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SIG552
June 23, 2007, 05:47
Hi everybody,

My lower receiver (metric para) has been reparked and I am a little concerned that the threads in the back of the lower receiver might need to be chased. I am referring to the threads into which the stock bolt is screwed. I was looking at the sticky on threads and Gunplumber refers to the thread being 9/16 32 TPI.

My question is: why does a metric para lower receiver use a thread which is of an "inch designation"?

I am not schooled in metal work of any sort so go easy on me gentlemen :)

Thanks guys,

SIG552 :fal:

shootist87122
June 23, 2007, 08:15
The term Metric FAL has nothing to do with teh metric system of measurements.

SIG552
June 23, 2007, 08:52
Thanks, I realise that but I was wondering why they didnt use the "European" way of defining the thread?

SIG552

hanko
June 23, 2007, 09:10
Originally posted by SIG552
Thanks, I realise that but I was wondering why they didnt use the "European" way of defining the thread?

SIG552
Because the original tap size was English. Metric dimensions were simply converted from English.

-hanko

gunplumber
June 23, 2007, 10:01
life would be easier if "inch" and "metric" were replaced with "commonwealth" and "european"

Radio
June 23, 2007, 13:35
Here in da USA we call it SAE :biggrin:

SIG552
June 23, 2007, 16:58
I have found a place in the UK who sell the tap I need, however I think I'll chase the threads with the old Stock Bolt first and see what happens: if no joy I can always order the tap to chase the threads properly.

Thanks for your help guys,

SIG552