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Smart & Brown 1024 Coventry drive clutch adjustment?

sandiapaul

Titanium
Joined
Mar 19, 2004
Location
Princeton, NJ USA
I have been using my S&B 1024 for awhile now and I have developed some slippage with the Coventry Tool Matrix drive. It has tow speeds and I have mainly used the low range. When I put the machine back together the drive seemed to function fine so I didn't mess with it. I have taken pretty decent cuts with no issues up till about a month ago. Now it stalls with very light cut on some 6" OD cast iron parts I am cutting. The input shaft is spinning but the output is not. The lathe has had very minimal use, seems odd for this to just crop up.

I looked at some posts here about a similar clutch but it hasn't really helped me. Can someone shed some light on exactly where you put the feeler gauge when you adjust it? The instructions and the diagram are not that clear. I am attaching some pics.

Any help will be appreciated as the machine is currently useless and a job is siting in the chuck now!

Thanks,
PaulMatrix box.jpgClutch.jpg
 
Once I'd adjusted a few of these clutches I never bothered with the feeler gauges. I went off " feel ". When you throw the " forward " lever over the clutch should engage with a nice positive click.

What is the "reverse " mode like ?

Regards Tyrone.
 
I was hoping you would respond! So this is not fwd and rev, it is a low and high speed. There isn't a "click" its more lumpy. Should I just keep playing with turning the knurled ring until I get something good? Is turning the ring toward the clutch plates tightening it?
 
Should I just keep playing with turning the knurled ring until I get something good? Is turning the ring toward the clutch plates tightening it?

Surely. You can ALWAYS back-off, yah?

That little experiment should let you ascertain right quickly and easily if there is even enough facing material LEFT to be useful. We are ass u me 'ing it hasn't been doused in K-Y Jelly, Moly-D, nor Astroglide?

:)

If "No Joy"? (the adjustment, not the lubricants).

THEN it must come out, apart, be put back to rights.
 
"We are ass u me 'ing it hasn't been doused in K-Y Jelly, Moly-D, nor Astroglide?"

Ummm so it runs in an oil bath, so its pretty well doused. Is there a way to tell if there is facing material left without pulling it out?(aside from adjusting it to where it works properly?)
 
"We are ass u me 'ing it hasn't been doused in K-Y Jelly, Moly-D, nor Astroglide?"

Ummm so it runs in an oil bath, so its pretty well doused. Is there a way to tell if there is facing material left without pulling it out?(aside from adjusting it to where it works properly?)

The PROPER oil is what was meant, in case you are not "personally familiar" with the other slippy stuff!

Seriously. Clockmaker of my employ was used to tall clocks coming in doused in automotive motor oil or Vaseline, and DID get one lubed-up with K-Y Jelly! What a HOOT when he went-off over THAT one!

:)

Meanwhile.. I still have a tiny Graham "ring drive" that wants "traction fluid", not gear oil. Same again with modern-day "CV" transmissions.

So.. an INADVERTANT change to the oil bath lubricity characteristics IS at least a "possibility" when such a change occurs as suddenly as you report this one has?

Gots to rule that out, yah?

As to facing thickness:

You might wanna put a camera or phone on the end of a "selfie stick" take a whole BUNCH of foto shots down in there, get 'em onta your screen, discard the blurs, wrong aim, and bad lighting ones.

One or two out of three dozen happen to have good lighting and focus aimed in the right place?

You'll have a klew how much facing is left to work with, and not have tore up your bod getting the klew.

Full-motion video mode, you can even set up to monitor the shifting results.

Gots us "modern technology", already paid-for, no need of 35 mm film and processing time?

May as well put it to work, yah? Cheap enuf. FAST enuf. Beats guessing. No need to even "post" it - or MUCH of it - here.
 
I was hoping you would respond! So this is not fwd and rev, it is a low and high speed. There isn't a "click" its more lumpy. Should I just keep playing with turning the knurled ring until I get something good? Is turning the ring toward the clutch plates tightening it?

Yes, turning the knurled ring towards the clutch ( normal thread rotation ) tightens the clutch. Back the knurled ring off carefully until the clutch goes in easily. Then advance it until the clutch goes in with a nice positive clunk/click.

Do both clutches have the same feel ?

Regards Tyrone.
 
Have you verified that the clutch operating mechanism is in good order and correctly adjusted?

Smart and Brown had an unfortunate habit of being occasionally over clever with the controls and levers necessitating rather precise adjustment for proper operation. Fine until "someone" goes on the fiddle. If my reading of the parts book is correct it could be awfully tempting to tweak the operating link if following the clutch instructions isn't immediately satisfactory. My Mk1 parts book copy has some cryptic hand written notes basically given the same advice as Tyrone.

I thought I had an electronic copy of the Matrix clutch manual hoovered up from the internet some years ago. Unfortunately the scan resolution was so low as to make the text unreadable and the diagrams very hard to follow. I can send it over if you think it might be of some use.

Clive

PS (Had a high old time properly sorting the direct drive engagement on my 1024 VSL which had been "fiddled with", apparently by a garden gnome. And that is just a simple sliding dog ring affair.)
 
