On 2012-03-15, Spehro Pefhany wrote:
On 15 Mar 2012 05:35:03 GMT, the renowned "DoN. Nichols"
wrote:
On 2012-03-14, Spehro Pefhany wrote:
Looking at using some relatively small screws tapped into (probably)
6061 aluminum.
6061-T6 or a softer version?
[ ... ]
Second -- you need something which will hold the tap straight
(especially for something as fragile as an 0-80) (which, BTW, you only
mentioned in the "Subject: " header, and some newsreaders stop
displaying the "Subject: " header once you are into composing a reply).
The ideal thing is a smaller (say 30X) TapMatic tapping head,
which can be set to limit the torque so when a tap dulls it will stop
turning. And when you set it up, use the depth stop to stop the feed of
the assembly at a proper point.
[ ... ]
Thanks for the comprehensive reply, DoN. I agree about the reverse
switch- the little guy has a rocker, which is a lot smoother.
That helps. Sounds like my AEG/Milwauke electric screwdrivers.
(I think that Panasonic made them for a while too.)
My local guy has a self-reversing head for $200 new (it says that it
backs up at 0.140" after the spindle stops moving down at double
speed),, but the smallest size says it's good down to 0 in steel, not
00 (and up to 1/4"). Think it might be okay at 00 in Aluminum?
http://www.accusizetools.ca/upfile/2...2155414451.jpg
http://www.accusizetools.ca/upfile/28.pdf
Hmm ... looks as though the patent on the TapMatic heads has
expired. :-) The price is certainly attractive.
Note that in your Subject line, you said 0-80, not 00-xx.
I suspect that it would work well, with one possible exception.
The torque limiting clutch might not go down quite low enough. Normal
practice with the TapMatic heads is to start with the clutch fully
loose, and slowly adjust it with a *brand* *new* tap until it will feed
all the way though. Adjust it just a little beyond that point, and when
the tap starts to dull, it will slip again -- warning you to change the
tap before it breaks off in a workpiece.
As for the 0.140" self feed (this is at single speed, BTW, the
higher speed is only when backing it out) -- I have my own preferred way
of setting it which does not require measurement. If you pull out on
the tap chuck you reach a point where you can rotate it by hand and turn
it about 1/6 or 1/4 turn you will reach a point where it will rest on
the dog clutch extended. Then adjust the stop on the drill press so it
will stop before you run out of threads on the tap (leave a couple spare
threads unless you are working with a deep hole). Then tease it to
rotate a little and it should snap back to the engaged position to
reassure you that you set it while the dog clutch was released.
When using it, if you pause feeding the dog clutch will
disengage and start going clack-clack-clack. Feed a bit more and it
will start threading down again. When it reaches the stop, you will get
the clacks again, and that is the time to let the quill back up slowly
(especially slowly with an 0-80 or smaller) to back it out. With
something like a 1/4-20 it will back out a lot quicker.
At that price, I would get one, and try it with your #00-96 was
that the pitch for a #00?
Enjoy,
DoN.
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