No such luck unfortunately.

Sorry yes though, it's end float of course! I should know by now from messing with car engines & cranks etc.

So the end float is about 42 thou, with no means of adjusting this unless you make shims yourself and that's not easy for me to do, because the collar only has a slightly bigger diameter than the screw shaft itself, so it's like a washer but with a small difference between the hole diameter and the outside diameter.

As it happened I began measuring various things to find a suitable shim source, and found some clear plastic packaging for Woolies dust masks of all things. 35 thou thickness precisely - perfect, and easy to cut with scissors, just I doubt it will last all that long.

I've kept the rest of it so I can make more if need be in future.

I would LOVE to fit some sort of thrust bearing or ball race but I'm no way confident enough about machining out the recess to fit something just right. I'm too inexperienced not to balls it up!

Here are some pics to show what's what:

Old collar thickness:


Old recess depth:


New collar thickness:


New recess depth:


As you can see from the numbers that gives a relatively huge increase in endfloat, and I think that's really poor. Like I've said, yes you can learn to work around backlash and probably should do as a skill to learn, but it's not the point. You don't buy parts to improve a machine and have them make a particular tolerance of it 4 times worse!

Can you imagine if you bought a new porsche*, then bought a sports upgrade package from the porsche dealer that made it worse? I doubt you'd be happy to accept it and I don't see why this should be any different. I'm not sending it back since I've fixed it, but I think Sieg ought to either machine it with a better tolerance, or else supply a shim package or a bearing with it.

*Arbitrary car since I'll never have the money to buy one and would probably get something else anyway.