Insert Lathe Tool - What type of steel for body?

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Exodus
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Insert Lathe Tool - What type of steel for body?

Post by Exodus »

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
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BadDog
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Post by BadDog »

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
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bigsaxdog
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Post by bigsaxdog »

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.
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mechanicalmagic
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Post by mechanicalmagic »

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.
SteveM
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Post by SteveM »

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

Post by websterz »

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
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Post by Exodus »

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
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BadDog
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Post by BadDog »

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
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JHenriksen
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Post by JHenriksen »

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.
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mechanicalmagic
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Post by mechanicalmagic »

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.
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