Tools and Surface Plate Questions

Splat

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So I'm starting to do more projects now that require more accurate measuring than I've been doing. I don't do many big >12" parts so I'm considering a 12x18 size plate. I can pick up locally a grade-B Standridge surface plate via McMaster Carr (love that place!). I know I can get much cheaper via Woodcraft or MSC but shipping is killer or the quality might be/is suspect. From what I've read most home shops are using the 12x18 so I think I'd be ok with that size. Any opinions on the size? How are you guys supporting your plate?

As far as measuring I now have: good 123 and few angle blocks, good set of parallels, good hole gauges, good analog and a decent digital micrometers. Should I get a height gauge, combo square set, or something else? I'm leaning towards a height gauge but but figured I'd ask you guys. If height gage what type? Vernier, dial, etc? Thank you.
 
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I personally prefer vernier height gauges, pretty much bullet proof. A dial is OK, but I wouldn't have a digital as my only height gauge, and I do own a cheap one, guaranteed that the battery will be dead just when you need it.
 
Height gage will measure and scribe lines . Surface gage has many uses . You'll use them all . I'm getting ready to unload a lot of both . :encourage:
 
I have both a vernier height gage (12" Starrett with 50 division vernier) and a few sizes of surface gage. The surface gage is good for rough layout work and many other jobs, if used on the surface plate for layout, a rule holder that clamps your rule vertically is handy; also I would not be without a combination square set, and don't settle for cheap crap, buy a (very) good name brand; I found two sets at an estate sale, both unused B&S from the 1940s, one resides in my wood shop, the other in the machine shop.
Bottom line, I mostly use the height gage for any and all layout work.
 
I have a import 18x12 grade a granite w/ ledges that I got when enco was selling them for dirt cheap with free shipping. I get by with it but I really wish I had a bigger one. I also have a 12x9 that I picked up from my local MSC when they were cheap but I only use it for lapping. Perfect size for standard sheets of sandpaper.

I agree, I prefer vernier height gauges too but I use a 6" M-DRO/SRA digital most of the time. I like my 12" Mitutoyo vernier, it's in nice condition & it always goes back into the wood case when not in use. But most of the time it's too cumbersome to use. So I bought the 6" digital to use for laying out lines. Compact, much easier & quicker to use. I just leave it out. Yeah it's Chinese so it likes to eat up batteries but I still like it.

I don't work on big stuff & I easily run out of room with a 18x12. I'd say if you're able to, get at least 24x18 (or bigger) but that's about the size where the price jumps (from what I remember). Size of the plate doesn't dictate what size parts you can measure, remember you need space for the measuring tools to sweep the part, etc.

That reminds me, I need a smaller surface gauge too, my Starrett surface gauge is kinda of too big. Well I guess it really means that I need a bigger surface plate (wish I had the room). :)
 
I have a 18 x 12 and it is good enough since my work tends to be on the smaller side. I also have a little 8 X 12 Starrett toolmaker's flat for layout work. Depending on what you need to do, I would suggest you consider:
  • A height gauge - if you want a good one, look for a dual column Mitutoyo. Very rigid, heavy and accurate in the thousandths. My most used one is a little 6" Starrett dial height gauge - light, fast, accurate and easy to use. If you can, buy a carbide scribe for your height gauge; they last forever. Most height gauges can hold an indicator with the right attachment.
  • Surface gauge - get a big, heavy one and maybe a small one for basic layout work. These also hold an indicator for assessing flatness, just like the height gauges do. If you plan to do layout work with a surface gauge, buy a rule holder as this will save you time; Starrett makes a nice one or you can make your own.
  • Cylinder square - useful for checking if a square is actually square. I want a 6" high cylinder square but don't own one yet. I have a little 3" Murkens magnetic cylinder square that is perfect for evaluating how square a vise or angle plate is; very useful.
  • Make a box or at least a lid to cover your surface plate when it isn't in use. If you don't cover it then you'll sit something on top of it and nothing should touch the surface except for your measuring tools.
Here is some info from Starrett on supporting your plate:


How should my surface plate be supported? Does it need to be level?
A) A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface.
The plate should be supported at these points during production, and it should be supported only at these three points while in use. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same 3 points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. All Tru-Stone steel stands have support beams designed to line up with the proper support points.

If the plate is properly supported, precise leveling is only necessary if your application calls for it. Leveling is not necessary to maintain the accuracy of a properly supported plate.
 
I feel that the quality of the surface plate is immaterial for those using scribing etc. as their main marking out technique.

Airy points are also immaterial until one gets into volumetric single microns.
Aka x by y by z measurements for some datum in 3d space.

S:
Look at suburban tool videos on cylindrical squares and lapping.

A gage block set / stack can give a very good 1 micron (2 micron) length.
So will any medium-good import micrometer set.
 
Initially I bought a 12 x 18 surface plate from Lee Valley Tools here in Canada. It was great, but I found it to be too small. I could measure or lay out most of the time but was putti g my height gage or surface gage onto the bench, which meant wiping the bottoms of each over and over. While it may seem trivial, after a while it just becomes aggravating. I purchased a second 18x12 plate (a Starrett) on Kijiji, Canada’s version of Craigs List for $100 and put them side by side which was ok, but not ideal. To my point then...... I ended up with a 24 x 36 x 4 Starrett, toolroom grade plate and I LOVE it. My wife sewed a vinyl cover for it and not once have I remarked that I wished it was smaller. My shop is 11 x 10 and that plate takes up a bunch if realestate, but it is worth every inch to have it. It cost me $250. I sold both 12 x 18’s; the Lee Valley one for $50 (lost $10) and the Starrett one for $150. Get a good plate and buy the largest one you can afford/have space for. And be patient, one will crop up. I only wish that there were people in Canada who could do the calibration/resurfacing like there are in the States. My plate is good, but I’f like it calibrated and cannot find anyone in Ontario to do so. As for height gages, Starrett or Mitutoyo digital all the way. Verniers are great, if you can figure out how to read them......

Cheers all.


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Initially I bought a 12 x 18 surface plate from Lee Valley Tools

Do you mean the 9 X 12 from Lee Valley? I don't remember them ever selling a larger 18 X 12, but if they did I should have bought it. The 9 x12 is a nice surface indeed a bit tight for anything bigger than a few inches square.

-frank
 
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