Drill chuck key (Jacobs-type) dimensions?

I had the same issue a while back. Someone scanned a page from a catalog and sent it to me as a jpeg. Email me directly and I'll send it to you if you like. De-spoof my address.

Tom Dacon

If you have a Jacobs chuck you can just look in any catalog to see what key it takes. If you don't then even if you had a table of all the Jacobs key sizes what good would it do?

GWE

It's a Jacobs-type (not genuine Jacobs) and has no number.

I had the same problem. The best I could come up with was a chuck-to-chuck-key chart in the Enco catalog. Don't know if it's still there.

I'll just co-miserate here. I bought a small drill chuck with 40 taper holder. No numbers. Bought two of the four way keys and still didn't get a fit. Ended up turning the closest key down so it fit the pilot hole. There must be a dozen standard sizes and then a zillion non-standard.

Karl

I found myself in a similar situation a couple of months ago. I did all the stuff you did, buying the 4 way key that didn't work, looking stuff up in the catalogs, Machinery's handbook, etc. In the end, the "Key" was simply to measure the diameter of the key hole in the chuck. I then looked it up in (I think) the MSC catalog and bought it. It fit. Of course I now have enough other chuck keys so I could go into business for myself!

Pete Stanaitis

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WoofWoof wrote:

Measure the hole diameter. ...lew...

Dimensions? We don't need no stinkin' dimensions!

Do what real men do..... Just stick the back end of an appropriate sized drill bit in the chuck key pilot hole to use as a fulcrum. Then pry against the gear teeth with a BF slot screwdriver.

Jeff (It woiks, but don't take me seriously. )

If you have a key with the correct size pinion (meaning tooth mesh and centered over the hole), but the pin is the wrong size, you could cut off the pin and drill the key body for the correct pin size. Press in a short length of drill rod, a hardened dowel or piece of an old drill shank.

WB ...............

Better to search for your chuck # to find the correct key.

Tom

And be prepared to consider the diameter as metric as well as fractional inch. Depending on where it was made, either is possible.

Is a country of origin stamped on the chuck somewhere? That might give a clue as to which set of units it should be measured in.

I presume that it is not necessary to say this -- but just in case:

You can convert an inch dimension to Metric (in mm) by multiplying the decimal size by 25.4. Converting the other way involves dividing by the same value, of course.

Enjoy, DoN.