School Me On Boring Bars And Holders

great white

great white

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My setup is an old atlas TH42. Simple, easy to use and just generally gets the job done well for me. It has an AXA QCTP I put on last year and that helped immeasurably.

I only do simple work on it, mostly motorcycle parts and bits. IE: spacers, axles, bushes, small brackets, etc. I have an atlas milling attachment (thanks again Ulmadoc, it gets lots of use!) that lets me do small brackets and some facing operations.

I find myself at a point where I think a boring bars might be a useful addition to the tool shelf.

I would be doing bores probably no bigger than a few inches at best. Usually under an inch I would think (motorcycle parts: axle spacers, bushes, etc).

I need a bar holder for a QCTP obviously, but there seems to be all manner of boring bars and sizes.

I'm guessing larger diameters are for deeper and larger bores to resist deflection. But they would also limit the smaller ID they could be used on.

I'm also not looking to "break the bank" on this and ebay stuff usually will work to the tolerance I need. I have a busy bee locally (I'm in Canada), but their prices are just stupid compared to what I can order off ebay. Their tools all seem to come out of China anyways, so I can't bring myself to pay their stupid mark up on a China tool when I can just order it myself and wait a couple weeks.

I don't screw cut, so internal screw cutting is just not even an option right now. I'm just not good enough, yet.

Most of the bars I've seen are carbide inserts, although I have seen a few HSS ones. Most of my cutting tools are HSS as I am trying to force myself to learn how to grind cutters. HSS is fine for 99.9% of the work I do anyways (typically Al or mild steel).

Can someone recommend a good "all around" size for a boring bar that typically does light work?

Once I have an idea on what bar size will cover my use, I can start hunting for a holder....
 
I use a 3/4 inch holder in my QCTP. I have bored holes to well over 4 inch diameter with it. To use smaller diameter bars I made a set of split bushings for the holder. My bars go from 4 inches to 10 inches in length. That's the short answer my friend, hope it helps?

"Billy G"
 
Bill Gruby said:
I use a 3/4 inch holder in my QCTP. I have bored holes to well over 4 inch diameter with it. To use smaller diameter bars I made a set of split bushings for the holder. My bars go from 4 inches to 10 inches in length. That's the short answer my friend, hope it helps?

"Billy G"
Click to expand...
Ah, I never thought about bushing a larger tool holder to use smaller bars!

That opens the options up quite a bit.

Thanks!

:)
 
One of the cheapest and quickest solutions is the brazed carbide sets for use in a boring head. They'd can be had in shank diameters from 3/8 to 3/4 for very reasonable prices. In each set you have a number of diameters and lengths.
Either buy for your Utica change tooling or build bushings for fit them.
 
With the boring head comes a problem. That problem is depth of cut without chatter. A good idea yes, but a 3/4 inch bar going 6 inches deep is a better solution. If you are only doing short depth holes the boring head will suffice.

"Billy G"
 
I agree Bill. The suggestion was for an easy way to get started. Once you actually have a need for a longer bar, then buy it.
Don't want to suggest buying a bunch of tooling just on spec that it might someday be needed.
 
What I strived for with my answer was not to short change your idea as it really was a good one. I sought to inform the OP of the negative side of the idea, that way he is better informed on which path to take. I meant no disrespect in my post. My apology if any was taken.

"Billy G"
 
None taken at all Bill. I should have expanded on the post.
I just looked again. Were you thinking of using the entire boring head in the tail stock?
Might be a great idea but I was just using the bars from the head in the QC tooling.
 
My brother likes carbide boring bars for rigidity, he cruises ebay for these and often picks them up for a fraction of new price.
 
If you have the tailstock taper on the boring head you can use the head in the tailstock. This allows for short depth holes. Yes that is what I was referring to.

"Billy G"
 
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