Mirror fit issue?

Dremel on high speed with a diamond wheel. The use the Dremel to polish the cut edges.

Thanks, I have a Dremel. A diamond wheel sounds costly but I'll check that out once.

Will that work with tempered safety glass?

Ted

If you check the surplus shops (I like American Science & Surplus) you can find cheapy (likely Chinese) diamond wheels at decent prices (as well as other Dremel bits). Just remember to polish the cut edges -- important to prevent future chipping.

With a diamond coated wheel at sufficient speed you'll cut through the tempering. The trick is to take your time -- don't try to cut too deep too fast. Better to cut a shallow line all the way along (on both sides, if possible) and then go back and deepen the line gradually (from both sides), not letting one section get too much deeper than the rest. This will help control any tendency to crack as well as Keeping the cutting bit cool. Polishing will smooth out any irregularities as well as rounding/buffing the edges to avoid chipping.