Super7 Spindle run out opinions

[chrisemParticipant @chrisem]

Howard. I have spent pretty much my entire working life rebuilding machine tool spindles. In a temperature controlled environment. And I’m good at it.

In retrospect, I suppose I should have asked: in the experience of other super 7 owners, would you expect be able able to put say a piece of 1/4” bar in a 1/4” collet on a super 7 and it have better run out than sticking it in a 3 jaw? As it stands, the answer to that is no on my one, and I was a bit surprised. In the end, once I am happy that the main spindle bearings are good – and they seem to be, and there really is an error on the taper – not just something weird going on, I will bore or grind it.

Cedric – that flange mount collet chuck is a really good idea 🙂

Sorry -,I’m a bit grumpy as it’s nearly Christmas.

 

[chrisemParticipant @chrisem]

Please don’t think I’m not grateful for all the advice and input above by the way.

[cedric 1Participant @cedric]

I’d apply a thin thin layer of bearing blue (non drying) to a  known good MT2 taper shank and then have a real good look at any high spots in the spindle taper and then dress them down.

Seems unlikely that if your spindle and bearings are ok, the tapered hole could mysteriously move and become out of true. But it is very common for this taper to suffer bruising and burring over 50 years of use and abuse.

 

[howardbParticipant @howardb]

The headstock spindle on the S7 has always been described as hardened.

While the ML7 spindle is known to be soft-unhardened

How hard? I don’t know. I’m not going to go the workshop and attack mine with a file.

[Author]

Posts