Spark plugs with 3/16 x 40 thread.

[Bruno Mueller]

Guys, I am looking for a delivery address for spark plugs with 3/16 x 40 thread.

 

[stevehuckss396]

Same as #10-40. Rimfires are out there somewhere. I think the Chinese are making them now also.

 

[SmithDoor]

Guys, I am looking for a delivery address for spark plugs with 3/16 x 40 thread.

Try Ebay
It hard one use model engines in 1930 to late 1950’s. The it was all glow plug with think is a odd size ¼" . There maybe 3/16" glow plug that with some work could be a spark plug.

It can be hard one to find

I would try what

stevehuckss396
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Today at 5:17 PM
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#2
Same as #10-40. Rimfires are out there somewhere. I think

and modify to fit.

Dave

 

[Bruno Mueller]

I can see that it will be difficult to get spark plugs of this type. I may drill out the spark plug thread and cut 1/4 x 32 threads. However, I still have a question about this. Does this thread have a flank angle of 60° or 55°?

 

[gbritnell]

60 degrees. 55 I believe is Whitworth

 

[SmithDoor]

I can see that it will be difficult to get spark plugs of this type. I may drill out the spark plug thread and cut 1/4 x 32 threads. However, I still have a question about this. Does this thread have a flank angle of 60° or 55°?

Where I live everthing is 60° unless it was made in the UK then bring out the dies .

I would check the plug

Dave

 

[SmithDoor]

Guys, I am looking for a delivery address for spark plugs with 3/16 x 40 thread.

To see if 55° or 60° I like using this a pocket comparator. I have a 10X and about 6 disk only two I use.
The first has both 55° and 60°.
I only use this for threads on old British equipment and engines.

Dave