Mortises and Other Holes - Part 3
2009.10.06
Today I continued drilling holes and clearing mortises. I started working on the sliding vise. There will be three bolts going through to attach another piece of wood. I drilled the countersink holes on Brian’s drill press the other day. Now, using a brace and a 3/8″ auger bit, I drilled the through holes. I went slow and checked with a square a couple times to try to drill a straight hole. I was probably off by maybe 1/16″ or so in the back, but close enough for this purpose. I checked the first hole to make sure the bolt and washer would fit before drilling the other two.
Through Mortise for Parallel Guide
I moved to the front left leg, where the main vise will pass through. This leg will look like swiss cheese by time all the mortises and other holes are complete. On the drill press, I had started the through mortise for the parallel guide for the leg vise. Since the 1–1/8″ forstner bit was not long enough to drill all the way through, the rest had to be done by hand. I started with a 1–1/8″ auger bit and my 14-inch brace. But after only drilling down about an eighth of an inch, the bit just spun in place. I thought maybe the bit was dull, so I spent some time sharpening the cutting lips.
Didn’t help. I tried a 1″ bit, but got the same results. So I tried a 3/4″ bit. It took some effort, but it drilled all the way through no problem. Hm? On the next hole, I tried a 7/8″ bit. It was more difficult, but again I drilled through. I guess I just can’t exert enough pressure to keep the larger bits going through the wood. Amazing that just one more eighth of an inch could stop me dead in my tracks.
With the holes drilled, I fell back on my previous methods of using the jigsaw, chisels, and rasps to finish out the rectangular mortise. Since there will be no glue in this mortise, I did not have to worry so much about the surface of the sidewalls. And the fit is intended to be fairly loose. So there was not a lot of work to do.
Parallel Guide Cuts
I took a short break from mortising to deal with the parallel guides. First I needed to rip the board to the final width. I always seem to burn this white oak with the circular saw. I did this rip in three passes, which may have helped a little, but mainly I think I need to push through at a faster pace. Oh well, it’s the bottom side, I’ll never see it.
Then I crosscut the board in two to separate the guides. Finally I mitered the corners on the back end of each guide. Then I used one of the parallel guides to check the fit of the mortise until it could slide through easily.
Mortises for Stretchers
After that, I moved on to the mortises for the short stretchers. Because my jigsaw blade oscillates deeper than these mortises, I made a cutout in a scrap piece of wood placed on top to elevate the jigsaw so the blade would not bottom out. After getting the sides mostly straight with the jigsaw, I worked with the rasps and chisels to fit the mortises and tenons together. I did some tweaking of the tenon with the block plane as well. The end results are still sloppier than I would like, but I think better than my attempts a couple months ago.
Drill Press