Strange Noise from Myford Super 7+

Some help need I have a Myford Super 7 Big bore had little use, but used it is. I purchased it second hand last nov. it is 10yrs old. I have cleaned Oiled everything that should be. When I am using the Lathe it suddenly emmits a sound like when your parting off and it screeches.then it stops it only seems todo it when the clutch is driving the chuck. Yes the oil is in the spindle cups and oil is in the gear box the pulleys run on.. Any thought whe it might be comming from. Werst case in my mind spindle / back gear

HELP

Slipping belt?

Hi There
My ML7R had a no oil problem, inside the oil ways is a felt wick. The wick had dried out and did not absorb oil.

I replaced the wick and it was fine. The large bore may be similar.

You have to remove the mandrel to replace the wick but it was not a difficult job. I can't remember how I did it but I expect I followed the manual.

If the back gear is diengaged it should not be a problem.

Does the headstock front get hot?

I think mine did before I fitted the new wick.

regards David

David,

Did you change the flint as well ?

John S.

Yes the oil is in the spindle cups

...and it's being replenished regularly...

Otherwise no oil is getting through (aaargh)

Bob, does it do it on all speeds or only on high speeds? I have a S7 long bed purchased c1977'ish and had a problem on top speed--the bearing was too tight, Not sure if the big bore has a plain front bearing???

On mine I adjusted the bearing as per instruction book and it has been fine ever since -- will run contiuouse on top speed.

John

Bob:

I've had (have?) the same problem with a Connoisseur - I don't have a definitive answer as yet, but this posting will at least let you know that you are not alone! Apologies in advance for the length of this one.

On my machine, the spindle would slow dramatically, accompanied by the squealing noise. But knock out the clutch, and the spindle would rotate freely thereafter. The noise is the belt slipping - on my machine, I think (but can't be sure) that it was the primary drive belt that was emitting the noise, the spindle was siezing, but not always completely. In fact, I'm not sure it did ever actually stop completely of its own accord, as one's inevitable reaction was to knock the clutch out pdq.

It would do this every time I tried to run it from cold at speeds of say 1500 rpm upwards, but if I warmed it up gradually, it would behave itself. Then having done some work at say 2000 rpm, leave it for half an hour, then go back and start it at 2000 ... and the bloody thing would try to sieze again!

I've had the spindle out a number of times, and was surprised to find that despite Myford's much-vaunted scraping of the front bearing bush, the spindle was only contacting the rear half of the bearing, which did indeed show some signs of ... how shall I describe it ... well, wear, or rubbing, or slight siezing. I did give the bush a very gentle rub with 1200 wet & dry to clean it up, but that didn't seem to have helped. And yes, I was VERY careful to ensure that I didn't leave any nasties in there when I re-assembled it!

I adjusted the bearings several times, according to Myford instructions. Not the ones in the manual, but as more recently recommended by Myford. I've put a copy in a new album, Myford spindle adjustment. But I never seemed to absolutely cure the problem. So I decide to kill it or cure it - use the machine until it siezed solid, then at least I could identify exactly what was siezing, even if I did have to take it apart with a hammer!

I used it to do a lot of cast iron machining to convert my S7 to poly-vee drive on both primary and secondary drives, so it did a lot of heavy cutting (four castings, plus the original Muford clutch pulley), but never got above about 800 rpm. Since that exercise, it hasn't siezed once, despite being subsequently run up to 2500 rpm a few times! So the question is - did that heavy use 'bed it in' and eliminate the problem, or is it still there, waiting to appear again? I don't know, and it will take some time, and a lot of use, before I get any confidence that the problem has indeed gone away.

I'm tempted to take the spindle out again, and have a look at the bush. But I'm reluctant to do that whilst it seems to be behaving itself.

It turns out that poor scraping of the front bush is not unusual - I had to remove the S7 spindle to fit the poly-vee conversion and found that spindle had only been running on the front half of the bush for nearly 40 years! Machine made in the second half of 1975, been in my possession since new, and never siezed, even though it's spent most of its life on top speed. But there were some signs of distress in the bush, including one score line around the bush, but nothing on the spindle. As before, the score was removed with 1200 wet & dry, the machine re-assembled, the bearings adjusted as per the latest instructions, it went straight on to top speed, and was left to run for several hours. No problems with the S7, and it takes good heavy cuts without chatter, so the bearing adjustment is obviously not too slack.

None of which is of much actual help, I'm afraid. All I can suggest is that you pull the spindle out and inspect the front bush to check its condition, and the state of the 'precision scraping', see if you have the same features as found on my machine(s). Pay particular attention to the top and rear section of the bush, as this is the area that takes the belt and cutting loads. Then re-assemble and adjust the bearings as per the revised instructions.

