You could invest in a Thread Gauge and one of those metal or plastic cards that has holes in it of various sizes and the diameter measurement on it.

I had missplaced my Metric Thread Gauge (it came with the cheapie metric Tap, my SAE Thread Gauge also came with a Tap Set) so I bought a combination Metric and SAE one on eBay; $12.45 Free Shipping.

The new Thread Gauge has more thread sizes on it then my other 2 combined do so it looks like it will be more useful.


Some of the Internet Parts Places will once in a while also give the size and thread pitch of the Bolts they sell. But, that will take a lot of searching.

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84 300D, 82 Volvo 244Gl Diesel