I recently built Nick Offerman’s leveling jig from Fine Woodworking (I think it’s from #222). I made it a little stockier than his, longer and wider, to allow leveling slabs up to 8’ x 5’ in size.
I’m in the process of building a workbench. The first step was to use the jig to level the bench. I used shims to level an area of garage floor under the support beams. I placed the workbench top (which is made of two layers of 6/4 elm and weighs about 200 pounds) on the beams. The adjustment of the sled was straightforward, and I began leveling by taking a shallow pass. Adjusting the sled for each pass easy. I made two more passes of 1/16”, and was done leveling the workpiece. I learned a few things:
1) I began by making one pass to the left, which followed the cutting action of the bit, and then one to the right, which worked well but was slower on the second pass. I ended up making the pass to the left, then doubling back at the same level, which ended up much faster
2) I initially traveled as much as possible with each cut. The bit that I was using (not ideal for the purpose—too narrow at 3/4”) seemed to cut a little deeper in the center. This must be a mild tilt to the router as I am dragging it from side to side. Cutting the travel per pass in half made the surface smoother.
3) Anything to improve the quality of the surface prior to sanding is well worth it. Especially if you don’t have a belt sander.
4) I will be buying a surface planning bit soon to cut down on time. However, even with a small bit this is an amazing time saver over hand planning
5) If you use Douglas Fir (as recommended), be warned: it is very expensive (here in Montana ~$6 per bf). And it splinters constantly. Wear gloves.
To be continued (with photos)...
-- My projects are imperfect in every way, just like their creator. Their creator loves them nonetheless, just like mine.