Sleeve Removal Problem

Gorton 375-4 Cutter Grinder

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My Gorton Model 375-4 Cutter Grinder came equipped with a Tool No. 717 Universal [workholding] Head (which is engraved "No. 717" on it, so I'm sure of the model). Here's a picture of it with a Collet and the Collet Draw Bar in place:

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Here is the Universal Head again, removed from the machine and shown without any Collet or Collet Draw Bar in place. I'll be referring to the parts lettered A, B, C, and D in the discussion below.

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In operation, a collet is placed into the Collet Holder Sleeve (the cylinder that runs the length of the unit) and is drawn in with a Draw Bar as shown in the first photo. The Collet/Sleeve assembly then can be rotated by hand. When this happens, the parts labelled A, B, C, and D also rotate; they're either affixed to or tightened on to the Collet Holder Sleeve. The rotating assembly may be indexed by sliding the Pin to the right to engage the Indexing Hub labelled 'A' above.

However, if I understand things correctly a second motion should be possible. It should be possible to loosen the Collet Holder Sleeve so that it can move in-and-out and (I think) be removed entirely from the machine with the Collet still held in place. But on my machine at present I cannot do that - either I don't understand how this works, or something is stuck.

Before proceeding further, though, I should note that there are two different versions of Tool No. 717. The older version, which was supplied through at least the Model 375-2, is shown below (from Gorton Form 1385-E, Instruction Book & Parts Catalog for Gorton Pantographs, from 1956).

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This is the style of Universal Head shown on James Riser's website for his Gorton 375-2: It has two clamping pieces, tightened by 1/4 inch cap screws (it's easier to see them on James Riser's photos than in the drawing) one of which clamps the Collet Holder Sleeve in place.

The Universal Head on my machine is different. It does not have these two clamps, but instead has a series of rings of various sorts. Here's the second photograph again:

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The ring marked "A" is the Indexing Hub. As one would expect, it rotates with (whatever is holding) the Sleeve, and may be indexed to various positions with the Pin.

The ring marked "B" may be called the "Bearing Locknut" (I'm not completely certain). It rotates, but on a screw thread so that it moves between rings "A" and "C". It looks kind of like it has two pieces, but if it does they're stuck together really tightly, because it rotates/screws as one unit.

The ring marked "C" is, I think, called the "Clamping Ring." As the unit is at present, ring "C" rotates with the Sleeve and cannot be otherwise moved. If it comes off, it's on very tightly. I'm pretty sure that it is the root of the problem, so I'll skip it now and cover it more later.

The ring marked "D" may be called the "Stop Collar." It, too, rotates with the Sleeve and not otherwise.

A problem is that none of the drawings in the Famco/Lars literature which show this style of Universal Head are as crisp as the earlier Gorton drawings. Here is (an extract from) the drawing I have which shows it best. This is from the out-of-print Famco Form 2006-A. The resolution as shown here is as good as it is in the paper original that I have; the important details cannot really be made out. It calls out part numbers using older-style Gorton (not Famco) part numbers, but does not name the parts.

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Here is the version of this drawing that appears in the current Gorton 375 manual as purchased directly from Famco. It is clearly a multigeneration photocopy-and-digitization-and-printout from the Form 2006-A drawing. The drawing itself is almost impossible to read. It calls out the parts using current Famco part numbers. These parts are (finally) named in later pages of the manual. I've added these names in the image below:

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With everything locked up solid and no way to take it apart, and no clear drawing, I really don't know what is happening inside this unit. Here is what I THINK is going on:

There is an overall Collet Holder Housing (p/n 154 in Famco part numbers / p/n 9677 in Gorton part numbers). It has two ball bearings in it. In these two ball bearings runs a hollow cylinder, the Collet Holder Spindle Sleeve (Famco 183 / Gorton 22635). This Spindle Sleeve rotates in the bearings, but does not move longitudinally and is not removed from the unit (unless you're just tearing it apart). It is what is indexed, if you're indexing.

In the Collet Holder Spindle Sleeve runs another hollow cylinder, the Collet Holder Sleeve (Famco 157 / Gorton 9682). This Collet Holder Sleeve can either be secured to the Spindle Sleeve in which it runs, or can be moved longitudinally in the sleeve (or slipped out of the unit entirely).

I believe that the Sleeve is secured to the Spindle Sleeve by rotating the Clamping Ring (Famco 184 / Gorton 22636). I'm betting that the Collet Holder Spindle Sleeve is threaded, and also cut longitudinally so that it itself behaves a bit like a collet. Tightening the Clamping Ring on the Collet Holder Spindle Sleeve should tighten it down on the Collet Holder Sleeve.

STOP PRESS: yes, this is how it works. Put a 3 foot pipe as a cheater bar on a pin-spanner and got the Clamping Ring off.

The Stop Collar looks as if it will set the distance the Sleeve goes into the Spindle Sleeve. It seems way to tight a fit on my machine.

The Bearing Locknut looks as if it probably allows you to preload the bearings? Not sure about this.

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