taps Re: Shoddy Hardware (Was: Re: WW fixtures (was Re: "New" PDP-8))

From: Richard Erlacher <edick_at_idcomm.com>
Date: Thu Apr 4 08:33:11 2002

See below, plz.

Dick

----- Original Message -----
From: "Joe" <rigdonj_at_cfl.rr.com>
To: <classiccmp_at_classiccmp.org>
Sent: Thursday, April 04, 2002 5:41 AM
Subject: taps Re: Shoddy Hardware (Was: Re: WW fixtures (was Re: "New" PDP-8))


> At 12:31 AM 4/4/02 +0100, Tony wrote:
> >> I personally have used a die for threading rod only once in the ~30 years
over
> >
> >I've used small metric dies quite a few times for making custom
> >screwposts for IEEE-488 connectors, etc. It's a pain to use a lathe to
> >cut short, fine-pitch, threads unless you have to.
> >
> >> which I've owned one. Normally, when I needed a tap, I simply bought
one, for
> >> about half a dollar. Now, I'm not quite ready to give up the tap
wrenches I
> >
> >There's something wrong here. You get taps for 50 cents? Over here I pay
> >about \pounds 5,00 for normal sized ones and a _lot_ more for very large
> >or very small ones.
>
Large taps cost more because there's more steel in them. A small tap is the
size of a pencil lead, while a large tap is the size of a drinking glass.
Common sizes are cheap, but the smaller ones are easy to break. Most of the
taps I've seen broken, or broken myself, have been broken in a hand operation
rather than in a machine. Once set up in a machine, they generally go dull
before they break. A few out of every box do break, however.
>
> >Of course I only buy known name-brand HSS taps. The cheap carbon steel
> >ones with badly formed threads are not worth bothering with....
>
> That's probably why he's throwing them away and buying new ones
everytime! I have some taps that date back to the early 1900s and are still in
good condition. Odd size taps costs a small fortune! I've got some that cost
well over $200 each (not that I paid that much for them). I probably have over
$5000 worth of taps alone and they all fit into cabinet that measures 8 x 12 x
15".
>
That's not necessarily the case, if you tap 10K holes per day. You buy lots
of taps because every 30th-100th time you have to replace the by now dull tap
with a sharp one. You then decide whether you want to buy new ones or have
them sharpened. New ones are generally cheaper, so you sell the ones you
don't break to someone who sharpens them and resells them You can buy
resharpened taps, too.
Received on Thu Apr 04 2002 - 08:33:11 BST