Insert Lathe Tool - What type of steel for body?

All discussion about lathes including but not limited to: South Bend, Hardinge, Logan, Monarch, Clausing and other HSM lathes, including imports

Moderators: Harold_V, GlennW

Post Reply
Exodus
Posts: 14
Joined: Sun Apr 19, 2009 1:58 pm
Location: SE Kansas

Insert Lathe Tool - What type of steel for body?

Post by Exodus » Thu Jun 04, 2009 10:38 pm

I want to make a couple of special lathe insert holders. What would be the best steel to use that will hold up long term in the insert seat area? Should this area be hardened or the whole tool?

Something similar to this, but different angles:

Image

Thanks

User avatar
BadDog
Posts: 4739
Joined: Wed May 17, 2006 8:21 pm
Location: Phoenix, AZ

Post by BadDog » Fri Jun 05, 2009 1:40 am

That appears to be a negative rake holder that uses an eccentric to lock the insert to the back of the pocket, and they (good ones anyway) usually have a carbide seat under the insert. The holders themselves are generally not hard, though the material is very "tough" and wants carbide for machining.

And I'm all for making stuff yourself. More than once I've spent a day and $50 worth of materials to make a $10 part. But when you can buy good Kennametal and other name brand holders for less that $20 (I mostly pay $0 to $10 or so) it really doesn't make much sense. The smaller (1/2" or so) often bring out the HSMs bidding wars. But the really cool thing is that you can get the larger 1" holders that nobody wants because they are "too big" for little or nothing. I've literally gotten Kennametals in GREAT shape off ebay for $0.99 single bid and no other bidders. And better yet, they use common/plentiful size/style inserts that are cheap (sometimes free!). I now have a lathe that can utilize large holders, but I was using 1" holders even with my old 11" Rockwell by milling them down to 1/2" thickness (though for smaller lathes you want either positive holders or positive rake inserts). I even found a CNC lathe lathe at a scrapper still loaded with tooling. I got 6 holders, including a Kennametal Top-Notch #3R for (IIRC) $0.10 a pound! Something to think about...
Russ
Master Floor Sweeper

bigsaxdog
Posts: 133
Joined: Fri Aug 08, 2008 8:47 am

Post by bigsaxdog » Fri Jun 05, 2009 8:02 am

are kennemetal, valenite, etc, toolholders soft enough to mill? i got a valenite facemill that seems pretty hard, though i haven't tried anything. i do see alot of these on ebay, and i'd like to try a 1/2" one.

User avatar
mechanicalmagic
Posts: 1431
Joined: Sun Nov 04, 2007 12:11 am
Location: Pleasanton, CA Land of perfect weather

Post by mechanicalmagic » Fri Jun 05, 2009 9:25 am

I made a half dozen insert holders for my 12" lathe. I started with 5/8" square bar stock, 4140 from McMaster. After machining, I hardened them. That was about a year ago, they seem just fine. I didn't use anything special under the inserts, since I didn't expect any interrupted cuts or hammering.

Dave J.
Every day I ask myself, "What's the most fun thing to do today."
9x48 BP clone, 12x36 lathe, TIG, MIG, Gas, 3 in 1 sheetmetal.

User avatar
SteveM
Posts: 6846
Joined: Mon Jun 27, 2005 6:18 pm
Location: Connecticut

Post by SteveM » Fri Jun 05, 2009 9:38 am

BadDog wrote:But the really cool thing is that you can get the larger 1" holders that nobody wants because they are "too big" for little or nothing.
Can you take one of those big toolholders, mill a dovetail in it and mount it directly to the Aloris-type toolpost?

Only downside I see if that they tend to take large inserts which are more expensive than small inserts.

Steve

websterz
Posts: 392
Joined: Thu Oct 09, 2008 7:35 pm
Location: North Central Oklahoma

Post by websterz » Fri Jun 05, 2009 10:15 am

SteveM wrote:
Can you take one of those big toolholders, mill a dovetail in it and mount it directly to the Aloris-type toolpost?


Steve
Yup, you sure can!!

Exodus
Posts: 14
Joined: Sun Apr 19, 2009 1:58 pm
Location: SE Kansas

Post by Exodus » Fri Jun 05, 2009 1:22 pm

mechanicalmagic wrote:I made a half dozen insert holders for my 12" lathe. I started with 5/8" square bar stock, 4140 from McMaster. After machining, I hardened them. That was about a year ago, they seem just fine. I didn't use anything special under the inserts, since I didn't expect any interrupted cuts or hammering.

Dave J.
I'll give 4140 a try.

Thanks Dave

Image

Image

User avatar
BadDog
Posts: 4739
Joined: Wed May 17, 2006 8:21 pm
Location: Phoenix, AZ

Post by BadDog » Fri Jun 05, 2009 1:49 pm

Sure you can mill them. As I said, I've done quite a few from various manufacturers, but you're gonna want carbide to do it.

Yes, several people have milled dove tails right in the holder, but I would be looking more for the sizes over 1" to do that.

And the larger inserts are often CHEAPER than the small ones. They are also VERY common on ebay, local auctions, and you even see packs at flea markets some times. I prefer to stick with the the 3xx and 4xx sizes because they seem to be by far the most common, best variety, and the cheapest. The only thing I use in the smaller sizes are for my solid carbide boring bars...
Russ
Master Floor Sweeper

User avatar
JHenriksen
Posts: 286
Joined: Mon Jan 06, 2003 8:39 pm
Location: Roscoe, Illinois

Post by JHenriksen » Fri Jun 05, 2009 9:54 pm

One of my customers makes tooling. Lathe tools and mill cutter bodies are almost always made of 4140 there. Ingersoll also used 4140 while i was with them.

User avatar
mechanicalmagic
Posts: 1431
Joined: Sun Nov 04, 2007 12:11 am
Location: Pleasanton, CA Land of perfect weather

Post by mechanicalmagic » Fri Jun 05, 2009 10:04 pm

Exodus wrote: I'll give 4140 a try.
Do NOT get PREHARD 4140, if you have a choice.

Let me know if you need your stuff hardened.

Dave J.
Every day I ask myself, "What's the most fun thing to do today."
9x48 BP clone, 12x36 lathe, TIG, MIG, Gas, 3 in 1 sheetmetal.

Post Reply