Roller Bearings for a Myford Super 7

[Neil WyattModerator @neilwyatt]

In response to a query from a forum member, here's a reprint of an interesting and useful 2011 article by Ken Willson.

**LINK**

Neil

[Neil WyattModerator @neilwyatt]

[Ex contributorParticipant @mgnbuk]

Logged in, MEW subscriber & can't access this Neil ?

Nigel B

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Nigel B on 23/02/2017 12:59:18:

Logged in, MEW subscriber & can't access this Neil ?

Nigel B

.

Working fine [for me] now, Nigel

… maybe Neil posted the note, before the link was activated.

MichaelG.

[Ex contributorParticipant @mgnbuk]

Sorry, this is Subscriber-only content…

No difference when I just tried again, Michael

Nigel B

[Neil WyattModerator @neilwyatt]

Nigel, I've sent you a PM.

I hadn't meant it to be subscribers only. I want those without subscriptions to see what they are missing

Neil

[Brian WoodParticipant @brianwood45127]

For those who might be considering the modification, I made the change to my ML7B as a direct result of this article and have no hesitation in recommending it to others.

​Bearing adjustment has not been needed since

Brian

[KWILParticipant @kwil]

Brian, Thank you

[Dick Ganderton 1Participant @dickganderton1]

Definitely well worth doing. However, there are a few problems with the drawings and part numbers in the article.

I have since found that the useless oil nipple on the rear bearing housing wasn't letting any oil through. I have replaced this with a brass oil cup that really does let the oil get through to the bearings.

Here is what I found. (I think it was later published in MEW.)

I have just completed the mods to my Myford S7 Headstock as described in Ken

Wilson's Article in the April 2011 Model Engineers Workshop.

I have never been able to get this machine to run on the top speed range or to

get the rear bearings to properly adjust to take end thrust when drilling with large

drills. This is in complete contrast to my previous, earlier S7, which spent most of

its life running at top speed with no trouble. Now I can run at top speed – I have

even tried it at twice top speed as I have a 3-phase motor fitted driven from an

invertor to give speed control.

However, I think that there are problems with the dimensions given for the

modifications to the two locking rings and the new spacer. The recess depth,

given as 3.4 – 3.5 mm (0.134" – 0.138" in understandable units) is not deep

enough to clear the inner race of the new bearings. I had to increase the depth to

0.140" to just clear the inner race – 0.144" would be better. It's very frustrating to

discover this when you have got the headstock in bits and no way to remachine

the rings! Fortunately, I had opted to buy new rings from Myford – the part

number is G2340 not G2430 as quoted in the article, order that part number and

you will get a driver plate – so I was able to put the headstock back together and

take the extra few thousandths off.

Having gone to the trouble to make a new spacer to the dimensions given in the

article, I found that with it fitted the front locking ring protruded too far into the

headstock while the rear one was so far into the housing that the C-spanner

could not get hold of the slots. So I put the old spacer back and everything was

OK.

It's definitely worth doing the mods as it now runs faster and quieter and is much

easier to adjust than with the standard ball races.

Dick G

[KWILParticipant @kwil]

Dick,

I am sorry you had the difficulties you describe. As stated in the article the bearing are metric and so I kept to those units (I too am an imperial person). Dyslexic fingers are the cause of the G number error in transcribing from the Myford parts listing.

As you had only one lathe you could well have tried the bearing against the modified locking ring whilst still in the chuck so avoiding any interference troubles, a long term held view of this hobby, never trust drawings!!

I am pleased, that in the end, you found it all worth while. Long may your lathe run well.

Ken Willson

[Author]

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