Author Topic: ATD  (Read 192 times)

Offline rgsjohn

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ATD
« on: October 16, 2020, 10:19:46 AM »
Just removed the magneto from my A10 to have it refurbished. I noticed one of the fibre gear teeth was chipped so I'm seeking advice. Go with a new fibre gear or opt for an ally one. I'm leaning towards ally because fibre gear failure appears to be a relatively common occurance. Personal experiences anyone?

Offline Rex

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Re: ATD
« Reply #1 on: October 16, 2020, 11:05:28 AM »
Never had any problems with the fibre gears personally, but go for the alloy one as it will give you an extra 10mph on the top speed. ;)

Offline iansoady

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Re: ATD
« Reply #2 on: October 16, 2020, 12:01:36 PM »
The fibre ones do occasionally shed teeth. I did read that their advantage over alloy ones was that they would act sacrificially in the case of the mag seizing. No, I've never heard of that either......
Ian
1952 Norton ES21955
Francis Barnett Cruiser 75

Offline rgsjohn

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Re: ATD
« Reply #3 on: October 16, 2020, 02:09:48 PM »
Rex, Lol! well that's convinced me ally it is. That is an irresistable argument

Offline rgsjohn

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Re: ATD
« Reply #4 on: October 16, 2020, 02:13:03 PM »
Ian, no I have never heard of a mag seizing either, but I am worried by the fact that repro fibre gears have an iffy reputation in some quarters.

Offline chaterlea25

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Re: ATD
« Reply #5 on: October 16, 2020, 09:00:36 PM »
Hi All
I have seen the old shellac insulated magnetos "seize"  when the insulation runs out of the winding's when hot then solidifies into a "glue" as it cools


John

Offline iansoady

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Re: ATD
« Reply #6 on: October 17, 2020, 11:17:35 AM »
Ah, that's maybe where the story comes from.
Ian
1952 Norton ES21955
Francis Barnett Cruiser 75

Offline R

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Re: ATD
« Reply #7 on: October 17, 2020, 10:54:24 PM »
The name of that disease is 'shellacticus'.

Them being insulated with shellac.
When it degrades and turns to mush, you have a problem.

Offline john.k

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Re: ATD
« Reply #8 on: October 18, 2020, 04:23:17 AM »
The fibre gears are also used  to transmit heavy loads without noise......quite common on some electric motor drives in largish horsepowers.........also use in lathes and drill presses to reduce noise from meshing gears..........which would be why they are used in mag drives ,to cut noise.......Only time I see them stripped is when large spanners are applied to mag drive nuts.......They are however notably abrasive ,and will wear contacting steel gears,unless the steel is very hard.......Ally used for cheapness,the fibre is very costly.........The large ally idler gear in the Vin. cam drive was notorious for shedding teeth.