Remember those fire safety tips you used to get in grade school, about the dangers of oily rags? It was linseed oil they were talking about. All oily rags are dangerously flammable. Linseed oil will self-combust. Linseed oil doesn't evaporate, it oxidizes. The oxidization generates heat, and the increased temperature increases the rate of oxidation.
Put the upper panel of MDF on your glue-up surface, bottom side up. Put the bottom panel of MDF on your other surface, bottom side down. (The panel with the holes drilled in it is the bottom panel, and the side that has the your layout diagram on it is the bottom side.) Chuck up in your drill the appropriate driver bit for the screws your using. Make sure you have a freshly-charged battery, and crank the speed down and the torque way down. You don't want to over-tighten the screws, MDF strips easily.
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.
Another aspect that might irk some buyers is the fact that the capacity of this bench is less than great outside of weight. The top’s surface area is a bit on the smaller end, though its length is more in line with larger models. The width though is less than two feet which can limit some projects. Similarly, the vice capacity is the second smallest on our list at 4 ½”, though this too can be modded with optional additions.
To mark the centerline, set a compass to span something more than half the width of the leg. Draw an arc from corner of the leg. The point where the arcs intersect will be on the centerline. With a centerline point on each end of the leg, place a scribe on the point, slide a straightedge up to touch the scribe. Do the same on the other end. When you have the straightedge positioned so that you can touch both points with the scribe, and in each case it is touching the straightedge - without moving the straightedge - scribe the line. Use scribes, rather than pencils or pens, because they make more precise marks.
I marked out the one hole location, drilled a shallow 1/16" hole into the top. I then put a 1/16" bit through the hole in my template and into the hole I had just drilled. I lined up the template, and drilled a second hole, then put another bit through that. From then on, I worked entirely from the template. With two bits through the holes pinning the template in place, the other holes in the template would be precisely located (or so the theory goes) on a 4x4" grid.
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.