[How do I?] Help Removing Boring Head Shank

[DAT510]

Hi All,

I have a Criterion DBL-202 Boring Head with an R8 Shank. I've been trying to remove it so I can switch it to a 3/4" straight shank to do some ball end turning.

I tried mounting it in my mill with a 1/2 steel bar in the cross holes of the boring head - The design of my mill prevents me from "locking the spindle", so I'm left using the spindle spanner and I can't even come close to to getting enough torque to break the head loose from the shank.

Next I grabbed the shank in the 3 jaw chuck of my lathe. Engaged the back gear to lock the spindle. Applied a fair amount of torque, such that I started unscrewing the Chuck from the spindle.

Next I clamped it in my vice with soft jaws - No luck, started to bend the 1/2 rod and spin in the jaws.

Next while still in the vice, I heated the head with a heat gun, til it started to smoke, applied torque - Still no luck. I even tried shocking it a bit by hitting the bar with a hammer while applying torque to head.

Criterion specs show it's RH tread, so I double checked I've been applying torque in the counter clockwise direction.

Anyone have any other suggestions? I'd prefer to not destroy the R8 shank, since I still plan to use it.

Thank in advance,

Chris

 

[Ebel440]

Hold the shank in a vise with padded jaws and use a big pipe wrench with padding to turn it.

 

[Uglydog]

Sorry to ask such an obvious question.
However, in my piles I've got a Criterion with an integral B&S taper shaft.
Are you sure its two pieces?
Try Kroil and patience.

Daryl
MN

 

[DAT510]

I wondered the same thing. I checked under my stereo microscope and I can see what appears to be a parting line. But it's super tight with no visible treads. It very well could be an integral shaft.

A buddies going to lend me his cheap boring head to use for ball turning.

Thanks for the thought.

 

[EmilioG]

Try contacting Allied Machine. I have a DBL202 b and was able to remove the kwik switch arbor on a
vise with copper jaws. I've never seen a DBL202 with an integral shank, but who knows, it could be a special order
or limited model. Maybe someone used LocTite or some other thread adhesive. Theres a YouTube video showing a guy
cutting off the arbor and going through hell getting it off, but he got it off. Call Allied.

 

[DAT510]

Thank EmilioG. I'll look into Allied.

 

[4GSR]

I have a DB203 boring head that was pretty much trashed out when I got it. So at the shop I used to work at we had a special pipe vise that is made to grip "round" things. We applied an 36" pipe wrench with 250 lbs on the end of the wrench. After bouncing on the pipe wrench a couple of times, it broke loose! In my 30 something years of using Criterion boring heads, I have never allowed mine to get that tight, ever! I occasionally break mine loose, if for anything, for cleaning. Usually apply some never-seize to the threads before remounting too.

 

[EmilioG]

Did you ever get the shank/arbor off the Criterion or was it integral?

 

[Uglydog]

...we had a special pipe vise that is made to grip "round" things.....

4gsr, wondering if you have a pic or a link to the vise in question. I'm imagining a pipe vise like this only larger. How are you best able to make sure that the jaws don't permanently mar the finish and still get her to hold. Aluminum shimstock pads?

Daryl
MN

 

[4GSR]

Here's a couple of pictures of the vises we use. The one marked with the name "Elder" is similar to the one I used to break the shank free from the head. And yes, it did leave bite marks on both pieces. But a skim cut over the OD cleaned up most of them when I rebuilt them a few months ago.
Oh, the vise in the first two pictures is a part that is about 12" OD to give you an ides of the size of these vises. The vice in the second picture will handle about 9" OD. Ken