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Drummond / Myford M Headstock Bearing

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James Jenkins 129/04/2017 10:37:00
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125 forum posts
Hi all,
 
I have eventually got around to putting the flat belt pulleys in my longbed Myford M, so that I can replace the standard Drummond one on the treadle stand.
 
I have got the headstock apart and removed the thrust bearing from from behind the left hand bronze bearing. However, on inspection the trust bearing case has been crushed somewhat on one inner edge, trapping three of the balls which now have flats on them. Clearly this was not the right bearing for the job, but obviously I don't really know what the correct one is. It's been suggested that a roller bearing such as this one: **LINK** would be a good fit?
 
Just as an aside, I see that some people use two thrust bearings. Not found definite information on this - such as where the second one goes, but it seems to be quite popular
 
Any advice?
 
Kind regards,
 
James
 
MABEL & CO
 
Establishing an organic tweed weaving studio on the Suffolk Coast.
 
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Edited By James Jenkins 1 on 29/04/2017 10:41:13

geoff walker 129/04/2017 13:36:35
486 forum posts
186 photos

Hi James

Go to the simplybearings.co.uk website

The bearing you need is FT 3/4 Imperial thrust bearing 3/4 x 1.313 x 0.281.

This bearing is the same size as the original drummond spindle thrust bearing.

I would recommend adding the extra bearing as this eliminates end float of the spindle.

For details of this bearing and how to fit it go to the drummond user site and in the files look up "Eugenes bearing dodge".

Eugene explains in detail what to do and gives you the part number for the additional bearing, also supplied by simply bearings.

Hope this helps geoff

David George 130/04/2017 18:07:12
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1808 forum posts
503 photos

Hi James

I have done the Mod and fitted the extra thrust bearing NTA1625-TRA1625 from Simply Bearings and it is as straight forward as just fitting it between the bronze bush and spindle at the chuck end as it fits straight into the recess.

I have also done a few other mods like a quick change toolpost and a proper saddle clamp which clamps the saddle to the main way and not pull the saddle to the rear if you use the bolts to the back of the saddle. see attached pictures and if you look in my album there are some other pictures etc. And if you want any further information send me a PM.

David

slideway clamp 3.jpg

Myford Lathe

slideway clamp 4.jpg

geoff walker 130/04/2017 19:21:03
486 forum posts
186 photos

Hi David/James,

David I am intrigued by your bearing mod. The early drummond m types (1921-24) had the spindle thrust bearing at the chuck side of the right hand main bearing behind the flange on the spindle, so nothing unusual in your mod.

I assume you have omitted the original thrust bearing which locates on the spindle on the inside of the left hand main bearing. Would that be right as it would seem impossible to adjust both bearings simultaneously when tightening the adjustment nut on the end of the spindle? Or am I missing something?

The saddle lock looks good, the rear saddle lock can be pain to use especially when the cross slide is in overhanging at the rear. Can you add some more details to your sketch? Is the lever connected directly to the bronze bush?

cheers geoff

David George 130/04/2017 22:31:11
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1808 forum posts
503 photos

Hi Geoff

I kept the original thrust bearing in place as when I checked the clearance it was an exact gap size for the new bearing only giving two or three thousands of nip on the new bearing. Also the handle for the saddle lock is not connected directly to the bronze clamp, angled and a slide fit but it is just a length of screwed rod inserted into a indexable handle so that you can position the handle where you like radially. Bought from ARC EUROTRADE part No 084-013-00063.

David

geoff walker 101/05/2017 11:07:48
486 forum posts
186 photos

Thank you David,

That's good information. I intend to service the headstock this summer so I will see if your mod can be done on my M type. Always thought it was logical to have the main spindle thrust bearing as close to the business end as possible.

Just ordered a handle from arc euro, definitely do that this summer as well.

cheers geoff

Ady102/05/2017 10:55:48
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5067 forum posts
734 photos

I got both front and rear this AM for less than 20 delivered from simply bearings

Might be a while before I fit them but well worth doing if you plan on hanging on to your Drummond M series for future years

James Jenkins 104/05/2017 16:46:44
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125 forum posts

Hi all,

I am so sorry, I always click "Email me replies" and as nothing had come through assumed that no-one had any experience of this. All very helpful information - so thank you!

I struggle to get on to the Drummond Group website, although I am an email member. However, it seems very simple, so hopefully I can do it without needing to.

As I say, apologies for the slow reply and thanks for all the info.

James

Ady105/05/2017 02:58:46
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5067 forum posts
734 photos

Arrived today, fitted it tonight, (boys and their toys eh) only used very mild preloading which I presume is correct

Runs smoother but the real test will come later when I put it through its paces

edit: the back of my spindle shoulder is not square , it's slightly tapered so all the loading is going up through the thrust washer from its internal diameter point to the rollers, I would prefer it if the shoulder was square but we shall see

The rear bearing uses a similar system, but with a much thicker washer which is less prone to distortion under load

Edited By Ady1 on 05/05/2017 03:21:33

Ady105/05/2017 09:47:30
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5067 forum posts
734 photos

Chucked a bit of 15mm and took rough 0.5 mm cuts with ease, there is a noticeable increase in the amount of power available for the cut with this mod, I'm a happy bunny.

James Jenkins 105/05/2017 11:11:44
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125 forum posts

Hi all,

This all sounds very good, so excuse my slowness but if I am reading it correctly:

NTA1625-TRA1625 on the inside of the bronze bearing at the chuck end, between bronze bearing and the back gear plate (with the main shaft through).

