Bolt sizes

A place for general Nuffield questions and chat
Post Reply
Tom brokeit
Posts: 22
Joined: Tue Dec 10, 2019 7:16 pm
Great Britain

Bolt sizes

Post by Tom brokeit » Wed Jan 08, 2020 1:06 pm

Hi can anybody tell what size bolts the pto cowl and drum covers are attached with.

Thanks tom



Nowtnew
Posts: 190
Joined: Sun Apr 01, 2018 8:49 am
Great Britain

Re: Bolt sizes

Post by Nowtnew » Thu Jan 09, 2020 12:56 pm

Hi Tom
I cant help regarding lengths but the threads are most likely unf with the possibility of unc particularly if going into an aluminium alloy component.

Take your time if trying thread sizes. Don't break it! :D

Incidentally, the standardisation on unified threads only took place in 1948 so maybe the very first Nuffields didn't use them. I wonder if anyone knows?

I should have checked first! According to Rick's post in the 'Data' section, 1953 marked the change point.

mike.l
Posts: 171
Joined: Fri Mar 30, 2018 10:29 pm
Location: london ontario
Canada

Re: Bolt sizes

Post by mike.l » Thu Jan 09, 2020 7:09 pm

Hi not sure on the length but they are either 5/16 or 3/8 unf And my pm4 is 1954 and that is a mixture of bsf and unf and was a real problem to sort bolts after i put them all in a can together!!!!!! i think the engine and components were bsf frame and the rest were unf . the unf and a f are not exactly the same but the pitch and dia is . it was just a case of running a tap into the holes to adjust the top of the thread to conform Mike

Rick Cobley
Senior Member
Posts: 340
Joined: Fri Mar 30, 2018 9:32 pm
Location: Leicestershire, UK
Contact:
Great Britain

Re: Bolt sizes

Post by Rick Cobley » Fri Jan 10, 2020 12:38 am

Hi, Its quite simple bolts with 1/2" head are 5/16 unf (pto cowl) and bolts with 7/16" head are 1/4unf ( drum cover).

Regards Rick Cobley

Rick Cobley
Senior Member
Posts: 340
Joined: Fri Mar 30, 2018 9:32 pm
Location: Leicestershire, UK
Contact:
Great Britain

Re: Bolt sizes

Post by Rick Cobley » Fri Jan 10, 2020 8:23 pm

Rick Cobley wrote:
Fri Jan 10, 2020 12:38 am
Hi, Its quite simple bolts with 1/2" head are 5/16 unf (pto cowl) and bolts with 7/16" head are 1/4unf ( drum cover).

Regards Rick Cobley

Further to yesterdays reply, the drum covers are held by 5/16 bolts with a 1/2 head and the pto cowl is held by 3/8 bolts with 9/16 heads.

Regards Rick Cobley

Tom brokeit
Posts: 22
Joined: Tue Dec 10, 2019 7:16 pm
Great Britain

Re: Bolt sizes

Post by Tom brokeit » Fri Jan 10, 2020 8:38 pm

Thanks rick it the only bolt didnt have

Tom brokeit
Posts: 22
Joined: Tue Dec 10, 2019 7:16 pm
Great Britain

Re: Bolt sizes

Post by Tom brokeit » Mon Jan 13, 2020 8:43 pm

Ive order some now hopfuly here for next weekend

Post Reply