Looking for a gauge for 30 degree trapezoidal thread tool grinding
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  1. #1
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    Default Looking for a gauge for 30 degree trapezoidal thread tool grinding

    Just need a gauge for grinding 30 degree metric trapezoidal thread tools. Need to thread about 14" of Tr16x5LH and while I could just use a 29 degree tool and eyeball the nose flat to match the old thread, I'd rather do it correct. All I can find are imports from China, which I don't care about, but they all have to ship from China. The quickest I can get one it seems is end of July. So if anyone wants to let me borrow it for one job and send it back, that's fine too. I just need it relatively quick.

    Thanks

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    Have you got a protractor? Have you got a loupe with a measuring scale? Have you got a bench grinder? If you say "yes" to all three you have everything you need to make the tool.

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    Quote Originally Posted by Illinoyance View Post
    Have you got a protractor? Have you got a loupe with a measuring scale? Have you got a bench grinder? If you say "yes" to all three you have everything you need to make the tool.
    No to the loupe, yes to the other two. I realize I can make it work and be reasonably accurate.. Any other methods for measuring the tool flat or I'm best just getting my angle correct and eyeballing it to the old thread?

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    You can approximate the width of flat using a mike or caliper.

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    Quote Originally Posted by Illinoyance View Post
    Have you got a protractor? Have you got a loupe with a measuring scale? Have you got a bench grinder? If you say "yes" to all three you have everything you need to make the tool.
    Surely...

    But easier yet.... one can "gage the gage" (metal) against two lines on ignorant paper. Or scribed on Dykem'ed metal.

    And if one can't grind a metal gage? How TF did'yah plan to grind the metal TOOL?


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    Quote Originally Posted by thermite View Post
    Surely...

    But easier yet.... one can "gage the gage" (metal) against two lines on ignorant paper. Or scribed on Dykem'ed metal.

    And if one can't grind a metal gage? How TF did'yah plan to grind the metal TOOL?

    I guess, I was just going to hope that if I stared at it longingly enough it might grind itself! Thank you for the assistance, it's been greatly appreciated!

    Is grinding gauges hard? no. Is grinding toolbits hard? no. I'd just like some quick and easy setup and repeatability. I'm sure you have a 29degree and 60degree gauge in your chest somewhere! Either way, I'd already taken the advice given, tools done, threading's done, thanks for the adivce given.

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    Quote Originally Posted by naru View Post
    I'm sure you have a 29degree and 60degree gauge in your chest somewhere!
    Uhhh.. you don't really want to know, actually. "Be prepared" can eat yer lunch as well as a huge ration of storage....



    But you, I - any of us - can fab an accurate angle in metal faster than we can get to FedEx or the Post Office, yah?

    So if a tool or instrument this simple is to be "borrowed"? Well.. to be of any use, time-wise, it would have to be from another craftsman no further away than the next bench.

    Now... if I wanted to make it complicated.. ? Guess I could set up with a Dividing Head or a rotab, and ...

    Sorry. That's rude.

    Didja not know that for a 30-60-90 right triangle the longest side (hypotenuse) is exactly twice as long as the shortest side?

    No need of a precision protractor to lay out that one.

    Nor even a square. Nor even a scale or rule. How big is "don't care".

    Dykem. Compass or trammel points. Straightedge.

    And you soon have all of 30, 60, and 90 degrees.

    Gradeschool classwork was that? Paper & pencil, not Dykem & scriber, but same process..


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    Quote Originally Posted by thermite View Post
    Uhhh.. you don't really want to know, actually. "Be prepared" can eat yer lunch as well as a huge ration of storage....



    But you, I - any of us - can fab an accurate angle in metal faster than we can get to FedEx or the Post Office, yah?

    So if a tool or instrument this simple is to be "borrowed"? Well.. to be of any use, time-wise, it would have to be from another craftsman no further away than the next bench.

    Now... if I wanted to make it complicated.. ? Guess I could set up with a Dividing Head or a rotab, and ...

    Sorry. That's rude.

    Didja not know that for a 30-60-90 right triangle the longest side (hypotenuse) is exactly twice as long as the shortest side?

    No need of a precision protractor to lay out that one.

    Nor even a square. Nor even a scale or rule. How big is "don't care".

    Dykem. Compass or trammel points. Straightedge.

    And you soon have all of 30, 60, and 90 degrees.

    Gradeschool classwork was that?

    You're right, and I appreciate you pointing that out. You clearly have a level of experience over me and I won't question that. But what's a forum if not a place to ask for help and advice? Just was looking for a tool, no need to belittle someone. But yes, you're right in every sense.

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    Quote Originally Posted by naru View Post
    You're right, and I appreciate you pointing that out. You clearly have a level of experience over me and I won't question that. But what's a forum if not a place to ask for help and advice? Just was looking for a tool, no need to belittle someone. But yes, you're right in every sense.
    Not "belittle". Remind. Bet you knew this and forgot you knew it? As a society, we can get to leaning too heavily on 'puters, hand-helds...... store-bought tools..., etc. .

    This is only one of SEVERAL "trig tricks" - special-case triangles, really - that don't actually require any of math, linear units, or trig to deliver very precise results.

    And I didn't LIKE trig class!!!



    Y'see.. before there were electronic calculators.. one had a Log-Log-Duplex-Decitrig slide rule. With only 3 places of accuracy. Which wasn't GOOD enough.

    So that meant toting around a book of log and trig TABLES. And only the HEAVIER ones (9-place...) were much good, even then.

    Shortcuts, OTOH, one can learn to love. Even get wealthy off the back of those, diligently applied.



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