PP Thornton (successors)

[Michael GilliganParticipant @michaelgilligan61133]

I don’t use Facebook, but I stumbled across these whilst searching for something this morning: **LINK**

https://www.facebook.com/PPThorntonsuccessors/videos/10201053960773462/

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Some interesting short videos …

[John HaineParticipant @johnhaine32865]

Good link, thanks Michael! Now if we had a video of how they shape the profiles on their HSS blanks…

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Haine on 23/09/2020 10:29:27:

Good link, thanks Michael! Now if we had a video of how they shape the profiles on their HSS blanks…

.

The frustrating thing, John, is : I’m sure I have seen one [or at least some photos] years ago.

They cut the HSS with a carbide profile tool, in the lathe, I believe.

MichaelG.

[egaParticipant @ega]

I hastened to view MichaelG's linked video lest it be censored (I admit I don't feel sure about the working of the new rules).

I suppose that the oil in the sump beneath the cutter is there to capture any grinding dust that doesn't go into the funnel?

[Michael GilliganParticipant @michaelgilligan61133]

John,

Thanks to the wonderful digital archive … and to my own search skills

I have, at last, found what is probably the definitive article about cutter manufacture at

PP Thornton (successors)

.

Horological Journal

December 1995

pp 416-418

by J K Nicholson

.

MichaelG.

[John HaineParticipant @johnhaine32865]

Aha! Good stuff, I'll peruse that.

[John HaineParticipant @johnhaine32865]

Well, that was an interesting read Michael! Not entirely clear, but it seems that they produce the cutters using in effect the "button" method to impart the required profile to the teeth, the "buttons" (or their equivalent) being made from carbide, ground to shape using diamond wheels. The "soft" 12-tooth HSS blank is turned on a form-relieving lathe after gashing, then vacuum heat treated to harden. Doesn't sound easy to reproduce at home!

[BazParticipant @baz89810]

John Haine if you substitute gauge plate for soft HSS and use the Ureaka form relieving attatcment it is perfectly do-able in the average workshop.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Haine on 23/09/2020 17:53:09:

Well, that was an interesting read Michael! Not entirely clear, but it seems that they produce the cutters using in effect the "button" method to impart the required profile to the teeth, the "buttons" (or their equivalent) being made from carbide, ground to shape using diamond wheels. The "soft" 12-tooth HSS blank is turned on a form-relieving lathe after gashing, then vacuum heat treated to harden. Doesn't sound easy to reproduce at home!

.

Not forgetting the pantograph reduction, and the inspection work

…. suddenly, it makes the price look very reasonable

MichaelG.

[John HaineParticipant @johnhaine32865]

Posted by Baz on 23/09/2020 18:02:00:

John Haine if you substitute gauge plate for soft HSS and use the Ureaka form relieving attatcment it is perfectly do-able in the average workshop.

Indeed, but in another thread people have been discussing manufacture of HSS tools on the Quorn.

[Martin KyteParticipant @martinkyte99762]

Posted by Michael Gilligan on 23/09/2020 18:32:18:

Posted by John Haine on 23/09/2020 17:53:09:

Well, that was an interesting read Michael! Not entirely clear, but it seems that they produce the cutters using in effect the "button" method to impart the required profile to the teeth, the "buttons" (or their equivalent) being made from carbide, ground to shape using diamond wheels. The "soft" 12-tooth HSS blank is turned on a form-relieving lathe after gashing, then vacuum heat treated to harden. Doesn't sound easy to reproduce at home!

.

Not forgetting the pantograph reduction, and the inspection work

…. suddenly, it makes the price look very reasonable

MichaelG.

Especially as they do a sharpening service at half the price of the cutter.

regards Martin

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