Delta 14-651 (Benchtop Mortiser) with Lee Valley Premium Hollow Chisel Mortise Bits

[Mark Visconti]

I saw a post that said the Nakahashi bits from Lee Valley were compatible with the Delta 14-651. Some of my original chisels were pretty blue, so I ordered a set. After sharpening, I noticed that the bit is much longer than the original set and does not seat deeply enough in the chuck to work with square mortiser - not even close - I would need to cut the bit. Is this expected? I do believe the chuck is open as far it can go, the bit fits in it, but only seats an inch to an inch and a half.

Am I missing something?

Thanks!

[Mark Visconti]

Picture of the original Delta chisels vs the Lee Valley (Nakahashi). Chisels are the same length but the inner bit is significantly longer on the Nakahashi.
20240407_103421.jpg

[Bryan Cramer]

I have the same machine and got replacement premium chisels from Rockler and yes I did have to cut the drill bit.

[Cameron Wood]

Thank you for identifying the machine by name, and not just a relatively meaningless number.

[Tom M King]

Those bits come long so you can cut them the exactly right length for whatever mortiser you have. If you rely solely on the chuck to hold the bit in place, it can easily be forced up into contact with the chisel, causing damage to both. By cutting it exactly the right length, so you can seat it all the way home, it eliminates that possibility.

If also saves fiddling time at setup. You just put the chisel and bit in and go to work. With short bits, you put something, like a dime, under the shoulder of the chisel, put the bit in, take the dime out, and move the chisel up that spacing, all the while hoping the bit doesn't move.

I understand that several of the better quality chisel and bit sets come with long bits just for that reason.

I cut the bits with a Dremel steel cutting disc.

[Mark Visconti]

Thanks all!