Hello: When cutting though mortises by drilling and then cleaning up with a chisel do you all use the exact size brad point drill or do you go one size under? I’m having some trouble getting the far side of the mortise to be exactly where it is supposed to be. Should I run my marking around to the far side and go at both sides toward the middle or work more on keeping my chisel exactly parallel to the piece and the marking on the “first” side ?
Thanks, KDM
“… if people did not die so untidily, most men, and all women, would commit at least one murder in their lives.” R. Kipling
Replies
Using a drill press I have found the bit to wander so little that it is usually not a problem, assuming that you work from the visible side of the joint. The tenon's shoulder will normally cover any slight problems on the "backside" of the joint. That said, I always chisel from both sides to meet somewhere in the middle. It prevents tearout and is just plain easier than going deep. So yeah, I mark it from both sides.
DR
I have been taught and learned that it is better to drill from both sides with a Forsner bit, stiffer than a brad point, and stay away from the lines slightly. If the mortice is large I also use a smaller Forstner bit to remove stock from the corners, again staying slightly away from the lines.
Probably a more important key to through mortices is dead accurate layout.
Larry
dekeone,
I just made a few through mortices and tried to focus on getting the 'show side' tight...ie, mortice fits well around tenon you see. I don't know if this is the correct way but here is what I did on 1/2" M&T:
Layout and cut in on both sides of the leg about 1/4"deep...under cut the show side slightly. Drilled with 7/16" bit and pared/cleaned up from the show side in...leaving the show side extra tight. As the mortice comes through usually only slight paring or filing was required to produce nice results.
If you are drilling on a drill press then a level table becomes a must, it is easy to blame your drilling when the table may be a degree or so out of alignment. Then if possible hold the stock in a universal machine vice which gives you x-y control of the drilling and relates holes to the face side of the stock.
Thanks all for the help. I'll keep these ideas in mind for the next project and see if they will help on the current one in which the mortices are all ready drilled through and just need cleaning up. They are not far off but could still use improvement. KDM"... if people did not die so untidily, most men, and all women, would commit at least one murder in their lives." R. Kipling
This forum post is now archived. Commenting has been disabled