Adjustable boring bar

[Arcticfox46]

I am looking for an adjustable boring bar holder

Machine: Nakamura WT150
Max RPM = 6000

2 holes – one is brass -- one is bronze
Hole size: .1565+/-.0001
Roundness within .00015

Live tool
Cross hole
ER-32 collet holder

I am currently using a Criterion TMT-0750 boring bar holder in an ER collet.
Solid carbide boring bar.

I am having a difficult time adjusting size.

I need a super precision adjustable holder so that I can adjust within at least .0001 – preferably adjustable to within .00005

Thanks,
Leo Voisine
Manufacturing Engineer
Mahr Federal Inc.
Providence, R.I.
Leo.voisine@mahr.com
401-784-3370

[jcoats]

Adjustable Boring bar - is posting in multiple forums the exact same question going to get you a better answer?

[HuFlungDung]

Brass or bronze both machine easily (and accurately), but not with honed inserts and not with positive rake. Take any insert, grind the chipbreaker off (just enough to create a small flat spot on the top face along the cutting edge) and create neutral or negative geometry. The tool will likely cut accurately all day without replacement. IMO.

[Arcticfox46]

Adjustable Boring bar - is posting in multiple forums the exact same question going to get you a better answer?

No I don't expect to get a "better" answer - just more exposure - or just simply an answer.

Do you have a problem with me posting the same question in multiple forums?

Do the forum rules prohibit multiple postings of a question?

Do you think there is something inherently wrong with multiple postings?

Or perhaps you maybe have some constructive help to the question?

[muddobber76]

So do you need an adjustable bar to be held in a ER-32 for a live tooling application? I have this problem on a routine basis. I really like the adjustable holders from KOMET that I use on the mills but they are like most others and do not offer anything in a straight shank that would work in a ER collet. It's all HSK type tapered stuff. If you are doing a hole on cylinder then you will likely run into clearance issues when indexing. My KENNAMETAL guy told me that he had something that would work but I haven't looked into it yet. I've been lucky and always been able to get away with interpolating endmills (shallow depths). Get in touch with a couple of the top tooling companys to let them know what your application is. Good luck and please let me know what and if you find anything.

[Arcticfox46]

So do you need an adjustable bar to be held in a ER-32 for a live tooling application? I have this problem on a routine basis. I really like the adjustable holders from KOMET that I use on the mills but they are like most others and do not offer anything in a straight shank that would work in a ER collet. It's all HSK type tapered stuff. If you are doing a hole on cylinder then you will likely run into clearance issues when indexing. My KENNAMETAL guy told me that he had something that would work but I haven't looked into it yet. I've been lucky and always been able to get away with interpolating endmills (shallow depths). Get in touch with a couple of the top tooling companys to let them know what your application is. Good luck and please let me know what and if you find anything.

Thank you - I will look into the KOMET

We didn't have much luck with interpolating the .156+/-.0001 diameter holes

I found a nice adjustable bore bar set up at Big Kaizer. It screws directly onto the ER32 holder.

I am also looking into the Kennametal tooling.

I did get the Criterion tool to work, but it takes some real fussing to get it there. I am hoping to find something a little more user friendly for my operators. We don't make much money by fighting with boring bar holders.