Gage blocks

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John Hasler
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Re: Gage blocks

Post by John Hasler »

I can get within .001" with what I have now but I think that it would often be easier if I had a set of gage blocks. It also might reduce my scrap rate.
Downwindtracker2
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Re: Gage blocks

Post by Downwindtracker2 »

I bought a set of import gage blocks and a set of pins. They looked like a handy way of measuring. But if I hit within 1/2 a thou, I'm bragging. I think that's the limit of my machine tools., not to mention the operator, chuckle.
A man of foolish pursuits, '91 BusyBee DF1224g lathe,'01 Advance RF-45 mill/drill,'68 Delta Toolmaker surface grinder,Miller250 mig,'83 8" Baldor grinder, plus sawdustmakers
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Harold_V
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Re: Gage blocks

Post by Harold_V »

I agree totally that gauge blocks are not a requirement for most home shop work. The one place they have high value, assuming the home shop is not engaged in grinding critical angles, is in calibration. By using blocks for that purpose, assuming they are traceable to the Bureau of Standards (they are calibrated), critical work can be accomplished in more than one shop, with assurance that when they are brought to a common place the parts will fit as designed. Said another way, it's a great idea for my inch to be the same length as your inch, and that's what the use of certified standards do (assuming parts are made to design specifications, and the engineer understands proper dimensioning and tolerancing).

There was a time when most everything in the machine shop was measured by a ruler and spring caliper. By improving our ability to make more precise measurements, and by using a common standard, industry was able to move to mass production. In order for that to work, everyone must be on the same page, which, in this case, means that the inch (or millimeter) is a constant, it does not vary shop to shop.

I don't like to talk about right and wrong, as that's not really what this is about, but if one learns to work properly, making good parts isn't nearly as hard as it is when one ignores all the standards and procedures that have been put in place to ensure quality. Use correct procedures and you can predict the outcome. Close your eyes to acceptable procedures, picking and choosing the things you feel are important and ignoring the rest, pretty much assures that you will achieve success only by chance. Learn to do it right, and that is no longer true. Use calibrated measuring instruments. Make sure your inch is the same as the other guy's inch.

H
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10KPete
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Re: Gage blocks

Post by 10KPete »

Well said, Sir, well said. The Foundations...

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pete
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Re: Gage blocks

Post by pete »

Almost guaranteed there would be zero performance difference Mauro. Unless that drill and my use of that protractor was just slightly off and the drill landed only part way into the valve cavity, then I might have a real problem trying to move those holes. Small engine cylinders don't leave much fudge factor. I didn't say it was the best or only way, but it's always worked so far. Yes I can and have drilled lots of holes using little more than the mark I eyeball and hoping for the best and have used that protractor method to line up the drill angle as well a few times. But calculations of what should happen don't lie if the numbers are correct. And my use of a good sine bar and gauge blocks still won't allow 100% certainty I'll get what I want. A drill can wander, the casting have a hard spot or inculsion etc. It could do exactly the same lining the drill up by eye. But I didn't buy my gauge blocks for that one task nor did I say anyone has to have them. My scrap rate has dropped as I've started to use better tooling and have the ability to double check what I'm buying.

I mentioned what I thought was important. It's up to anyone else if they think I'm right or not and what would work the best for them. Since I have the blocks and bought them for multiple reasons I use them for that job as well as calibration of everything else because it just betters my chances of getting it right and knowing so when it is. Machining is also about using the best methods you have available and not depending 100% on skill or probable odds of being correct. Jigs and fixtures are also used to remove the need for higher skill levels for simple tasks. We all use those as well. Before I bought my blocks I used to use my adjustable parallels preset to the proper stack height. It's likely whatever precision I got with those was more than good enough. Using the blocks is still faster and easier. Time wise a real machine shop and most hobbiest guys wouldn't bother with a lot of what I do. But I can afford that time to play at being accurate. And when the inevidable pear shaped problem pops up and I can't fault the equipment or set up then I just have to look in the mirror to find who to blame. :-)

A lot of what I've bought is with the thought that at some point I'll have a surface grinder. So I've bought and planned for better than what my needs are right now. Had I not considered that there's quite a bit I wouldn't have bought.
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tornitore45
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Re: Gage blocks

