Myford ML7 headstock restoration: bearing scraping, testing and spindle alignment

[@neil1058]

Nice Jan. I'm about 2 weeks away from the headstock. The bed surfaces are progressing well at the moment.

[@jansverrehaugjord9934]

Sounds good! It is a bit of work, but rewarding to see how it progresses

[@Sigmatechnica]

Always found that bearing arangment with the ball thrust bearing rather odd

[@somebodyelse6673]

I can follow the vertical corrections and shim compensation. I don't understand how horizontal correction is done. Because cutting forces do apply some side load, there must be wear in that direction also. Once there is wear side-to-side, wouldn't it take an excessive amount of material removal to move the spindle bore down to expose fresh side bearing material? Maybe some side gap is simply disregarded? Treat the bearing halves sort of like V blocks, with enough lower and upper contact to control spindle position?

[@jansverrehaugjord9934]

Hmm.. to my knowledge/experience (which isn't all that great all thing considered) this is also "scraped out". At least, I have managed to get the bearings to cover radially. That said, an ideal bearing like this shouldn't cover 100% or be exactly circular. The theory, as far as I have understood it, requires you to scrape segments/pads and/or make the inside into 4 (or more) flats. On these small and soft bearings I don't bother with this (and I think Myford didn't either).

[@HM-Projects]

Complex restoration! Do people retrofit these with tapered bearings ?

[@jansverrehaugjord9934]

Just what needs to be done :) Not that I know, Myford offers a replacement kit for the now no-longer-sold white metal bearings. This consists of a similar constructed bearing set, ie. parallel and spilt, in bronze with a hardened spindle. The Myford Super 7 that was designed after the ML7 has a different spindle/bearings, where the front bearing is a conical sleeve ie. tapered.

[@svenhoftmann7663]

Top videos you make, not to mention the work, which basically deserves a lot of respect 👌👍. I also have an ml7 and I'm also scraping the bearings, I have the problem that I can't play the side of the spindle get minimized, maybe it's due to my spotting process or I have to go down further?! Can you tell me which spotting color you use? best regards Sven

[@jansverrehaugjord9934]

Thnks for the nice comments! Regarding the spotting color, I normally use a product called Canode, which is water soluble, usually the blue color as well as a yellow contrast color. However, you may use other products/colors.. not really of importance as long it gets the job done ie. makes the high spots stand out so you can see and hence scrape them. Not sure what is the problem in your case, but if you have used the template spindle and only get it to spot in the middle, it is probably to shallow, yes. Then you have to go deeper. If you have an email or use messenger we can discuss further there

[@svenhoftmann7663]

yes by e-mail is better, where can I find your e-mail address? Kind regards Sven

[@jansverrehaugjord9934]

@@svenhoftmann7663 jshaugjord at gmail .. or a PM