Lathes for < 1" OD parts

 © Brooke Clarke 2000 -2007

This was a page I developed when looking for a chucker lathe.  Prior to screw machines, chuckers were the best way of making the same part over and over again.  They have a hollow shaft holding the head stock and it's fitted with a collet system.  The "5C" was the one our shop had at Aertech.  In the shop there was a hand made plywood board about chest high and slopped back so that it was easy to read the printing on the face of all the collets that were held by round holes.  Maybe 50 to 100 collets.  There were stock ones for various diameters of round stock and for common square and hex stock.  In addition a "blank" collet could have a pocket machined into it's face to hold a custom shape. 

Instead of a tail stock there was the chucker turret.  It held a number of tools and every time the lever was cycled back and forth either a new tool would be brought up in line with the collet.  The cross slide was also lever operated.

These typically were used for diameters under 3/8" but I didn't remember the max rod diameter that could be used.

The collet was opened by working the left lever. 
A pneumatic ram or spring or manually the long rod stock was feed until it hit the stop on the turret. (this part I'm not clear on).
The collet was closed by working the left lever.
The turret was rotated by working it's lever which would bring up the next tool.  Say it was an end drill.  There would be a way to feed the drill into the work piece and a stop would control how deep it went.  It might be hand fed for a small diameter or lever fed for a bigger drill.
The turret was rotated again to bring up the next tool.  Say it was a tap, the operation would proceed as the prior step.
The turret was rotated again to bring up the next tool.  Say it was to turn a specified diameter.  This could be done be feeding the tool from the end using a lever.
The cross slide might have tools on both the front and rear that could be brought up to a stop with a lever.
The turret was rotated again to bring up the next tool. Say a different diameter was needed closer to the collet.  so the work piece may need to be moved forward so the tool would be a stop in a new location.  The collet lever on the left would be opened and after the work piece moved closed.  The turret cycled and the new cutter used.
The turret was rotated again to bring up the next tool.   Say it was a cutoff tool which could be fed using a lever.

You can see that there are no skill type operations, it's all cycling levers to stops.  The dimensions are controlled by machine setup.  A skilled machinist is not needed.

I don't have a feel how hard the setup is on a chucker compared to a modern CNC type lathe.  So can't coment on their viability today.  But in the days prior to screw machines they were the way to go.

The Enco Turn-Pro Second Operatin lathe looks exactly like the Hardinge chucker.  Better photo in their online catalog page 419.
Optional:
Vertical Cut-off Slide

Has the 5-C collets and laver collet closer system.   Didn't check all of them but it looks like they have 5-C collets ready made for round stock in any size up to 1  7/64" in 1/64" steps.