Left hand thread nut for Pinnacle Bench Grinder

[Roger Owen 5Participant @rogerowen5]

Metric or Imperial?

[Roger Owen 5Participant @rogerowen5]

I have a Pinnacle 6" bench grinder, bought around the early 1980's and I've lost the left hand threaded end retainer nut. Does anyone know what the thread is? Looks coarse, measures 13mm – but I wonder if it might be imperial. The thread on the shaft is 18mm long (7/10th inch) and over than length I count 9 thread ridges. Any ideas?

[JourneymanParticipant @journeyman]

Possibly 1/2" Whit which is 12 TPI roughly 2mm crest to crest.

John

[not done it yetParticipant @notdoneityet]

Two wheels? If so, remove the other side and check that?

[BazyleParticipant @bazyle]

Measure again carefully. Likely to have been built for the American market where UNC 1/2 in has 13tpi.

[John ReeseParticipant @johnreese12848]

If the thread diameter is 1/2 inch I would bet the thread is 1/2-20. I have never seen a coarse thread on a bench grinder. No experience with bench grinders made to metric standards.

[not done it yetParticipant @notdoneityet]

Just a rain check.

 

 

(7/10th inch) and over than length I count 9 thread ridges

 

 

 

 

How many valleys? Wondering here whether first ridge counted was number zero.

 

 

 

 

 

Edited By not done it yet on 12/06/2017 06:32:44

[John ReeseParticipant @johnreese12848]

Can you use a bolt of known pitch to check the pitch of your threads? Do you have a friend with thread pitch gauges?

[Roger Owen 5Participant @rogerowen5]

Posted by Journeyman on 09/06/2017 18:26:06:

Possibly 1/2" Whit which is 12 TPI roughly 2mm crest to crest.

John

Hi John,

You could be right there. I got a gauge which only goes down to 13 TPI – it's close but I think 12 would nail it.

[Roger Owen 5Participant @rogerowen5]

Thanks for all the responses. Next Question – bearings are a bit dry. Should I attempt to pack with grease, straight 30 SAE oil, heavier oil (EP90) – or does it not really matter.

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