Where can I find out what 4R and 16R graduations mean?

[WobblyHand]

Not sure if this is a Beginner's Forum question, but it's being posed by a beginner

I've seen various scales and rulers for sale with nomenclature like 4R and 16R. What does that mean? For instance, I have a #305R Starrett scale, which I rather like. It has 32nds and 64ths, on one side and 10ths and 100ths on the other. What would it's nomenclature be? Obviously, if I wanted a 12" scale, I'd wander over to Starrett and look up the number or fumble around until I found it. But if I wanted a PEC scale, or noname, or combination square, what kind am I looking for? If I had my druthers, it would have both 10ths, 100ths, and mm on it. 9/32 doesn't do much for me, all I get out of it is that it's 1/32 larger than 0.25".

Really, this isn't a rant... it's more of an annoyance. I've found that detailed pictures of merchandise online can be a crap shoot. Some are so blurry that one can't tell what one is getting. It is like they run the pictures through a blurring filter, or cover the camera lens with vaseline.

So what exactly is a 4R, or 16R? Where can I find the definition?

Whoops! I found the answer at: Graduations Hmm, why didn't I look here first?
My #305R is a 5R or 6R, guessing it's technically a 6R.

• 5R—1/100″, 1/64″, 1/32″, 1/10″
• 6R—1/32″, 1/64″, 1/10″, 1/100″

An E/M has

• E/M—edge 1: 1/10″, edge 2: 1/100″, edge 3: 1.0 mm, edge 4: 0.5 mm

Oh, well, it might be helpful to others. As you were...

 

[Nogoingback]

My Starrett No. 27 catalog lists 11 different combinations
of graduations. I shows a 4R as 64ths, 32nds, 8ths and 16ths.
It shows a 6R as 50ths on one side and 10ths on the other.
Yours is a 5R if you have 10ths and 100ths on the front and 32nds and 64ths on the reverse.

It is an older catalog and Starrett sells other combinations now. If you want metric, there are newer rules that have it.
I own a 6" rule that I bought a few years ago: it has 32nds, 64ths plus 1mm and 1/2mm graduations.