They are for the old plugs that you can take apart to service. Most were
3/4 or 1" pipe thread.- Vote on answer
- posted
11 years ago
What is it? Set 457
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- Vote on answer
- posted
11 years ago
I went to an antique machinery show a while ago, where I came across a large display of a couple thousand vintage spark plugs and an on going spark plug auction. There was a plastic container holding some porcelain parts, I cropped this photo to post the one on my site:
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I guessed at the inch and a half size but as you can see there are number of different sizes and shapes.