By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum House Ad Zone

Scraping and Shimming Myford Headstock Bearings

MEW 292 article

All Topics | Latest Posts

Search for:  in Thread Title in  
Graham Stoppani17/04/2020 10:52:59
avatar
157 forum posts
29 photos

Having read the above article I thought I'd check my bearings as described. The initial measurements taken at the nose showed pulling the chuck upwards gave a deflection of at least 3 thou while pulling down was less than a thou and backwards and forwards less than a thou as well.

Removing the bearing caps and the shaft for inspection showed the shaft to have very little wear. Likewise, although the bearing shells showed some wear marks they weren't in bad condition considering the age of the machine.

However, applying blue showed that the top of the front bearing was barely in contact with the shaft at all - that would explain the play only in the upwards direction. The blue had been applied with the shims removed and the bearings tightened until the shaft would not rotate and then slackened off until rotation was possible.

Here are a couple of pictures:

bearing caps.jpg

Here you can see the lack of contact.

bearing cap surfaces.jpg

This picture shows blue showing that the white metal bearings are touching, just, and not the bearing caps themselves when assembled without shims. It is also visible on the right side of the shell on the bottom of the picture that a recess has been milled along the edge of the shell. There is a corresponding milled edge on the other half of the bearing. (not by me)

Before I try to fix this, I'd thought I'd ask for your opinions of what to do and of any other things to test for. Thanks in advance.

Hopper17/04/2020 11:55:30
avatar
7881 forum posts
397 photos

It depends. If you have a small scraper and the skills, you could scrape the high spots down a little until you get a better reading across the full length of the bearing.

Don't tighten the bearing cap bolts down too much when doing this, it can squeeze all the blue out and create metal to metal contact that leaves no blue marks. And you only need to rotate the shaft about a quarter turn or so.

But the bearings do not look too badly chewed up so you may be able to simply remove about three thou from the shims and see how it goes as is. I might be tempted to try this first, seeing the smooth condition of the bearings -- at least from the photos anyhow.

Pete B

Graham Stoppani17/04/2020 12:51:01
avatar
157 forum posts
29 photos
Posted by Hopper on 17/04/2020 11:55:30:

It depends. If you have a small scraper and the skills, you could scrape the high spots down a little until you get a better reading across the full length of the bearing.

Don't tighten the bearing cap bolts down too much when doing this, it can squeeze all the blue out and create metal to metal contact that leaves no blue marks. And you only need to rotate the shaft about a quarter turn or so.

But the bearings do not look too badly chewed up so you may be able to simply remove about three thou from the shims and see how it goes as is. I might be tempted to try this first, seeing the smooth condition of the bearings -- at least from the photos anyhow.

Pete B

Thanks for the words of advice. I was very reluctant to start cutting away at metal, given that this is the first time I've played with white metal bearings. I do have a small scraper that I inherited but have never wielded it in anger before. I'll go and have another try this afternoon and let you know how I get on.

Steviegtr17/04/2020 15:21:50
avatar
2668 forum posts
352 photos

There is a guy on youtube who does this job in detail. Worth watching. Jan sverre Haugjord. **LINK**

You will have to search as he has done a lot of Myford rebuilds.

Steve.

Pete Rimmer17/04/2020 17:35:03
1486 forum posts
105 photos

Jan Sverre's videos are always worth watching. He isn't in it for 'likes' 'subs' or money, he just enjoys sharing his knowledge and helping people.

Graham Stoppani18/04/2020 05:57:05
avatar
157 forum posts
29 photos

Just taken a look at Jan Sverre's videos. Hadn't come across him before. Thanks for the 'heads up'.

Graham Stoppani18/04/2020 18:11:52
avatar
157 forum posts
29 photos

Having reassembled the lathe I now have less than a thou movement on the nose in all directions. However, I ended up not adjusting anything! All I can think is that the front bearing housing just needed tightening up a little rather than re-shimming or scraping. Still I'm not complaining as:

a) The shaft is now in spec for bearing play;

b) I got to learn more about my machine long the way.

Thanks Pete B for another interesting and useful article

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Sign up to our Newsletter

Sign up to our newsletter and get a free digital issue.

You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy

Latest Forum Posts
Support Our Partners
cowells
Sarik
MERIDIENNE EXHIBITIONS LTD
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest

 

Donate

donate