Boring bar

[Joels]

I need to hog out a 6061 aluminum slug and hold +/-.001 os 2 diameters. Can anyone recommend a boring bar that i could use? I was thinking of a one inch dia bar with about a 5 deg lead angle.

[chris m]

Don't know what size the hole is but I'd put the biggest friggin bar in there that'll fit in the hole. Rough it leaving .005-.010 on a side and finish it with as positive a cutting edge as you can get [i use either Sandvik's CCGX or CNMP depending on application]; the 5 degree lead is a good choice.

 

Depending on how much stock you're hogging out you may run into some stress relief issues so don't be too surprised if you get an out-of-round condition. You may want to go at it in 2 chuckings, take out most of the stock [leave about .030 on all surfaces unless its a huge piece, which will want more] in the first op, take it out of the machine and rechuck it in another op with very light chuck pressure to finish it up.

 

C

[billystein]

how deep is the hole?

For those cheap criterion heads I like to take a solid carbide em shank and solder a nice coated insert on the end. just grind plenty of relief. and put a nice sharp corner on it.

[robk]

I swear by Urma brand, fully adjustable and balancable heads with either steel or carbide bars (depending on dia. and LOC). The inserts last forever, at least in 420ss. They're available through Command Tool. Pricy, but very well worth every penny. Urma

[Keith Graydon]

Are you using a lathe or mill?

[JAMMAN]

Diameters and depths a must.

[jeff]

quote:

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Don't know what size the hole is but I'd put the biggest friggin bar in there that'll fit in the hole.

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+1

[Joels]

Thank you for all of your inputs. I decided to purchase a Kennametal 1 inch dia bar that holds a 80 deg insert that we already stock. I am going 3 inches deep to a diameter of 3.500. I hope this works. I am using a old HAAS lathe.

[Thad]

quote:

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Are you using a lathe or mill?

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The icon is usually a pretty good indicator.

 

Thad teh antagonizer

[specv]

My favorite insert to use other than diamond inserts , are Korloy CCGT polished inserts. They seem to take chatter out of any bore.

[Philcott]

Joel,

 

I like using kennametals CNMG431P in KC5410 grade for hogging aluminum. These inserts really break your chips up well and make stringy chips a thing of the past. Your 1" bar should do fine on the 3" deep hole. Id it applies to this job you should take Chris's advice on the "stress relief issues".

 

Good luck.

 

Phil