[How-To] Bore and Turn in a single operation, possible?

[dml66]

The goal is to bore and turn a short length of tubing in a single operation, the tube's wall thickness will be reduced 0.002" or less, split evenly between OD and ID let's say.

I'm thinking my QCTP could do the job but, it doesn't allow two holders to be mounted simultaneously. I think I could "fix" that by cutting or grinding the QCTP holders so they both fit. However, the holders are heat-treated, I'm not sure what I could use to cut or grind them in a reasonably accurate fashion? If it's possible to mount them both, I can devise a way to adjust the outside cutter in order to achieve the desired offset from the inside cutter.

Below is a picture showing what I'm imagining; the boring bar is really an O-ring grooving tool and the turning cutter is not the one I'd use, they're just actors.



Even if it's possible to do this, it may be a bad idea for reasons I've not considered, that I can't find anything on the Internet about doing this is a good indication it might be in the same league as the square wheel .

Thoughts? And, thanks!

 

[durableoreo]

I have AXA tool holders and I had to enlarge the slot for a 5/8 shank tool. It milled fine with a 3/8 carbide roughing endmill. YMMV

 

[jwmay]

What’s the finished part look like?

 

[jwmelvin]

Seems like a good idea to me and I’d think some carbide would have an okay time with the tool holders.

 

[mmcmdl]

Called gang tooling . That can be easily done with one holder . More to come after game is over .

 

[strantor]

I predict that using the same tool post for two tool holder simultaneously will result in good grip on one of them but not the other. But I wouldn't be upset at being proven wrong.

 

[benmychree]

With such a small stock removal, I'd think chances of success would be small. Why be in such a hurry?

 

[mmcmdl]

A right and left hand boring bar is needed , preferably micro . All bars have an " F " dimension . The distance between your two holes is determined by your f dimensions . Go .005 under for adjustment . The inside tool will stay on center . The outside tool can rotate off center for fine adjustments or use a diamond file or stone .

This is just a rough/easy sketch . The ones I made up have oversize holes for eccentric bushings that hold the bars . You can rotate the bushings way off center and line the bars up tangent to the stock . There is a pic or two of these bars somewhere on here . Not going out to the garage tonight . .

 

[MrWhoopee]

I've done a lot of machining on QC tool holders. Most are decently machinable, even to the point of drilling and tapping. I did get a BXA holder recently that was rock hard. Couldn't touch it with a HSS drill. I started drilling with carbide, then realized there was no way I was going to tap it.

 

[jwmelvin]

I predict that using the same tool post for two tool holder simultaneously will result in good grip on one of them but not the other.

Good point! Dave’s approach of making a single holder for two tools is probably better.