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Tap and Die 101


#1

I hope that someone would give me step-by-step instructions on how to
use a tap & die. I called Contenti (who I bought the set from) and
was told that “it’s like using a hammer - you don’t need
instructions, just do it”. I could probably fool around with it &
figure it out, but I understand that the taps can be easily broken.
So, some guidance would be helpful.

Thanks in advance -
Sheila


#2

To use a die, first chamfer the top edge of the rod you want to put
a thread onto. Then apply cutting compound. Locate the rod in the
centre of the die ensuring that the side where the die lies flush
with the ‘turning tool’ is facing down the length of the rod.

Turn clockwise a few times with a bit of pressure making sure you
keep it level, as soon as you feel the tool start to ‘bite’ the rod
continue to turn it 2 maybe 3 times. Now you need to follow a pattern
of turning. Turn anticlockwise a quarter, followed by clockwise a
full turn, followed by anticlockwise a quarter, followed by
clockwise a full turn and so on until you have applied a screwthread
on as much as the rod as you desire. Once you are finished unwind
all the way to the top in one go. To use a tap you follow the same
method of turning one full turn then a quarter back and so on. The
quarter back serves to cut off the waste metal that has been
removed.

There will be a chart somewhere on the net about what size rod to
use with what size of die and so on.

Hope this helps.

I have just been teaching my Year 7 classes how to use tap and die
sets, they love it, it’s good fun.

Ali
Sheffield UK


#3

Ok I’ll try to do this in 101 words. Go…

Get yourself a tap chart, it tells you what size drill or rod to use
for what size tap/die, critical. After you drill, lube with tapping
oil and begin turning the tap clockwise into the hole. Go slow. After
you get a bite on the metal with the cutting edges, back out a little
and then proceed back into the hole. Repeat this back and forth
procedure, it cleans out the metal chips and you get a better feel
for when the tap binds. Broken taps usually occur due to brute
forcing it, or having too small a drilled hole.

That was amazing.


#4

Sheila,

No kidding taps break VERY easily. My rule #1 is to always buy the
best quality taps. Expensive and hard to do for jewellery sized taps.
If your set was made in India or etc. beware, Swiss or US are much
better. One case where $ is not a concern.

For tapping you need the right hole size, maybe 60 -70 % thread
engagement. Bigger holes greatly improve your odds. Put another way,
if your desired screw size in 1mm tapping a 1mm hole will ruin your
day, 1.1 -1.2mm much better odds with very little loss of strength. I
don’t have exact numbers for you but a bit of time spent with google
is a good investment, a broken tap is the best way to ruin (and
waste) a day.

The alignment of the tap with the hole is critical, drill the hole
with a drill press if possible and use the same set-up to start the
tap if possible. Use cutting oil, best are ones sold for threading.
Get the tap started, maybe a turn or two. Back off 1/4 turn to cut
chips and then another 3/4 turn. Repeat until done, maybe back the
tap out completely to clear chips every now and then. Gentle… if it
feels bad it IS.

Dies are much much more tolerant, get them going at 90, oil, and chip
breaking.

Hot alum or fresh pickle is good for dissolving broken taps :slight_smile: And
you WILL break some. On a more cheerful note I found that as my
broken tap skills (painfully) the incidence of broken taps decreased.

Always around to answer questions, my auto pilot bench skills are
usually better than my explanations, I’ve got to think to type.

Jeff
http://www.gmavt.net/~jdemand


#5

Hi Sheila,

You will probably get twenty responses to your request, but here
goes with my contribution.

One of the keys to doing a proper job with a tap is to start with
the correct drill size. (A drill approximately 2/3 the diameter of
the thread will be about right.) A drill too large will cause a weak
thread.

After drilling the hole, start the tap slowly and carefully. Keep it
straight and aligned with the axis of the hole. While making the
cut, turn the tap a half turn or so, then reverse it to break the
chip. Continue in this manner until you have completed the thread.
Use a little oil if necessary, depending on the metal you are
cutting. If you are tapping a blind hole, you have to change taps to
a bottoming tap. (Bottoming taps don’t have the lead-in taper.) When
the tap bottoms, don’t twist it further or it may break. If you are
going through the metal, you don’t have to be concerned.

For using a die, it is easiest to hold the blank in a vise in an
upright position. Be careful to start the die without tilting it off
axis. As with the tap, turn a half turn or so at a time, backing
occasionally to break the chip. You can run the die up and down a
couple of times to be sure you have a smooth thread.

A useful tool to go along with a tap and die set is a thread gage sif
you have to match the tap or die to whatever nut or machine screw you
are trying to fit.

Good Luck!
Dick Davies


#6

Hi Neil…that was amazing - I counted 99 words - congrats. I just
got a new student who wants to do Tap and Die - so guess who is
looking to do my first one…need the suggestions.

Thanks
Rose Marie Christison


#7

I meant to do this yesterday, I forgot… Here:

http://www.discount-tools.com/techmain.htm

is everything anybody will ever need to know about taps and dies -
drill sizes and stuff. That’s what the Machinist’s Handbook is for,
too, but that’s like $100 new.


#8

Many, many thanks to all of you who responded to my appeal for
instructions for tap & die - It surely isn’t like using a hammer!
I’m pretty overwhelmed right now - have to sit down & figure out just
what I’ll need - my thought were to use this as a cold connection on
earrings that have components that can’t take heat. I’m tired of
rivets. Maybe I’m biting off more than I can chew. You all are great

  • I’ve asked a lot of people (teachers, classmates, old timers,
    etc.) hoping that someone could show me how these things work (I’m a
    visual learner.) No one could help me & I thought I’d just put it out
    there to Orchid & your responses have been so helpful.

Thanks again,
Sheila