At the risk of asking perhaps a silly question, do you think the flywheel had originally been plated? Your description of the 'raised edges' suggests it is plating that has eroded. Personally, I'd be tempted to try polishing them gently out with a small buffing wheel and compound in a multi-tool. You're unlikley to do overmuch damage with that.
If that _is_ the case Bob, I'd agree, but I assumed that the flywheel is just a flywheel and that the capstan spindle is another bit. Didn't you say above that you "assume that this Teac deck drives on the periphery of the flywheel."? Now you're suggesting that the flywheel is _driven_ from its periphery by the belt...
Let's not fall out over this :-)
First of all I suspect the capstan is already undersize from wear, so any polishing to the flywheel may well be of benefit. The flywheel is truly a beast and I doubt there'd be much variation in speed from light polishing.
As the wanderer suggests, the flywheel may have been coated and it may be useful to take a photo for us to see.
It would be best if the flywheel had a smooth surface so not to abrade the belt.
The sort of rubber drives used are very gentle. A decent metal loaded filler would be the equal in strength to some of the rubbish they cast these things with, I'd say. And I assumed there must be enough damage to be causing problems of one sort or another.
In message , "Dave Plowman (News)" writes
What makes you think that ?
pissing about just for the sake of it gives some people a reason to live
right. i missed that.
Hey Rick, that "he" is a "she" anyway, if you want to start nit- picking,
Bollocks to that for a game of soldiers.
But if you _insist_, then the things you're looking for are "Micromesh" abrasives. CSM Abrasives sell mixed packs for the best price you're likely to find (which still isn't cheap). If you're serious, it's worth keeping a range of a few sheets handy.
D.M. Procida wrote:
OK, now we understand. Technically that component is both a flywheel and a pulley then. A pulley because it is driven by a belt and a flywheel because it is massive so as to damp out variations in the running speed of a mechanism. There's no rule in engineering that says a single component can't be both things.
I'd still really prefer to know what material we're talking about here and a photo or measurement of these pits because neither "lightly pitted" or "very lightly pitted" is a technical term that gives me any grounds to assume how deep they are but if all that goes round this is a rubber drive belt I wouldn't worry. If anything they'll stop the belt slipping. I've got an old belt driven Black & Decker valve refacer and the only way to stop the rubber drive belt slipping on that is to deliberately knurl the rims of the aluminium pulleys with the sharp edge of a file. Basically knock seven bells out of them all round for a few minutes until they're evenly scarred with small dings and scratches and voila, no more slippage.
However, back to tape recorders. Pitting suggests corrosion in a plating material to me and if so I'd be more concerned about chunks of that coming off than the pits themselves. I suggest treating it as I would a crankshaft journal needing light polishing. Assuming the pulley is already removed from the machine and can be cleaned up afterwards and any bearings or sensitive areas masked off. Get a sheet of 800 grit wet & dry paper and cut a strip off a little wider than the pulley. With some paraffin (kerosene) or WD40 as a lubricant, both hands holding the ends of the paper and someone else holding the pulley, 'strop' the pulley rim lightly, turning it about a third of a turn every few seconds so as not to over concentrate on one area. Run the tip of a finger over the pulley rim and continue until you can't feel any edges on the pits. As the strip of paper wears down you'll get a finer surface finish and a trick I used to use on cranks for a final shine is reverse the paper so you're using the non abrasive back of it and use it as a strop with brass or silver polish or T-Cut. You can get a crank like a mirror doing that if you spend enough time on it. I once left an apprentice polishing a Ford crank with Brasso and when I came back you could see your bloody face in it. He'd kept on polishing it for about 2 hours and all it was going back into was an old Transit engine. He said he wanted to see how shiny he could get it :)
Not saying that's what you want of course. Be guided by the original finish on the pulley rim. Too smooth and the belt might slip. If you want more of a matt finish use the paper dry and even go a bit coarser on the grade. Maybe down to 400 grit although you'll be able to remove a tenth of a thou or two of material eventually with a grade like that. Once you know what finish each grade gives you, you can change grade as necessary but start off fine and go coarser only if you need to.
A final trick for keeping abrasive paper working flat and evenly over the whole width of a crank journal or pulley rim is get an old toothed camshaft drive belt off a car engine - any garage will have a few in the waste bin or be able to keep one for you. Cut that down to a manageable length and use the non toothed side to drive the abrasive paper if you see what I mean. You don't have to glue the two together, friction will stop the paper falling out. You can manage without though for what you need to do.
Mr Procida doesn't normally ask stupid questions?
Nowt wrong with that. If it gets you away from the family.
How stupid do you feel?
Such surface pitting will have no effect on the sound whatsoever, and no effect on the belt driving it. Any micro-vibration induced by possible imbalance caused by asymmetric pitting is going to be miniscule compared with vibration from other sources - and at the end o the day, will still have no real world effect on the audio specs of the machine. You can certainly cause problems by trying some of the suggestions given though.
Its a non-issue. And no, this flywheel won't be plated!!
NT
The message from "Dave Plowman (News)" contains these words:
Unless you all do it together :-)
In message , "Dave Plowman (News)" writes
"I want to make an unopenable jam jar - one that will resist the strongest grips.What's the best way to achieve this? I imagine that filling it up with boiling water, running a seam of superglue along the rim and thread then screwing the lid on tightly would get the best results. Just in case anyone else requires an unopenable jam jar, I made one that so far has satisfactorily resisted all attempts to unscrew it. I roughed up the glass rim with sandpaper, and ran some superglue aroundit. Since that seems to do the job, I haven't felt the need to try any of the more ambitious methods suggested."
I rest my case ...
^^ ????
Somebody doesn't read all the thread do they (He's an Italian bloke)
AWEM
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