# Gage Blocks



## ddickey (Dec 27, 2018)

Any suggestions for a set of gage blocks for general shop use?


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## Bob Korves (Dec 27, 2018)

For having around just to check tools and use comparatively, a 36 piece grade B Chinese set can be had cheap, used ones even cheaper.  That is what I am using until I can find the right 81 piece set of a higher grade at a really good price.  The 81 piece sets are much easier to make up stacks with than the 36 piece sets, and the higher grades will wring together properly -- and would be traceable to NIST.  All of this is really overkill for a home shop that does not do precision work for commercial customers, but hey, it's fun!


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## pstemari (Dec 27, 2018)

For general shop use, the 36 piece round spacer block sets are handy. I use them to set the end stop on my lathe.

I save the good gage blocks for checking instruments and surface plate work.

Sent from my Pixel XL using Tapatalk


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## mikey (Dec 27, 2018)

I'm probably a shabby hobby guy because I can't work to 50 millionths of an inch so I rarely use blocks. I have them but I don't use them in the shop because then I can't use them for metrology purposes, which is why I bought them in the first place.

If you need USER blocks, I would buy a cheap import set or a used set and just use them. No point in spending big money on blocks that you're afraid to scratch. Just confirm the size of the block before you trust it, then use the heck out of them.


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## Technical Ted (Dec 27, 2018)

I bought a set similar to these: 

https://www.ebay.com/itm/81-PCS-PRE...DE-AS-2-new-/311839247228?hash=item489b114b7c

Plenty good enough for what I use them for.

Ted


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## Technical Ted (Dec 27, 2018)

mikey said:


> I'm probably a shabby hobby guy because I can't work to 50 millionths of an inch so I rarely use blocks. I have them but I don't use them in the shop because then I can't use them for metrology purposes, which is why I bought them in the first place.
> 
> If you need USER blocks, I would buy a cheap import set or a used set and just use them. No point in spending big money on blocks that you're afraid to scratch. Just confirm the size of the block before you trust it, then use the heck out of them.



I agree and have a set of these I picked up for $10 used that I use for "rough" shop use. I try to keep my new set in good shape for tool calibration, etc..

Here's link to a set similar to the used set I have:

https://www.ebay.com/itm/SHARS-36-P...h=item460e94fc31:g:EEIAAOSwbehbvQ1t:rk:1:pf:0

Ted


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## benmychree (Dec 27, 2018)

I have two sets, a DoAll set of rectangular blocks 81 piece, A+ grade (+4 -2) and a Brown &Sharpe accessory set for them and a set of Pratt&Whitney Hoke blocks with accessories and a set of P&W 1" - 4"; I like the Hoke blocks best for most things, as they do not have to wrung together; they are 1" square, and have a hole through the middle that is countersunk for a flat head screw, you just stack them up and with a connecting rod and flat head screws, they are held in the stack. I do not much use them in the shop, just for calibration.


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## T Bredehoft (Dec 27, 2018)

Jo Blocks and Accuracy. If you work in a shop that supplies Jo (or by any other name) blocks, They must by law be calibrated every six months. 
How far out do you suppose the rejects are?  I have a set given me over 20 years ago that was made up of rejects, I guess its a 36 pc set, or there abouts.  I've never been able to detect why they were rejected, never been callibrated, I use them whenever I want to set stops on my turret lathe. 
For what I do they are close enough. I would support anyone who wanted to get the cheapest set they could find.


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## Bob Korves (Dec 27, 2018)

Jo blocks are totally optional in a home shop, but they really are a good arbiter when your mic gives you one reading, your calipers give another reading, and neither match the travel shown on your DRO.  Then it is nice to have blocks, even if you don't trust them beyond .0001" (which is actually pretty damned accurate), for something you can trust implicitly, will solve the discrepancy, and will get you back to work.

"Man with one watch knows what time it is..."


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## jrkorman (Dec 28, 2018)

Was lucky to pick up an import set (more than good enough for my purpose) at a good price and I've watched the videos and played with them for some various stacks. So a question has come to mind.

The smallest "tenths" blocks are 0.1001 through 0.1009. What is the procedure for creating a stack that is less than 1/10 of an inch?

Thanks,


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## ezduzit (Dec 28, 2018)

As important as jo blocks, or perhaps even more so, are pin gauges. Preferable to imports, which can be expected to rust dreadfully, would be used domestic.


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## mmcmdl (Dec 28, 2018)

I had a couple sets of blocks over the years and have since sold them . My current employment doesn't require the accuracy of tenths or millionths , and in most instances , thousanths . No dial bore gages anymore , no cylindrical grinding , jig grinding etc .. I have ground blocks and adjustable parallels when I need to use sine bars or vises . They were nice to have when needed though , and they were calibrated every 6 months .

What's a millionth or 2 in a company this size ? ( that's what I used to tell them )


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## ThinWoodsman (Dec 28, 2018)

jrkorman said:


> The smallest "tenths" blocks are 0.1001 through 0.1009. What is the procedure for creating a stack that is less than 1/10 of an inch?



Relative difference. Put the work/workholder on a 0.1008, set a 0.1009 next to it, adjust then remove both gage blocks. Probably easier to imagine the two blocks on either end of a sine bar.


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## ddickey (Dec 28, 2018)

.


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## ddickey (Dec 28, 2018)

.


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## jrkorman (Dec 28, 2018)

ThinWoodsman said:


> Relative difference. Put the work/workholder on a 0.1008, set a 0.1009 next to it, adjust then remove both gage blocks. Probably easier to imagine the two blocks on either end of a sine bar.



Thanks - That's what I was thinking.


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## PMartin (Dec 29, 2018)

I bought an 81 piece imported set, SPS brand, grade B from Enco before they disappeared into MSC. They are more than good enough for the work I do. Only needed them for setting a sine bar, but have used them a few times now.


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## P. Waller (Jan 12, 2019)

jrkorman said:


> Was lucky to pick up an import set (more than good enough for my purpose) at a good price and I've watched the videos and played with them for some various stacks. So a question has come to mind.
> 
> The smallest "tenths" blocks are 0.1001 through 0.1009. What is the procedure for creating a stack that is less than 1/10 of an inch?
> 
> Thanks,


Do you mean 1/10 of 1/1000"?


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## Dabbler (Jan 13, 2019)

Doing accurate stacks les than .100 thick is tricky, and you have to think outside the box.  Find a way to use a reference surface tha allows you to build a stack in the .200 to .300 range, and you will find it easier.  When that's not possible, I substitute a dowel pin or precision pin instead.


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## T Bredehoft (Jan 13, 2019)

They exist, I have a few between .010 and .045, but  they are random, not a "set."


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## warrjon (Jan 14, 2019)

Gauge blocks are calibrated at 20°C. At 23°C the uncertainty of steel blocks would be approx  ±1500nm. Stacking blocks increases the uncertainty and potential errors. The guys in the cal lab never stack more than 2 blocks

If I need an accurate block I machine a 20mm diameter round bar in the lathe and check it with a micrometer Zeroed at whatever temperature I am working at.


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## Janderso (Jan 14, 2019)

I watched Mr. Lipton use a set for making up the pressure difference when locking a piece in a set of Kurt jaws.
This way the jaws have an equal pressure bearing side to side.
I hope I am explaining myself well enough.
I would think the cheaper set would be used for this type of application.


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