Bruce :
Hand taps come in three different tapers, commonly known as 'taper', 'plug' and
'bottoming'. If your set only has one taper of tap in each thread, it is most
likely 'plug'. So, what you need is a 'bottoming' tap in the right size. Give
your local hardware store a call, they may have one on the shelf. Be careful
with the bottoming tap, they are easy to break (and if you think you've got
problems now, just wait until you break a tap !) And yes, the procedure is to
thread first with the plug tap, then remove it and finish with the bottoming
tap.
You can make a reasonable approximation to a bottoming tap by grinding away the
end of an ordinary plug tap. A soft, fine grinding wheel works best, or you
can use an abrasive cutoff wheel in a Dremel or die grinder. Be sure to use
plenty of coolant to keep the tap cool, so you don't draw the temper. I use a
plastic spray bottle, like Windex comes in, filled with water, to frequently
spray both the tap and wheel. (You could probably use Windex for that matter,
it's mostly water and the soap and alcohol won't hurt anything.) Don't let the
tap get hot enough to discolor.
Randall
On Tuesday, November 07, 2000 3:32 PM, Eganb@aol.com [SMTP:Eganb@aol.com]
wrote:
>
> Now, an interesting problem has come up. The blind bottom holes are very
> shallow, and the tap doesn't go far enough in to cut enough threads to make
> me feel comfortable. As you know, the tap is the largest about in the
> middle, so you really need to have the middle part go all the way to the
> "bottom" of where you want threads.
>
> Possible solution -- buy a second tap, and cut it off a third of the way up.
>
> Use the first tap to get started, and the second to finish the job? Is that
> possible? and can you even cut through these taps? Or is there another
> obvious solution?
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