[How do I?] Help Removing Boring Head Shank

Hi EmilioG,

No, I never did get it off. What I had in my shop wasn't good enough to clamp it, so when a friend offered to lend me his, so I could make the ball ends I needed, I put it off until I could find a better way to clamp it without destroying the shank.

But your post and Daryl's made go back and take a better look at it again. There does appear to be a parting line and something I didn't notice when it first arrived is the Shank is marked 7/8-20, which should confirm is removable.

IMG_3577.JPG IMG_3579.JPG
 
That one should be easy to break loose. I know you don't want to put pipe wrench marks on the boring head but you may have to. Here's what I would do. Clamp the head in the mill vise. Be sure to clamp on the flats of the part that accepts the boring bars. Next take a pipe wrench and grab the surface almost at the base of the taper on the R-8 shank and bite the shank there. Put some right hand torque on the shank and see if you can get it to break loose. The bite marks left can easily be filed off or either turn down this area out to about 1-1/4" from the end so i leaves a undercut. You can find this on most R-8 shanks. Let us know how you make out.
 
I have an idea ... yeah, I know its dangerous when I get ideas but hear me out.

Take a squarish piece/plate of 6061 aluminum and bore a hole with an ID the same as the OD of the head, the round part. Then cut a slit from the outside edge of the plate into the hole. This is what we use to clamp the body of an Albrecht to remove stubborn arbors.

Weld a nut on the end of the arbor. You were going to sacrifice the arbor to a pipe wrench, right?

Clamp the plate in a vise with the boring head body in the hole so that when you tighten the vise, it clamps the body circumferentially. Now use an impact gun on the nut at the end of the arbor and I bet that sucker will come off.

Told'ja not to let me get an idea ...
 
Impact gun is the tool but a strap wrapped around an extension can grab the shank like an oil filter strap wrench.

Do not use the quill.

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If it's a mechanical lock (crossed threads) or heavy rust or stripped threads, it's going to be a big problem.
I would soak the threaded shaft line in Kroil or other penetrant after some heat with a torch.
Not too much heat. Then try Mikey's idea. I bet it's old rust holding that shank. Did you see this:

 
If you apply heat to the head body to try to loosen, don't worry the body is made of a very soft metal like 12L14 or 1215 steel. I found this out when I rebuilt three of them a while back. That reminds me, I need to start a thread on the rebuild I did on the three donors that were repaired. ken
 
You could use your lathe chuck as a 3 jaw vise to hold the body, and put a center in the end of the arbor, and then wreck the shank with the pipe wrench. If your low gear won't hold it, cut a 2 x 4 the right length to prop the jaw up by putting between the jaw and the bed. And a little heat certainly won't hurt it.

Just make sure the head is dialed "to center" so the jaws bear evenly on the body. Or wrap it in copper or aluminum.
 
Cut some oak timber to make clamp "jaws" for the head.
//cloud.tapatalk.com/s/587955ae7ecdc/20170113_163212.jpg?

Put powdered rosin (a rosin bag can be had at a sports equipment store) on the jaws and clamp the whole lot in the bench vise.
Make another set of oak jaws for the r-8 shank and jury rig a long handled clamp such as this20170113_161638.jpg
Clamp it till the wood starts to crush! Then put the torque to it.

If you have a shop press that can replace the vice, it would work better.


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Another idea for gripping the shank might be to mill a pair of opposing flats on the shank 180 deg. apart just deep enough to get the largest possible open end or Crescent wrench on it. Then grip the head using one of the other ideas here like Mikey or Tony suggested.

Ted
 
I have a Criterion DB204 head I bought for a song. The shank was welded on. Went in, cut the weld off as close to the body as I could get it. Couldn't get the shank to loosen. cut the shank off, bored out the dutchman to the thread bore. Then had to face off about 1/8" of the body to get the rest of the dutchman to come out. Deepen the counter bore enough to get a new shank to fit. May have to do this if you can't get the shank broke loose. Ken
 
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