# Surface Plate & Gage Blocks



## abrace (Jan 22, 2016)

All,

              How essential is a surface plate in a beginner's shop? Is it something I can wait on, or is it something that I should have immediately?

              Same question goes for gage blocks.


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## wrmiller (Jan 22, 2016)

I would venture to say that they are not essential until you actually need them, as silly as that sounds. It's been my personal experience to get what I need, as I need it.


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## abrace (Jan 22, 2016)

wrmiller said:


> I would venture to say that they are not essential until you actually need them, as silly as that sounds. It's been my personal experience to to get what I need, as I need it.



Yogi Berra would be proud of that response 

No, that makes sense to me.

I just don't know what I need, and don't want to have to hold up a project for 2 weeks waiting for an enco discount.


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## Paul in OKC (Jan 22, 2016)

Never needed one at home. Had one given to me years ago and I stored it at the shop. Actually uncovered it the other day, after about 7 years! Unless you are doing a lot of layout type work, may never need one.


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## wrmiller (Jan 22, 2016)

What I do is this: As a idea for a project starts forming in my mind, I will start mentally going through the steps that it will take to do what I need. When I run across a setup, or measurement, or cutting operation that I don't have the parts for, I identify what I need and start setting aside money to get 'em. 

I recently bought a set of radius/corner rounding end mills for a upcoming project. Never thought I'd need them. Now I do.


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## planeflyer21 (Jan 22, 2016)

abrace said:


> Yogi Berra would be proud of that response
> 
> No, that makes sense to me.
> 
> I just don't know what I need, and don't want to have to hold up a project for 2 weeks waiting for an enco discount.



In machining it is very easy to get sucked into "Wow!  I have to get me one of those!", when in reality thinking about what your task at hand is and problem solving it with what you have will very often get you by.

Example:  Everyone should have a collet closer for their lathe.  Well while that would be nice, your 3-jaw chuck will handle a great deal of small work very well.  Is loosening and tightening a 3-jaw chuck as easy as popping a handle back and forth?  No.  Does the 3-jaw chuck have the "Oooo & aahhh" factor of a collet closer when all your machinist buddies come over?  Nope.

But the 3-jaw will hold a 3/16" bit of brass rod while you face, turn, and drill it, just as the collet will.

As to a surface plate, we rarely used them unless doing a QC setup for checking tolerances of 0.004" or less.  In those cases we would set a height guage with Jo Blocks, the check the datums as they came off the machine.  Even on the "manual side" of the shop, surface plates were just not in use very much.


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## wrmiller (Jan 22, 2016)

I call my surface plate and height gauge my 'poor mans optical comparator'.


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## T Bredehoft (Jan 22, 2016)

I use the cast iron surface top of my table saw.  I know it's not optically flat, but it's smooth and large enough (by about 6) for anything I do. Another possibility is the mill work surface. it's probably flatter than my table saw, but not as large.


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## yendor (Jan 22, 2016)

I know any of the purists here will scold me for saying this but if you want a poor mans surface plate you can often get one for free by stopping into a Granite Counter WORKSHOP not Sales Facility and asking for an Old Sink Cutout. they keep big pieces of slabs and sell them as remnants but the sink cutouts they just throw away.

I'm on a VERY Limited Budget and until the day when I can float a Real Surface plate past the CFO (make that wife), the old sink cutout will just have to do for layout work.


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## P T Schram (Jan 22, 2016)

I used a table saw for 20+ years until a friend found a dump of granite countertops


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## mzayd3 (Jan 22, 2016)

i would suggest that: if you are asking if you need it- you don't need it...


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## Whyemier (Jan 22, 2016)

I have a surface plate and gage blocks but have yet to use them.


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## Tony Wells (Jan 22, 2016)

You don't need it, it's just one of the many wants that develop when you see others with them or hear them discussed. For most things people really use them for, you can use a mill table, a table saw table (I wonder how flat the Rigid granite table saws are). Until and unless you can really understand the major advantages of a precision surface over a saw table or similar, don't worry about it.

