Building a real woodworker's workbench

Step 18 The vises, step one - mounting bases to top

The end vise will have both jaws made out of 1-1/2" thick oak. The front vise has its moving jaw made of 1-1/2" oak, but uses the edge of the bench as its stationary jaw. So while for the end vise, if we mount it lower, we can make both the jaws deeper to compensate, for the front vise we cannot, so we want it mounted as close to the edge of the bench as possible.

So I decided to add an extra layer of 3/4" MDF under the end vise only, and not under the front vise.

It's usual to attach vises with lag screws from the bottom, but there is a limit as to how many times you can tighten up a lag bolt in MDF. I decided to use bolts from the top down, embedding the heads of the bolts inside the top.

First step was to cut a piece of MDF the size of the base of the vise. I scribed the positions of the bolt holes in it, then driilled small pilot holes. I also drilled larger holes at the corners of the rectangular cutouts, and the joined them with a jigsaw.

Then I flipped the top and the base, lied up the base in the proper location relative to the top, I then positioned the front vise and the support MDF for the end vise, and marked the locations of the bolt holes. Then I flipped the base right side up, drilled small pilot holes from the bottom side where I had marked the locations, and then drilled shallow countersink holes from each side, then a through hole that matched the bolts. Finally I tried out the bolts and washers, and deepened the countersinks until the heads of the bolts were just below flush.

With the holes and countersinks in place, I inserted the bolts, used tape to keep them from falling out, flipped the top, applied glue to the support piece of MDF, fit it over the bolts, added washers and nuts, and tightened it down.