Sash window - a bit lost

[Pineapple]

Cutting Glass,,I was told that with secondhand glass, that being the only stuff I would ever need to cut myself, it was best to let it warm up and not try when its freezeing cold, to give the cutting line a good clean then to give it a vigorous polish with a rag just before the cut, I think the idea was to warm it a bit but I liked it because it helps remove any little bits that might make the wheel skip. Im not a confident glass cutter though and Ive got a couple of old bulleyes to trim a bit off each end,,any tips other than asking the local glass merchant to do it?

When I worked as a Salesman for a double-glazing manufacturer, the foreman in the workshop told me that "You should always use a glass-cutter Very-Quickly - Because the High-Pitched Sound that it makes will increase the penetration of the fracture. - That wil make the final break much easier & cleaner."

 

[Jacob]

When I worked as a Salesman for a double-glazing manufacturer, the foreman in the workshop told me that "You should always use a glass-cutter Very-Quickly - Because the High-Pitched Sound that it makes will increase the penetration of the fracture. - That wil make the final break much easier & cleaner."

A good cut seems to be fast, light pressure, with a slight hiss; a bad one slower, heavier and scratchier.
Mines a Toyo TC 20 Toyo Straight “Dry Wheel” Glass Cutter - TC20 which has been working well for years n.b. stand it in oil in between cuts. The other is a Shaw with oil in the handle and doesn't work too well.
Carbide wheels - I thought they were some sort of diamond. Used to have a diamond cutter which looked just like the Toyo but it seems to have disappeared.