Gage block are another issue, IMO. The are useful for many things and relatively inexpensive. I think everyone should have a set, but that's my opinion. They can be used independently from a plate in so many ways it's not a fair pairing to ask about.


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## JimDawson (Jan 22, 2016)

I bought a set of gauge blocks because it was a really good deal, and one day I'll find a sine table or vice to use them with.  I haven't had a use for them yet.  I bought a surface plate for about the same reason, really good deal.  It lives under my tool box well protected in it's own enclosure, I use it about once a year.  I also have 3 height gauges to use with the surface plate.  I actually use them, but normally use my mill table for layout.  Now once I get one of my surface grinders set up, I will be using the surface plate more, but too many other projects for now.

As said above, granite sink cutout is more than adequate for most home shop work.


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## Bob Korves (Jan 22, 2016)

I absolutely cannot get along without a surface plate and gage blocks any more.  If you do not have known accurate references, you are guessing at everything you do.  You buy a new digital micrometer, it reads to 50 millionths.  Great, but is what it says really true?  Grab some Jo blocks and test it at different increments, especially the important increment you need to hit dead nuts for a precision project.  Without known good references, all your tools become guess-o-meters, and you just hope it is correct because you paid a lot for it.  Instead of believing the advertising, test it!  Having a surface that you know is flat to within 50 millionths over the compete extent of the plate, and Jo blocks accurate to a few millionths, you know the answer pretty much for sure.  I have a bunch of machinist squares of various sorts, no two of which gave the same indication of squareness.  If you have a surface plate and a granite angle block or a cylinder square, you can make them all correct to close limits and they all will actually agree with each other.  I have slowly been calibrating my (old) Starrett squares to make them correctly square.  Just takes time, a little effort, and accurate references.  If you like to be a believer, that is an easy way to get by in life.  If you want to know the truth, test it and find out.

Some very good import surface plates are now available quite cheap.  The freight can cost more than the plate.

Inexpensive Jo blocks as well...

If you have a very accurate flat, a very accurate 90 degrees, and very accurate length references, you become your own reference standard in a home shop.

The precision I need is almost always way (WAY!) lower than what I can test, and that is a very good thing...

But to answer your question, no, a beginner does not _need_ those things.


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## stupoty (Jan 22, 2016)

If you get a top notch set, you will want some lesser ones to use in the workshop 

Stuart


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## brav65 (Jan 22, 2016)

Well I am a beginner and have both a starrett 3"x12"x18 surface plate $60 and SPI 81 piece gauge blocks $70. Both used items from guys in the metal working club I am involved with.    I have used both a couple of time for setting up some project, but more importantly practiced measuring thing accurately.


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## David VanNorman (Jan 22, 2016)

You have a machine top or a mirror. Most any thing to get you through so you see what you need.


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## TOOLMASTER (Jan 22, 2016)

TEMPERED GLASS IS GOOD N FLAT..GLASS SHELVES ECT.


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## Charles Spencer (Jan 23, 2016)

I've got a Stanbridge surface plate and a set of gauge blocks.  I've also got a piece of 6" steel machined reasonably flat and some blocks that I made that are fractional sizes.  I use them way more often than uncovering the surface plate and breaking out the box of gauge blocks.  They are easily accurate enough for most things.

That being said, Enco has import surface plates on sale starting at $33.00.  Not a bad deal if you wait for a free shipping code from them.

http://www.use-enco.com/CGI/INLMK3?PMK0NO=1637713


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## BGHansen (Jan 23, 2016)

I picked up a 12 x 18 granite surface plate, Starrett 18" vernier height gauge and a shop grade set of gauge blocks from a shop sale around 30 years ago for under $100.  I've used the height gauge once or twice along with the surface plate.  I've used the gauge blocks to check 1-2 and 2-3 mics until I picked up some standards.  

If I had it to do all over again I'd still buy them, but not an essential for what I do.

Bruce


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## kingmt01 (Jan 23, 2016)

I too often think about & have visions of surface plates floating in my head. Oh the thoughts of if I only had one... But in reality I have little use for one that I can't find another way around. 

