Friday, November 8, 2013

ER40 Collet chuck with pass through on a South Bend 9a lathe



Tom Rafalski at 02again  (www.02again.com)  let me get my hands on a test unit for an ER40 Collet chuck intended for a South Bend 9a lathe.  This allows you to use the full through and hold up to 1" of material. The chuck is threaded for the nose of the South Bend.  (1 1/2-8)



I've been wanting a better system for holding material.  My ER40 collets hold a wider range of materials much tighter than my 5c or 3c collets.  Currently the best available is a MT3 collet chuck which doesn't allow a through hole.




In order to give myself an idea what the runout was I tried to create an ideal runout test given the age of my old South Bend 9a lathe.  I recognize the age and accuracy of this old lathe is questionable.  In order to remove as much of that as possible, I am going to do a dynamic runout test (running)  rather than a static test.  There are many factors which play here.   I spent some time looking into the ANSI standards.

I found the best information came with the Mach3 support for thread turning.
http://www.machsupport.com/wp-content/uploads/2013/02/Mach3_Threading.pdf




I tested with a .0001" Tesa indicator.  The tests were quite impressive for such an old lathe.







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