Re: [CAD_CAM_EDM_DRO] New guy with questions

GM4T from KM6VV,

Tapping a hole in CRS?

Drill the appropriate hole size for a tap, use a tap wrench to hold the
tap. Assuming you're drilling hole in drill press or mill, you can use
the drills quill after drilling to get the tap lined up.

In the Sherline mill, I often chuck the tap in the drill chuck I used to
drill the hole, and with the chuck's taper loose enough so that it is
about to come out, I bring tap in the chuck down in Z until it enters
the work. Then I can *BY HAND* rotate the chuck to engage the hole, and
start the threads. Use thread cutting oil, and turn the tap in a turn
or two, then back it out 1/2 turn. After the first two turns or so, you
can back the Z axis out of the way, and continue to tap by hand. Clear
all the cuttings by backing the tap completely out of the hole
occasionally, especially if the tap is small, or the threads are fine.
If you "feel" the tap get harder to turn, it's an indication that the
cuttings are binding up the tap. Too much, an the tap will likely
break!

On a normal drill press, something similar can be done. Assuming you've
just drilled the hole; If the chuck is one that can be similarly
"loosened" like the Sherline example above, it is an easy way to get a
good square start of the tap. If it can't, then examine the back end of
the tap. Does it have a small hole, or a little point? If you have a
hole, then a small similarly sized steel rod with a 60 degree or so
point on the end can be chucked in the drill press, an with the tap in a
tap wrench, centering and slight pressure can be brought to bear on the
backside of the tap, keeping it properly square to the work. A small
rod with a "cup" end can be made to push against a tap with a point on
the backside, or you'll find that even a twist drill of similar size to
the tap's shank can be chucked BACKWARDS, and the drill's back end can
be used to press against a tap's flat or drilled back end (held in the
tap wrench). Do the usual one or two turns into the work, back out 1/2
turn to cut the thread, use cutting oil. The chuck can be backed out of
the way after a few turns of the tap into the work, as previously
mentioned.

I might mention that there are blocks made to guide a tap that can be
purchased or made, and tapping jigs, etc. as well.

That's one question, Hope this helps! Any yeah, I've tapped MANY a hole
with a small crescent wrench (don't tell anyone!).

Name here is
Alan, KM6VV
Central coast California

P.S. You'll also fine the Sherline list (also on Yahoo) to be a good
source of answers to these questions; as a lot of "Amateur Machinists"
start out on small Sherline equipment.



gm4ta@... wrote:

>
> Hi I'm new to this group and I have a few questions that may seem so
> basic it will probably be ignored. But here goes . . .
>
> How do I tap a hole (in plain cold rolled steel) with a tap? Could I
> do this with a wrench?
>
> What is the standard (or at least most popular) program for CNC
> machines? Just like how AutoCAD is the standard for CAD drawing.
>
> What is a good price guide that machining services charge?
>
> I have been making CAD drawings and 3D models of a part I might have
> to make if it isn't available for buying later.
>
> Thanks!
> -GM4T
>
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