I have had the same experience as Tyrone with these gearboxes. They work well when they are properly adjusted, then you can leave them alone for years. The linkage from the gearbox to the control lever at the front of the lathe can have some wear which makes the engagement feel less crisp. This doesn't matter usually because you adjust the clutches until you feel a light snap into engagement. It is difficult to operate the lever at the front of the lathe and adjust/watch the engagement of the clutches at the back, so you might need a helper. Of course the whole gearbox cover needs to come off to make the adjustments; these lathes are not noted for easy maintenance.

One thing to be careful of with these gearboxes. They are designed so that you can switch speeds on the fly - no need to stop the spindle. BUT they are not intended to be used as a general purpose spindle clutch, so if you feather the engagement into a very heavy cut, that will probably cause premature wear to the clutches. This is not explicitly mentioned in the manuals as far as I recall.

The 1024 uses the two speed gearbox case as the oil resevoir for the whole headstock and associated gearing. There is a circulating pump and a filter for the whole system. You must use clean oil of the correct viscosity and a filter in good condition. The sight glass on the front of the headstock should show a strong flow of oil almost as soon as the spindle starts, although you may see a few bubbles for the first few seconds. The oil should appear light golden colour through the glass. If you don't see this behaviour you need to check through the fairly complicated lubrication system and sort it out. If the oil is too heavy or dirty I would imagine that the clutches could have a problem and even worse the very expensive spindle bearings. The oil in your gearbox looks a bit dark, but that might be just the camera. Have you changed the oil?
 
Thanks for the replies!
To answer a few questions:
Oil was changed and old purged out, new oil of the correct type was added and it is perfectly clean and clear now. This was about 2 years ago and its had very little use.

So this "clicking" into position. After MUCH playing around with the the rings I got it to click into place. I have to admit this was the first time ever this happened. Before it would come to the end of travel but nothing happened. Now there is a defined "click". So that made a difference!

However, now I have the problem that the two extremes of the travel of the lever are not at all even, and the fast position is so far off that the spherical knob hits the feed selector knob!

How should I center this? Adjust the mechanism that leads from the lever to the box? I purposely did not alter any of that when I took it apart and reassembled it know that it might change things.

So progress, but not out of the woods...
 
How should I center this? Adjust the mechanism that leads from the lever to the box?

Ah.. that might be why it IS adjustable?

:)

Side note, but just for giggles... and "CCC" - Clever Coventry Craftsman... I've had a life-long habit of adjusting auto steering so when the road wheels were tracking dead-nuts "on line of march", the STEERING wheel favored my way of resting an arm for cramp-free long-distance driving.

Enter my "new to me" 2005 Jaguar XJ8-L.

172 MPH-capable, 150 MPH or so "governed" bugger's "brains" have a progressively more insistent self-centering assist built into the steering system that gets more aggressive with speed. Sort of a fly-by-wire non-linear substitute for NON velocity-adaptive mechanical "castering" effect.

Oops! I did say "Coventry"?

Can't fight THAT!

Hadda change my "grand touring" posture, and rather late in life.

At least when you re-set your shift lever, the "Smart" part of the lathe won't offer to "Brown" your smalls and Connelly hides by trying to run your aluminium-clad ass into an unpretentious, but stolidly indifferent steel guardrail at full-gallop whilst you are adapting to the "new normal"!

:)
 
Yep. Adjust the link rod for near equal movement each side of central. Page Nineteen in my MK1 parts manual pdf gives a nice diagram of how the arms lie. Central, rest position shown I think.

Operating arms are not parallel to the gearbox shaft in the position shown in the parts book. About 10° off by the looks of it. You need to get that angle right for it to work properly. Sounds like someone has been in there without access to diagrams or proper instructions and after failing to get the clutch adjustment correct resorted to playing with the link length adjustment.

At least the arms are keyed on. Looks as if the keys and keyways are at 90° to the line of the gearbox shaft. Failing inspiration or better information I think I'd start there.

Clive

Picture of the page from my manual.

Gearbox control B&W.jpg
 
Thanks Clive. As i said I had that all apart but didn't mess with the settings, now I will have to!
After spending a LOT of time in that small area I'd love to go back in time and have a good talk with those that designed it! If there was even as much as 1" more space all around things would be so much easier to work on!

I will mess with the linkage this coming weekend.
 
Indeed.

I'm convinced that the first tools issued to a new hire on the Smart & Brown assembly line were a big shoehorn and hefty prybar.

Reckon standard practice was to hang the motor up in the air and build the lathe round it. Seems to apply to all models.

Allegedly pulling the three speed motor and gearbox out of a Holbrook C10 is even harder.

Clive
 
I made a new motor mounting plate when I converter my Mk1 1024 to inverter drive. That meant a lot of time getting all the fixing holes in the right places since the new motor was an entirely different shape and I wanted to keep the original flat belt drive. I must have taken the motor/plate in and out three or four times in doing this job. Even with a wooden platform made so that I could slide stuff around I was totally wrecked by the time I finished. The position is ridiculously difficult. You are lucky to get this job done without dislocating something or crushing a finger, and it all needs to be done lying on the floor.

It is worth it in the end. They are a lovely lathe.
 
Indeed.

I'm convinced that the first tools issued to a new hire on the Smart & Brown assembly line were a big shoehorn and hefty prybar.

Reckon standard practice was to hang the motor up in the air and build the lathe round it. Seems to apply to all models.

Allegedly pulling the three speed motor and gearbox out of a Holbrook C10 is even harder.

Clive

They grow them in situ from a seed.

" Matrix " clutches are good once you get them set up right.

Regards Tyrone.
 








 
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