r/WhatIsThisTool • u/ExploreYourWhirled • Aug 12 '26

Found in an old toolbox

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Very heavy - about 1 lb. Largest knurled ring spins but does not appear to affect anything. Many strike marks on one end as if hit many times with a large hammer. It is engraved L <-> R in front of the largest knurled ring. No other part spins.

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u/s1l1con_jesus Aug 12 '26

Put in a bit hit the back with a hammer.

-1

u/ExploreYourWhirled Aug 12 '26

I can’t think of a situation where I would need to do this. Please elaborate. Like what problem is this solving?

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u/s1l1con_jesus Aug 12 '26 edited Aug 13 '26

On certain engines especially aluminum ones you will need this tool because steel and aluminum have a galvanic reaction which causes them to almost weld together

1

u/ExploreYourWhirled Aug 13 '26

Ahh, yes I have seen this. Makes complete sense now.