Gauge blocks I actually have a project that I believe them & a sine bar would be the key but other things need that cash ATM so that project keeps getting pushed back.


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## Eddyde (Jan 23, 2016)

I use my surface plate and height gauge very often, it's the fastest way I have to do layout on work, check work and take off dimensions from parts. Gauge blocks not so much but they do come in handy for checking the accuracy of measuring tools. Need depends on what kinds of work you want to do, what tolerances you will want to achieve and what tools/machines you have?


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## abrace (Jan 23, 2016)

Thanks everyone, this is very helpful.


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## joshua43214 (Jan 23, 2016)

Gauge blocks - yes.
They are invaluable. Use them for setting depth stops, spacing stuff away from a hard stop on the mill, etc.
They are consumable items, and get a ton of mileage around the shop.

I use my surface plate a lot. Your mileage will vary on what you do.
If you don't find yourself wishing for one, yo probably don't need one.


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## rlgustin (Jan 23, 2016)

Inspection and setup instruments are a absolute essential in the shop.


Sent from my iPad using Tapatalk


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## P T Schram (Jan 23, 2016)

Bob Korves is my new best friend and hero!

Bravo.

Reading these posts reminds me that I have evolved from a hammer, chisel, hacksaw and file to where I am now and perhaps that is why I cannot live without my busted piece of a granite countertop and Enco (or worse) height gauge.

I do still lust for a set of gage blox. OTOH, I hope to never have to live without 1-2-3 and 2-4-6 blocks which I use for everything from layout to small tubing Bender (need a hypodermic needle to oil something difficult to access?).


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## Bob Korves (Jan 23, 2016)

P T Schram said:


> Bob Korves is my new best friend and hero!


Gee, well, shucks.  I guess I have you fooled then.  I am just a hack compared to many of the fine people posting to this group.  Seriously.


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## janvanruth (Jan 25, 2016)

once you have a mill you will want a granite/cast plate and some measuring equipment to go with it


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## toolroom (Jan 25, 2016)

abrace said:


> All,
> 
> How essential is a surface plate in a beginner's shop? Is it something I can wait on, or is it something that I should have immediately?
> 
> Same question goes for gage blocks.


abrace, I will put this as gentlemanly as possible for the benefit of the forum rules... investing in a surface plate and or gage blocks is very much like using toilet paper... once you do, you'll never go back to corn cobs!
In other words you're always on target, and that is what all these great guys are suggesting! YES, there may be many other tooling you may need to invest in, but for {sines} and inspection/layout, nothing beats a (decent) surface plate, granite block, or Rock...what ever you call it, be it grade B or grade 2! It all depends on what you're attempting to achieve.
just experience talking!
toolroom


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## Rik Shaw (Jan 31, 2016)

I have a 400mm square granite surface plate and an old set of imperial Matrix slip gauges which I use a lot in conjunction with a digital vernier height gauge. I know you can get by using other more basic kit but I would not be without these three items which I use daily. - Rik


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## British Steel (Jan 31, 2016)

Bob Korves said:


> I absolutely cannot get along without a surface plate and gage blocks any more.  If you do not have known accurate references, you are guessing at everything you do.
> . [snippety snip]
> If you have a very accurate flat, a very accurate 90 degrees, and very accurate length references, you become your own reference standard in a home shop.
> The precision I need is almost always way (WAY!) lower than what I can test, and that is a very good thing...
> But to answer your question, no, a beginner does not _need_ those things.



Exactly what I'd say! At the other end on the spectrum, I grabbed a steel rule in a cheapo shop (Wilkinsons for the others in the UK), only when trying to use it did I notice the 12 tenths to the inch... I hang it by my PC at work, where we do metrology as a speciality, for when someone doesn't get the point!

If you don't have accurate references, nothing else will be accurate: what if every part you made had a 0.3" dimension measured with that 12-tenths rule?

As an aside, what I do all day is build networks (not very mechanical, sorry, but kind of explains a couple of useful principles of metrology) that deliver timing  to banks, stock exchanges etc - they're having to meet new rules that mean they have to timestamp every deal to 100 microseconds (0.000100), lots of penalties if they don't - and it has to be "traceable" to an international standard (UTC, administered by the BIPM, same people who define very exactly what the Metre, Kilo, Inch etc. are).

