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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 24th Dec 2016, 12:28 pm   #21
mole42uk
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Default Re: Mazak flywheel.

I too have heard that cyano works in thus situation.
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Old 24th Dec 2016, 9:42 pm   #22
G6Tanuki
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Default Re: Mazak flywheel.

My experience with Mazak and similar Zinc-containing 'monkey-metals' is that once they start going-off there's Llareggub** you can do to save them. They will crumble to dust as the various metals de-alloy and crystallize.

[this is also a big issue in the classic rail- aviation- and car- worlds where Mazak etc were used extensively in the 1940s-1960s for trim, handles, doorlocks/hinges ashtrays carburettors and the like].

If you can take a mould from the part and re-cast it in resin I'd suggest that would be the best approach. I've seen metallic or mineral powders mixed in with the resin to give an appropriate degree of weight and 'feel' to the resin-cast part.

I have here a 1960s-era Redifon antenna-tuner where the cams used to detent and interlock the series/parallel capacitor/inductor selectors are Mazak and they've crumbled beyond the point where I could take moulds; I have to guess when the switches have closed.


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Old 24th Dec 2016, 10:53 pm   #23
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Default Re: Mazak flywheel.

Hi.

I remember about 20 years ago I had a similar crumbling metal problem with a Mazak (monkey metal) waveband switch lever assembly in an up market piano key Grundig valve radio. I can't remember the model but unusually it had an added valve stereo decoder fitted to the inside of the back cover.

I managed to do a successful repair using chemical metal which held very well and was dependable.

It's interesting to note from previous comments that this type of metal deteriorates further once the problem has manifested itself.

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Old 25th Dec 2016, 12:06 am   #24
julie_m
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Default Re: Mazak flywheel.

It's simply positive feedback in action. Once bits begin breaking off a spinning flywheel, it goes out of balance and starts shaking even more bits off .....
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Old 25th Dec 2016, 9:33 pm   #25
Jimmyhaflinger
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Default Re: Mazak flywheel.

The replacement flywheel looks fine, I took it from a from a scrap 1982 radio while this one is from 1980, hopefully they're made out of a better alloy.
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