Arbor for No.0 Jacobs Chuck?

[Bo’sunParticipant @bosun58570]

Good afternoon All,

I have a No.0 Jacobs Chuck, which I want to put on a 2MT arbor. The designation on the Chuck reads "No.0 0-5/32 H78". I assumed that H78 was the mounting interface, but can't find any reference to a suitable arbor.

Any ideas you clever lot?

[Bo’sunParticipant @bosun58570]

[Thor 🇳🇴Participant @thor]

Arc has drill chuck arbors for Jacobs No.0. Code 040-020-00400 for an arbor with M10 drawbar thread, 040-020-02100 for an arbor with tang.

Thor

Edited By Thor on 13/02/2020 13:13:04

[not done it yetParticipant @notdoneityet]

If I were to assume anything, I might assume that the code was for the chuck key that fitted that chuck?

[Roderick JenkinsParticipant @roderickjenkins93242]

Just to confirm that 0 chuck takes a 0 Jacobs Taper. I turned one on to the end of the spindle for the drilling head on my George Thomas pillar tool.

Rod

[Bo’sunParticipant @bosun58570]

Thank you Rod,

I've just measured the taper in the chuck (as best I could) and it pretty much measures up to the JT0 specification.

Can I assume then, that the JT taper number is the same number as the chuck size?

[Martin ConnellyParticipant @martinconnelly55370]

Machinery's Handbook I have gives maximum drill size for each size of Jacob's Taper under normal drilling loads and for JT0 it is 5/32".

Otherwise it is rare for the chuck designation to match the Jacob's Taper size.

Martin

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