Before a system gets used for timing, they have to look at the increase in error every time a measurement's "handed down" to the next stage - we supply the bank with time certified and guaranteed (yep, penalty clauses for us too!) to be 100 times better (1 microsecond, 0.000001 sec.) to allow for that loss of precision once we let go of it. Before we hand it over, it's actually running at 50 - 100 nanoseconds (0.000000050 - 0.000000100) because WE need to allow for OUR loss of accuracy too - and when traced back to source, we finally run into the laws of physics at about the 5 - 10 nanosecond level (where moving the clock from the floor to the bench changes the gravitational pull and means adjusting the clock...) - and long term it's appalling accuracy, a second in 158 million years, the shiny-domed  scientists are working on the next improvement, when it shouldn't gain or lose more than a second in the lifetime of the universe (so far...)

I guess I care about Precision Measurement 

Back on topic!

As Bob, I get a lot of use from surface plate, precision squares etc. qualifying other tools and made parts, and use measurements to get to what I want to make (my lathe even has gauge trays and a micrometer built in for when the +/- 0.001" of the Trav-A-Dial doesn't cut it) - and correct measurements mean that what I've made fits, no faffing about adjusting parts as long as the accuracy I require in making it isn't as good as I can achieve in measuring it!

Sorry for the ramble, but perhaps it gets a principle across?

Dave H. (the other one)


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## ogberi (Jan 31, 2016)

I agree with Toolroom.  I got along fine with a thick granite floor tile, a home-made height scriber, and (don't laugh) a home-made machinist's jack for layout work.  I'd set the length of the jack with a hygrometer, then use that on the tile to set the scribes height.  Transfer my layout marks to the workpiece, then verify with calipers.  Usually got within a thou or two, which is plenty for when cutting to a line.   But now I have a proper granite surface plate, Jo blocks, height gauge, etc.  Makes it a lot easier for layout work, and tons easier for inspection work.  I recommend at Jo blocks at least, and a sheet of tempered glass or granite sink cutout to get by.  When enco has a sale on, and you have the spare cash, nab a surface plate.  Once you start using one, you'll probably either use it all teh time, or hardly ever.


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## Chip Hacket (Jan 31, 2016)

I actually think a surface plate and height gauge is most useful.  I use mine to scribe measured lines.  I got the idea from watching Tubalcain videos.  I don't have gauge blocks but would like to have some to check my measuring tools if nothing else.


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## Mike Jones (Feb 1, 2016)

TOOLMASTER said:


> TEMPERED GLASS IS GOOD N FLAT..GLASS SHELVES ECT.


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## Mike Jones (Feb 1, 2016)

The last time I used a proper cast iron surface plate was when I came out of my time and that was 62 years ago. During my
service.Best as an Engineer in the Merchant Marine I used a large piece of  porthole glass. These days in my shop I regularly use
a piece of plate glass when marking out with my height gauge and sine bar.  I also use a glass plate when grinding in flat
surfaces with grinding paste. I would say Save your money for a start and buy something more useful.
Best wishes and many happy hours in your shop  Mike Jones


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## gi_984 (Feb 1, 2016)

Agreed, a good surface plate, height gage, and set of gage blocks are must haves.  Once you use them you'll use them a lot.  Check Craigslist often in your area for surface plates.  Or get a import from Enco cheap when they have the specials.  Either way will be light years ahead of using a substitute.  I use my height gage and surface plate for scribing layout lines all the time.  I have a nice Mitutoyo A grade set of gage blocks for testing but I use a cheap import B grade gage blocks for setting up on the lathe and mill.  On the lathe the shop grade blocks work great for setting your hard stops for a specific length of cut or depth for boring.


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## Guv (Feb 1, 2016)

abrace said:


> All,
> 
> How essential is a surface plate in a beginner's shop? Is it something I can wait on, or is it something that I should have immediately?
> 
> Same question goes for gage blocks.


