Question How to cut arch top glass

[Melinda Tennis]

My customer has 2 antique clocks with an arched top but both sides have a wider notch at the bottom of the arch. Picture may explain better than my description. How would I cut this without the scores running through the center? Make the scores not meet at the corner of the arch?

 

[wpfay]

Get a glass bit and drill a hole at the point of the two inside corners.
Small diameter would mean less cleanup (hand filing) but larger diameter might have a greater success rate.
That should keep the score from running into the center.
Probably a lot of practice needed.

option B is have a glass company do it.

option C use acrylic instaed.

Read my tag line about skill sets.

 

[JFeig]

Is this drawing of the inside or outside of the door of the clock? In many cases, the back of the door will not have this 90° corner, rather an extended lip to avoid this issue.
If this is the inside, showing the rabbit lip, the only safe way is to drill a hole at each 90° corner, to avoid any "running of the scoring" of the glass for removing the excess.

In modern CNC cutting with a waterjet this will not be a problem.

 

[Bruce Papier]

Another helpful hint would be to use a diamond glass cutter like is used for stained glass. Having to roll a cutting wheel along an arc is more difficult than scribing with a single point.

 

[Melinda Tennis]

I'll check out the diamond glass cutter. I would be making the arch cut with my oval/circle cutter. But I have had good luck following a sharpie line for circles and ovals.

 

[Framer Dave]

Another helpful hint would be to use a diamond glass cutter like is used for stained glass. Having to roll a cutting wheel along an arc is more difficult than scribing with a single point.

I've been doing stained glass for about thirteen years now and know a lot of stained glass artists, some of whom have been doing it for decades, and I've never run across anyone using a diamond cutter. Not to say it's never done, but it has to be very rare.

My customer has 2 antique clocks with an arched top but both sides have a wider notch at the bottom of the arch. Picture may explain better than my description. How would I cut this without the scores running through the center? Make the scores not meet at the corner of the arch?

Cutting it exactly as drawn is impossible. Glass wants to break from edge to edge, and there is no way to make the score somehow stop at that inside corner. Once could use a ring saw made for stained glass work, but it will create an area of stress at that corner that will break eventually. As Jerome pointed out, the rabbet on the door frame is likely rounded off and the front is shaped to give the appearance of the 90 degree corner. When you cut the glass that inside corner will be rounded off, and the larger the radius the better.

 

[Dostie Bros.]

Inline Ovals might be able to help cut a custom shape, I would also second reaching out to a local glass company, we do this quite a bit for oval and circle mirrors, easier than breaking a few in house.