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 Lead weight on tuner dial
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 Return to top of page · Post #: 1 · Written at 10:57:08 AM on 16 January 2020.
mawdryn's Gravatar
 Location: Gosford, NSW
 Member since 4 December 2005
 Member #: 7
 Postcount: 45

Hi again,

Just curious, what do you call the heavy (lead?) wheel which is attached to the tuner dial neck? It looks like it's about to break into a dozen different pieces, so I might need to replace it.

It's purpose eludes me other than to possibly give the tuner dial a bit of centrifugal force to make going from one end of the scale to the other a little easier. The dial station window is about the height and length of a standard ruler and the dial is the size of a 20c piece, so it takes a while to go from end to end...

Thanks in advance.


 
 Return to top of page · Post #: 2 · Written at 11:04:47 AM on 16 January 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 5997

Those die-cast wheels are usually made of pot metal (aka 'muck' metal) and are very fragile. Yes, they are to give the tuning mechanism a bit of heft. It can be glued together, although a replacement is a better idea if you can find one.


 
 Return to top of page · Post #: 3 · Written at 11:37:01 AM on 16 January 2020.
mawdryn's Gravatar
 Location: Gosford, NSW
 Member since 4 December 2005
 Member #: 7
 Postcount: 45

Cheers GTC,

I thought that might be the case. Had no idea what it was made of though. maybe I could fill the massive cracks with epoxy or something.

I don't like my chances of finding a replacement. I did a google search, but don't even know what they're called, so it reduces the effectiveness of a search.


 
 Return to top of page · Post #: 4 · Written at 11:43:12 AM on 16 January 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 5997

JB Weld is an excellent epoxy for metal repairs.

https://www.jaycar.com.au/j-b-weld-epoxy/p/NA1518


 
 Return to top of page · Post #: 5 · Written at 11:50:48 AM on 16 January 2020.
mawdryn's Gravatar
 Location: Gosford, NSW
 Member since 4 December 2005
 Member #: 7
 Postcount: 45

Thanks.

I actually have some JB floating around. I've give it a go.

If it comes to it, I can probably make a cast from it (It's still in one piece presently) and have something made to replace it.


 
 Return to top of page · Post #: 6 · Written at 12:03:14 PM on 16 January 2020.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 939

Its maybe called a flywheel.
Being zinc it has a bit of weight to give it some inertia, so you would need to use brass or steel to give it equivalent weight.


 
 Return to top of page · Post #: 7 · Written at 1:05:28 PM on 16 January 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1895

It is called a flywheel. Most of the ones I recall seeing were made from lead. You could easily cast a lead one yourself.

Make a plaster cast and use plumber's lead or flashing. If the old one is lead it will provide most of the material.

Then drill the spindle and lock screw holes.


 
 Return to top of page · Post #: 8 · Written at 7:20:31 PM on 16 January 2020.
Fred Lever's Gravatar
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 872

I had a tuning dial wheel made from muck metal disintegrating badly.
I soaked the lot in epoxy resin and made it whole that way.
Quick spray with alloy paint and it looks like new.
Fred.


 
 Return to top of page · Post #: 9 · Written at 9:01:44 AM on 17 January 2020.
mawdryn's Gravatar
 Location: Gosford, NSW
 Member since 4 December 2005
 Member #: 7
 Postcount: 45

Thanks for all the help everyone. I really appreciate the input.


 
 Return to top of page · Post #: 10 · Written at 10:05:27 AM on 17 January 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4330

That is "pot metal" aka "Die cast" of which there are a few differing alloys. Principally the issue is a large quantity of Zinc and metals that are known to exfoliate & create whiskers: That is literally what blows it apart.

Lots of parts were made from it as it could be cast with little heat. There has been success & there is an example on the American Radio Forum where new parts have been printed. I have a turntable from a Philips here where they made a large proportion of the Motor gearbox out of it and it has broken apart.

What you have in that Inertia wheel is a Flywheel. Epoxy High strength I have found the best as it soaks into the pores. However, there is such a thing as "stuffed" and beyond redemption. Normally it is near impossible to get good one, or it off a shaft. I may have one in a scrap set? So it boils down to Araldite, or New if you can get one on, or off a shaft, or my normal: Get an idea of the weight, diameter & width and turn up a new one.

If you use insulation tape around the outside, that becomes a removable former for the periphery. That also works on valve base to envelope bonding.

Marc


 
 Return to top of page · Post #: 11 · Written at 3:38:30 PM on 17 January 2020.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 939

If the zinc of the flywheel is a lost cause,but its axle is OK, it may be possible to replace the zinc with a number of large steel washers of the right diameter with the axle through the centre, all held together with araldite.


 
 Return to top of page · Post #: 12 · Written at 9:54:26 AM on 18 January 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4330

Much simpler here to go scavenge a lump of Aluminium, or something & feed it to the Lathe, on the odd occasion you can turn the shaft & wheel as one bit. Even extension shafts, can be turned as one bit, & replacements for broken dial pulleys have happened here. Even the replacement ball & socket on the tractor's throttle is home made.

Marc


 
 Return to top of page · Post #: 13 · Written at 1:06:58 PM on 21 January 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4330

Noted there is one minus shaft in the engineering shed.

Marc


 
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