# Question on metal lathe tool



## D_Allen (Oct 11, 2010)

Hopefully there are some folks here with experience with these things.
I got a freebee boring bar this weekend as part of a package deal.
It is a Valenite 1/2" x 6" with a place for a carbide insert. My hope is to find some inserts to use this when turning small pieces of brass and aluminum. However, I cannot figure out for sure which inserts it takes.
The model # is S06M-SCFPR-2 Other info stamped on it is 1T3-H PT-589T and CP-21.5
I think maybe 2 numbers that will fit ar CPGT 21.51 and CPMW 21.51….but I'm not sure.
Anyone out there know about these? Thanks.


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## lew (Feb 13, 2008)

http://www.dermu.com/allegati%5CGreenleaf0304.pdf
http://www.pts-tools.com/Catalog_pdf/PTSTOOLS/PTS2011CATALOG/J0338.pdf
Not sure if this will help but may give you a start.


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## D_Allen (Oct 11, 2010)

Thank you Lew.
The link to PTS was most helpful.
I'll give them a call and see if they can tell me if the one I found will work with the bar I have.


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## MrRon (Jul 9, 2009)

Check around in different catalogs. Some companies sell only in packs of 10 which can be costly. A place like Wholesale Tool sells them individually.


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## Ruaidhri (Jun 10, 2012)

For brass and aluminium I wouldn't bother - have a go at making a tip up from a piece of scrap steel. A couple of minutes on the grinder and the right size hole and you'll have all you want 
Properly tempered and honed you should be able to get a superb finish straight from the tool, and a better cutting edge than from carbide. You can also have one with no rake for the brass, and another with a suitable rake for aluminium.

Cheers,
Ruaidhrí


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## tyskkvinna (Mar 23, 2010)

I agree that for brass and aluminum I wouldn't bother with carbide, unless you intend to use it pretty often. I make my own inserts for wood all the time (my lathe is a metal lathe) and I do as Ruaidhri suggests. Works really well!


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## D_Allen (Oct 11, 2010)

Well, I'm no machinist by any means but this is the best cut I have been able to do on brass.
My woodworking tools would chatter and leave ridges. This thing works good and I haven't even made a handle for it yet.
I made an educated guess about what insert would work and this one fit perfectly.
However, it does not do that well on plastic and wood. The inserts used in the woodworking tools must be decidedly different.


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## tyskkvinna (Mar 23, 2010)

If it does a good job on brass, it's going to do a horrible job on plastic and worse on wood.

The wood inserts come to a sharp centre point and usually have more carbide.


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## D_Allen (Oct 11, 2010)

Thanks Lis, that's good info.
Since this boring bar was free and the insert cost me about $12, it was worth the risk.
If it does this well on aluminum then I'm all set. It is what I wanted to use it for to begin with.


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## Planeman40 (Nov 3, 2010)

The truth is those carbide inserts are designed for production machining of steel and very hard to turn alloys where carefully calculated speeds and lots of lubricant is used. Surprisingly, the machining of steel doesn't require a razor sharp edge like wood and soft metals, thus most inserts are made to the sharpness required which is usually not sharp enough for wood. I guess you could sit down and sharpen a carbide insert, but then that defeats the purpose of having a throw-away insert and you might as well just have a good steel turning tool.

Planeman


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## tomd (Jan 29, 2008)

When maching brass or aluminium, carbide is not even needed. I purchase small square pieces of HSS which are about 3 inches long and come 1/4, 5/16, 3/8 and 1/2 inch square from Enco for less than a dollar each. Just grind a tip of any style you desire and you can sharpen both ends. HSS does an excellent job on steel, brass, aluminium and wood. Good wood turning tools use HSS and you can get a very sharp edge on HSS. When it dulls just go back to the grinder for a minute and you ready to go again.


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## D_Allen (Oct 11, 2010)

Well, I finally made a handle. It is oak with an aluminum ferrule. The blank I used was not large enough to end up wider than the ferrule. But it will do.


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