Chasing threads

[ajcooper4]

At the moment I am cleaning up the main body of my Lister D including repainting. In order to get a tidy paint job the engine is mostly stripped down although I have left the governor in place as I am not confident enough to strip this out and there is no evidence yet that it is not working.

Some of the studs and nuts on the plate above the magneto need 'chasing'. I have a Zeus guide and I am happy to buy a set of Whitworth taps/dies but is everything on the engine Whitworth please? Also can someone recommend a good thread gauge please? There are so many and it's hard to see the wood for the trees. Ideally I'd like to be able to measure bolt threads and internal threads.

Also I am struggling to find my way around the Zeus just now and wondered if there's a guide anywhere that lists the sizes of all the D's nuts and bolts etc.

Thank you in anticipation of your help.

[Appletop]

43 years with old engines and never used a thread gauge or Zeus guide. 99% of the bolts on a D are Whitworth.

[ajcooper4]

Thank you Appletop.. question is how do you work out which BSW?

[Woodsman]

Thank you Appletop.. question is how do you work out which BSW?

BSW has a coarser thread. For example, 1/4" BSW is 20 tpi, whilst 1/4" BSF is 26 tpi.

As for thread gauge, I got a Silverline combined metric/imperial for about a fiver.

[Appletop]

Most of the engines I've had are either BSW or BSF, I've never found the need for anything else, I work out what tap or die I need by just trying one, if it fits then it's right, if it doesn't fit then it's wrong. These old engines aren't hard to work on and you can soon get bogged down worrying about the small stuff when in reality it's easy to just try.
A half decent BSW tap and die set should do all you need, my set is a Draper one, cost me a tenner 20+ years ago....

[Alanengine]

I found on a Villiers and my JAP what I thought were BSF were in actual fact Cycle threads - close to BSF but not interchangeable!
My 1952 Morris engine uses a lot of metric threads, apparently a lot of tooling was bought from France, but the nuts used although tapped metric have Whitworth hexagons!
As for UNF and UNC, close to our BSF and Whitworth but different.
Measure twice, tap or die once!

Alan

[Foden]

I found on a Villiers and my JAP what I thought were BSF were in actual fact Cycle threads - close to BSF but not interchangeable!
My 1952 Morris engine uses a lot of metric threads, apparently a lot of tooling was bought from France, but the nuts used although tapped metric have Whitworth hexagons!
As for UNF and UNC, close to our BSF and Whitworth but different.
Measure twice, tap or die once!

Alan

Morris engines had some metric threads because the first Morris Cowley 'Bullnose' models used imported French Hotchkiss engines.

On a Lister D practically everything is BSW, the vertical throttle rod is BA/metric and there are BSP threads on the bungs and pipework but all the main engine threads are BSW.

Pete.

[Alanengine]

Didn't know it went back to the Bullnose!

Alan

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