mill collet removal help

[K Effective]

I bought a Gorton brand vertical milling machine at an auction and am having an issue. The Gorton #8.5 has a Brown and Sharpe #9 taper in the spindle. This machine came with the Gorton proprietary collet adapter installed, so B&S#9 to ZZ collets. The ZZ are quite hard to find and expensive.

I can get a full set of B&S#9 collets and just remove the adapter for under $300, or seek to have the spindle reground to something more modern, like a R8.

But first, I cannot get the adapter out of the spindle. The drawbar top end is half-inch square male, with a larger threaded cap that fits over it- (it looks like a 3/4" socket with the half inch male of the drawbar coming out of the drive hole.)

I examined the socket closely, and saw that it was marked LEFT HAND, and threaded onto the top of the spindle. Soaked with Kroil, I was unsuccessful in removing the socket with channel-locks, pipe wrenches of vice grips. I finally heated it carefully, trying not to heat the top of the spindle itself. This got it loose, and when turned off, I was able to turn the square drive of the drawbar and unthread it from the adapter.

I tried to tap down on the drawbar while loosely threaded into the adapter, but the adapter is not budging from the bottom of the spindle. More Kroil soaking, but no help. The last half inch of threads on the drawbar are pretty buggered up already, I don't want to destroy them if possible. I also don't want to drop a rod down from the top of the spindle and bang on it, lest I mushroom it out and get it stuck in there, too.

This may have been some drawbar driven by an aftermarket air or electric system, but I really see no evidence of such a driver.

I could clean and lube and reinstall the parts, then turn the square drive to screw thread the adapter out, or possibly get a ball-joint fork between the adapter and the bottom of the spindle. Or, a steel rod or brass rod from the top and hammer. Heat seems like a bad idea...

 

[dr sportster]

Can you take out the big screw and knock it out through the top? I bought Chinese collets on eBay 40 bucks I say it may have been a Chinese guy running an American machine to make them perfect. I like them

 

[Janicholson]

Left hand thread threaded rod screwed all the way into the adapter. Use the Ball joint (pickle fork) idea, or machinist wedges to tension it.
Heat the spindle with a blow drier only, cool the adapter in ice water, and hit the threaded rod Jim

 

[Stan Coryell]

I don't disagree with Jim at all. But,
this might be worth asking on Practical
Machinest.

 

[Ultradog MN]

I had a similar problem on my own mill when
I got it.
It had a 3/4in collet in the spindle and
used for one function for who knows how
many years.
It also uses B&S 9 collets.
I tried tapping on the drawbar but it would
not come out.
I screwed the drawbar almost all the way
into the collet.
Then I blocked up under the spindle so I
would not shock or damage the precision
(pircey!)spindle bearings.
And gave the drawbar several hard raps with
a 2 lb brass hammer.
It came out.
It looked like old oil had glued it in
there so I washed it all out with lacquer
thinner.
Maybe this crude drawing will help?
For blocking I used some big 3/4in lathe
bits between the mill table and spindle
and held down on the quill as I pounded.
I looked in to having my spindle reground
to R8 but it costs a Lot
So I just bought the BS 9s

 

[K Effective]

Thanks for the input, gentlemen. I suspect this old machine was set up for one repeated operation and rarely changed for many years, as well. I searched the area around the mill when I picked it up for a rack of ZZ collets to fit the adapter, but even the long-time maintenance guy did not remember any. Fortunately, someone had stamped ZZ on the adapter end and BS9 on the taper end to identify it, and also the LEFT HAND on the drawbar nut.

I'll try some pictures this morning, also.

I don't think it's rusty in thereabout likely dried cutting oils, etc as described. I'll first clean up the threads on the drawbar to make sure I don't destroy them.

UltraDogMN: when you say it was expensive to regrind your spindle, how much, if you remember a ballpark figure? One thread on PM suggested $300ish...we have a thriving machine shop industry in SW MI, and several coworkers from the trades, I think I can find a local place to give it a shot, but have yet to follow that route.

 

[Ultradog MN]

It will be 3 years this fall since I got my
mill. The prices I saw at the time - maybe
on PM? was around $800 to grind it to R8.
You may remember my posts about this old
Millmaster when I got it. Was pretty
excited about getting it.
It works as intended but is old and
somewhat limited so my enthusiasm for it
has since waned a bit.
Now, I wouldn't spend $800 on a spindle
upgrade. I would sell it and add the $800++
toward one that is a little newer.
I do keep watching auctions, etc for one.
Yes, do post some photos of yours. I/we
love photos here.

 

[Ultradog MN]

Edit:
To be clear, I did not have it reground.
I bought the right 9 B&S collets for it.