Boring Bar Sings

[kd4gij]

The speeds & feeds I quoted were with the bar in it's normal position with the neg rake. I didn't go heavier than .040 doc because it's only a 3/8 bar. Your post did make me realize two things. Although the bar didn't cut well with the original insert, I have replaced that one with the same ones that I use for the rest of my insert bars which are for external cuts. This may be a contributor. The second thing you made me realize is that although this bar cuts great at zero rake I tried it in a one inch hole, not the .458 hole that I'll be using it in on my project. It's possible that I won't have sufficient clearance in the smaller hole. I'll have to try it in some scrap. At lest with the adaptor I made I can use any rake angle I want including the factory angle. Thx for the help.

That changes things. What is the number of the insert that you are using. And what is the number of the insert that came with it.

 

[epanzella]

That changes things. What is the number of the insert that you are using. And what is the number of the insert that came with it.

I just looked up the set I bought. It's from CDCO and it's set # 41201. It has 4 external tools and the one boring bar. They all use 3/8" insert # 41054. They don't list the geometry but the same carbide insert is used for the internal & external tools. It has a chipbreaker. I bought 20 inserts with the set. These are the only inserts I have. It never occurred to me that the boring bar and the external tools might use different inserts but as it turns out in this case they don't.

 

[barrydc1]

Yeah, here's another vote for the circle or micro 100 all carbide boring bars. I love them for smaller (less than .500") bores. The only downside is the depth of the hole sometimes. They are often limited to less than 1" or even .5" of depth. For more you'll need to make your other boring bar types work.