Member postings for Graeme Durant 1

I just tried to print a couple of pages from the new edition of MEW - something I do successfully and on a regular basis via the Pocketmags site. However today I get an error message as follows;

{"message":"An error has occurred."}

Not particularly informative I think you'll agree!! I tried the latest versions of Chrome, Firefox and Edge - they were all the same. It looks like there has been some kind of software update on the site, but for me at least it has broken the printing.

Any feedback or support - or even just commiserations - would be most welcome!

All the best
Graeme

I just wanted to follow up with my conclusions, and also thank everyone that helped with their thoughts and feedback. There's nothing worse than a thread in a forum that doesn't tell you the ending, especially when you are looking for help and find what seems to be the answer - but doesn't give you the punchline!

Either way, my Startrite Mercury is all back together now, and much quieter than when I started. The changes I made were;

• Replaced the motor bearings - not sure if that made much difference, but they seemed a bit gritty and were not expensive. The originals were also open bearings, so I replaced with something to add a little protection against dust ingress.
• Stripped the spindle (which was not as difficult as I'd thought it might be), cleaned the old grease out of the thrust bearings, re-greased, and re-assembled. This also eliminated a tiny bit of vertical play, which may or may not have been a contributing factor to the noise.
• Added the missing O-ring identified by KWIL in the thread above.
• Greased the splines - these were dry from the outset.
• Replaced the belt with a good quality notched type. It certainly has no bumps in it like the one it replaces!

The noises I had at the start were I believe from the spline rattling, but may have been a combination from other sources too. Now these have disappeared. My belief is that the main remedy was the new belt, and getting the tension right. Too tight and it oscillates, and the noises come back as the spines pick up the speed variations. Looser seems to be the order of the day. And since the notched belt has "raw" rubber sides, it grips much better on the pulleys, and so doesn't need to be drawn so tight to avoid slipping.

I did have high hopes for the O-ring helping too, but for me it seemed to make no difference. I must confess I'm not sure what it is supposed to achieve, sitting where it does - but it does no harm, and is supposed t be there looking at the exploded diagrams!

Anyway, I think I'll live with it for a while and use it in anger and see how it goes. Hopefully the improvements are permanent! But it certainly sounds much smoother and quieter - which was my intention. All in all a good result!

Cheers
Graeme

Many thanks Dennis - more proof that this is a "Z" type belt, of around the 1m length.

I'm currently planning on ordering a notched SPZ 1010 or similar tomorrow, so hopefully I can try it at the weekend. My hope is that a better quality belt than the one I have - with the added advantage of the notches (as described by earlier posters) will help damp my belt oscillations. That plus the newly discovered missing O-ring, may just fix my noise issues.....

So is a bump an indication of a lower grade belt? Any suggestions on brands to go for would be useful - I can't find a Fenner at any kind of reasonable price!

Also, any thoughts on choosing a cogged or notched belt? Just looking for ways to reduce the opportunity for belt oscillation - as I have currently.

Many thanks KWIL. SPZ 1010 is what I'm using currently - so that's extremely useful to know. Mine is a Medway - so a budget one I think - and does have a bump at the join, which I wonder might not be helping my belt oscillations. Maybe time for an upgrade....

Mmmm, all very interesting - seems like a few things coming out today!

First the O-ring. Looking at the parts diagram I found online, item 45 seems to pushed onto the splines, on top of the collar that in turn sits against the upper bearing of the quill. Is that about right? Then when the quill is in the resting position, this O-ring may well contact the pulley bearings, and maybe damp any spline movement?

If my assumptions above are right then my response would be - wot O-ring?! My machine has no O-ring there! So maybe something that needs to be remedied. An essential - and easy - addition to my noisy machine!

Secoind, the belt. I measured the top of the pulley grooves - it's around 9mm. I found an old A-section belt and held it in the groove, but it barely went into the groove. So it doesn't look to me like it's an A section. Maybe mne is a later model which went to a Z or whatever? KWIL - when you mentioned an A400, what did you mean by that? Please pardon my ignorance if it's obvious to everyone else!

On a related note - I am now wondering whether I am using the right vee belt profile. The one my second hand machine came fitted with is a "3V", which appears to be a narrow wedge belt. I replaced it a few years back with an "SPZ" wedge belt, which I seem to remember was touted as being an equivalent. Certainly their dimensions are close - though not identical.

