Quick change tooling

Very neat.

I guess that the lever operated ring moves forward to clamp the accessory, as well as turning it with the pin?

Doesn't look impossible to copy.

Neil

It appears to me that the action is similar to the camlock pull together system.

The taper on the rear of the holder fits into the socket on the adaptor. The pin fits in one of the three holes shown to prevent rotation of the taper. The locking ring rotates the 3 wings over the matching 3 wings of the tool holder and at the same time, by means of an internal thread pulls it all up tight. The wings are not cams but merely overlapping matching fingers.??

As regards the 3 half moons could these be to do with a holding jig connected with the assembly of the adaptor, providing a certain/accurate non rotating positioning.?

Edited By KWIL on 30/01/2016 16:11:43

KWIL, if it is a thread that draws the toolholder into lock, the pitch and timing of the thread would have to be spot-on, because there is very little rotational tolerance for the 'locked' position. It would also seem that the thread would have to be LH, because the 'RELEASE' action is towards the operator.

Hmmm, thinking about it, the thread timing wouldn't be a critical problem, you would just need to make sure the main taper is installed in the tailstock barrel at a suitable rotational angle. That angle, and the pitch, would still need to be accurate so that the locked position had the 'wings' suitably engaged.

It sure looks like a handy device to get away from all the barrel-cranking / tailstock-moving to clear a large taper when changing tools.

Roger

EDIT. Looking at the last of the three pics, it appears that there is a weld seam running around the bottom of the uppermost of the 'wings' on the toolholder. Part of the normal construction, or repair of an over-stressed holder?

Edited By Roger Head on 31/01/2016 00:25:46

Just a thought, but the late JA Radford, a friend and contemporary of George Thomas, published a design which gives a similar effect to the Arrand quick change toolholder. He called it a "quick-change toolholder for the lathe tailstock". It's in his book "Improvements and Accessories for your Lathe" and the design was originally published in ME in about the late 1960s or early 70s. It's intended for home shop construction and is Myford sized. It uses a different method of attachment, using a dovetail slide, reminscent of a "Dickson" type Q/C holder, at right angles to the the lathe centre line. The toolholders, of which he describes many types, lift/slide vertically out of the mounting block so requiring no winding back of the tailstock, just like the Arrand type, Might be easier to make, - did we decide if Arrand are still extant?

JAR QC tailstock toolholders:

I made some of these many years ago, use them all the time and wouldn't be without them. There are some photos in my Miscellaneous album. The Arrand design looks very good but, so far as I understand it, much more difficult to make. The JAR design involves dovetail slides and the turning of a morse taper. Lacking a mill, I did all the work on the Myford.

Tractor man: might you get your camera out and treat us to a video?

I have difficulty getting my head around the pin concept​... I assume the pin is to stop rotation plus help in alignment; but how do you release the pin to change tooling... is it a spring loaded detent, or do you have it extended at the rear to 'pull' the pin out... not having a rear view I can only surmise ?

George.