The International Cessna^® 170 Association

Thanks Mike

My lens could be a lot smoother on the edges but it works and no one will know but me and the forum because it's covered by a metal band.

I did very lightly dress a few of the sharpest edges with a fine grinding wheel but only the worst parts because it would easily cause chipping that would ruin the lens.

I know the grinder was not the right tool and would be interested in what is the right tool. What is a glass router? Where can you get a glass or mill file.

BTW this project is done and installed in my plane as of today so this is for the next one I or should I say Buck does.

Well, I actually have one (a glass router), believe it or not. It is a left-over from a previous life that included stained-glass work as a hobby. But it's too late now, and wouldn't be worth even the shipping for such a small item as one lens.
It looks like a small table saw or upside down router, except it has a rotating diamond-encrusted grinding wheel that edges the glass.
I keep it next to my geiger-counter.

The files can be had at most harware stores. Just be sure to get one that has very fine 'teeth' that go diagonally across the face of the file in reference to the edge of the file. If memory serves, a mill file's 'teeth' are at 90 degrees to the edge. These will work as well. The stained glass supply shops might carry them, but they're about 3 times as expensive. Hand filing is a bit 'old school' these days. Plus, they'd rather sell you a $200 glass router.

Thanks Mike

I googled glass file as well as mill file. I thought a mill file was just what I'd call a regular metal file. The glass file I found for sale was $6.75 ans said it was good for lawn mower blades as well. BONUS

I'm going to have to keep my eye out for a glass file for my tool collection.