Interesting problem. I think that you can just as effectively measure the distance of the arbor (center of blade) in order to make the adjustments you desire. I have not tested this solution, but intuitively it seems to make sense (I have no such problem as, my Shopsmith saw has a finely-adjustable stop device on the table height adjusting column.) If your insert has some room alongside it, or if it is zero-clearance but you can remove it easily, I would suggest the following:
Grab your arbor wrench (hopefully, one of those nice flat and
parallel-to-the-blade-face jobs - the flatness is important here.)
Get another straight, rigid, thin slat, something like a 6"" aluminum
ruler, a rare-earth magnet, a marking knife, and a length of adhesive ruler
tape long enough to measure the deepest non-through-cut you'll want
to make (with satisfactory resolution - 16ths, 32nds, whatever.)
- Adjust your depth of cut to exactly 0" somehow - your choice of
method, and take your time, you'll only need to do this once.
- Remove your insert if necessary so that you can reach down to the
arbor nut with the wrench.
- Reach down with the wrench and engage the arbor nut as though you
were going to loosen or tighten it.
- Lay the ruler down on the table so the end touches or almost touches
the face of the arbor wrench (their faces will be at right
angles). Plunk the magnet down on top of the ruler to hold it in
- Rotate the wrench (and blade since they're engaged) so that the
wrench is vertical.
- Scratch a reference mark into the arbor wrench along the top edge
of the ruler. This is your zero reference. Remove the wrench
from the arbor nut.
- Apply the ruler tape to the wrench with zero positioned at the
zero reference and the numbers increasing in the direction of the
wrench opening (center of blade).
You now have, in the form of the taped arbor wrench, the ruler, and if needed, the magnet, a tool for measuring the amount the blade cuts above the table. To set a cut depth:
- Remove your insert if necessary
- Grab your taped wrench and ruler, set the ruler on the table next to
- Apply the wrench to the arbor nut and rotate to vertical with one
hand, cozy the ruler end up to the taped side of the wrench with the other. Apply the magnet if needed.
- Let go of the ruler, reach over (while keeping the wrench vertical
with first hand), and adjust your blade height (and thus the wrench
height - it's connected to the arbor) until the edge of the ruler is
alongside your desired depth of cut.
- Remove wrench and ruler, replace the insert, and make your cut.
Best I could come up with, I think it'll work for a lot of people, and is a dirt-cheap solution. Cheers!