# Revamping my Delta Contractor Saw #9: Taking Back What I Said, and An Experiment

 Blog entry by Mark Colan posted 09-01-2010 01:39 AM 2334 reads 0 times favorited 7 comments
 « Part 8: Problem Solved! Phase I Complete: Success! Part 9 of Revamping my Delta Contractor Saw series Part 10: The Core of the New Extension Table »

Taking Back What I Said

Mark Mueller disagrees with my statement (in Part 8, Conclusions for Phase I) that “re-zeroing the fence will be required any time the positioner base unit is moved.” He points out that the fixed stops (against which the base is positioned) make re-zeroing unnecessary, and he may well be right (he should know). I will revisit this subject later, after doing some experiments to learn the truth.

An Experiment

I want to make a new extension table measuring (with trim) 29” x 36”. This extension table will be two layers of 3/4” MDF, in order to make a router base that will maybe stay flat. I envision cutting two pieces of MDF a bit larger than I need, gluing them together, then trimming them to exact size.

But how can I get very exact 90 degree angles, and exact sizes? The obvious answer is to use my table saw with the new fence… except that the standard setup yields a cutting capacity of 32” to the right of the blade, and I need 36. The instructions say that the standard setup give 14”-0” range on the left of the blade, and 0”-32” on the right.

So I have moved the rails 8 inches to the right, in hopes that this will modify the capacities to 6 – 0”, and 0-32” plus 8-40”. (The carriage arm does not give a 40” range, so wider cuts require moving the base.)

I plan to experiment with this setting for awhile, to see if I could be happy with that as my standard set up. I imagine I will, as I almost never make cuts to the left of the blade with a rip fence.

Since I have to live with having two ranges, it would be good to have stops set to quickly move between the two ranges.

A Problem I Haven’t Been Able To Solve

In setting up the 8-40” range, I cannot figure out how to precisely zero the fence. The fence won’t reach the blade. I could cut a strip of a specific width, then measure, and turn the micro-adjust the same number of clicks of the error in mils. But I don’t have a precise tool that can tell me how close it is in mils (thousandths of an inch), because my calipers only go to 6 inches.

The closest solution I’ve thought of:
• set the 0-32” range precisely using the standard methods described in the manual
• cut a strip of wood to 8”. This should be correct +/- 2 mils.
• move the base unit 8 inches to the right.
• place the 8” strip against the blade
• move the fence against the 8” strip
• set this to zero

This solution should give me accuracy of 1/64 to 1/32”. I’d like to do better. Any thoughts?

-- Mark, hack amateur woodworker, Medford (greater Boston) MA