Rear Partin Tool

[tornitore45]

I have a Chinese 9x20 lathe. The AXA100 parting tool holder has a built in 4 degrees positive rake. I guess the 4 degrees choice is a good compromise for most metals because it works fairly well.

A home made rear mounted holder would be much simpler if the built in rake was zero.

Presetting a built in rake requires the provision for height adjustment since depending on how far the tool protrude the tip height changes.

My question is: what kind of problems would result from setting the parting tool with zero rake.

[BadDog]

Other than requiring you to grind rake (depending on material)? And of course, as soon as you start doing that, then sharpening will require adjustable height anyway (unless you grind off all the old rake. I've seen folks run them (well, pictures anyway) with no rake on the back, but no idea how well they do. I guess you could always get another AX post from Enco and mount it a bit high on the back. Then you could flip the post on the holder to mount it upside down. Problem solved AND you could run other tools back there if you chose to do so.

[Mike_Burdick]

tornitore45,

I use zero back rake on my parting tools all the time - no problem! Matter of fact, I'd rather have it that way so it won't "dig" in.

[SteveM]

The problem with that dang cutoff tool is that when you have a large item to part, you have to advance the blade as you go, so that you keep the overhang to a minimum. When you do that, the height changes.

I parted wheels advancing the tool 0.25" each time and had to re-adjust the height.

I now have an AXA parting tool with the blade horizontal (shop-made unit I got from a retired machinist) and now I do not need to adjust height.

A rear parting tool holder would be sinple to make. The one for my atlas is shown here:



It's pretty much a tall block with a slot cut into it and screws to capture it. The bottom of the slot probably has a groove in it to locate the blade.


Steve[/img]

[pockets]

I made a rear parting tool for my 9 x 20, with zero rake and would never go back. It works just fine.

Greg B.

[tornitore45]

Thank you guys, the consensur seems that zero rake works and make the tool post construction much simpler.
Off to the recycling center to dig up some suitable chunk of steel.

[spro]

Winding a small chuck on right end of the grinder allows cheap little dremel or larger wheels to make that slight relief on parting tools etc.and not mess up main wheel edges.