Gorton drawbars and collet adaptor removal

Hi all,

I'm a new owner of a Gorton 8.5D mill, and am about to start cleaning it up (filthy!). Looking at the spindle, I believe it's a BS#9, and has a Gorton collet adaptor in it. I loosened the drawbar, and it came out freely from the top end. Out popped a gorton 1/2" collet from the spindle. The adaptor is still in place.

Reading some of the posts on here, the "correct" drawbar for the BS9 taper should have given me a second point of resistance, and further turning would pop out the BS9-Gorton adaptor. I'm thinking the drawbar I have is not that version - maybe a separate drawbar for the gorton adaptor only?

I understand it would be best to make the correct drawbar, but wanted to check first: is this actually the right drawbar, and I'm just using it wrong?

If I need to make it, would it be possible for someone to post a picture of it? I'm struggling to figure it out from the diagrams on the gorton website.

Thanks!

Lee

The draw bar you have there is for the Gorton collet. I believe it has a 3/8-24 thread on it for those little collets. The normal draw bar for the 8-1/2D head has a 1/2-13 thread on it for the No. 9 B & S arbors.
The current adapter in your spindle should be tapped for 1/2-13 thread. Take you a piece of B-7 alloyall threaded rod, with 1/2-13 thread and drop it down in the spindle. Thread it into the adapter that is "planted" in the spindle right now.
Next, start a couple of nuts on the all thread rod and run them down to about 1" above the top of the spindle. Put a couple of fender washers on next. Find a big block of steel with a hole in it and slide over the end of the all thread. Give it a couple of sharp blows and see if it comes loose.

If it doesn't come loose, squirt some penetrating oil down inside the spindle let set for a day or two. Try again. If no luck, let us know. I still have several "tricks" in my bag to try.

Hi 4gsr, thanks for the tip.

Why B7 alloyall? Would regular threaded rod be too weak?

I thought pounding on these spindle bearings was a no-no?

Thanks again,

Lee

Well, you have to do some pounding. As long as you don't get too carried away. If there is room on the bottom end of the spindle, make a bushing that will clear the arbor and go against the spindle. Let the table support the bushing/spacer, then you could beat on it a little harder.
I just suggested B-7. The Ace hardware stuff may work. Give it a try.

Back when I had my 9J mills, I would run the spindle in a high RPM to warm up the spindle, with the draw bar loose. And generally a sharp blow would knock them loose. If yours had the nut on top of the spindle that retains the draw bar, you could put it in a bind and generally break it loose.

The trick to these Gorton mills, was to use a 6" adjustable wrench to gently tighten the draw bar. Doing this would make it easy to remove the arbors. You have to remember, the Brown & Sharpe tapers are "self holding" and don't need much backup to keep them in place. But you have gorillas out there that think its a R-8 collet and want to tighten the crap out on a B & S taper tooling and don't understand why it doesn't come loose....

Thanks again. When I'm back over there, I'll need to measure that left hand thread on the top of the spindle to see if I can come up with a nut.

If I have it right: the drawbar is 1/2-13 threaded, and the top end has a shoulder which the left hand nut can bear down on? Which means the top end of the drawbar is a smaller diameter and passes through the nut, allowing it to be tightened/loosened independent of the left hand nut?

Thanks!

Can the 1/2-13 rod go in from the bottom of the spindle and thread into the adapter? Then side up some large washers followed by the nuts.
Draw the collet down rather than pinging the bearings.
If the threaded rod is long enough to pass from top to the bottom of the spindle it could apply a pre-load from the bottom while you give it a smack from the top.

Ugly drawbar

Thanks again for all the advice.

I went ahead and made up a quick and dirty drawbar, to try and remove the adapter "correctly" and avoid pounding on the bearings. I know it's ugly. I'll make it pretty later.

Here's a picture of what I have. It's a long piece of 1/2" threaded rod that threads into the back of the adaptor. I turned a nut down to be a slip fit inside the top of the spindle, and threaded it onto the allthread until it sat flush with the top of the spindle bore. I welded that in place, and it now acts as a shoulder to bear down on.

The large nut is a 1-1/8-12 left hand thread, which I welded a washer onto the top of. The washer allows the allthread to pass through, but bears against the shoulder created by the turned nut.

On top of the whole thing is a 1/2" coupler. This is temporarily held in place with the lock washer and a second nut, but will eventually get welded in place.

So far, so good. But.... I'm able to thread the LH nut down until it bears against the shoulder. I then get resistance, and I keep turning while using a second wrench on the coupler to prevent the drawbar (and/or the spindle) from turning. But, the resistance just keeps increasing, until the point where I can't turn it anymore using a 12" pipe wrench. It feels really solid.

I'm guessing the collet has been in there a very long time, and is either rusted in place, or galled in place, or something similar. I sprayed some PBlaster down the hole, and will have another go tomorrow, but I wanted to check my setup from people that have actually seen the real drawbar: does this look right?

It seems like it shouldn't be putting any pressure at all on the spindle bearings, in which case I can put cheater bars on the pipe wrenches without fear of hurting too much. Is that a fair statement?