I have a cast iron surface plate /marking table and hight gauge that I use a lot. I have made several tools that are featured in Harold Hall  books and it is so easy to do the marking accurately when using these tools. The gage blocks I don't have and never had a need for them.


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## janvanruth (Feb 1, 2016)

ogberi said:


> I agree with Toolroom.  I got along fine with a thick granite floor tile, a home-made height scriber, and (don't laugh) a home-made machinist's jack for layout work.  I'd set the length of the jack with a hygrometer, then use that on the tile to set the scribes height.  Transfer my layout marks to the workpiece, then verify with calipers.  Usually got within a thou or two, which is plenty for when cutting to a line.   But now I have a proper granite surface plate, Jo blocks, height gauge, etc.  Makes it a lot easier for layout work, and tons easier for inspection work.  I recommend at Jo blocks at least, and a sheet of tempered glass or granite sink cutout to get by.  When enco has a sale on, and you have the spare cash, nab a surface plate.  Once you start using one, you'll probably either use it all teh time, or hardly ever.



a hygrometer???


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## royesses (Feb 1, 2016)

janvanruth said:


> a hygrometer???


I'm thinking the same. Is that a sling hygrometer or is that a tool I've not heard of? Or a typo?


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## Guv (Feb 1, 2016)

I have a cast iron surface plate/marking table and a height gauge that I use a lot. I have made quite a few tools and projects as in Harold Hall project books. It makes it so much easier to mark out the project accurately and saves a lot of time. The gage blocks I don't have and never had a reason to acquire them.


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## edojan (Feb 16, 2016)

Maybe beginners do not need these things, but this doesn't mean they should not want them.... I am a beginner and I want it  After all the entire hobby by definition is not a need but a want


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## NCjeeper (Feb 16, 2016)

edojan said:


> After all the entire hobby by definition is not a need but a want


You speak the truth my friend.


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## Bill C. (Feb 17, 2016)

You are off to a good start.  Gage blocks and a height gage are a great pair I used many times.  Your surface plate is cast iron if I read the post correctly.  

A simple test for flatness is to use a straight edge or steel rule that is long enough to reach corner to corner and a set of feeler gages.  Start with the thinness gage and try to push it between the straight edge and surface of plate. If it can't go between the two then you are off to a good start.  If there is a gap might consider having the surface plate re-ground. 

I seem layout plates that looked more like anvils due over hammering.


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## Billh50 (Feb 17, 2016)

I have a 12 x 18 surface plate I got for free when I working at a place. It was time to get the surface plates resurfaced but the owner only wanted half of them done. When I asked what to do with the others he said he didn't care what I did with them. So when the resurfacer came to do the plates we picked the larger ones to do and I gave him the 12 x 18 along with them. Told him it was for me so he could charge me separate. When done he told me to forget about paying him separate. So I got mine for free. I already had a set of the rectangular gage blocks that I got free from another boss. Life was good when I was working.


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## abrace (Feb 20, 2016)

Well, 30% off day at Enco a couple days ago was a good excuse to pick up a set of import gage blocks.


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## housedad (Feb 24, 2016)

I now have one along with a 12" height gauge.  A cylinder square, A gage block set and an angle plate are on their way.  I got my mill one year ago and I intend to do a lot of custom work on my firearms.  ( an extensive collection)  for several of the things I wish to do, I know I will find the surface table convenient at the very least.  I am blessed with a mill that has a 11" x 54" table so the surface plate is not essential for the firearm work.  However, I would like to learn scraping so I can clean up angle plates, re do the saddle ways on my lathe, and I will afford me to be able to check spindles and such.  So it will be very useful in the future for me.


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## EmilioG (Apr 7, 2017)

Yes, what Bob Korves wrote.  Having a good, known reference point, that is flat, is a good idea.
I'm buying the small Starrett toolmakers flat. Just enough for what I do.  I recently purchased a very nice Mit 10" dial HG.
Very tedious to use when many scribe lines on a part have to be made. Now I want a digital 12" Mitutoyo. Yes, I'm getting sucked into that black hole called tool obsession. 
Actually, I'm all in, clinging to the rim of that black hole with white knuckles screaming for help.


