Pi Tape Again

[rake60]

I have my own 0 to 6" outside mics at work.
They cover almost everything I work with there, but occasionally
I need something to measure between 6 and 12"

A 2" to 12" Pi Tape would be the perfect answer but a new one costs about $100

An eBay search turned up a used 2" to 12" Pi Tape with a starting bid of $20
I bid that $20 and won the bid.

I know the chuck back plate on my 9 X 20 lathe has a nominal dimension of 100mm.
That is a "it don't mean a thing" size.
We would call it a Scale Dimemsion that is + or - .015"
I decided to check it with my Pi Tape.

Past the 3" mark, past the .900 mark, past the .050 mark and the vernier scale reads 5.

Hummmmm, 3.955" X 25.4 = 100.46mm
Who ever rough finished that back plate missed the size by .018"
I'd fire him!

Rick

 

[idahoan]

That's cool Rick; I have never heard of PI Tape. I do have a wrap around but that is in a different class.

Dave

 

[Justin_Sane]

I thought I would throw this out there.


If youre looking for a 0-12" micrometer set thats more reasonable for the hobby machinist, check out STM. They're chinese made, but I picked up a full set for i think around $350 canadian. They are accurate, trust me, I used them in an industrial manufacturing setting full time. I could buy a new set once a year for like 10 years before they measure up to the cost of a mitutoyo set.

But for 20 bucks thats quite a deal.