jakesmodela
Junior Member
I need to clean up the spark plug threads and I found a tap that is 7/8-18 NS.... Which i believe stands for national special. Is that the correct thread type? Thanks for your help in advance!
Spark plug threads
- Thread starter jakesmodela
- Start date
hardtimes
Well-known member
Hey Jake,
I've heard/own/used NF and NC, but not NS
You are correct in doing your research where fords threads are concerned ! I'm aware of correct tools necessary to 'chase' threads, however , just any tool sold and claiming to do such job correctly..is not true..in most cases. If you 'chase'/ incorrectly 'clean up' plug threads and / or block threads..you've caused more head aches than you've cured.
James Rogers
Well-known member
I just went down and checked mine and yours is correct. I believe NS stands for National Standard.
C26Pinelake
BANNED
are you attempting to use a spark plug that was not meant for a Model A ?how could the threads get damaged enough to have to recut or chase ? At 3 or 4 bucks a plug I would be chucking those plugs and buying new ones.
Wayne
Wayne
machine girl
Senior Member
do not use the tap the dreamer says, rocket 1 is right. a machinerys handbook#24 can help.
Last edited:
BILL WILLIAMSON
Well-known member
An old plug, with 3 or 4 grooves ground in it, makes a good thread "chaser"!----Bill W.
Bill in SoCal
Senior Member
Good for Bill. Ground or filed - that's a good way to make any thread chaser. Bill
Tom Wesenberg
Well-known member
I use my Dremel with a thin cutoff wheel to slice 4 grooves into old bolts and spark plugs. This makes good thread cleaners/chasers.
