Ulma Doctor

Infinitely Curious
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Feb 2, 2013
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Hi Guys,
i'm at it again...:pickaxe:
here it is ,
a 3/4"-10 TPI 3 Flute Wood Tap, from Scratch MKI
this is my first attempt at tap making.
i have recently become interested in making some threads in wood to make clamps and other wood projects that could use threaded parts.
there are many reputable companies that manufacture them.
i, instead, took it upon myself to make one from scratch.
the material is 7/8" 12L14 hexagonal steel.
overall length is 3-1/2"
minor diameter is .625"
major diameter .740"
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the hex was turned on a lathe to .670" to get the major diameter
then threaded to 10 threads per inch to a minor diameter of .625"
the end was tapered to 15*, the pilot end is turned to .600" diameter.
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the flutes were cut in a vertical mill, at 10* relief angle.
this steel is relatively soft and doesn't harden or weld well due to small traces of lead, but it is a dream to make things from 12L14 because it machines very nicely.
the nut was store bought, to test the class of fit on my turned piece.
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project cost $2.89
total time 45 mins :grin: (1 hr 20 mins with mistakes...:bang head: )

i hope this inspires others to make their own tools, even if they think they can't !
as always, thank you for reading!

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Maybe I'm seeing it wrong, but isn't your gash/relief on there backwards? Unless it is a left hand tap, that is. And 0.670 seems awful small for a 3/4-10 tap OD. But, it's really late so maybe I'm all wet.
 
Nice work........buttttt

Minor dia for a 3/4-12 is .624......a 3/4-10 is .600. Rut-row Reorge

I KID, I KID!!

Actually my dims ARE right, according to a 1944 Popular Mechanics I found while trying to figger it out.

https://books.google.com/books?id=I...ved=0ahUKEwiipNDt3avLAhXJvoMKHTBADpcQ6AEIZjAQ

It never occurred to me that taps would be used to make threads in wood.....and I remember seeing threaded bungs on chair legs I took off my parents furniture as a kid.:confused 3:

There is a BUNCH of info on that link I attached....I hope is right. You opened my eyes, thanks!
 
Lot of good info in those articles, and the adds at the end are great. Thanks for posting. Mike
 
Maybe I'm seeing it wrong, but isn't your gash/relief on there backwards? Unless it is a left hand tap, that is. And 0.670 seems awful small for a 3/4-10 tap OD. But, it's really late so maybe I'm all wet.
Hi Tony,
i'm glad that you caught my mistake in the relieving of the tap. thank you!
i did make another mistake in reporting the major diameter, it is .740",
i don't even know how i did that...:bang head:
must have been looking at the wrong piece of paper, or trying to do too much again....:)
i guess this gives me opportunity to try relieving the tap once more, the correct direction!
thanks for your interest and input,
i'll be sure to post the end result!
 
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after making a couple mistakes, i think i'm back on track....
i changed mill tooling from a 3/8" 4 flute endmill,
to a 2 flute 3/8" ball endmill and reversed the tap in the vise and repeated the relief procedure, again!
here's the end result...
FullSizeRender%2B%25282%2529.jpg
it looks more like a commercial tap now.
whaddya think???

FullSizeRender%2B%25282%2529.jpg
 
Nice work........buttttt
Minor dia for a 3/4-12 is .624......a 3/4-10 is .600. Rut-row Reorge
I KID, I KID!!
Actually my dims ARE right, according to a 1944 Popular Mechanics I found while trying to figger it out.
https://books.google.com/books?id=I...ved=0ahUKEwiipNDt3avLAhXJvoMKHTBADpcQ6AEIZjAQ
It never occurred to me that taps would be used to make threads in wood.....and I remember seeing threaded bungs on chair legs I took off my parents furniture as a kid.:confused 3:
There is a BUNCH of info on that link I attached....I hope is right. You opened my eyes, thanks!

Thank you Tommy D.!
the information in the link is very helpful, i appreciate your input! :grin:
 
Of course, now you need to make a threading box for the mating tenons :)
Thank you Tony for your wisdom!!!:tranquility:
Yes Sir, the threading box is on the horizon.:big grin:

since i have a general plan as to how to make the taps,:black eye:
i'm considering making a few taps of different sizes since i'm in that mode right now.
i don't know if i'll make a "full set" but i'm thinking 1/2, 3/4, 7/8, and 1" for now.:grin big:
 
I've watched Roy Underhill a few times and he has access to, or owns, some pretty cool old tools. He has taps and boxes for various sizes. I don't know whether there is a standard (of course, we who make our own tools are not bound) pitch for wooden threads, but I suspect there are. I'm sure there are episodes on youtube. You might pick up some tips from him. In case you don't know who he is, he hosts the "Woodwright's Shop" I believe. It's not in production as far as I know, but I still record the reruns on Saturday evening for later viewing. Although he always seems a little rushed and rough doing his TV demonstrations, I'm quite sure he is capable of very fine work. He's the real deal.....lol, check out his cut and gouged fingers and hands. He nearly always has a black nail. Sometimes bleeds on episodes.

Keep up the good work, Mike. Someone has to make all the tools for woodworkers of the world!


I might add that if you settle on a pitch, your thread box need only to be adjustable to make all the common diameters you make taps for. Just a hint.
 
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