by Fred Connell

Chucking small work items on an ornamental lathe is always a challenge.  I recently discovered the ER (Erickson) spring collet chuck.  I'm using this a great deal in my shop.  The ER spring collet chucks with straight shanks are commonly used in the metal working industry for extending the cutting tool of a milling machine to reach inside a confined space.  ER collets are specified in several size ranges  from ER8 with a capacity of 3/16" to ER90 with a capacity of 2-1/8".  ER16, ER25, ER32 and ER40 are the most common sizes with spare collets readily available.

ER spring collets have several advantages over other chucking systems.  The eight sided, full contact spring design of an ER collet assures very strong and accurate clamping that minimizes axial run out.   ER collets cover a continuous range of sizes.  They are self releasing and do not project from the spindle as much as drill chucks.

I discovered a vendor on E-bay providing several sizes of ER spring collet chucks with Morris Taper shanks.  I think the most common internal taper for wood lathes and any Ornamental Lathe or Rose Engine I build will be Morris Taper #2 (MT2) in both the spindle and tail stock.  So, an ER spring collet chuck can be used to hold your work in the head stock or hold drills in the tail stock.

I chose an ER20 size collet chuck with a maximum capacity of 1/2" and a Morris Taper of #2 for my system because it was less expensive than the larger sizes and the 1/2" capacity was all I needed.  It fits the head and tail stock of all my wood lathes, rose engines and the tail stock of one of my metal lathes. Including shipping costs, I bought my ER20 collet chuck with a MT2 taper and a full set of 13 collets (from 3/64" to 33/64") on Ebay from CTC Tools, http://stores.ebay.com/CTC-Tools, for $63.75.  An ER32 MT2 collet chuck and a set of 19 collets (from 3/32" to 25/32") cost $137.50.  There are other vendors on E-bay providing ER collets and  Morris Taper chucks.

The MT taper ER spring collet chucks have a female thread in the back end for connecting a draw bar through the spindle of your machine to secure the chuck to the spindle.  My chuck has metric draw bar threads.  You can obtain a threading die from a metal working supply and easily fabricate your own custom draw bar for your lathe.

Above is a photograph of my ER 20 collet chuck holding the bone mouthpiece for one of my trumpet turkey calls.

This has turned out to be one of the most useful tools in my shop.