Removing the head from a boring bar

[PNW_Guy]

I have 2 boring bars I want to remove the head from. One is a nice Criterion head on a sketchy R8 adapter, and the other is an Yugoslavian import on a good R8 adapter. I want to put the Criterion on the good adapter, and sell the other one to a friend who has a mill that takes a non R8 shank - the adapter will be his problem.

So, I can't get the head separated from the adapter on either one. I've tried putting them into the spindle, with the mill in low range and using a strap wrench. No luck so far. How else do you securely hold an R8 adapter? I'd rather not add much heat to the boring head.

And yes, they both appear to be two piece units.

 

[Flyinfool]

Most boring heads have flats that can be put in a padded or soft jaw vice. then use your strap wrench on the R8.

 

[Dabbler]

All 3 of my boring heads have adapters on them. If I were to convert one to a CAT40 adapter I would *never* do this in the mill. Wrong place - the brake on the mill is too flimsy and not designed for the forces involved. You cannot get the right force by just putting it in gear.

Make yourself a split ring that will hold the R8 on the relief between the ground surfaces and clamp this in your bench vise. *then * use a strap clamp to try to remove it - keeping in mind the correct direction to unscrew it.

If your strap wrench slips (mine does too easily), then make yourself a custom wrench to remove it. This is a variation of a split ring, where you clamp the body and have flats milled in the split ring to remove the head. You can easily develop hundreds of foot pounds of torque to remove it this way.

There is plan B,C and D, but try the easiest and most likely to succeed first.

All the best!

 

[OTmachine]

It is possible that some sort of Loctite was applied during assembly. Most Loctite melts at about 300 deg. F. Use the oven when the wife is away.

 

[PNW_Guy]

All 3 of my boring heads have adapters on them. If I were to convert one to a CAT40 adapter I would *never* do this in the mill. Wrong place - the brake on the mill is too flimsy and not designed for the forces involved. You cannot get the right force by just putting it in gear.

Make yourself a split ring that will hold the R8 on the relief between the ground surfaces and clamp this in your bench vise. *then * use a strap clamp to try to remove it - keeping in mind the correct direction to unscrew it.

If your strap wrench slips (mine does too easily), then make yourself a custom wrench to remove it. This is a variation of a split ring, where you clamp the body and have flats milled in the split ring to remove the head. You can easily develop hundreds of foot pounds of torque to remove it this way.

There is plan B,C and D, but try the easiest and most likely to succeed first.

All the best!

Excellent idea - hadn't thought of a collar.

I'm assuming they are right hand thread so they don't loosen in use. Is that correct?

 

[PNW_Guy]

It is possible that some sort of Loctite was applied during assembly. Most Loctite melts at about 300 deg. F. Use the oven when the wife is away.

There are many joys of being single; this is merely one example.

 

[ChazzC]

It is possible that some sort of Loctite was applied during assembly. Most Loctite melts at about 300 deg. F. Use the oven when the wife is away.

Or use the Toaster Oven you bought for tempering tools you hardened.

 

[Dabbler]

I'm assuming they are right hand thread so they don't loosen in use. Is that correct?

Imagine you mill in high speed mode (not the back gear) turning forward. the force of the cutter will tighten the thread. You need to reverse that direction.

I'm not using RH thread and LH thread as descriptors, because that has mixed up people in the past.

 

[PNW_Guy]

Make yourself a split ring that will hold the R8 on the relief between the ground surfaces and clamp this in your bench vise. *then * use a strap clamp to try to remove it - keeping in mind the correct direction to unscrew it.

Thanks - it worked like a charm. One came right off, and the other needed a bit more persuasion, but nothing drastic.