Re: [CAD_CAM_EDM_DRO] Re: General Tool Life Question

"Fitch R. Williams" wrote:

> On Wed, 16 Jan 2002 15:05:36 -0800, Hugh Currin <currinh@...> wrote:
>
> >I was told recently that these spiral flute taps work better than straight
> >taps for both hand and machine tapping. Does your, or anyone's, experience
> >back this up? What are the advantages of these sprial flute taps?
>
> Are you talking about the spiral point that throws the chips ahead of
> the tap? If so, that is what I use in through holes if I have one in
> the required size. I nearly always power tap with them in both the
> lathes and the manual mill - I haven't gotten up the nerve to try
> tapping in the CNC machine yet. I don't have an accurate enough way to
> know the spindle speed, no tapping attachment, and the machine doesn't
> do rigid tapping (there is no spindle encoder).

Same here - just belt drive Bridgeport J head, and CNC with no spindle
encoder. Check out the Procunier "CNC" tapping heads, models
15000 and 16000 (0 - 1/4 and 1/4 - 1/2" sizes, respectively).
I have had excellent results with one.

>
> The spiral point taps are not as good for blind holes as they tend to
> pack the chips into the bottom of the hole.
>
> The other spiral taps I've not used.

You have to try them on blind holes in a material that will give a curly chip
when drilled, to appreciate what they can do! I drilled hundreds of blind
holes in aluminum in one peck per hole. If you don't foul up the feedrate
or depth, you can do hundreds of holes before the tap even begins to
slow down.

The thread-forming taps are also supposed to be great, but the past few
jobs had thin walls, and I feared the walls would show a bulge near the
tapped holes.

Jon