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Jo are the DA collets like 5C and MT being a fixed size?
Read too many people with problems getting direct fit ER chucks to run true which would put me off that way of mounting them, at least with a backplate you can make it to suit the individual machine.
Other than Colin at Cowells is there anyone else supplying M14x1 threaded DA200 collet chucks.
Inserting the cutting tool less than 2/3 the gripping length into the collet can permanent damage the colletFull length of the gripping bore must be maintained to achieve accuracy and safety
2/3rds of the gripping length on some collets is much shorter than the length of the collet
Well I suppose when the Cowells was first about none of us had heard of ER collets so the DA ones are a bit dated and makes sense to update to what is easily available
I purchased my Cowells lathe a couple of years ago and it is very nice. I purchased the DA200 collet attachment from Cowells at the same time. I decided to try and purchase the collets myself and ran into a real runout problem with a set from a commercial supplier (not eBay). I sent them all back. The holder itself was dead nuts on. After communicating with Colin he told me the specs for his attachment were from Ericson. I purchased some original (not new ones from India I think) and they worked fine, I now have a nice set with runnouts in .0005 or less range. I mentioned to Colin back then about an ER 16, not sure at this point I would change.As for the question about the WW set from Sherline. I have a full set of ww and or 8mm collets and use them in the Sherline lathe, they work very well, just do not go much more than - .002" or you will ruin them. I was told I could go -.004 but have not had the occasion to need that. In hind sight a ME Cowells with the 8mm / WW spindle would have fit my work better. The DA system works just fine.Bob
I can only find one supplier of a M14x1 direct fitting ER16 collet chuck and that is RC-Machines in Germany.