Super 7 headstock bearings.

[LambtonParticipant @lambton]

My Super 7 manual lists the rear head stock bearings as RHP 7205

These are angular contact ball bearings but the reference 7205 alone does not specify the angle of contact. The most common ones available have a 40 degrees contact angle denoted by a letter B after the 7205. Other angles are listed such as 20 and 25 degrees but these do not appear to be readily available.

Can anyone please tell me the what angular contact degree Myford originally fitted.

[LambtonParticipant @lambton]

[Keith LongParticipant @keithlong89920]

According to my copy of the RHP bearing replacement handbook the 4 angles available are 15, 20, 30 and 40 degree. 40 degree is denoted by suffix "B", 15 degree by "X2", 30 degree by "X4" and no mention of a suffix for 20 deg. It also states about the angles that "the two most popular are 20deg and 40deg. RHP adds a suffix B to deote the 40 deg series."

Looks like it's well odds on that you need the 20deg version which is the plain 7205.

The safest is to look at the bearing thats in (if possible) and go by the full code on that, it should be visible on the outside face of the outer ring.

Keith

Edited By Keith Long on 18/03/2013 12:28:52

[NJHParticipant @njh]

Myford list the bearing in the super7 spares section of their website – just to the right of your post!

Cheers

Norman

[John CParticipant @johnc47954]

I wanted to replace the angular contact bearings in my Super 7 headstock. The

bearings did not seem unduly worn, but as I had the headstock apart it seemed a

good idea. On removing the old bearings one was stamped RHP 7205 and the other

was R7M LJT25.  The RHP bearing was missing a ball! The Myford description in

the manual is RHP 7205. Searching under angular contact bearings suggests that RHP bearings without a suffix have a 20 degree contact angle. I could not source any of these through a number of bearing suppliers but was able to order a pair through Myford (RDG) sales. They duly arrived and are marked NSK 7205 BEAT 85. The B suffix on many bearingsindicates a 40 degree contact angle. I asked Myford (RDG) directly if these were from the Myford (Beeston) stores and the answer was yes. I also spoke toNSK (UK) who took over RHP. They confirmed that the B suffix indicated a 40degree contact angle, and that they had been supplying Myford with these bearings since 1995.

So it would appear that either the spec quoted in the handbook I used was wrong
or incomplete, or that Myford at some point changed from 20 degree contact to 40

degree. Research into the two angles indicated that greater angles are better

at resisting axial loads – which I have assumed is a trade-off to being less

good at resisting radial loads. However, using some of the formulae provided by

the bearing manufacturers would indicate that the bearings are relatively

lightly loaded, thus the effect of the change of contact angle would not be

significant anyway.


The 7205 bearings were used in MG axles, where the radial and axial loads were

probably much greater than in a lathe headstock.



The exact same bearings are available from RS components…..at a significantly

cheaper price!!



Rgds,

John

Edited By John Corden on 18/03/2013 12:39:36

[LambtonParticipant @lambton]

NJH, Thanks but I had already looked at the "current Myford" Website also that of Lathe Spares and those of various bearing suppliers. My question is what was the specification of the bearings used by the makers i.e. Myford Nottingham.

John Cordon has provided some evidence in answer to my question.

I guess in practical terms it does not matter what angle of contact is used in such a light application but I would prefer to use the original specification bearings if possible.

[sparky mikeParticipant @sparkymike]

As a matter of interest, could the angular contact bearings (ball type) be substituted for Timken taper bearings (taper roller type.) on the Super 7 ? Are there pros and cons for or against this.

The Timken tapers would I assume have more drag than the ball type.

Mike.

Edited By sparky mike on 29/03/2013 15:16:34

[KWILParticipant @kwil]

Mike,

Super 7 does use angular contact ball bearings as per above discussion. Are you asking whether taper rollers can be used? The answer is yes with some modifications to the clamping rings. See MEW article.

Edited By KWIL on 29/03/2013 15:57:00

[sparky mikeParticipant @sparkymike]

Hi Kwil,

Did a search but could not find the article . Any idea of the heading to put in the search box?

Mike.

[KWILParticipant @kwil]

Improved Bearings for the Myford Super 7 Headstock was the title.

[KWILParticipant @kwil]

Mike, MEW 175

[Brian WoodParticipant @brianwood45127]

Hello Mike,

I made the change to taper roller bearings. As KWIL says, you need to alter the clamoing rings to accept the wider bearings. I bought spares from Myford and modified them before I stripped the lathe.

It is a worthwhile mod in my opinion

Brian

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