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## jlsmithseven (Apr 7, 2017)

I have to say for any precision work, grinding or not...the surface plate has been my go to for measuring. The height gauge is quick and easy to accurately measure something once it's out of the vise or machine. Easiest to get repeatable results.


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## ghostdncr (Apr 8, 2017)

In the arena of precision surface grinding is where I've found a good surface plate and gage blocks to be most useful, and mostly indispensable when doing that type of work. I recently spent several years making precision gages and CMM fixtures for a tier 1 automotive injection molder and learned to uses these tools to accuracy about as far as I believe one can go using mechanical methods. We regularly worked in tolerances down around +/- .00005" and these tools are the only method I've ever seen for consistently producing results at that level.

All of our surface plates were Starrett black granite and were professionally checked/calibrated every six months. We had a few pink ones floating around, but they were individually owned, usually in smaller sizes and riding on someone's toolbox for use during machining. The laboratory-grade plates we used were flat within .000035" across a 30" diagonal plate (or smaller) according to Starrett. The calibration service we used claimed the plates were resurfaced to at least factory specs and usually just a little better. Of course, all the tools I'm mentioning here were used in a very clean environment that was kept at 72°F year round. It was important to never directly touch any of these tools, as your body temperature would be transferred into the tools and cause them to grow ever so slightly. No resting of the forearms on the surface plates, no breathing directly onto the tools when doing close work, gage blocks handled with large tweezers, etc.

In practice, we would be given a gage component that most typically needed some part of it (either a physical feature or its location on a gage plate) altered. We built these gages internally according to a CAD model provided by the manufacturer, but most finished gages would require some fine tuning after being checked against the model used for CMM verification. I always wondered why we couldn't use the CMM model to design the gage in the first plate, but I'm not a CAD guy and never could get a straight and coherent answer from anyone as to why it was done this way. Anyway, let's say a step machined into a block needed to be moved down .0004" (Z axis) and over .00125" (X axis). First, I would clean my surface plate with surface plate cleaner (no mineral spirits, acetone, Windex, etc.) and the part with acetone. I would go through the motions of "wringing" the part to surface plate. Although the surface finish wouldn't allow the actual wringing to occur, this usually provided the best contact between part and plate. Calibrated carbide gage blocks were built up to match a control surface, such as the top of the part, and the current height of the  feature I was measuring and these heights were verified using either a .00005" or .00002" dial indicator mounted on my heavy Starrett surface gage (p/n 57D, I believe). Once these heights were verified to my satisfaction, I could re-stack the gage blocks (for the surface I was moving) to the desired finished dimension and proceed with grinding. 

After grinding, the part was cleaned and again wrung to the surface plate. After verifying my control surface and corresponding gage block stack co-witnessed, I could check the newly-ground surfaces against their corresponding gage block stacks and say definitively that, in this example, the surfaces were moved precisely .0004" down and .00125" over. This info was documented along with the control numbers of the tools used to verify, and sent to the quality assurance lab for final verification and return to service. 

In addition to all these precision calibrated carbide gage blocks (in the neighborhood of $8-9000 USD a set!), many shops use master height gages, such as the Mitutoyo 515. Good, used examples can be bought all day for less than $1000. Combined with a really good surface plate, you can get pretty deep into serious dimensional accuracy for a minimal outlay of cash. Naturally, cheaper plates and gage blocks won't offer extreme accuracy unless they're properly reworked and calibrated, but they will provide you a way to do more precise work than what can be turned out using more common methods. I would have a difficult time getting by without mine, but then I've been using them for quite a few years.


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## FanMan (Apr 8, 2017)

I have a piece of precision ground steel flat stock, about 12" square, that is "good enough" for anything I've yet needed to do.  I originally got it to use with a drop gauge for reverse engineering parts, and I use an adjustable planer gauge and caliper in lieu of gage blocks.  Rubber feet and gun bluing makes it nicer to use.  It comes out of the drawer maybe once or twice a year.


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