# Help identifying machined taper



## RichardG (5 Dec 2021)

I'd like to repurpose an old drill chuck which is more like a mini chuck. It currently has a 1MT shaft and an unknown taper that fits into the mini chuck. The taper is 1.3 inch long, 0.5835 at the small end and 0.6675 at the wide end. Any idea what taper this is?

some pictures.


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## toolsntat (5 Dec 2021)

Maybe a Jacobs taper ?


Cheers Andy


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## Dalboy (5 Dec 2021)

toolsntat said:


> Maybe a Jacobs taper ?
> Cheers Andy


Does not match any jacobs taper measurements


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## Peri (5 Dec 2021)

The only common taper I know of in engineering is a morse taper.

Edit: Might help









Machine taper - Wikipedia







en.wikipedia.org


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## RichardG (5 Dec 2021)

I couldn't match it against any tapers specified on that wikipedia page. The chuck is old and could well be early 1900s so it may predate the jacobs?.


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## TFrench (5 Dec 2021)

What sort of adapter are you wanting to fit it to? I'd say there's 2 options:
1. dont waste your time with it - if its not an off the shelf taper it's going to be hassle. Just buy a cheap new one and move on.
2. Buy a soft arbor for whatever you're trying to fit it to, give it to someone with a taper attachment and cut a new taper to suit.


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## Fergie 307 (6 Dec 2021)

As it's American could be Jarno, although I think it predates that. May be unique to the manufacturer. You can get taper adapter to turn your MT 1 into a plain shaft or larger MT sizes if that helps. Also try Google on the manufacturer, might give some info.


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## RichardG (6 Dec 2021)

This is a useful page of tapers.

Dimensions of Standard Tapers - LittleMachineShop.com

Further searching found a page from a catalogue, so it was called and possible made in 1883 and the size of the taper changes but I presuming the taper angle doesn't...It is such a well made bit of kit that it seems a shame not to use it. Could it be reamed out to a standard taper?


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## Richard_C (7 Dec 2021)

My Newnes Engineers Manual c 1963 edition gives similar information to RichardG above, but mentions more tapers. There are pages of tables, but they all list the taper so that might help you narrow it down. Bit too busy for 'hard sums' right now.

Morse 0.625 in/ft typically, actual sizes vary a bit.
Browne & Sharpe 0.5 in/ft with one exception, H10 is 0.5161.
Jarno 0.6 in/ft
Sellers 0.75 in/ft with keyway
Reed, same taper as Jarno but standard sizes differ
Standard Tool Company short and standard versions 0.6 to 0.63 in/ft*
Cleveland varies with size 0.6 to 0.63 in/ft, with a tongue at the small end
Jacobs vary, 0.5976 in/ft to 0.97 in/ft.

_* ironic that the Standard Tool Company doesn't use just one standard._


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## RichardG (8 Dec 2021)

I could ream it out to JT6 but I may thread it and just use it as a small chuck on my model making lathe.....


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