Micro taps

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Hexhead

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I have some micro taps like 3x48 2/56 and such if you can't see what they are is there a screw card or something you can identify them with.

Thanks
 
You can always use a thread pitch gage and check the OD with calipers to identify them.
 
Hexhead said:
I have some micro taps like 3x48 2/56 and such if you can't see what they are is there a screw card or something you can identify them with.

Thanks
Click to expand...
the 2-56 tap is probably a unc form thread - 56 tpi - tapping drill is number 50 gauge drill. as to thread classification of the other tap I assume it could be a unf form thread, refer to a unc/unf tap ref.chart.
 
Hexhead said:
I have some micro taps like 3x48 2/56 and such if you can't see what they are is there a screw card or something you can identify them with.

Thanks
Click to expand...
back again, regards to the 3-48 tap is a num. unc classification british thread , the American equivalant is 3 x 48 tpi -anc . 2-56 tap is a num. unc classification british thread , the American equivalent is 2 x 56 tpi - anc
 
Bright light and magnifying lens - there is usually a label in the body of the tap.
 
2-56 and 3-48 are standard UNC sizes. There are also the 2-64 and 3-56 UNF sizes, but they're rare and I've never seen one. I don't thing of them as being "micro" but they I do a lot of small work. They're very common in R/C airplanes (or were, before everybody stopped building to buy Chinese RTF imports),
 
Your tap is not a micro tap. This one is. I have a set of them. The tap is 0.30mm diameter, .075mm pitch. That's .0118" diameter and .0029" pitch. This is the smallest one in the set that goes up to 1.20mm and .25mm pitch or .047mm diameter and .009.

P1010190.JPG P1010190.JPG
 
JeffInMonterey said:
Your tap is not a micro tap. This one is. I have a set of them. The tap is 0.30mm diameter, .075mm pitch. That's .0118" diameter and .0029" pitch. This is the smallest one in the set that goes up to 1.20mm and .25mm pitch or .047mm diameter and .009.
Click to expand...

This is the smallest one I have. This is a 0000-160 tap. That is a nickel it is sitting on. It makes a threaded hole .020" in diameter and 160 threads per inch.

Some of the metric sizes are so close to the TPI threads that it is pretty tough to tell with a thread gage alone. I have checked thread gages on an optical comparator and most are pretty close but the cheaper ones tend to be just sort of "in the ballpark" dimension wise. Because of this, the only method I really trust to determine the pitch of a mystery thread is to use an optical comparator to count at least 10 threads and then calculate the pitch. (The more threads you use in your calculations, the less error per thread.)

micro tap.jpg
 
Thanks for the replies, I wasn't clear enough though from the replies I got. I have a butch of small taps (sorry for saying there are micro but they are to me) the first thing I tried was a light source and a magnifier still couldn't make anything out. I was just giving the 3/48 and the 2/56 as examples of the taps sizes I was dealing with rather than like 8/32 or larger. I got a suggestion from Pdentrem about a amazon site to look at and that is what I was looking for, It was a gauge card. Thanks
 
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