Taps & Dies

[CabengParticipant @cabeng]

From Adam Gregory: “Just my luck to get a duff one.”

 

I suspect you might have to be very lucky to actually get a good one!

 

I’ve put some photographs in an album, but be warned -these are not for the faint-hearted!

 

First picture – a montage of nested taps. One might reasonably expect that the threads on each of a set of taps would match, but t’ain’t necessarily so. The carbon steel 5/32″ x 40 taps do fit together beautifully, the same cannot be said for the metric taps, despite them being ground thread HSS from a supplier to industry, and not cheap. Additionally, they don’t bear any resemblance to a metric thread profile.

 

Second picture – a thread cut in the lathe using a die in a tailstock die holder. Felt very strange when cutting the thread, subsequent inspection with a lens showed the thread WAS somewhat strange.

 

The third picture shows the die in question mounted on a properly cut thread – I think you can see why it cut a strange thread when held by the tailstock. Again, ground thread HSS.

 

Fourth picture – the teeth on some ground thread HSS dies, bought to go with the taps of the first picture, but a different supplier. Looks like they were ground with an angle grinder. Macbeth’s witches probably had better teeth!

 

Lest you think this unusual, have a look at the BA dies in the fifth picture, another supplier. These are just 2 examples rom a 0 – 10 BA set of taps and dies – NONE were usable. The supplier offered to replace them – REPLACE THEM WITH WHAT? MORE RUBBISH? Oh yes, ground thread, HSS again.

 

And if you want the really bad news it’s that, with the exception of the HSS taps, all the bad examples came from sources that have been mentioned on this thread. And I have examples from some that haven’t yet appeared!

 

The first (and obvious) moral of the story is, of course, caveat emptor. The second is that if you’re having difficulty with getting a good thread, your difficulties could well be caused by the tool you’ve been using. And the third is that paying more for a tap or die does not necessarily guarantee better quality.

 

Since those unsatisfactory experiences, I will only buy taps and dies
with the manufacturer’s name on the tool. If he doesn’t put his name on
what he makes… well, you can draw your own conclusions as to why he
doesn’t. That’s the manufacturer’s name, not the seller’s. I stick to Apex (the
5/32″ taps are Apex, from Kirjeng – never sold me a duff one yet),
Presto, Dormer and Lyndon. And even those go under the microscope
before being put into use.

 

[Sub MandrelParticipant @submandrel]

Andrew,

 

We DO need an electronic topic so we can stop hijacking this one!

 

This weekend I’m starting on a project that will see me trying out some accelerometers. Being short sighted smt doesn’t really worry me – I have managed to solder 0.5mm pitch SOIC by hand! But one of these accelerometers is an LGA package about 3mm by 5mm where, like BGA, about ten pads are completely hidden underneath!

 

I’ve also got a pair of FM RF solutions TX/RX433 modules, but they are so impressive I’ll swap them for the simple AM units in my weather station

Neil

[Author]

Posts