But my question is - are these the right choice? Could it need a classic Z type belt profile? They are less tall in profile, so would presumably behave slightly differently in the pulley. I was just copying the original I had, but can't find any technical sources online to say what the manufacturer fitted. And right now, I feel I need to fit the right type of belt to try and eliminate my oscillation issues.

Any guidance from Mercury owners - without oscillation or noise problems - would therefore be welcome!

So I parked the idea of changing the motor for a while, and had a look last night at the motor pulley concentricity. My DTI tells me it is 0.25mm out of true, and the "high spot" is in line with the single grub screw fixing. It clearly pushes the pulley off centre, due to a little slackness in the fit of the bore.

How to improve this? I stuck a small strip of self adhesive aluminium tape to the motor shaft, opposite the keyway where the grub screw bears. It had a thickness of roughly half the error.

It took a bit of persuasion for the pulley to go back on, but it did in the end. Tightening the grub screw, and re-measuring the run out, it had been more than halved to 0.1mm.

Running the machine, the belt still oscillates, but I could be convinced it is better! I tried all the pulley ratios, and a couple were actually quiet and oscillation free. So maybe this is one of the sources of the problem. It would be great to get the runout down by some more, but I'm not sure how best to achieve that. Adding more shim would make it very hard to get the pulley back on the shaft. And it doesn't feel worthwhile reboring the pulley - after all, I don't think it is not concentric - it's just 0.2mm oversize.

Any suggestions would be most welcome!

Edited By Graeme Durant 1 on 25/11/2020 13:39:12

Many thanks Chaps - more food for thought.

I did for a while try and use a little strip of shim stock in the motor pulley bore to try and correct for the runout, but struggled and so moved on. What you say however makes sense - I will investigate further on that score.

Notched belts are something I wondered about, as I'd read good things about them in the past. Useful to know they can help with smooth running. I had a quick look and it seems I can source a Gates one in the correct size and section for less than £10 plus postage. Not sure it equates to your "lab quality" recommendation - but if it would help, it doesn't seem too painful a price.

Thanks Pete! That is a useful data point. It either suggests mine isn't too far out of spec - or your machine has similar wear. But I'd favour the first!

Let's hope my experiments with changing the motor yield further evidence tomorrow....

Pete - next time you pass your garage, maybe you could grab the chuck on your dead drill and just see how much play is in the splines? Just as another data point? As I said, the body of my chuck moved about 1mm against the stationary shaft. I have no idea if that is "normal" or "badly worn", for the Mercury, hence all input is valuable!

Mmmm, interesting idea. I guess the drive is always in one direction, so the "tight" spline would only be taking up that unloaded rattle. Maybe option 1 in my ist isn't a case of just giving up after all....

I will try the spare motor though, as it's easy to do. May have no effect, and then that starts to narrow the answer at least!

It is. If you lock up the splines, the noise disappears. So from what's been said so far, it sounds like either;

1). The splines are worn, so making more noise then they should - and AFAIK there's no easy fix for that beyond replacing them - which is scarily expensive. I'd live with the noise in that case.

OR

2). The spines are OK, and it is the drive that is surging. I guess I read that as varying in speed, sporadically for some unknown reason. From what Clive said, it could be due to many things, and may never be determined. Hence my question about the motor itself, since it does seem to be prone to vibration.

Just been thinking about this whilst out for a late night bit of fresh air. I have a similarly dimensioned cap start motor kicking around, and might see if I can temporarily replace the original, in case it alters the behaviour. All data here is useful after all. Won't be able to do that until tomorrow, but unless any better ideas surface in the meantime, I think that'll be my next experiment....

Yes - which seems to be coming form the spline - since jamming this kills it completely....

I guess it does annoy me! But if someone told me "they all do that guv" then I'd forget it and move on. As has been stated - and Martin confirmed this for his - it drills well and works perfectly. But since it's in bits on my bench right now, it feels like the time to address it - now or never. And in some ways, understanding the problem is a part of the fun. Isn't it?!

So here's a question - how "smooth" is the drive from my single phase motor? It's casing vibrates quite a lot to the touch, but is the actual rotation "noisy" due to the imperfections of the split phase style motor? I have felt some of my other motors around the workshop, and this has loads more vibration associated with it. Compared to Cap start and 3-phase via a VFD. It is the only split phase motor I have.

And if it were considered noise in the rotation, could this induce the surges that Clive talks about - and hence my belt oscillations? I think those belt oscillations do coincide with the noises in the splines, as the effective speed of the drive changes, and shunts the splines back and forth. So finding the source of the oscillations could be the key here.

Or am I on the wrong track?

