Well... I've got a problem.? I ordered a 3C Collet Draw Bar from Ebay that is a bit longer than the Dalton draw bar I have.? I chose to do this because I didn't want to butcher the Dalton draw bar for more extension.
I received the draw bar but when I went to screw in the Dalton collet it just slid right in. No thread engagement at all.? I looked up 3C collet dimensions and as you would expect there are more than one dimension documents that don't appear to match.
South Bend collet dimensions for a #3 collet which is claimed to be compatible with 3-C collets shows an overall length of 2 7/16 which matches my Dalton collet.? The diameter of the collet shaft is .6495 on the chart and my Dalton collet diameter is .645, a difference of .0045.? The thread length on the chart for a 3-C is .750 and the Dalton collet thread length is .600.? The thread diameter on the South Bend chart is .642 which is very close to the Dalton collet thread diameter.
The inside diameter of the draw bar where threaded is .654 which allows my Dalton collets to slide in and out.
Before I ask to return this draw bar I want to make sure that it is not 3-C as advertised.? I can't find a thread diameter on the SB chart that matches it so it may be a metric draw bar.
I was under the impression that 3-C was a hard standard but if mistaken please set me straight.
I want to make sure that I am correct before I ask to a return the draw bar.
Thanks,
Peter
