Spiral taps

[sasquatch]

Bill, i,m thinking your'e old school ways are just fine, nothing wrong with all the old school methods they did work after all for decades.
There are many many new improvements that are fantastic, but the old methods still apply, depends on the individual.
The older i get ,i,m 66, some new things are just,,,,,awwww, naw, i,ll do it the old way i,m comfortable with.

 

[Tony Wells]

Spiral taps are made with a pattern similar to twist drills, with generous gullets for chips. In my experience, they are absolutely relegated to power tapping. They do have a definite advantage. When under the load of cutting torque, they "untwist" and grow just a bit. Then when you back them out, they revert to normal sizes and are easier to turn. Tapping by hand, this effect is inconsistent, and works against you. I broke quite a few before it dawned on me what was happening.

The twist brings the chip out of the hole, making them work well in blind holes. In my view, unless you are into production tapping of blind holes, spiral point is far superior for general use.

Plus, when one is broken off in a hole, a normal tap extractor with fingers will not work on it.

 

[Tony Wells]

snip
This is what the tip of a spiral FLUTE tap looks like.snip <<<<<<<<<you sure?

I'm thinkin ya meant spiral point

We always just called them spiral and spiral point taps, never referring directly to the flutes, although that is correct terminology.

 

[Tony Wells]

Duh. I shouldn't be typing when I'm overtired. Thanks for catching that Tony. I fixed it.

I know that of which you speak! Sometimes it takes several tries to get down on the keyboard what I mean, and then I read it the next morning and say: "What!?!?!?".

If only all my mistakes were that small, I would be a happy man.

Bill,
since you do have a tapping head, I wouldn't completely dismiss the spiral flute taps. If for no more than the education, I'd get a couple and try them. You may find that for your project it works out well. Just get the good ones, as Paddy recommended.

 

[Pacer]

I can see myself asking these questions about taps (and dies) not so very long ago - and didnt nearly get the very good description/s that is collected here in this one post - nice!

Yes, definitely choose the spiral point as your primary tap choice - if like me, youll think somethings wrong with the tap, or youve drilled the hole oversize, itll make threads so easy. I eased into my collection, first buying the 3-4 that I use the most, 1/4, 5/16, 3/8, etc, and adding other sizes along - fine threads, #taps, etc. Now I have even added several of the spiral flutes - those chips/curls coming out back-ass-wards out of the hole is pretty handy in blind holes.

 

[Pacer]

I have quite a few "Hertel" brand taps, and have had good luck. I get them from Enco, who seem to always have them on sale in the 'Hot Deals' monthly catalog.

I checked the May issue and they are listed - for example a 1/4-20 uncoated spiral plug is $2.89, these prices will be good til the end of June. If you can put together a $25 (or more) order you get free frt - (code FSCMAY- good til end of June) http://www.use-enco.com/CGI/INSRIT?PMAKA=337-4408

FWIW - MSC has a sale today and tomorrow on hertel products with 45% off, but a little mental arithmetic looks like thats about the same as Encos price.

Dont understand MSC's pricing - way higher than Enco's, and they're the same company!