Author Topic: Plunger Columns  (Read 323 times)

Offline dsj666

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Plunger Columns
« on: 26.09. 2018 19:02 »
Anybody know what is the thread size and type is in the end of a plunger column please?
The one where those aluminium caps on the top screw in.

Cheers
1954 A10 Plunger (in bits)

Online Rex

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Re: Plunger Columns
« Reply #1 on: 26.09. 2018 21:50 »
I can measure the TPI and major diameter tomorrow if you wish. Best send me a PM tomorrow afternoon as a reminder though... ;)

Online Rex

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Re: Plunger Columns
« Reply #2 on: 28.09. 2018 10:09 »
It comes out at 0.875" dia and 20 TPI. HTH.

Offline duTch

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Re: Plunger Columns
« Reply #3 on: 28.09. 2018 11:07 »

 I bought new SS ones from Lightning Spares and always figured they are BSC whatever size
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline dsj666

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Re: Plunger Columns
« Reply #4 on: 28.09. 2018 11:16 »
It comes out at 0.875" dia and 20 TPI. HTH.

Thanks Rex...it would appear that's a 7/8 x 20 TPI  BSC thread then, and taps seem to be available..!!

I was contemplating cleaning up the threads so they don't damage my new end plugs..!!
1954 A10 Plunger (in bits)

Online Rex

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Re: Plunger Columns
« Reply #5 on: 28.09. 2018 13:11 »
I recently bought two new stainless end caps and I had to spend ages lapping them in to fit the plunger column threads, just like I did with the stainless fork seal holders and stanchion top nuts too.
Close, but not close enough to fit perfectly.

Offline duTch

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Re: Plunger Columns
« Reply #6 on: 28.09. 2018 17:56 »

 I should add that I had a mate fabricate new columns from Chrome bar which entailed machining threads in to match, so probably also needed to tidy the plug threads.
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia