On Fri, 2 Apr 2021 18:39:09 +0100, John Rumm
wrote:

Best you can say of that is if you are going to have an error in
alignment, then that is the safer direction to have it.

Eh... depends?

I know of a table saw, large, cross slide over a meter, and the cross slide and
fence were not a 90° to each other, but very slightly off. It bothered me, but
the machine was new, and rather than fool with it myself, I asked when it was
first serviced by the manufacturer:

This saw was (also) used for melamine-faced chipboard, generally using
many-toothed carbide blades with specialized tooth shapes.

It is set assuming that the "good" piece from a cut was either between the fence
and the blade, or against the cross slide. Cutting against the fence, the saw
blade enters into the material from the top, leaving an unchipped edge on the
top. At the back end of the kerf, where the blade comes up, there is a bit of
clearance. This keeps the edge unchipped. The clearance was below 1/10th of a
millimeter. Cutting with the material held against the cross slide, the
clearance was on the other side, i.e. the piece on the fence side got the teeth
where they came "up", with more noticeable chipping.

(Some of these table saws have a pre-cutter to avoid tearing on the underside of
the chipboard, but this machine was also used for solid wood, where the
pre-cutter is in the way...)

The machine was a similar model to this one:

https://www.felder-group.com/en-gb/products/5-function-combination-machines-c1952/combination-machine-cf-741-p142858

Cutting with material against both the slide and the fence is a no-no, for one
because the two are not at 90° to each other. (Also because there is no place
for the wood to fall away freely, and scrap can get caught between fence and
blade, and shoot out the back...)



Thomas Prufer