My main reason for posting this blog is in the hopes that if, someday, someone is looking for a replacement chuck key for their Delta 14-650 mortiser, they can avoid the frustration of trying to find one that will work. This solution works for a 14-650 Type 2 mortiser, I cannot guarantee it will work for Type 1 mortisers (see below about those).
The Delta 14-650 chuck key has been marked as obsolete, and is unavailable for order from Delta or any of the other part replacement sites I could find. The chuck manufacturer is “Select” and it is a 3/8” chuck with a odd-sized small pilot for the chuck key.
I recently got a great deal on one of these mortisers, but it was missing the chuck key. Normally, I would remove the chuck and bring it to the store, and try to find a match, however the bit and chisel were still installed, which would make removal of the chuck impossible without destroying the bit and chisel.
The pilot for the chuck key measure 13/64”. There are chuck keys available in stores that have this pilot, however they’re all designed for 1/4” chucks, and the 14-650 has a 3/8” chuck. The teeth on these chuck keys do not come close to touching the teeth on the chuck.
I had found a post by a fellow LJ’er that stated that a certain Black & Decker chuck key (p/n 621400-00) happened to fit, available from ereplacementparts.com. Since I happened to be placing an order for a couple parts for a different tool, and it was only a few dollars, I ordered one. It did not come close to fitting. I ground down the pilot and the teeth still did not engage. The other LJ’er had a Type 1, and claimed it fit, so perhaps there is a difference in the chuck. I don’t have a Type 1 so I don’t know.
After a couple failed attempts, I found the solution that does work. The Jacob’s 1/2” chuck key, with the 1/4” pilot (p/n 30251) has teeth that will engage the chuck on the mortiser. The pilot is too large and must be ground down, this took me about 10 minutes. I place the chuck key in a vise and used some linesman pliers to wiggle out the pin. I placed the chuck key in the chuck of my drill press, and set it too its highest speed (3100 RPM). The chuck keys are pretty hard, so instead of a file I used a large angle grinder wheel instead (not on the angle grinder). It’s pretty slow-going, but eventually the pilot is the correct size. I held a file to it just to remove the majority of the grinding marks.
Summary : If you need a new chuck key for your 14-650, buy Jacob’s 30251, and grind the pilot down. Total cost was $3 (not including my 2 other failed attempts with incorrect-sized chuck keys).
-- - The mightiest oak in the forest is just a little nut that held its ground.