Quick question on Deckel tapers

[Adam HarrisParticipant @adamharris13683]

[Adam HarrisParticipant @adamharris13683]

I have a shank that has a taper about 80mm long and 44mm Diameter at the fat end and 40mm diameter at the narrow end and then followed with an external thread for drawbar. I assume this is a Deckel taper as it doesn't match any other taper I can google. Is it Deckel, what number Deckel is it and what Deckel Mill would it fit?

Edited By Adam Harris on 29/04/2019 19:12:00

[BikepeteParticipant @bikepete]

Doesn't sound like Deckel to me. Deckel mills either use shortish 4 Morse (older ones) or 40INT tapers (more modern ones). If it's for Deckel, the external thread will be 2mm pitch, saw-tooth thread form, 20mm OD.

Edited By Bikepete on 29/04/2019 21:50:05

[Adam HarrisParticipant @adamharris13683]

Ah , many thanks . I will have another search then

[SillyOldDufferModerator @sillyoldduffer]

Might be a short MT5 – can you measure the dimensions to determine the angle accurately?

Short tapers aren't obvious about the location of their large and/or short ends, making it necessary to put some effort into measuring two diameters and the distance between them accurately. As the MT series varies by only 0.0786° between largest and smallest, identifying an unknown taper from its angle (which is a strong clue) requires accurate measurement. Try marking two diameters with tape to help position a digital caliper more precisely at two points on the taper. Finding two diameters and the hypotenuse distance as accurately as can be managed will give the sine of the taper angle.

Dave

[Adam HarrisParticipant @adamharris13683]

Thanks Dave but I am going to end this enquiry ( I did title it "Quick" )

[SillyOldDufferModerator @sillyoldduffer]

Posted by Adam Harris on 30/04/2019 11:17:44:

Thanks Dave but I am going to end this enquiry ( I did title it "Quick" )

Gosh Adam, a triple first – a time limit on answers; hiding the limit in the title; and then assuming you can end a thread! Not on this forum – it could drift on to Regular Expressions or Cat Allergies.

Although you might have moved on suggestions on how to identify an unknown taper may be of interest to others. You asked a good question and a search engine will find this thread long after we are both dead…

Dave

[Oily RagParticipant @oilyrag]

It may be a Thiel taper – I need to dig out my collection of Thiel tooling to check it and IIRC the Thiel taper does differ from Deckel – but not by very much!

[Adam HarrisParticipant @adamharris13683]

Yes indeed Dave, I like the sound of that! You may indeed be held in high regard for posterity, I will be stuck for ever as "what a blinkin' idiot that bloke must be!"

Edited By Adam Harris on 30/04/2019 22:28:44

Edited By Adam Harris on 30/04/2019 22:29:50

[Adam HarrisParticipant @adamharris13683]

your idea to use sticky tape for accurate measurement is simple but brilliant 

Edited By Adam Harris on 30/04/2019 22:31:54

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