I needed to make a couple of glass disks for my levitating motor. All attempts with a diamond coated hole saw resulted in disks that could be done better by a neolithic flint knapper (Photo - bottom right).
I eventually succeeded (Photo - Top right) by first glueing scrap pieces of glass with cyanoacrylate to either side of the target piece.
The rubber ring was also glued down as a coffer dam to hold water / coolant (you can use modeling clay).
First attempt failed along with the adhesive - you need to let it cure for about an hour.
Second attempt - much better - but my drill press chuck does not run very true - transfered to the minimill where I finally succeeded.
You do not have to apply a lot of force - being particularly prudent at the breakthrough's. Make sure the glass is spotless in order that the superglue layer is very thin (dust specs will increace the thickness).
The diamond bit went through about 10mm of glass in under a minute at about 500 rpm.
After removing the three layered glass sandwich from the bit, I heated it (slowly) with a propane torch until the glue decomposed - cleaned the disk up and voila.
The sacrificial glass should be thiner than the target glass - I noticed a tendency for the thinner glass to crack on heating - probably due to differential stresses and the splintered edges.
Ken
I eventually succeeded (Photo - Top right) by first glueing scrap pieces of glass with cyanoacrylate to either side of the target piece.
The rubber ring was also glued down as a coffer dam to hold water / coolant (you can use modeling clay).
First attempt failed along with the adhesive - you need to let it cure for about an hour.
Second attempt - much better - but my drill press chuck does not run very true - transfered to the minimill where I finally succeeded.
You do not have to apply a lot of force - being particularly prudent at the breakthrough's. Make sure the glass is spotless in order that the superglue layer is very thin (dust specs will increace the thickness).
The diamond bit went through about 10mm of glass in under a minute at about 500 rpm.
After removing the three layered glass sandwich from the bit, I heated it (slowly) with a propane torch until the glue decomposed - cleaned the disk up and voila.
The sacrificial glass should be thiner than the target glass - I noticed a tendency for the thinner glass to crack on heating - probably due to differential stresses and the splintered edges.
Ken
