Calculator
Thread finder
Enter the outside diameter and the pitch and get the most likely metric thread. Also for flywheel threads such as M22x1.5 or M27x1.25.
Likely thread
The finder knows metric coarse and fine threads from M3 to M30 as well as the special flywheel threads M17x1, M26x1.5 and M27x1.25.
Thread rule 1:1 for printing, if there is no vernier caliper to hand.
Identifying a flywheel thread
The easiest way to check the female thread in the flywheel is with a bolt that fits. Alternatively, measure the inside diameter: it corresponds roughly to the tapping drill, that is the nominal diameter minus the pitch. An inside measurement of 20.4 mm with a pitch of 1.5 points to M22x1.5. The flywheel threads in use and the matching ELDI pullers are listed in the thread table.
Questions
My measurement falls between two threads. What now?
Threads almost always measure slightly below the nominal size, never above. 21.8 is M22, not M21. Once the pitch is known, the match is unambiguous.
Does the finder know imperial threads?
No. On German mopeds they practically never occur. On British and American motorcycles an imperial thread gauge helps.