You can easily check that the bush is lubricating adequately - clean the inside area of the headstock casting, adjacent to the bull wheel, then fill it up and run it, oil should run out down the headstock casting. Mine suffers from incontinence, there's always an oil puddle in the tray to the left of the headstock raisning block.

Oh, what belts do you have on your machine, vee or poly-vee?

One other snippet - I know someone else who has a Connoisseur, and he says that he never runs it at high speed from cold, always runs it up gradually, letting it warm up. I have never been able to find out exctly why he does this, he seems a bit cagey about it.... maybe he has the same problem? Or maybe he's a just member of the Royal Society for the Prevention of Cruelty to Myfords? It's not something I've ever found necessary with the S7, to which I have been unremittingly cruel over the years.

My experience with a S7 learned me that you must be able, when turning between centers, to use reasonable pressure from the tailstock on the headstock spindle without seizing it. If that is not possible and the spindle seizes under that pressure you have to adjust the back angular bearings to give the spindle a little more slack at the front bearing. These adjustments are of course very little and you make it easier if you mark the position of the adjustment rings on the headstock casting before you make changes. I have been learned that when a lathe or mill is used for the first time on the day, you run it for few minutes at its lowest speed without load, so all bearings have the oil they need. If that is still necessary with modern machines I do not know, but the I would certainly do it with a Myford.

At first I thought this was a similar problem to what I had with my 1326BH taiwanese lathe, but then I remembered that my trouble was in back gear, with the pullies running loose they ran dry, and seized, it was only then that I found the oiler, a grub screw at the bottom of one the Vs in the pully group. The bearing was OK, so reassembled, and oiled. Some interesting reading above. Ian S C

Hope this helps having had a similar problem I traced it be the clutch a small adjustment cured it ..

I have just brought into use a new Super 7 Plus bought in the Myford closing down sale. Actually, it was made in 2001 and run as a demo machine at exhibitions but appears never to have cut metal.

While checking it over, I was not pleased to find that the headstock spindle seems to be displaced to the left relative to the backgears. The bronze gear on the end of the pulley does not fully engage the larger of the two gear on the backgear cluster by about 1/8". Worse, the half moon on the spindle pulley lock in the bull wheel catches the larger of the two gears on the backgear cluster, which could bring the works to a sudden stop.

As a temporary measure, I have moved the bull wheel to the right to avoid the second problem but the side play in the pulley is now excessive. Can't go back to Myford now so I have to figure out a solution. Either a wider distance sleeve on the left of the pulley which means stripping out the spindle and ideally the use of another lathe, or altering the backgear eccentric which probably also means taking out the spindle. Has anyone else had this problem?

Andrew M

Hi Andrew

Email me direct and I will put you in touch with DagBrown.

regards David

Andrew Moyes wrote:

I have just brought into use a new Super 7 Plus bought in the Myford closing down sale. Actually, it was made in 2001 and run as a demo machine at exhibitions but appears never to have cut metal

Mine was very similar provenance - I bought the long bed Connoisseur that was displayed at shows. And a total dog of a machine it turned out to be! It had never been run, which was just as well, since it vibrated so badly that no-one who heard it run would ever have dared buy a Connoisseur! So it wasn't just the 'siezing' problem that I've had to deal with, to that we can add:

Rattling, eccentric and wobbling countershaft pulley, motor out of alignment, wobbling motor pulley, motor clamping arrangements rattling, main spindle pulley wobbling and rattling, leadscrew bent, tailstock out of alignment in two planes, various grub screws loose - to mention just some of them. Net result - the machine was unusable as bought. Overall, I've formed the conclusion that the demo machines were thrown together, never test run, and perhaps even never intended for sale. At least, not before they'd been back into works for sorting out.

I've stripped it so many times that I can now take apart the spindle, countershaft, clutch and motor assemblies in less than 15 minutes! At least that's made me very familiar with the components of a big bore spindle assembly.

The spindle cannot be displaced left relative to the headstock casting itself by more than a midges nudger, otherwise the spindle would lock tight in the front bearing bush.

Changing the distance sleeve won't make any difference to where the spindle sits, the only effect of making/installing a longer one would be to shift the angular contact bearings leftwards to achieve the correct spindle/bush clearance for the front bearing, and push the gear sleeve left as well, thereby affecting the mating of the gear sleeve with the tumbler gears.

The spindle pulley then sits and runs against the right hand edge of the distance sleeve - since this abuts and is clamped against a step on the spindle, the pulley will sit in exactly the same position, once the front bearing clearance has been adjusted.

You say: The bronze gear on the end of the pulley does not fully engage the larger of the two gear on the backgear cluster by about 1/8", by which I take it that you mean that the large cluster gear sits to the right of the pulley gear, and overhangs it by 1/8", running into the groove between the end of the gear teeth and the bull wheel drive collar.

