Thread: Fitting an ER 40 to an AL320G

Eskimo,

As Dave mentioned...the TIR is caused by the grub screws engaging the milled flats on the collet holder...........there is no runout on the housing/back plate as they are turned in the lathe it is fitted too.......the way of mounting the thing up initially is to work on the boss registration in reverse........ie, do your measuring up for the boss etc and then cut it out - when you have it close enough, remove it, turn it around and mount it with the marked holes....it will involve trial and error to fit the registration.....once that is sitting true then everything else you cut or mount to it from then on will be true to your own lathe...there will be no runout from your holder (assuming none in your spindle etc)

I did not use the 3 jaw in making it so I simply measured the registration on the 3 jaw while it was off the lathe and cut the plate to that fit.......

MK11 for me will involve the same process as above but cutting the ER taper instead of boring a recess and fitting a bought one and then threading the housing to match the ER40 nut......

One project leads to another and I have since made a verticle milling slide attachment to go with this on the AL320......it's a modified bought one with full rotation as distinct from some methods of mounting them --- can post that process if you are interested............Lee