Workbenches have flat tops, though sometimes at the rear there is a cavity called a tool well that contains tools and components (and prevents them from falling off). One advantage of having the well set into the top of the bench is that, even with a variety of objects in the well, a large sheet of material can still be laid flat over the entire surface of the bench; the contents of the tool well offer no interference.

So drill the benchdog holes through the MDF layer. Begin by laying out their positions. You'll want these to be precise, so that the distances between the holes are consistent. The vises you are using will constrain your benchdog spacing. My front vise worked most naturally with two rows of holes four inches apart, my end vise with two pairs of rows, with four inches between the rows and eight inches between the pairs. Because of this, I decided on a 4" by 4" pattern.
If the holes of the first jaw are in the proper position, drill holes in the same locations on the other jaw. I lined the drilled jaw on top of the undrilled jaw, clamped things down, and then drilled about 1/4" into the undrilled jaw, to mark the location. Then I removed the drilled jaw and drilled out the marked locations the same way I did the first.
When you're working with linseed oil, never -- I mean NEVER -- leave used rags lying around. Hang them up outside, away from anything combustible, and where there's enough air circulation to keep them cool. Or put them in a bucket of water, and hang them outside later. If you're just setting a rag down for the moment, set it out flat, without folds, on something non-flammable. Hanging outside in the breeze, the oil in the rags won't retain heat while they oxidize. For the oil to completely oxidize can take in a couple of days, if it's warm, or more than a week, if it's cold and rainy. When fully oxidized, the oil will be solid and the rags will be stiff. At that point, they're safe, and can be thrown in the trash. Toss them in the trash before that, and you might as well say goodbye to your garage.
Professional woodworker Jim Tolpin offers solid instruction on the principles of measurement and proportion, walking you through every step of the woodworking process. From design and layout to developing a cutting list, his easy-to-follow style introduces a variety of tools (new and old) used to transfer measurements accurately to the wood. You’ll learn the best cutting techniques, how to prevent mistakes before they happen, and for those unavoidable mistakes, you’ll learn how to fix them so no one will know!
With the shelf secure, get a couple of friends to come help, and stand the bench on its feet. I said earlier moving the top by yourself is dangerous. Trying to lift the entire bench is foolhardy. Of course, I already said I'm stubborn, so I did it myself by rigging a simple block-and-tackle using lightweight pulleys I got at the hardware store. (Not the lightest-weight pulleys, those are meant for flag poles and have a design load of something like 40 pounds. These had a design load of 420 pounds.)
Beyond the weight capacity, the Grizzly is also the largest table top on our list and in more ways than one. For a workspace, the Grizzly provides 5’ of length by 2 ½’ of width. There is not another table that really comes close to that size. Another size advantage of the Grizzly bench is the table top’s thickness. While the standard thickness of the table top for a quality woodworking bench is 1” with lesser models often offering only ¾” of thickness, the Grizzly provides a 1 ½” thick table top.