So, since the pulley is more or less correctly located (it must be, unless there's something else drastically wrong, and I can't think what that might be), your problem must be that it's the backgear cluster that's displaced to the right. Since the cluster gear position on the eccentric shaft is fixed, the eccentric shaft must be displaced to the right.

Have a look at the backgear operating lever - it should sit close to the front of the headstock casting, and, of course, the detent should engage with the holes in the casting. Since anything wrong there would be immediately obvious, I guess it's ok, so look at the protrusion of the eccentric shaft from the operating lever - there shouldn't be any, it should be flush.

If it does protrude, that will be the problem, fortunately it's easy to fix. There are two grub screws securing the lever to the shaft, undo them - they're bloody awkward to get at! Then insert a flat bladed screwdriver into the top detent hole and twiddle it round - there should be a slotted head grubscrew down there, that fixes the longitudinal position of the eccentric shaft by engaging in a groove in the shaft. Loosen the screw, so that the shaft can move, but keep a little turning pressure on the grubscrew. Push the shaft to the left whilst gently turning the grubscrew against the shaft and you should feel when the groove gets to the screw as it will suddenly turn and enter the groove. Keep turning the grubscrew to fully engage it, but don't tighten it onto the shaft or it will prevent it from rotating. Then engage the gears with the spindle, as per the instructions in the manual, re-fit the handle and tighten the grub screws.

Now, if my analysis of the problem is correct (here's hoping!), the cluster gears should align correctly and you can re-adjust the position of the bull wheel on the spindle. There should be a little clearance to the pulley, the book says 0.005", but I've not found this to be critical.

But if it's not fixed, there's one other possibility that I'm aware of, but this has to be very unlikely - assuming that the S7+ big bore has the same components as the Connoisseur, which I think it does, except for the pulley itself, your machine might have the wrong eccentric shaft fitted! The big bore headstock has many detail differences to the old S7 version, one of which is that the backgear cluster sits further to the left in a big bore machine than it does on an old S7, so the eccentric shaft seems to be longer. Can't say by how much exactly - I measured the shaft from my S7 when I had it dismantled for the poly-vee conversion, but I haven't yet measured the shaft from the Connoisseur - but I think, from comparing my machines, that it's about 1/8", so you might (unlikely, but might) have an eccentric shaft from an S7 in there. On the other hand, given what I've learnt about Myford's assembly quality on their demo machines, I wouldn't be entirely surprised.

Just a brief note. If you are using the latest Myford bearing adjustment guide mentioned above and you are fitting new bearings you will need to tighten nuts A & B first before hand tightening the Split Collar. This will ensure that the bearing outer raceways are in fact tight up against the bearing spacer. Then hand tighten the Split Collar, loosen A & B, adjust front bearing in the usual way and the apply soft faced hammer as described!

Are we talking about the £8,000 plus Myfords that were the ultimate in model engineering lathes or one of the cheap machine Mart Chinese lathes that hardly work out of a £400 box ?

The lines are getting very blurred here.

John S.

The lines are getting very blurred here

Not at all

We're talking about good solid BRITISH engineering here

There was probably a small team of specialised guys who did the final setting up and testing routine before delivery, or upon delivery to a customer

Drummond had the same system

This was probably not strictly adhered to in certain cases where a demonstration model was purchased "sold as seen" or suchlike

Lathes are high precision gear and an average turner will struggle to set up a headstock properly anyway

John S, you beat me to it, I'll stick with my Taiwanese lathe for now, would like a smaller lathe as well, but a little bit bigger than my current second lathe, a Super Adept. Ian S C

Cabeng - thanks for a most helpful reply. I take your point that the distance piece cannot be altered to move the pulley to the right. I did not realise it abuts a step on the spindle.

I think you must be right in saying the fault is in the backgear cluster mounting. Unfortunately the solution is not as easy as resetting the grub screws that attach the handle because the endwise position of the backgear eccentric is determined by another grub screw (left loose) that sits in a groove in the eccentric. Releasing the two grub screws that attach the handle to the eccentric does not help. They are only adjusted to let the handle find its own position when the detent is engaged and adjust the depth of engagement of the teeth. The right hand end of the eccentric is flush with the handle casting so outwardly all looks as it should be.

Your suggestion that I may have a small bore eccentric in error sounds very plausible and I will pursue that avenue of investigation next. RDG lists the backgear eccentric for the small bore Super 7 but not big bore so I might still have to sort it myself. Many thanks for your help.

I think that's a bit unfair. Had Myford still been in business, I expect these demo machines would have gone through final inspection again. In any case, I am sure they would have dealt with any problems without the need to raise them on this forum.

Andrew M

I think the noises must be just the echoes of the "KERRR-CHING" noises emitted by the Myford cash register...

Regards,

Tony