NTA1220-TRA1220 on the inside of the bronze bearing at the change wheel end, between bronze bearing and the main drive pulley (again with the main shaft through).

Is this correct?

James

geoff walker 105/05/2017 13:31:29
486 forum posts
186 photos

Hi James,

On my lathe I have the standard original thrust bearing and an additional needle roller thrust bearing. Replacement for the standard bearing from simply bearings is FT 3/4 imperial thrust bearing. (0.75 x 1.313" x 0.281"

The needle roller bearing is fitted on the spindle on the left hand side of the left hand main bearing, (gear train end). The part number for this bearing from simply bearings is NTA1220 with 2 TRA1220 washers. (0.75" x 1.25" x 0.1381".

With both bearings in place it can be seen that by by tightening the adjustment collar you will simultaneously adjust both bearings. They can be lightly loaded to eliminate any end float of the spindle which is the reason for fitting the additional bearing. End float is common cause of "tool chatter" so eliminating it is clearly a good idea.

David's idea was to add an additional bearing at the front. I have no experience of this mod so I am unable to comment. I can say that my mod (Eugene's idea) is certainly worth doing and improves stability.

cheers geoff

Ady105/05/2017 14:58:17
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5067 forum posts
734 photos

NTA1625-TRA1625 on the inside of the bronze bearing at the chuck end, between bronze bearing and the back gear plate (with the main shaft through).

No, it goes on the thrust side, which is on the outside of the bearing housing at the chuck end, between the rear shoulder of the spindle nose and the castellated nut

Hopper05/05/2017 23:57:44
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6200 forum posts
321 photos
Posted by Ady1 on 05/05/2017 14:58:17:

NTA1625-TRA1625 on the inside of the bronze bearing at the chuck end, between bronze bearing and the back gear plate (with the main shaft through).

No, it goes on the thrust side, which is on the outside of the bearing housing at the chuck end, between the rear shoulder of the spindle nose and the castellated nut

You might want to put a cover over it to keep swarf out in that zone. I made such a cover for mine, just to keep oil from flinging out everywhere, out of the top section of a stainless steel solar garden light. Pushes right on over the castelated nut and has a solid end that I bored to fit the boss on the chuck back plate. Not a hermetic seal but stops flying oil and debris for the most part.

One of these from the local hardware shop for two dollars. The top piece is the exact size to push firmly over the castellated nut. Then bore a hole straight through the solar cell unit on the top to fit the spindle nose/chuck boss.

Ady109/05/2017 01:14:23
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5067 forum posts
734 photos

It's made quite a difference to the chuck stiffness and the amount of power to the cut, vibration only seems to come from the tool itself if I push too hard

This one has other possibilities if you have "a machine tool that turns" IMO

This kind of Mod can improve the performance of any spindle on any machine if you can fit it, I think it could be because it moves the levering action further away from the centreline of the spindle, giving you the performance of a bigger spindle size, as shown by the right hand diagram

bearing mod.jpg

I'm thinking in particular if you wanted to make a small milling attachment for a lathe cross slide, theoretically this kind of mod could seriously improve performance

Edited By Ady1 on 09/05/2017 01:34:26

Hopper09/05/2017 01:29:50
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6200 forum posts
321 photos
Posted by Ady1 on 09/05/2017 01:14:23:

It's made quite a difference to the chuck stiffness and the amount of power to the cut, vibration only seems to come from the tool itself if I push too hard

This one has other possibilities if you have "a machine tool that turns" IMO

This kind of Mod can improve the performance of any spindle on any machine if you can fit it, I think it could be because it moves the levering action further away from the centreline of the spindle, giving you the performance of a bigger spindle size, as shown by the right hand diagram

Ady, can you post a pic of how you have done this? I'm trying to get my head around how the thrust bearing flat washer sits on the castellated nut and can't quite picture it. (As Curly from the Three Stooges said "I tried thinking about it but nuttin' happened"

Ady109/05/2017 01:47:42
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5067 forum posts
734 photos

It's the bit of metal behind the spindle shoulder and fits quite beautifully into the recess of the castellated nut

dscf3085.jpg

dscf3089.jpg

Ady109/05/2017 01:55:06
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5067 forum posts
734 photos

I've bought another front bearing tonight btw, this has legs if you're a drummond dude

The front washer is tight on the spindle because the spindle tapers slightly towards the back of the spindle nose, this helps to transfer the load of the cut to the roller bearing sitting behind it

For an off-the-shelf bearing it's an amazing fit

Edited By Ady1 on 09/05/2017 02:09:22

Ady109/05/2017 09:52:17
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5067 forum posts
734 photos

Perhaps it allows a higher pre-load between the two headstock housings, the original setup had the spindle simply sticking out of the front bearing and all the roller bearing work being done at the back.

Hopper09/05/2017 10:42:37
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6200 forum posts
321 photos

Aah, CLUNK, penny drops. The bearing fits inside the nut and bears on the nice flat end of the actual bronze bearing. Looks like a nice fit.

Although, that would put axial cutting forces on to the tapered bronze bearing, pushing in the direction to loosen the bearing in the taper and the end loading would be taken by the threads on the end of the bearing and the castellated nut. Will be interested to see how they stand up over time.

Taking .5mm cuts? Mine will take .100" cuts (2.5mm) with the standard thrust bearing all day long without drama. So maybe the extra thrust bearing is making up for some other wear on your lathe? I do keep my headstock bearings good and tight (just free to turn) and bed is in very good nick. Maybe I am lucky with this old machine.

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