Notes for 5C lever action collet closer

Close5C  This drawing shows the assembled unit and the relationship of the individual parts to each other.

Close5C1 Detail drawing of the main body. This part is accurate and will work as drawn except for the mounting flange and bolt hole dimensions.

Close5C2 The collet actuating sleeve. This sleeve carries the collet and is the part that directly closes the collet.

Close5C3 The actuating sleeve. This is the part that will be operated by the hand lever to open and close the collet.

Close5C4 Closer adjusting nut. This nut sets the tightness of the collet when closed.

Close5C5 Closer cams. These are the cams actuated by the actuating sleeve that operate the collet sleeve.

Close5C6 Front stop nut. This nut sets the length of the closer stroke and provides the control surface for the actuating sleeve.

Function and Operation
The main body mounts to the lathe spindle directly or through a mounting adaptor. The main body must be finished and threaded on the machine it is going to work on. The collet is threaded into the main body with the collet sleeve on the collet. When the collet is threaded in to the depth desired a dog point set screw is aligned with the slot in the collet. Do not tighten this set screw tight, only enough to keep the collet from rotating.
The adjusting nut in conjunction with the front stop nut controls how tight the collet sleeve will close the collet when actuated by the actuating sleeve through the closer cams.
I started on this project about three years ago in order to use 5C collets on my South Bend lathe or the Taiwan 9x20 lathe. The GA drawing shows the 1 1/2-8 spindle mounting for the lathe as part of the main body. The main body drawing shows a later idea of using a seperate mounting back plate. This would make it easier to adapt to different machines. 
The machining of the main body and its three threaded areas control the total accruacy of the unit. The collet sleeve must be made first. It must be made of at least 304 stainless as should all other parts for strength and wear. It needs to be a free slip fit no more on the collets that you will be using. .0005 clearance maximum. The collet sleeve should fit the bore in the main body to the same fit. This will insure that a TIR of any work in the collet is no more than .001. The closer cams pass through three slots milled in the main body and work against the shoulder on the collet sleeve. The adjusting nut controls the tightnness of the collet. The actuating sleeve closes and opens the collet by pushing the closer cams against the collet sleeve when moved to the rear. The actuatin sleeve is operated by a hand lever with pivioting bronze shoes riding in the outside groove. The hand lever and shoes, as well as the mounting for the hand lever have not been drawn at this time.
The front stop nut controls the open position of the actuating sleeve, provides a precision surface for it to ride on at the front and generaly keeps the whole thing togeather.
I know that this unit will work as drawn for 5C collets and the design can be altered for almost any other type of collet. Last year I constructed 3 air operated versions of this closer with a rotating main body and fixed outer unit containing a double acting air piston for 300 DA collets on a machine at work. Also I have at home the unit that i took the basic design and operating principals from. I was made I was told by hardinge for the South bend and Logan lathes in the late 40s. The collets for this unit are nice and allow me 3/4" bar through the spindle but are very hard to find. Over 25 years I have only found 5 plus the 6 that came with it.
I hope that you all find this interesting and if  in my area you may drop by and I will show any who are interested how and why such a simple design works. I have found over the years that many like to make things more complicated than neccessary, I just do not know why they like complication so much. I remember my grandfather and the first three old timers that i worked for when I was learning my trade. Their most common statement was KISS, and when I asked the first time was told "keep it simple stupid". I have lived and worked by that principle for 45 years now and it does work.
Thank You
James W. Early