Thanks again,

Lee

IF you have the mill hooked up the power, turn on and run in one of the higher speeds to warn up the spindle. Don't get it too hot! but just warn enough to cause thermo expansion in the metal and hopefully with all that compression put into the draw bar, it should come loose. After warmed up, see if the draw bar will take some more compression. If it doesn't pop loose, got to plan B.

That #9 B&S (if so equipped) drops out the bottom, not the top.
Pull from the bottom of the spindle and tap from the top.
The 8 1/2-D Universal has a "spindle sleeve clamp" lever on the right side of the head. Is that the same spindle sleeve clamp on the left side of your mill?
702-1 is the #9 B&S adapter.

Here are two section views of the spindle. The outline of 702-1 is in the drawing of the spindle. The drawbar is present in the drawing.


John

Hi John,
Yes, I was wondering what that lever is for. How is that different than the quill lock, and could it be preventing me from getting the adaptor out?

I'm not sure I understand why you say to pull from the bottom. I thought the 8-1/2 originally came with a drawbar that had the integrated left hand nut on the top, that was used to force the drawbar down and eject the bs9 tool. Isn't that the way it's best done?

Thanks

Ha....another niteowl
I just updated with the spindle assembly drawing in post #9.
That lever does one or the other. Does it clamp the quill when applied?
If that is a piece of 'all thread' that extends out the bottom and the top, think of Dr. Seuss. and 'push me pull you'.
I did something like that getting the set of belleville spring washers out of horizontal bar mill that was a draw-bar.
That #9 is going to hold on tight compared to a steep taper. Running it to warm up may help. If it was not hardened I'd cram dry ice in the hole to shrink it.

Be careful with how much twisting torque is loaded on to the threads. That's a big pipe wrench.
Photo of the top end. Second photo shows the end of the #9 B&S adapter.

John

Yup, on vacation so no work tomorrow

Thanks for the pictures. I'll give it a shot from the bottom as well, thanks for the tip.

The lever is not actually on the mill right now, but it was in a bucket of parts that came with it. There is a smaller screw lever on the front-right of the casting, beside that arbor for the sleeve lock, that functions as a quill lock. I think I tried the lever on that arbor, but it didn't move easily and I didn't want to force anything without knowing what it was. .

A 1950 pdf; http://www.iamachinery.com/brochures/scans/0195.pdf

The site; George Gorton Machine models

Manuals; Manuals for George Gorton Machine tools

1936; George Gorton Machine Co. Superspeed Mills, 1936, Form 1400

Stuck #9 is a pain to get lose.

Dont go beating on it. You will kill the bearings. Dont want to fess up as to how I know.

The draw bar arrangement is about right.
The Gorton draw bar has a shoulder captured on both sides.
When tightening the collet it pulls the drawbar into the spindle.
When loosening the left hand nut with cap acts as an ejecting shoulder.
The ejection shoulder meant that Gorton did not have to consider hammer blows on the draw bar when they designed the spindle, and the bearing arrangement is not designed to take that kind of insult.

The lever mentioned in previous threads is a break/spindle lock that clamps on the rim of the drive pulley.

Truth is you should expect to crank like hell to break that #9 sleeve lose.
Its probably been in there a long time and stuck well.

I would recommend you turn the machine on, and warm the bore up with a propane torch.
Dont get it super hot, but boiling or a bit better.
Heat will loosen any dried oils in the bore that "glue" the system together.

If heat fails, shove a piece of dry ice in the hole and press the quill into a block of wood. Then squirt a few CC's of gasoline or rubbing alcohol down the spindle to up the heat transfer rate. Insert the draw bar and shove.

A few hot/ cold cycles should break it lose.

Tweaking the spindle with hand tools would not concern me.
My little Gorton will ring of a 1/2 end mill without batting an eye.
Your more likely to shear a drive key or slip the break.

Ugh... still having trouble with this removing this gorton adapter...

I've now made 2 drawbars. The first, I sheared off the top end (admittedly, a poor design with only 3/8" of meat holding it on). The second, I actually sheared off 4 threads on the bottom end of the drawbar (thanks for the warning jhruska)... tried heat/ice in the spindle, maybe I need to try more heat...

I think there's still some good threads in the adaptor itself (I hope, anyway). In the event that the adapter threads get buggered with further attempts, I'll need a different solution.

There's about 3/16" of daylight between the shoulder on the adapter and the bottom of the spindle. I'm thinking of making a couple of u-shaped wedges to fit in there, then tightening them down with a c-clamp to avoid beating on the adapter/spindle. Any flaws in that plan? Think it might destroy the gorton adapter?

Another member suggested running a large face mill without tightening the drawbar, to shock it loose. Unfortunately not possible, as the drawbar for the gorton adapter threads into the gorton collet itself, and is needed to hold the tool in place.

Jhruska had suggested pulling from the bottom with a piece of allthread, but that won't work either. I think the adapter has a shoulder that prevents the 1/2"-13 allthread from passing through to the threaded portion from the bottom end.

This is frustrating!

Any and all suggestions are welcome at this point...

