clarification of for this symbol ( ` )

[FranLopez]

I have this plate identification part and on the print the dimensions look like this 76.2 `1 by 152.4 `6 the first dimension is on metric but the symbol ` and number 1 o `1 I cant seem to understand the meaning. does anyone know?

 

[KENAT]

152.4 `6 given that 152.4mm = 6 inches it's tempting to think it's meant to be some way of denoting the inch equivlent - but that doesn't work for the other dim.

Can you give any context to help?

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[FranLopez]

no , what I did, I sent a clarification request for that symbol with the PM of lockheed for this part. nobody knows what this symbol means where I work.