Strangest tap I've ever seen!

**LINK**

Not seen one like this before!

Jim

Oddball !, no good for 4 - 5 & 8 -10 mm blind holes methinks, doesn't show HSS so take them to be carbon steel. Anyone used one ?

George.

Only applicable to a limited material thickness as well before fouling on the next size increment

A rather silly gimmick in my view

Brian

Not sure about these particular examples but the type is used in production to reduce the number of tool changes needed on an automatic. Job is done faster because one tap can cut 3 different threads without having to reset the machine. Obviously only worth using when a job requires several short threads of different diameters to be cut, like making metal boxes or radio chassis perhaps. I doubt they'd get much use in my workshop.

I think I,ll pass on this one.

Clearly for sheet/thin materials.

My guess is a specialist production system as has been said to reduce toolchanging.

At that price I expect there was an oversupply or more left at the end of the job when expected and chronos snapped them up cheap.

Probably worth having for hand tapping things like garden gateposts or roof trusses when you don't want to risk your best set. For about £4 keep it in your toolbox for emergencies.

Neil

They look to be quite poorly ground. I can't imagine any self-respecting machine shop using them. Generally sheet/thin metal isn't tapped in the conventional sense. One either uses self-tappers or inserts.

I've never seen anything like them and I've spent many a happy hour poring over professional catalogues! I definitely won't be buying a set.

Andrew

I guess you can get a stepped drill to go along with it

Combination drill-taps are also used to speed up production:

They might be handy for electricians or control panel builders / service guys to tap or chase the odd thread as required in sheetmetal up to about 1.6 mm thick max. I don't think they are intended as a production tool, or for model engineers particularly. Vote with your wallet, or not.....

I have one of these which is handy the odd time. Not a big-use item though

I have seen the multiple tap setup before. Many years ago I had a similar tap except it was on a screwdriver handle. It was primarily an electrician's tool. I used it for cleaning up cross threaded holes on electrical boxes. I would sometimes drill out the mangled threads and use the next larger tap. A screwdriver handle on the tap is much more convenient than having to use a t-handle tap wrench.