Sharpening taps and dies?

[File HandleParticipant @filehandle]

Never occurred to me to try this until recently.
Is it possible? If yes what it the best way to go about it?
I came see that if a slit die is slightly warn it won’t matter, but this could be more critical for taps.

[Thor 🇳🇴Participant @thor]

If you have a tool grinder – something like the Quorn – you should be able to grind taps. Prof. Chaddock’s “The Quorn Universal Tool and Cutter Grinder” describes how to sharpen taps.

Thor

[Clive Brown 1Participant @clivebrown1]

He also describes sharpening dies. For this he used a very small carborundum grinding point driven at 15,000rpm. The pulley to give this speed on the Quorn was a home-made wooden one. The set-ups are pictured in ME 1976.

[John ReeseParticipant @johnreese12848]

Poly Choke made a fixture for sharpening taps and drills that provided eccentric relief on the chamfer.

[Martin Johnson 1Participant @martinjohnson1]

Jacques Maurel has just done a series in MEW (I think) within the last 6 months.  Very well thought out and explained in Jacque’s usual way.  It relies on cams with a conventional sliding workhead to give true spiral relief.

Martin

[Thor 🇳🇴Participant @thor]

Martin, you are right, February and March MEW (issue 324 and 325).

Thor

[File HandleParticipant @filehandle]

Thanks for all of the replies. I haven’t got a Quorn or equivalent. It was just a passing thought, but I guess I am better off simply replacing them, a bit like I do with small drills.

[Nigel Graham 2Participant @nigelgraham2]

If you are faced with having to scrap the blunt taps, you won’t lose anything by trying using freehand a grinding-point or small grit disc in a hand-held “micro” power-drill (a ‘Dremel’, ‘Proxxon’ or similar).

Grip the tap shank in the vice, and use both hands on the tool for best support and control.

Note the flute is undercut a touch to give a cutting-angle to the tips of the thread. Examine a reasonably large, sharp tap to see the geometry.

‘

Similarly with a die, provided you can get a carborundum point into the side holes. If not, a lap made from a bit of brass or aluminium rod with fine grinding-paste on it, may do the trick.

.

I must admit I’ve not attempted this myself, but have often pondered it. I have wobbly hands though, and yours might be as steady as a neurosurgeon’s or a clock-maker’s!

[Nigel Graham 2]

On Nigel Graham 2 Said:

If you are faced with having to scrap the blunt taps, you won’t lose anything by trying using freehand a grinding-point or small grit disc in a hand-held “micro” power-drill (a ‘Dremel’, ‘Proxxon’ or similar).

Grip the tap shank in the vice, and use both hands on the tool for best support and control.

Note the flute is undercut a touch to give a cutting-angle to the tips of the thread. Examine a reasonably large, sharp tap to see the geometry.

‘

Similarly with a die, provided you can get a carborundum point into the side holes. If not, a lap made from a bit of brass or aluminium rod with fine grinding-paste on it, may do the trick.

.

I must admit I’ve not attempted this myself, but have often pondered it. I have wobbly hands though, and yours might be as steady as a neurosurgeon’s or a clock-maker’s!

Thanks
This is exactly what I wondered when I wrote the OP. When I am feeling steady handed I might give it a try.
Has anyone else tried it.

[Andrew TinsleyParticipant @andrewtinsley63637]

Yes it does work. Results depend critically on what you drank the night before. For 1/4″ diameter taps and up, then the results are quite pleasing, below that size I had variable results. I always finished up with better results, but how much better depended on skill (or luck).

Andrew.

[File Handle]

On 22 October 2023 at 18:00 File Handle Said:

…

I came see that if a split die is slightly warn it won’t matter…

Sort of, but the split is more for adjusting the size of the thread rather than compensating for wear.  Threads of a given nominal size are sometimes specified to be of a more or less tight or loose fit, which is achieved by compressing the die in the holder.

Tightening a die to compensate for wear is a bodge, reasonable enough if it saves a few quid doing rough work, but far from best practice!  Cutting tools are meant to be sharp, and a blunt die risks deforming the thread or worse.

Brass distinctly prefers a sharp new die.  New dies that have been used only once on steel perform noticeably worse on Brass, so it’s best not to mix them.  Conversely, dies too blunt for Brass still have a useful life cutting steel.

Dave

 

 

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