spring washer on magneto sprocket ?

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alan.moore
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spring washer on magneto sprocket ?

Postby alan.moore » Wed Jul 25, 2018 12:37 pm

When my Mag came back from Tony Cooper there was a new magneto nut and spring washer. There was no springwasher on it origionally and the parts book does not mention one. So my question is should there be a spring washer or just the nut.


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Re: spring washer on magneto sprocket ?

Postby cmfalco » Wed Jul 25, 2018 9:14 pm

alan.moore wrote: So my question is should there be a spring washer or just the nut.
To quote NASA Publication 1228 'Fastener Design Manual' on spring washers "In summary, a lockwasher of this type is useless for locking."

If anyone knows better than NASA on this subject, complain to them about their conclusion, not to me.

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Re: spring washer on magneto sprocket ?

Postby alan.moore » Wed Jul 25, 2018 10:23 pm

Thanks for the info but , in the case of my VH Ariel should I be using the spring washer. Come on chaps someone must know.

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Alan
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Re: spring washer on magneto sprocket ?

Postby robjameson » Wed Jul 25, 2018 10:40 pm

I’ve had several back from tony with the spring washer. Personally I have never been happy with the thread engagement if the washer is present, so I leave them off.
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alan.moore
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Re: spring washer on magneto sprocket ?

Postby alan.moore » Wed Jul 25, 2018 11:29 pm

robjameson wrote:I’ve had several back from tony with the spring washer. Personally I have never been happy with the thread engagement if the washer is present, so I leave them off.


Cheers Rob,
I agree. I just needed to check as Drags show a link to a lock washer when you select the magneto retaining nut in their parts list. Seeing as it is a common setup on most Ariels I thought there would be a simple yes or no answer'

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Alan
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Re: spring washer on magneto sprocket ?

Postby nevhunter » Wed Jul 25, 2018 11:42 pm

Sometimes the thread bottoms out, or nearly so, before it forces the sprocket fully on In that case I would fit some kind of washer. Most magnetos have an ordinary nut there and have a washer. The Lucas magdyno has always had a special nut with a substantial plain shank You should have a bit more than 3/8" of thread engagement. A badly shaped spring washer would not be a good idea and as stated, they aren't really a means of securing a nut. Nev

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Re: spring washer on magneto sprocket ?

Postby john.whiting » Thu Jul 26, 2018 12:31 am

Some motors seem to have the washers......BSA WM20 always had washers ,but usually chain sprockets dont need them.

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Re: spring washer on magneto sprocket ?

Postby Leejm » Mon Jul 30, 2018 7:12 pm

Alan I always lap the sprocket onto the mag end with grinding paste to ensure a good fit. And never had one come loose, as for the spring washer there is no need. Lee
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alan.moore
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Re: spring washer on magneto sprocket ?

Postby alan.moore » Mon Jul 30, 2018 10:57 pm

Thanks for the advice chaps,

Leejm wrote:Alan I always lap the sprocket onto the mag end with grinding paste to ensure a good fit. And never had one come loose, as for the spring washer there is no need. Lee


Lee: I only have 45 thou clearance between the back of the sprocket boss and the start of the taper so I'm a bit concerned that if I lap it it will bottom out but thanks for the tip.

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Re: spring washer on magneto sprocket ?

Postby Dave.Thomas » Mon Jul 30, 2018 11:04 pm

It'd take an age to lap 10 thou, never mind 45, you'll be fine


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