Flat sided thread tap

[I.M. OUTAHEREParticipant @i-m-outahere]

[I.M. OUTAHEREParticipant @i-m-outahere]

Today i was rifling through some taps i purchased off ebay a while back and in one bag was a mixed allotment of 1/16 bsw taps , some are three flute with a sqare end for a tap wrench some are like a threaded piece of 1/16 rod with two parallel flats ground along the threaded portion to act as flutes and have no sqare on the end .

Any ideas ?

Ian.

[mechman48Participant @mechman48]

Are you sure these are taps, may be they were use as thread cleaners/chasers …but then you would use ordinary taps in that case… ?

George.

[I.M. OUTAHEREParticipant @i-m-outahere]

Dunno , i bought the allotment because it was mostly BA taps by the bag full – New and i believe English made .

The seller added some other stuff to the sale , some very small screws in BA size , can't remember exactly but i think 14 or 16 BA .

They were like a little screw the same diameter as a #80 drill , i had to get a magnifying glass out to see them !

I was thinking maybe something to do with clock / watch making ?

I sacrificed one and they do cut a thread in mild steel up to about 1/8 thick but any more than that jam .

For now until someone can correct me i will call them a spade tap !

[Michael GilliganParticipant @michaelgilligan61133]

Do you have the facility to photograph one of these taps in detail?

My guess is that they are [as you say] flat; and will therefore be 'zero rake'

… That would make them O.K. for use on hard leaded brass, bur risky on steel.

MichaelG.

[Tim StevensParticipant @timstevens64731]

Sounds to me like a forming tap (as distinct from one intended to cut metal) – the hole size needs to be bigger as the metal is squeezed into the thread form. A similar process to thread rolling, except that the tap slides instead of rolling.

It might be worth an experiment with different sizes of hole, and then peer closely at the thread looking for a full form. If you need that size, of course.

Cheers, Tim

[Ian S CParticipant @iansc]

They sound something similar to Threadflo taps, these are slightly triangular, with no flutes, they are good in brass, aluminium, and stainless steel, the tapping hole is a little larger than for a conventional cutting type tap, as the thread is formed rather than cut, and no metal is removed in the forming of the thread.

Ian S C

[I.M. OUTAHEREParticipant @i-m-outahere]

Edited By XD 351 on 17/09/2016 04:29:37

[John ReeseParticipant @johnreese12848]

A while back I purchased a watchmaker's lathe. Included with it were some very small taps. They had no flutes but had some flats ground on them. The flats are not parallel, resulting a starting taper on the end. I guess that would work in soft metals like brass. I would like to hear from the clockmakers on this forum. Is this kind of tap common?

[Michael GilliganParticipant @michaelgilligan61133]

Dan [and John, for info.] … Thanks for the photos; which are as expected.

I stand by my original comment, that they are most likely intended foe use on Brass.

Brass [especially the grades used by watchmakers and scientific intrument makers] cuts very cleanly with tools having near [+ or -] zero rake; producing chips rather than swarf. … This style of tap is therefore quite effective, as well as being stronger and much easier to make, than its fluted eqivalent.

MichaelG.

.

P.S. … Fluted taps [and beautifully made small dies] are avalable from Bergeon, and these will cut steel; but the prices are eye-watering.

http://watchmaking.weebly.com/uploads/1/1/7/9/1179986/bergeon_taps_and_dies.pdf

Edited By Michael Gilligan on 17/09/2016 08:10:02

[I.M. OUTAHEREParticipant @i-m-outahere]

Thank you to everyone for the replies.

I will try one in brass and see how they go , I don't see them getting used as I don't make clocks or anything really small .

In the same bag there is some three flute taps , some with a square end and a few are with a blank end like the flat sided taps pictured .

Ian

[Michael GilliganParticipant @michaelgilligan61133]

Sorry, Ian … I called you Dan, this morning

[ not enough coffee ]

MichaelG.

.

P.S. … If you're not expecting to use them; I'm interested.

[MuzzerParticipant @muzzer]

They look a little bit like Taptite screws, which are also(?) thread forming rather than thread cutting. They aren't recommended for reuse and in practice they do make a little swarf but can be driven directly into diecast holes without any machining required.

Edited By Muzzer on 17/09/2016 23:34:37

[I.M. OUTAHEREParticipant @i-m-outahere]

Posted by Michael Gilligan on 17/09/2016 21:56:20:

Sorry, Ian … I called you Dan, this morning

[ not enough coffee ]

MichaelG.

.

P.S. … If you're not expecting to use them; I'm interested.

No probs Michael i usually don't wake up until I'm on my second cup !

P.M me an address to send them to and i wil post them to you.

Ian.

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