Hello. I'm after a flywheel of decent weight (1 kg) to help smoothen out the movement of a turntable on my layout. I've had a good web search, but can't find what I'm looking for. Can anyone point me in the direction of a supplier of larger flywheels, with a 4mm shaft diameter, and at least 1kg in weight?
TIA
Ian J.
I think you'll get an answer on sources in the model engineering group - uk.rec.models.engineering
The best effect comes from the largest diameter you can accomodate run at the highest speed. So, fitting a larger diameter, but lighter, flywheel is usually an advantage, as is gearing it up so it runs faster.
- Nigel
But then you'll have a problem in stopping the TT, you will need to implement some form of brake I suspect.
Actually I need the weight more than I need the flywheel effect, as the turntable won't quite sit properly on the turntable base, and I can't modify anymore as it's built now. The only thing I could think of was adding weight to the centre spindle, and the best way I could think of was to attach a fairly weighty flywheel.
Will try uk.r.m.eng to see what they have to advise,
Ta,
Ian J.
Well, if it's weight you need more than the flywheel effect, what about adding some weight to the turntable itself? Lead shot glued under the bridge, for example. Another way would be lead tape (available at golf or tennis shops, used to balance clubs/racquets). It's neater than the shot, self-adhesive, and can be cut to shape.
Unfortunately the turntable is now constructed in such a way that it can't be disassembled, so the option of adding weight to the bridge is out.
Ian J.
Another source of solid self-adhesive weights are balance weights for car wheels.
Lead shot, or liquid lead products, suffer from having a lot of fresh air between the pieces of shot.
A friend of mine did a calculation on the density of a pile of lead shot. It came up that spherical balls weighed between 52% and 74% of the mass of the equivalent solid lead for the same volume filled (depends on the packing structure - cubic or hexagonal). In a bench test (ie. random packing), he came up with only 42%. So, in all cases, its better to have a lump of solid brass than an area filled with spheres of lead.
- Nigel
In message , Ian J. writes
What about an old record player turntable, if you can find one? The older the better, really - one from a 1950s radiogram, designed to play everything from LPs to 78s would be perfect.
There might be some machinery that uses such flywheels, somewhere in the world and you might stumble on one in a scrap yard - X-ray tubes use one that _might_ fit the bill :-) My suggestions:
- get a general engineering firm to machine you one from 1/4" plate. (balance it yourself)
- put a much smaller one on your drive motor where the vastly greater rpm will give the same effect with the much smaller flywheel.
- make your flywheel out of wood or other material that you can work yourself. (see next point) Make the final reduction step in the turntable drive a belt or a small rubber wheel onto a wooden full diameter disk.
Regards, Greg.P.
Ian, As far as I can understand your problem, you have a turntable bridge that is sitting too high with respect to the turntable pit, and to correct this you intend to apply a heavy weight to the centre spindle of the bridge, in the hope that this will pull it down to its correct position. But to do this surely you will have to distort the turntable pit to accomodate this movement. Is the structure and material of the pit such that will accomodate this distortion without cracking or breaking up? Would it not be better to raise the edges of the pit, or the rails on the pit edge that lead onto the bridge? Or have I misunderstood the problem? Regards,
Bill.
"Ian J." wrote in message news: snipped-for-privacy@individual.net...
It's the standard Peco turntable, with a slightly different mounting of a centre shaft (Peco's design being very lacking in strength). Unfortunately the bridge shifted slightly when gluing the metal shaft in place, and to get it out would mean breaking the turntable bridge. The only remaining solution I can think of is to put enough weight on the centre spindle to counteract the sufficient force of the springs of the pick-ups which are causing the bridge to sit slightly high and unstable.
Ian J.
O.K. Ian, now all is clear. I did have a Peco turntable and know what is happening. So what you are trying to do is to overcome the effect of the contact springs. In that case you should be able to move the bridge down without causing any distortion to the pit structure by the use of a suitable weight. But how can you attach it to the turntable spindle to clear any gearing that you may have, or is the bridge not powered but just pushed around by hand?. Regards, Bill.
The shaft has a single large toothed gear that is chain driven to the motor which is mounted on the frame of the baseboard. This has left enough shaft to hang the weight on.
Ian J.
Ian, Is it still possible to get Meccano parts? If so I was thinking that you could use what I think was called a shaft connector , which is a cylindrical bush with a longitudinal hole and with two grub screws, fit this to your shaft extension, then make up a hook from a bit of coathanger wire and fit that into the lower part of the connector bush, and from the hook hang a suitable weight (half brick in a cord sling or a net, perhaps) if you have sufficent space below the t.t. to do so. The weight doesn't have to look nice, as long as it pulls the t.t. bridge down against the contact springs.I know Meccano parts will fit onto a Peco t.t. shaft, I had one once and used Meccano bits to provide a drive for it. Regards, Bill.
"Ian J." wrote in message news: snipped-for-privacy@individual.net...
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