Lee

Two thoughts:

1. How big is the through hole in the adapter? Can you build a puller which reaches up into the adapter from below? You might have to get creative and drill and tap the end of a 1/2 rod which replaces the drawbar. If it rests on top of the adapter, you can strike it from above, while simultaneously applying pressure with a screw from below?

2. How hard is the metal the adapter is made from? As a last resort, I would consider (with the 1/2-13 drawbar installed) boring out the adapter to a thin shell. If you know the specs for the spindle taper, you should be able to calculate a series of stepped cuts which will approximate the outer taper. Then clamp an appropriate boring bar to the table, and use the spindle as an inverted vertical lathe. You will have to be careful of spinning the adapter in the spindle.

allan

leeko said:

Any and all suggestions are welcome at this point...

Lee

Click to expand...

Busy week, and overcommitted next two days here, but ..

Please post or PM/email me a photo of the Gorton collet holder and at least one collet.

I SUSPECT I have their twins here for my #9 B&S Burke #4 horizontal, several of the seldom-seen collets, and it came in the door with three shop-fabbed drawbars.

I'll need some time to re-read the other contributions to this thread, then go and play with all that to see if we can be of some help to each other.

Bill

Bill,

Thanks very much (again). Some day, I hope I can repay the favours...

Here are a couple of pictures of the adapter and collets. There's also a picture of my shonky drawbar - the top end, anyway. The bottom end is just a 1/2" rod, threaded to 1/2"-13 on the end.

Allan: I think the through hole is 7/16". I'll try to brainstorm what a puller would look like - are you talking about a puller which grips the adapter from inside? I can't strike anything - the spindle on this mill isn't designed to take any sort of axial blows like that, as they were relying on the captured drawbar to eject the collets. Lot's of stories about buggering up the bearings from hitting on the drawbar.

If I can't get it out with more heat/cold cycles +- a sturdier drawbar, I may have to drill it out. I hate to do that to a working Gorton adapter, though - the things are like gold dust. Maybe before that, I might rig up some sort of clamp arrangement around the outside of the adapter, with a "cutting tool" attached to it. Then fire up the mill and start cutting on a piece of stock. That might be enough to jar it free? Not sure... it may just spin on the adapter, scoring it up. Or bend it. No idea, whatever's holding it in there is pretty damn solid...

Best,

Lee

No, don't grip the inside of the adapter- thread into the end of a long 'nut' that replaces the draw bar. Use a big washer and a section of hollow tube that goes around the outside of the adapter, and presses against the spindle end, assuming it is accessible. If the adapter is the same OD as the spindle nose, you would have to slip a 'C' shaped washer between the two parts.

allan

leeko said:

Here are a couple of pictures of the adapter and collets. There's also a picture of my shonky drawbar - the top end, anyway. The bottom end is just a 1/2" rod, threaded to 1/2"-13 on the end.

Click to expand...

OK... just back to the house, mine is in drawer, same 'tround' collet tails, same critter.

The master-chuck / adapter appears to have been made as five pieces.

- Three locating studs to engage / guide the 'tround' shape,

- main body

- shrink-on shoulder that captures the three locating pins.

Spindle-facing side of the shoulder on mine has one major, several minor, marks indicating it was wedged or pried at a time or three.

The B&S 9 tail wudda been MIRROR bright as new, dasn't miss it by much even today.

It differs from most of my other #9 goods in having only a chamfer at the small end, no relieved section. Same again at the large end, where it transitions from taper to straight cylinder and immediately runs under the shoulder/collar.

Drawbar threads in the adapter's arse-end only run about 30-40% of it's length, but that IS substantial. Forward 60% of the bore is unthreaded, appears to be thread minor diameter.

A 'puller' would simply be a rod that passes thru the drawbar bore and hangs out the spindle nose.

Figure a capscrew with a head that will pass down the drawbar bore, ditto a stand-off/sleeve that 'bears better' on the precision arse-face of the master collet/adapter, and a long enough body with threads that projects at the 'table' end.

Rig a 'bridge' like a Japanese Geisha's platform 'street shoe' to transfer force to the face of the spindle, draw tension on the puller by cranking down on a nut or longer "coupler".

Once under tension, I'd try to heat-cycle it whilst Kroil was replenished.

IF, then a SHARP rap whilst spindle is warm dasn't budge it?

I'd go and rent me a Dewar, carry-home a bit of liquid Nitrogen, and start trying to turn what may be rust into LOOSE fretting corrosion particles.

MANY cycles of major temp dif between host spindle and Gorton adapter.

OTOH, cryogenics WAS (one of) my Military MOS, so I'm au fait with the stuff.

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You might bore it out with Cardide(s). Seriously doubt you'll be drilling it out with HSS. This bugger reeks of Gortonization - nary a corner cut on alloy, heat-treat, fit and finish grind.

No fear if you have to do that.

I'll set this one aside for you. 1/8", 3/16", 1/4", 1/2" collets with it.

I'm not one to use collets on a milling machine anyway. Would use ER (on-hand arredy) or TG (on the RTWL) if I were to do.

Bill