Anyone got any recommendations for alternatives to the Myford 2MT collets. I was prompted to check the accuracy of the Myford ones I have and found TIRs of between one thou and four thou on the ones I checked. I also checked the MT socket in the lathe mandrel and it was OK.
I'm looking at trying some of the Vertex 2MT collets supplied by people like Chronos, but they have the drawback that I can't feed barstock through them from the back.
I saw that ER25 adaptor but was looking for a bit of positive feedback before I laid out 70 odd quid plus whatever collets I get. I'm feeling a bit touchy after considering what I spent on my Myford collets for questionable accuracy :-)
Hello folks, I have just given the ER25 collet system with screw on chuck holder [direct on to lathe mandrel]a very thorough work out,building the little Stuart 10v engine. For tight accurate work with bar,round hexagon or square,screwcutting or turning,I would find it hard to beat.Rod can be extended through the collet and up the centre of the mandrel [up to bore size of head mandrel]. I have measured for deflection...run off......zero. Although a rather costly set up,it pays for itself in the end, All the best for now, John.
Yes they were/are. Most were bought during the 70s but the most recent one was bought off their stand at Bristol a year or two ago.
I found out about the problem when, on another list, someone mentioned the fact that Myford 2MT collets were known to be variable in accuracy. I then checked some of mine and found the variation I mentioned. The one collet I use a lot has the least runout - about
0.0004", but the others, which I only use occasionally, had runouts of around 0.0008" - 0.001", with the 1/2" one being especially bad at
0.004" out.. I trusted them to be accurate and put the occasional assembly inaccuracy down to myself :-)
I might try and get Myford to replace them but they might suggest that a thirty year delay in complaining might be a bit too much, and I might have to spend a lot of time cherry picking the best of a bad lot :-) It'll probably be easier to get an ER25 nose and collets from Chronos :-)
Just coming back to this subject a week or two later, I got an ER25 adaptor for my Myford ML10 from Chronos and things are not too good. The fit between the holder and the register are what might be termed a gentle, rattling fit and I'm getting a runout of about two to three thou at the nose of the fitting. I'm not sure whether to blame the fitting or the register on the mandrel :-)
I'll have a word with Chronos and see if they have any at the tight end of the tolerance. :-)
Mine was a definite loose fit on the register. Just today, to be sure that the fault was not in my equipment, I took the spindle from my ML10 to another model engineer to check the diameter since I have no micrometers large enough. The register checked out to exactly 1.25" and was the same as the register diameter on his Super 7, and the Myford nose on his Rishton mill. As you would expect, the collet adaptor was a loose fit on the Super7 and the Rishton.
We did try to measure the bore of the collet adaptor, but were not too sure that we could do it accurately, but it looked to be about 1.251" in diameter. I've emailed Chronos to see what they can do.