Odd sized chuck keys

[John Rumm]

A friend recently donated a Multico bench mortising machine to my tool collection. Seems to be working nicely - especially now I have fashioned a hold down clamp for the work. Only slight problem was when I went to change the chisel, and found my chuck key was too big to fit in the hole on the chuck! Its a fairly small chuck (similar or perhaps a bit smaller than a 10mm one). Measuring the hole, it seemed to be a tad under 6mm, and the smallest spare key I had was a tad over. The first bright idea I had of attacking the key with the bench grinder was only partly successful. The key now fits the hole, but the teeth on the key don't reach the teeth on the chuck.

Any idea what size key I need to look for, and where I might find one?

[Spamlet]

You used to be able to buy star shaped multi keys, so at one time there were at least 4 different sizes. It's a long time since I needed to use one though and I don't know what happened to mine.

Here is a site that professes to be selling a blackened hard steel version, but I have to say the picture looks rather like one I had that was made of painted ally and wouldn't turn anything. You may want to look for more links.

S

[The Medway Handyman]

Maybe

[Bob Minchin]

Chronos have one of the best ranges of keys that I have come across but on the worst site for navigation! The keys are characterised by the diameter of the spigot and the number of teeth. Sounds like you need a small spigot and a larger number of teeth to get the OD big enough. Which model Morticer is it? I might be able to ask around in a woodie forum to see if anyone has the same machine and can characterise their key for you. We can carry on by direct email if you like? HTH

Bob

[John Rumm]

ebay have them in quantity it seems. I suspect the ends are not going to match in this case, but it might be worth a punt to see if one can be fettled!

[John Rumm]

[John Rumm]

Good point, I had forgotten about them.

Its an old ish PM12

OK did a bit more research (i.e. got some emery cloth on the chuck to shift the surface rust!)

Its a Rohm S2A chuck. The full markings are 1/32 - 3/8 (which I guess is the usable diameter range)

1 - 10 L 3/8 - 24 (could the 24 be the number of teeth?)

and S2A W.GERMANY

I will order one of:

one down, ref S2, and see what that does!

[Bob Minchin]

>> or

John, the 3/8 -24 refers to the thread on the back of the chuck (24 threads per inch, 3/8 diameter) This is pretty standard for drill chucks

If you cant get a chuck key then the next best thing would be to get a new chuck. The old one will be on pretty tight but should unscrew anti clockwise (normal thread direction) The thread could be male or female so get the old one off first before ordering a new chuck. In the meantime I will try and find details of the chuck key for a PM12 and get back to you.

Bob

[John Rumm]

>>>>>

Ah, ok makes sense.

Just had a thought - Although I looked at all the small keys I had laying about, it did not occur to me to look at the larger ones. However, I just fished out an old green Bosch drill with a 1/2" chuck on it, and low and behold its key fits perfectly in spite of the fact that it looked like it ought to be way to big for such a dinky little chuck.

I knew if I kept it long enough it might come in useful!

[Andrew Gabriel]

I bought one once. It was made of some special metal with exactly the same physical properties as plasticene. Also, the 4 chuck keys somehow didn't match one single chuck I had in any tool.

[Bob Minchin]

>>>>>>>>>>>

My contacts have come back with 6mm x 12 teeth so the S2 would have been correct. Anyway glad you got it sorted. Bob