Originally Posted by
Elmer Hayes
Hi all...
Long time since I have been on this forum until now seeking advice. Excuse my absence!
I have a plunging Mortiser (Grizzly #T10816-Bench Top Mortiser), which I find pretty useful for regular woods but when trying to mortise hardwoods-- Sapelle, black walnut, oak, etc., it is mostly impossible to mortise these woods, even with brute force. Chisels are sharp as well as the bits.
Any solution to mortise these hardwoods? Thank you all...
r
Elmer
I have a Delta 14-651 Benchtop mortiser. In the beginning I had a lot of trouble with it, and actually broke the handle. I also thought the bits were sharp, and then learned I had to up my game on sharpening. I also found that even when properly sharpened, The machine just could not mortise a 1/2" hole, no matter what I did. 3/8" is a little tough but manageable, and the 1/4" has no problems.
I just got done mortising some Bubinga and Jatoba which are twice the hardness of walnut, with no issues, and I just have the OEM Delta Chisels that came with the machine.
I use the Lee valley Honing cone and a diamond sharpening plate for the chisels, and they are scary sharp. If you accidently brush them ever so slightly, there is blood.
The larger sharpening issue is the bit. It has multiple cutting angles and they need to be dressed and sharpened also, which requires a small set of ceramic sharpening tools.
The bottom of the bit needs to be honed and the initial bevel on the leading edge has to be sharp. Chisel sharp. The initial edge on the cutting flute has two angles, in and back. I sharpen that edge just like the hook end of a farriers hoof knife.
I suspect that your more significant issue is the drill bit is not sharp, or the angles incorrect, and you're not clearing away the debris. If the bit is set correctly, about a dime to a penny's width in front of the chisel, it makes contact first, and that really needs to happen, or the chisel is trying to do the bits job, and that won't work.
On my Delta I have to orient the open side of the chisel to the left or right, so that I can have the vacuum right at the point where the chisel makes contact with the wood. If any debris is allowed to accumulate it will clog up the flutes of the bit carrying the debris up and away.
"The first thing you need to know, will likely be the last thing you learn." (Unknown)