Hi, Jeff,

It has been my understanding that the standards, if they are followed, 
allow for a maximum width of 0.248" for the tape. That converts to 6.992 
mm. 6.35 mm converts to 0.250 inches. 6.3 mm converts to 0.2480315 
inches, which is pretty close to 0.248 inches.

The 1965 NAB standard specifies 0.246 +/- 0.002 inches, but I believe 
industry practice moved at some point to 0.248 +0/-0.004 inches, but I 
did not look for that.

The NAB standard further specifies the out-to-out track dimensions for 
both two- and four-track configurations at 0.244 inches.

There can always be out-of-spec tapes. There doesn't appear to be a spec 
for straightness of the tape (country laning), but that also greatly 
affects reproduction, as you know.

NAB Standard: http://www.richardhess.com/tape/history/NAB/

Cheers,

Richard




On 10/8/2016 09:44, Jeff Willens wrote:
> Uh, hold it guys. That tape box is partly in Japanese. Was this actually
> made by Scotch in Japan? If so, are we talking about a metric/English
> difference in cutting size? IOW, does US-made 206 come out to exactly 6.35mm
> or something slightly different?
>
> Just a thought...
>
-- 
Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada                             647 479 2800
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.