Cutting down indexable lathe tooling

[BadDog]

I've recently come into a couple of TPG lathe tooling holders that are WAY big for my little fella (11x37 Rockwell).

One was a gift from a friend in appreciation of some work I did for him. It's a monster 1.5" Valenite (SD-TML-24-64) holder. Neutral rake with largish screw through TPG carbide insert. I was thinking of cutting a dove tail in this and using it directly on my PII AXA Aloris knock off. Problem is, it's going to be a bit difficult to get it on center since the index end has a 3/8" step up. Still, I think it will work ok. Next question, how far back should I put the dove tail? I'm thinking maybe I should make use of it's rigidity and hang it out there a bit to deal with (imaginary?) cases where I need to reach way out and a normal cutter won't hack it?

The second part of this story involves (3) 1" Kennametal indexable toe clamp retained TPG holders. These are also neutral raked, and I have a left hand, right hand, and facing holder. I paid $5 each, so cheap enough to play with and “make work”. On these, I think I’ll just cut them down to a 1/2” x 1/2” tang for mounting in a regular AXA holder.

Any suggestions? I’m not sure the big one is even worth fooling with?

[Frank Ford]

I had the same situation - I was given a 1-1/4 x 1-1/4 tool, and cut a dovetail to fit my AXA toolpost:



I chose to mount it about as close to the post as I could, figuring that even though the tool would be rigid, the leverage would be a bit much if I hung it out too far. When I was at Boeing Surplus earlier this year I bought a hundred inserts for a buck apiece. This is one of my favorite lathe tools now.

Here's the whole process:

http://www.frets.com/FRETSPages/Mach...antholder.html

[madman]

I was just gonna sugest the dovetail teqnique (yeah im a spelling bee champ howd yah know?) to him. It was a fantastic idea. I was stupid as usual i ended up milling down my toolholders to s=uit my lathe and i shoulda done the dovetail. Shoot. Mike Buuuurp

[BadDog]

Thanks Frank. I remembered seeing yours when looking at your site, but had forgotten that it also has that annoying/troublesome step up. Good to know you are (still) happy with it. I may follow your lead and cut it close for the same reason. I was worried about the leverage, but then again, if you HAD to hang it out there, at least the holder wouldn't be the weak link, AND I would have the smaller Kennametals for close in insert work. Hmmm...

I notice that one has a heavy negative rake. I have been specifically looking for neutral as I didn't think my Rockwell 11 would handle the negative rake.

I also got a bunch of carbide this week end. 50 TPGs to fit the Kennametal holders for $20!

[Spin Doctor]

Bad Dog, The tool holders may be designed with negative rake tools in mind but there are plenty of inserts designed with a posite top rake and built in chip breakers. These are both modified Valenite 1" holders used in a AXA series tool post.



The tool holders are tough, but cutable. Just take you time. Also it is a good idea to waste out the dovetail slot as much as possible.

[BadDog]

Great, thanks for the additional examples.

Looks like you made one short and one long. Which do you prefer (based on hang over)?

As for cutting, I figure a 1/2 carbide roughing cutter for the main slot, then the dovetail cutter. Still have to get one of those, but maybe I can borrow a carbide dovetail from a friend...

[Spin Doctor]

Actually the one with the V series inserts (35D) is less rigid than I would like. The C432 series holder is just as rigid as the Aloris one in the top left corner. It has to do a lot with over hang issues. Personaly I have found that close to 90% of the lathe OD work I did on Hardinges (and plan to do at home soon) can be done with the 80D design inserts. Stronger than the T series by far. True you get less edges but the greater strength far out weighs that.

[wierdscience]

I've used tools with screwed up shanks to make specials before.In those cases I just chopped off the shanks completely and TIG welded them to whatever shank type I wanted.If the holders are free/cheap what do you have to lose?

[BadDog]

Oh man, I am such a moron (or very ignorant at best). Went down to my buddies shop to go through and find some inserts for my "monster" holder. Looked like it took the largest TPG insert I have ever seen, but I'm not expert, just figured it was "industrial grade", after all it's in a 1.5" holder!

Only to be told at a glance that it was not a TPG and I was holding it 90* out of position. It's actually a massive grooving/threading holder and the triangular insert cuts from what I thought was the side. He even had a hand full that fit beautifully. The inserts for this thing cost a FORTUNE! And there is no way I can thread at carbide speeds on my lathe (which doesn’t have that auto kick-out feature that the nice Mori Seki and such have so that you can thread at 1000+ rpm without worry). Since this is not something I expect to use or want, I suppose I’ll just return it to my other friend who gave it to me (also thinking it was a giant TPG), maybe he can find some use for it... <sigh>

But, I still have the Kennametal 1” cutters, and I picked up a base support thingy that one was missing. I’ve got an auction/sale to attend tomorrow, so I’ll probably mill them down tomorrow afternoon and give them a whirl.

Thanks for all the help!