Post by tornitore45 »

Pete, your response made me reflect. You have a point.
I found that may equipment, that was junk when I bought it, has steadily improved, reduced scrap substantially and turned out good parts. Tool breakage and parts jumping out of the fixture has practically ceased.
The point is that it was not the equipment that improved but my skills. At some point, not quite there, I will reach the limit of my equipment and new level of precision will require serious instruments. I am not there yet.
Mauro Gaetano
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pete
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Re: Gage blocks

Post by pete »

If I think back to how I progressed Mauro then as my experience / knowledge level increased then so did the disatisfaction level with a lot of what turned out to be less than ideal I'd bought when I knew a lot less. Sort of an ever expanding vicious circle maybe. I also hadn't really given much thought about your mention of the skills improving as a major cause of dropping the scrap rate. Obviously that helps a lot since I think I know much more about what not to do now. I mostly blamed that on the better tooling that replaced some of the junk. :-) I fully believe it's more about the person behind the hand wheels and what's between there ears than the equipment. But the better equipment and tooling make things a whole lot easier. My first Chinese mill vises tossed a few items out of them as well. My better replacements haven't yet even while pushing them a lot harder. Better equipment + more knowledge to understand why better might be needed = less problems, broken tooling and scrap I guess.

George Britnell as just one example has more than impressed me with his skills and build quality for a long time. Google images using his name as a search term shows some of it. He mentioned doing some highly complex 3D part contouring and doing so all on manual machines to the numbers. Machining the exterior surfaces on his working scale model Ford engine and it's transmission are part of what I mean. That really impressed me. A bit later I found out he was doing that with a stock round column Rong Fu 30 sized mill. Even most hobbiest's will advise people not to buy them since there's better and easier to operate equipment at around the same price. My BP clone and it's dro should be a whole lot better, so I wonder if I'll ever learn enough to get to the limits of what I now own since I may never be able to do what George can. It's still good to see what can be done with enough skill. And being disatisfied with your own ability's isn't a bad thing.
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ctwo
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Re: Gage blocks

Post by ctwo »

Would it be worth exploring a 10:1 mechanical amplifier, such as a classic fulcrum on a granite comparator stand to compare the Shars blocks with my calibrated Polish blocks?
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
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pete
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Re: Gage blocks

Post by pete »

Those Polish blocks should be real good. It might be worth it, who knows you might pick up something that shouldn't be there and could cause a future issue. If you don't check then there's no way to be certain there isn't any problems. I'd also be interested in what you find. I ran about a half dozen rough checks on my Mit. blocks when I got them just for my own satisfaction. They all checked as good as micrometers can resolve to and non perfect temperature conditions allow. For now I'll take the rest of them on faith.
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ctwo
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Re: Gage blocks

Post by ctwo »

The topic is at my fringes. This is what I was thinking, by swapping equal blocks I'd double my error.
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gauge-block-compare.png
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
pete
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Re: Gage blocks

Post by pete »

The idea looks pretty good. Having been burned or let's call it mislead a few times with indicators and the effects of gravity I'm a little leary of light weight horizontal bars sticking out in space when it comes to precision measurement. Then again you don't need to measure the blocks actual height, your only looking for a slight change either up or down on the horizontal bar that shows a deviation in one of the blocks against the other. And as a way to double any error that's a very well thought out and brilliant idea.
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ctwo
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Re: Gage blocks

Post by ctwo »

I was comparing my Polish and Shars blocks directly and convinced myself that the needle width on my finest 10ths dial indicator (old Fowler) is 100 millionths. I further convinced myself that I could see near half a needle width difference between a -11 and +23 blocks. That would be amazing.

For the little lever up there, the points would be 3 ball bearings pressed/glued into steel, two on the far end, and the plank could be much thicker.

I am just now eyeing a small v-block and imagining a ground dowel clamped into it. Heck, here is a crude test with my 0.5" blocks, +1 and +14. This is giving me 3:1x2 and I measured just a hair under 1 tenth pushing down on the block and swinging the end under the indicator to find the high. Looks like so many sources of error.
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gauge-block-comparitor-20180918_223021.jpg
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
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