# Round Or Rectangular Gauge Blocks?



## wawoodman (Dec 20, 2015)

A while back, I bought a set of Shars round gauge blocks (or spacer blocks, whatever) and have used them a couple of times to set up a sine vise.

Today, I scored a set of SDI gauge blocks at a reasonable price.

Do I need both sets, or should I dump the rounds? Are there situations where one is better than the other? Just stick them in the back of the drawer?


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## mzayd3 (Dec 20, 2015)

They don't cost anything to keep around.  I'd say hang on to them!


Sent from my iPhone using Tapatalk


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## Uglydog (Dec 20, 2015)

Consider identifying which is the more accurate set. Use this set for inspection, and calibrating mics, etc. 
Use the other set on the shop floor.

If you don't have an inspection plate/area yet.
Wait. It'll sneak up on you. And blam! You'll need those gages.

Daryl
MN


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## Ulma Doctor (Dec 20, 2015)

:+1: 
Keep Both Sets!!!!


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## extropic (Dec 21, 2015)

The round spacers usually have a center hole through and that can come in handy sometimes. Keep both sets.


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## chips&more (Dec 21, 2015)

I think you are trying to compare apples to apples, when it’s actually apples to oranges. The round ones I believe are called “space" blocks. Less accurate and intended for daily shop use in a shop environment. Like used for sine bar set-up or setting up the height on a project to properly machine it, etc. The "gage" blocks are typically more accurate and should be carefully handled in a controlled ambient environment and used only for calibration purposes. Note, that this is all good to read and do, but if you have one or the other  or both sets, you do what you gotta do in the HM world. Keep both, start a pile if you don’t already have one…Good Luck Dave.


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## Restorer (Dec 28, 2015)

30 years ago I had access to a shop with some very accurate grinding and lapping equipment as well as a Brown and Sharp bench micrometer.
I made a set of round shop blocks, the same sizes as commercial sets plus fractional increments.  These were hardened, tempered, rough ground, frozen to -150 degrees F. , tempered again, finished ground, and lapped to final dimension.
My make to tolerance was -0, +.0002.  Anything out of tolerance was made over.  My last measure of the blocks I recorded the exact size.

Years latter I purchased a set of 81 Gage blocks class B, for a very reasonable price.

The round set is used where their tolerance is acceptable.  Example, as intermediate stops on the lathe to position shoulders on  a part being turned.

The gage blocks are used for calibrating other measuring devices, and where the best precision is needed.

Keep both sets!

Restorer


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