Pete,

It is exactly like that - and it does! But after a lot of thought and experimentation I don't think that's the problem I'm seeing. When running the motor you can definitely feel the vibration it generates being transmitted into the sheet metal. But there are two parts to the sheet metal work - the main casing, and the "brackets" that attach the motor. These are separate, and don't touch. The motor mounting part is only attached (with fibre washers) to the solid casting. The main casework is also attached to that casting, but at different places. Hence the vibration isn't transmitted into the main casework - the slight flex in the motor mounts seems to detach the motor vibration quite effectively.

But that's not to say that the vibration isn't coming through via some other route. Via the belt maybe? Or even through the casting? That's one reason I wondered if the single phase version was noisier than a three phase version?

Dunno - more questions than answers at the moment!

Thanks Chaps.

Clive - I aligned the pulleys vertically using a straight edge, and the belt seems to run off them nicely - no binding visible from the side. But I have to say that the belt does oscillate in operation, on both sides but mainly the "slack" side. I have tried adding tension until it's clearly too tight - and also reducing tension, until it's too slack - but no tension I could set would fix it. The belt was new not long back, but on close examination it does have a small bump at its join, despite being a Medway brand. Or maybe because of that - I'm no belt expert!

I did also measure the runout on the pulleys - the motor one was 0.2mm, due to the grub screw fixing pushing it off centre. It sounds from what you say that any slight irregularities could be the cause of this. Would the belt oscillation count? And if so, how can I try and fix it?

Graeme

I have been the proud owner of a Startrite Mercury bench pillar drill for many years. And for as long as I can remember, it has been noisy! Hard to describe, but it seems to come from the spindle, and it's an intermittent kind of knocking. Maybe slightly rhythmic, coming and going over seconds. Not terrible, but annoying!

It drills accurately, and I love the feel of the sensitive feed, so no complaints about its capabilities. But I always intended to take a look at the bearings to make it run a bit quieter. Lockdown finally gave me the excuse!

I took the motor off first, and since it was a bit noisy on the bench, I replaced the bearings. One was slightly gritty, and because they are so cheap and easy to replace, I went ahead and replaced both. It's a single phase (split phase without any starting capacitor) so it's never going to be super smooth. Changing the bearings I think improved it a bit. Still hums and vibrates to the touch in use. But this wasn't what I thought was the source of the main noise. Hence on to the quill and spindle end....

I removed the quill and stripped it all down, but it seems to me at least that the bearings are all good. I exposed them all, cleaned and re-greased them, and tightened them all up again. They felt silky smooth, so as a test I then tried spinning them up at speed on my lathe. No noise at all - runout good too. Phew, because those bearings are not so cheap!

Whilst the quill was out, I also ran the drill so that the spindle pulley and its bearings were tested alone - as was the reinstalled motor. Nice and smooth and quiet. Certainly no knocking. So when I reassembled the quill onto the machine, and ran it again, I was disappointed to find the original noisiness return, unchanged.

Further experimenting suggests it's the backlash or slop in the spindle spline drive. The clue was that if you add a bit of load to the spinning chuck - gentle hand pressure - the noise ceases. And if you jam some wooden toothpicks into the spline to effectively lock it - again, no noise. So with no load applied, I think the spline is essentially rattling to and fro, making the noise.

So my question is - do they all do this? Or is my spline worn?

When stationary, you can feel the slop due to the looseness of the spline. A certain amount of looseness is I believe required so that you can actually move the quill up and down - but how much is correct? In my case, I can move the chuck about 2.5 degrees (measured as 1mm at the circumference of the chuck, if that makes sense). I should add that my spline looked unworn to me - at least the male steel part - blemish free with original machining marks intact. The bronze female part was hard to see, so that may be the culprit.

Or like I said above, do they all do this? Or maybe all the single phase ones do it, since the motors are a bit noisier, thus inducing noise into the spindle? Any thoughts or guidance most welcome!

Cheers
Graeme

Thanks Adrian - more confirmation! And yes, my base casting holes are oval.

Still begs the question why someone put an oversized but too short a bolt in the main casting by force or design....

Graeme

I don't think the bolt has to be fixed solid in the casting. There has to be wriggle room anyway,as this is the way to tension the drive belt. So a clearance hole is all that is required, and when I take out the stuck bolt, I reckon it will be good to replace with a clearance fit bolt.

The originals are Whitworth by the look of them, but replacing with metric like Bill is probably perfectly acceptable - unless you are keen to retain authenticity!

Graeme