Myford Super 7 headstock bearing replacement

[AStroudParticipant @astroud]

I am planning to replace the 2 angular contact bearings, they have started to be a bit noisy. Whilst removal of the spindle looks straightforward I wonder about the removal of the 2 bearing races.

How are they removed from the casting? Do they come out as a pair towards the front or singularly from each end ?

Can they be drifted out or do I need to have some rings and studding available to pull them out presumably only as a pair.

Same question when fitting the new bearings, are they pulled in as a pair ?

Finally is using 2 taper roller bearings instead of the angular ball type a solution to a non existent problem?

thanks, Andrew

 

[noel shelleyParticipant @noelshelley55608]

Use good quality AC bearings and follow the instructions Myford published to the letter, There out there on the web. You will need a C spanner to set up the 2 bearings. Good luck. Noel

[Dave WoottonParticipant @davewootton]

I’ve done the taper roller conversion that was at one time available on the site home page, and was published in M.E or MEW, carried out as the machine had been long term stored in less than ideal conditions and some slight corrosion was visible on the raceways. Didn’t really notice any major difference in performance over the standard arrangement, but did find it very easy to adjust the bearings, always found the standard bearings fiddly to adjust. It was an interesting little project, the published instructions were followed to the letter and it worked out well. Have now got a later power X feed model with the original bearings and would do the conversion again if the bearings needed replacement, but all the time the standard bearings are ok (probably see me out!) wouldn’t bother. One reason for considering the change in the first place was that I ordered a set of standard bearings advertised by the main supplier of spares and the bearings that arrived were not the quality make pictured on the website advert, but unbranded , so were returned. I was able to get branded quality taper roller bearings off the shelf locally from a trusted bearing supplier.

Just had a google and the article from MEW is still downloadable and was written by Ken Willson, worth consideration.

[AStroudParticipant @astroud]

Thanks Dave, I have the ME article and the conversion looks simple to do.

Whilst  the instructions in the O&M manual cover adjustment they do not mention replacing the bearings, I would be interested in how you removed the old bearings and pressed in the new.

[noel shelleyParticipant @noelshelley55608]

Angular contact bearings were used for a purpose and were seldom any trouble and I would be loath to change them. The important issue is the light preload needed and though many shy away from the task once you understand the idea it is simple to do and once this is arrived at then the front bearing is drawn back to a good fit running on it’s oil film. Test run and check that it does not run hot.

Removing the bearings, you loosen the cap head screw and undo the adjusting ring, remove the gear wheel, unscrew the 2 setting rings with a C spanner. The mandrel can now be freed and the bearings removed, use a brass punch if needed. Remember to fit a new A29.5 belt when doing this job. Good luck. Noel.

[Dave WoottonParticipant @davewootton]

Hi Andrew

It was  three or more years ago I did the conversion, can’t remember if the bearings were drifted out or more likely I wound them out with a simple spacer and studding cobbled up extractor, must have been easy as can’t remember doing it! I do always try to wind bearings and bushes out rather than drifting them if possible. The late Brian Wood, whose abilities and skill I have a lot of respect for was of the definite opinion that the taper roller conversion he carried out gave a definite improvement in performance, especially parting off. I can’t say I noticed any difference, but my S7 is mostly used at fairly high spindle speeds on brass fittings and the like, have a bigger lathe for larger work.

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