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Tap and die


#1

Hi everyone I am trying to tap a gold ball with a regualr tap and die
set to make this kind of thing you put on the tong, ( I don’t know
the name in english) but the tap is too long and the thread also if
I compare with a kind of thread I have in this stainless steel ball
. Where can I find the right tap and die set to do this short
thread? Thanks


#2

Hi Guy,

I am trying to tap a gold ball with a regualr tap and die set to
make this kind of thing you put on the tong, (I don't know the name
in english) but the tap is too long 

It sounds like you’re using either a taper or plug tap. What you
need is a bottom tap.

Taps for machine screws come in 3 styles, taper, plug & bottom. The
taper tape has a longer starting point than the others. The point on
the tap is about 2 or 3 times the diameter of the tap, with no or
very shallow threads. Depending on the material being tapped & the
size of the hole, the taper tap is usually used 1st.

The plug tap has a shorter point than the taper tap & the threads go
closer to the point. It’s usually used after the taper tap, again
depending on hole size & material being tapped.

The bottom tap has threads going just about to the end of the tap.
It’s used last & is meant to tap almost to the bottom of a blind
hole (one that doesn’t go all the way through). Even then some
bottom taps have a point on them that prevents them from going all
the way to the bottom of the hole by about 3 or 4 threads.

One thing you can do to get very close to the bottom is to grind any
of the excess point off. Grind the tap off until your’re just short
of the 1st thread on the tap. Be sure you keep the tap cool
(frequent dips in water) while grinding or you’ll soften the tap &
it won’t cut effectively.

Dave


#3

Hello Guy;

I have had this problem too. What is used in these cases is a
special tap called a “bottoming tap”. You might have problems
finding one in the small sizes you will use. What I do is this: I
drill the hole completely through the bead, then tap the hole, and
using a small bead of gold, just a bit to big to drop into the hole,
I plug the back of the hole by soldering the bead over the hole and
filing it even. If you do find a “bottoming tap”, you tap as far as
you can down into the hole with the regular tap then finish the
threading with the bottoming tap. I like my method just fine, as
long as you don’t heat so much that the solder flows down into the
hole and fills in the threads.

David L. Huffman


#4

you need what is call a bottom tap you can get them from most
industrial supply houses I have used this one online
http://www.mscdirect.com/

Rodney Abel