Flywheels

Hello. I have been advised to ask a question on this newsgroup (from uk.rec.models.railways) as it might be more useful for what I'm looking for.

I am trying to find a flywheel of approx. 1Kg weight, with a 4mm diameter shaft hole. Can anyone point me in the right direction as to where I might be able to get hold of one (short of having one custom made)?

TIA

Ian J.

Reply to
Ian J.
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Ian,

You queried a flywheel for adding mass to a model railway turntable. You say it is not going to be seen, and it will obviously rotate extremely slowly - so that accurate balance is not a problem.

Have you considered a slice off a 6" bar which you might well pick up at somewhere like Metal Supermarkets as an off-cut. Finding the approximate centre and drilling a 4mm hole should be possible with hand tools.

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Mike

Reply to
Mike Whittome

where do you live, someone may be nearby and able to help.

what about weights from a weightlifting set or those small ones tha women use for fitness training

-- bolma

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Reply to
bolmas

Does the flywheel actually need to run on the 4mm shaft, or is that a shaft that supports the existing turntable ? Maybe you could stick some lead sheeting (flashing) to the underside of the turntable - clearing the 4mm shaft rather than attempting to grip it.

-adrian

Reply to
Adrian Godwin

When I was a kid, my grandad and I used to make counterweights for my Mechano cranes out of lead. Use an old baking tray for the base of the casting, and a pastry cutter for the mould (round ones, not gingerbread men are better). Melt the lead on the gas stove in an iron saucepan.

Oh, and don't tell gran!

Reply to
John Montrose

Nice idea, I'll look into it, tho I'd still be interested to know if there were any ready to buy flywheels around.

Ian J.

Reply to
Ian J.

I think the biggest problem there would be filling the centre hole. I think it would have to be filled completely, then drilled out to a 4mm shaft. An ideas on what could be used to fill the hole?

Ian J.

Reply to
Ian J.

Unfortunately the turntable is now assembled in such a way that it can't be dissassembled, and I don't believe there would be enough space underneath the main 'bridge' to put enough weight. That leaves only the shaft in which to hang the weight on.

Ian J.

Reply to
Ian J.

My main concern here would be the use of lead, which I'm trying to avoid (for health reasons).

Ian J.

Reply to
Ian J.

Also LOTS of ventilation - leave the ouside door open and the interior doos shut. Don't breathe in the fumes and wear protective gloves, shower when finished. Drink some milk before and after casting.

Reply to
Neil Ellwood

In message , Mike Whittome writes

Which leads to a follow-up suggestion. Using no more than a hacksaw and a DIY drill in a stand, it should be possible to make a simple cross from two pieces of rectangular bar stock. For example two 6" lengths of

1" x 3/4" attached together to form a cross would (I think) weigh about 1.1Kg. Given that the density of mild steel is about 0.285 Lbs/cu.in. (or 7.9 Gram/cc) you can do your own calculations for other sizes of bar stock.

Alternatively melt some lead (density 0.41 Lbs/cu.in. or 11.36 Gram/cc) and pour it into a circular tin lid. When it sets, use it lid 'n all. When I was racing r/c yachts, a single visit to a friendly local tyre fitter resulted in enough scrap balance weights to last three boats. Don't worry about the metal clips, they float to the surface and can be skimmed off when you melt the lead. However, lead is poisonous. Work in the open air and avoid standing over the melt like 'The Bisto Kid'. Treat the stuff with respect and don't do it too often.

Good luck.

Reply to
Mike H

I have some 5" diameter cast iron bar that would do the trick. about a centimetre thick would be the right weight.

Would it be necessary to be able to remove the weight at some time in the future (maintenance etc)? If so then a tapered collet, a la Dremel would secure it to the shaft. If not, then it's a simple Loctiting job :-).

Let me know if this is of use. The trice of a pint of ale and the postage secures the finished item :-)

I could probably make it next weekend if I got the slice cut off the bar during the week.

regards Mark Rand

Reply to
Mark Rand

That sounds like it might be the right idea, and I'd be happy to pay for three pints of beer plus postage. It will be necessary to remove the weight on a regular basis, so some way to secure it removably would be useful. There is about 2cm worth of shaft to fix it to, so if the disc itself was

1cm, then there would be 1cm for a fixing.

The email address on this posting does work to a hotmail account where junk is destroyed straightaway.

Ian J.

Reply to
Ian J.

How about using concrete poured into a suitable round container whic

coulde be a pan or cardboard tube. Fixture or glue a 4 mm ID tube i the center of the form before pouring the concrete. Drill a hole i the tube and shaft a put a small bolt or cotter key to retain on th shaft

-- GailInN

First R/C 1956

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Reply to
GailInNM

I had meant _price_ not _trice_

Mark Rand RTFM

Reply to
Mark Rand

I just realised I said 'beer', when you said 'ale', and if you're a real ale man, that might have seemed almost to be an insult ;-) Many apologies!

Ian J.

Reply to
Ian J.

Araldite or plastic padding?

Reply to
Newshound

I took my lump of cast iron bar into work today and cut a slice off of it on the bandsaw. I'll get working on it this weekend.

Regards Mark Rand RTFM

Reply to
Mark Rand

Many thanks. Let me know how it goes, and when it's ready, we can work out how to get the ale money to you...

Ian J.

Reply to
Ian J.

Mark,

Have you been able to do the flywheel?

Cheers,

Ian J.

Reply to
Ian J.

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