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Import parting blade with isosceles trapezoid profile. Opinions?

rons

Diamond
Joined
Mar 5, 2009
Location
California, USA
Two parting blades I was looking forward to using. Supposed to be 5% Cobalt.


Web pictures are nice. Here is the real world. Tilted at 80 degrees.
And look at that grain structure.

The ground angle (not shown) is 77 degrees. Do they even grind it to be usable?

DSC_1532.JPG

It's funny. The distribution center is in Chino, Ca. The manufacturer is a Chino in the Big Chino. :D
 
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Assuming you mean the angled top and bottom, isn't the tilt for the holder to grip? I have blades like that.
Not so concerned about the holder's grip. Is this normal for cutting? It is like a shear scrape cut rather than a straight cut.
Thank you for answering.
 
That is a beveled cut off blade.
They come in 5 degree (Johnson) and 7 degree (Acme).
Pulls the chip away for a cleaner cut.
Thanks. I was thinking about the profile. The force of cutting would drift the blade to one side.
When I looked at the description I thought that "10 degree double beveled" meant the angle on the longest width.
Excuse me for being unfamiliar with beveled blades. I came from the wood turning world. :dunce:
 
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Well, I don't see a problem if the steel holds up like it should. If I use HSS I always grind the end and usually a bit off the top too, so both are what I need at the moment. I'd not expect a blank to come ready to use. A lot of top taper like that, if left as-is, might push to the side some depending on stickout and how agressive your feed is.
 
Well, I don't see a problem if the steel holds up like it should. If I use HSS I always grind the end and usually a bit off the top too, so both are what I need at the moment. I'd not expect a blank to come ready to use. A lot of top taper like that, if left as-is, might push to the side some depending on stickout and how agressive your feed is.
That is what I first thought.

I've done a lot of wood turning and the skew like that reminds me of a skew chisel.
The shear cut is across the grain and not directly in.

This is a wood turning parting tool. The top has a bevel on both sides. Balances the cut.
Not a good picture The width at the top here is .175. The width at the bottom is .100. The length from top to bottom is .950.

DSC_1536.JPG
 
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That blade will cut off clean on the acute corner. It will also pull to the side, and more if you force it. You can grind it to make it like you want.

What holder do you have?

These look nice.

 
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I like Luer's patent Empire Tool Co. (patent expired, so Somma and others now make them) T-shape blades, which fit my Hardinge cutoff holders. Hardinge knew a good design when they saw it. You just grind the end face and the hollow-ground top is never touched.

My old-school lantern tool posts that used forged holders were designed for top and bottom beveled blades. I used them for my first thirty years of running metal lathes. The bevels are only for clamping the blade in the holder, not to be used for a cutting edge. I always grind the end of the top bevel straight across to avoid side loading the blade. Forty years ago, when I got my Swiss Multifix holder set, I did not get any of their overpriced Swiss special size 10 mm cutoff blades that were beveled on the bottom and flat on top. Instead, I modified the holder to take the standard USA 1/2" height beveled blades. I milled the OEM top clamp to hold the top bevel of the blade and added a shim to aid clamping. That is what I still use on my Clausing lathe.

The picture shows my modified Multifix size A cutoff holder with a new 1/2" beveled blade, not yet ground with a top cutting edge.

Larry

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Go look at this:

 
I like Luer's patent Empire Tool Co. (patent expired, so Somma and others now make them) T-shape blades, which fit my Hardinge cutoff holders. Hardinge knew a good design when they saw it. You just grind the end face and the hollow-ground top is never touched.

My old-school lantern tool posts that used forged holders were designed for top and bottom beveled blades. I used them for my first thirty years of running metal lathes. The bevels are only for clamping the blade in the holder, not to be used for a cutting edge. I always grind the end of the top bevel straight across to avoid side loading the blade. Forty years ago, when I got my Swiss Multifix holder set, I did not get any of their overpriced Swiss special size 10 mm cutoff blades that were beveled on the bottom and flat on top. Instead, I modified the holder to take the standard USA 1/2" height beveled blades. I milled the OEM top clamp to hold the top bevel of the blade and added a shim to aid clamping. That is what I still use on my Clausing lathe.

The picture shows my modified Multifix size A cutoff holder with a new 1/2" beveled blade, not yet ground with a top cutting edge.

Larry

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Damn, so that's what was supposed to hold those things? My holders have all used the T-type blades and I had never seen anything that made sense for the others.
 
Damn, so that's what was supposed to hold those things? My holders have all used the T-type blades and I had never seen anything that made sense for the others.
If "others" refers to the beveled blades, they were originally made to work with Armstrong or Williams forged lathe tool holders around 100 years ago. Here is a page from the Armstrong 1951 catalog from Vintage Machinery. If you look closely, you can just about see that the top bevel is ground flat near the end.

Larry

Armstrong cutoff tools.JPG
 
The oldest thing I ever used was KDK and moved to Dorian about 18 years ago. My familiarity with Armstrong and lantern style tools ends with the Atlas 7B shaper and trying to find tooling for it on eBay.
 
I have a old lantern tool holder that uses a blade like that. It is designed and sold as a facing tool. Bit is held flush so it cuts all the way across.
Bill D
 
Penn Tool is offshore junk at high price.
Not true. Sometimes it’s on shore stuff at a doubly high price.

I’ve tried to order from them exactly once, a cable to connect a name brand German gage to something else. No information until I called after a couple weeks asking where my item was. They let me know they had the wrong price listed on their web page, that the real price was 53% higher, but they would help me out and only raise it by 45% if I still wanted it. I didn’t buy that and I haven’t been back since.
 
I have a old lantern tool holder that uses a blade like that. It is designed and sold as a facing tool. Bit is held flush so it cuts all the way across.
Bill D
The Armstrong forged side tools were a separate product (different part numbers) from the cut off tools. They hold different, thick beveled blades that are ground differently on the top for side cutting. Picture from the same 1951 catalog on Vintage Machinery.

Larry

Armstrong side tools.JPG

Armstrong blades.JPG
 
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