserts.

I would think you can easily turn the shaft.