MadModder
Gallery, Projects and General => How do I?? => Topic started by: Darren on December 31, 2008, 05:38:22 AM
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Hi Chaps, some adive if you would be so kind.. :wave:
I need to order some thread gauges. I see there are UNF/UNC and Whitworth/Metric types.
Do you really need both or will one suffice, if so which one would be best?
PS, at present I have none.
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Hi Darren
Depends on what you intend to do:- if your going to repaire renovate old machinery then I'd go for Whitworth, if your going to make new bits and bobs than Metric...To be quite honest I very rarely use them when confronted with a thread I don't recognise, I just try my taps or dies on them until I get one that fits, but I'm quite lucky in having inhertited a good selection from my father and uncles.
Have Fun
Stew
:wave:
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Hi Stew,
I'm pretty ok with just looking at metric threads and recognise them right off usually. If not I too use a tap.
Whitworth I can usually use a rule and count. But with finer threads it can be difficult, esp for internal threads. Almost all of my taps are metric so they don't always help :scratch:
Being a scrap collector :lol: I was thinking something better was in order :dremel:
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Darren,
Just to elaborate on what Stew has said.
UNF/UNC (Unified fine & course) use a 60 degree angle for the threads, and is mainly found on American products, but can sometimes be found on other countries products. Britain used it as one of it's standards for a short time.
Whitworth/BSF(British standard fine) use a 55 degree angle, and are found on all sorts of older machinery and products, from all over the world.
Both of the above work on the TPI (threads per inch) principle.
Metric works on a 60 degree angle and is measured by pitch (distance from one crest to the next), and as you know is becoming the standard from everywhere.
So if they are cheap enough, get the lot, but you will definitely require metric. You can use either one of the others for rough gauging the missing one (they don't fit correctly because of the different angles), but you can compare the pitches easily enough.
Hope this has helped.
John
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Thanks Guys, answered my question perfectly.
As they are low priced I'll go for both types and be done with it. :D
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Darn it, now I'll have to look up what a snap gauge is..... :)
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Darn it, now I'll have to look up what a snap gauge is..... :)
If I remember right, I'm sure I'll be told if wrong. :)
In the US were I worked they were a gage set at a certain distance between anvils for measureing. Our gages usally had a dial indicator (clock) on them. For example a gage would be set for .500". All you did was push the gage onto the round part and watch the dial indicator. That was usally set for the tolerences of plus and minus some quanity. It allowed you to check production parts faster than a standard micrometer. I'll look and see if i can find something on the net in the way of a picture.
Bernd
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Hi Bernd
What you described we would call a caliper gauge in the UK, The correct way to measure a thread to "Tailors Principle" is with a go ring and a no go gap. Now that's going to get you all going what's Tailors principle? well that's this weeks homework. :D :)
Have Fun
:wave:
Stew
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Sorry I missed the home work assignment. :lol:
The snap gage I described was used only on round ground work. I've never seen a snap gage for threads.
There are only two ways of measuring threads I know of and that's as you said with a go, no-go gage and the three wire method.
Do I still need to do my home work? :wave:
Bernd
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I'll give a B+ for that Bernd
:lol:
Stew
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Oww, good one Stew. :)
Bernd