? for Bert Weiss and others

Leslie Ihde · Post by **Leslie Ihde** » Wed Dec 17, 2003 9:16 pm

Hello Bert,

I saw a demonstration you led at the warm glass week-end on working with float glass. I don't know if you addressed this, perhaps I missed it, but my question concerns cutting a hole in the bottom of a bowl. I watched you cut a hole in a flat piece of glass, but not in a bowl. I have available a drill press with the slowest rpm of 625, a small hand drill which goes 300-500 rpm and 2 brand new diamond bits for cutting holes- one 1/2" and one 1/4". All excited and prepared to practice, I'm not sure how to secure the bowl (picture a large wok), nor fit it to my drill press. The hand drill seems even worse- it moves, I move, the glass moves. You had a handy tri pod thing, but I'm not sure even that would be big enough, and still how to secure the bowl.

I await your thoughts,

Leslie Ihde

Marty · Post by **Marty** » Thu Dec 18, 2003 8:51 am

Leslie- you've got lots of clay- make a base for the bowl to sit in. How big is the bowl? How thick? What's the reach on the drill press? Does it have a platform to put the bowl on? Will your drill press reach into the bowl bottom? If not, you may have to use the steady-n-go (tm) cheatin' technology with the hand drill but it will be hard to get a clean hole by hand.
Practice on scraps first- make a clay dam around the hole to contain the water, lift the bit out of the hole every few seconds to clear the grundge, be gentle when you get near the other side. Marty

Barbara Muth · Post by **Barbara Muth** » Thu Dec 18, 2003 10:48 am

Leslie, I wonder, is sandblasting an option? Given my lack of hand strength and dexterity, that's probably the solution I would be trying....

Gotta get my own blast booth!

Barbara

Bert Weiss · Post by **Bert Weiss** » Thu Dec 18, 2003 10:55 am

Leslie Ihde wrote:Hello Bert,

I saw a demonstration you led at the warm glass week-end on working with float glass. I don't know if you addressed this, perhaps I missed it, but my question concerns cutting a hole in the bottom of a bowl. I watched you cut a hole in a flat piece of glass, but not in a bowl. I have available a drill press with the slowest rpm of 625, a small hand drill which goes 300-500 rpm and 2 brand new diamond bits for cutting holes- one 1/2" and one 1/4". All excited and prepared to practice, I'm not sure how to secure the bowl (picture a large wok), nor fit it to my drill press. The hand drill seems even worse- it moves, I move, the glass moves. You had a handy tri pod thing, but I'm not sure even that would be big enough, and still how to secure the bowl.

I await your thoughts,

Leslie Ihde

Leslie

I drill my bowls upside down with a dam made of modeling clay or Mortite window caulk.

Hand drills are the worst alternative. Once the water gets cloudy, it is difficult to tell where the hole is. The technique invloves 10 seconds of drilling and then lift the bit to allow water to cool the glass. Drill bits wear out much faster in a hand drill then when used in a drill press.

If you figure out a way to secure the glass right side up, you would simply put water in the bowl and drill from the inside.

Chip out is the biggest problem to worry about. I place a block of something under the upside down bowl and put some of the clay on the block so that the clay is firmly supporting the underside of the glass. This up pressure helps to minimize chipout. Another help is to know when you are most of the way through and go very lightly. The glass drill comes with a simple gizmo that can do that.

We ran in to killer problems drilling through 12" diameter sink bowls with a 1.5" diameter drill. The glass broke as the bit came through. There are 2 things that could have helped that. One is to drill from the inside. The other would have been to flatten out the shape at the base.

The really good pro glass drills work from top and bottom at the same time. This eliminates chip out all together. I have had difficulty lining up when trying this by hand.

BTW diamond coolant is recommended for longer bit life.

Leslie Ihde · Post by **Leslie Ihde** » Thu Dec 18, 2003 4:44 pm

Thank-you Marty, Barbara and Bert.

I'm a little confused as to speed of the drilling. Some suggest a faster speed, but the web site where I bought the drill bits says go slow. (400-600 rpm) I guess practicing will give me some further info. I'll try it this week-end, and sand blast if I fail.

Leslie
ps clay to stabilize is a good idea.

Bert Weiss · Post by **Bert Weiss** » Thu Dec 18, 2003 4:48 pm

Leslie Ihde wrote:Thank-you Marty, Barbara and Bert.

I'm a little confused as to speed of the drilling. Some suggest a faster speed, but the web site where I bought the drill bits says go slow. (400-600 rpm) I guess practicing will give me some further info. I'll try it this week-end, and sand blast if I fail.

Leslie
ps clay to stabilize is a good idea.

Leslie

My "glass drill" is relatively slow. The drill bit specs usually suggest a much faster speed. It works fine though.

Bert

charlie · Post by **charlie** » Thu Dec 18, 2003 4:51 pm

Leslie Ihde wrote:Thank-you Marty, Barbara and Bert.

I'm a little confused as to speed of the drilling. Some suggest a faster speed, but the web site where I bought the drill bits says go slow. (400-600 rpm) I guess practicing will give me some further info. I'll try it this week-end, and sand blast if I fail.

Leslie
ps clay to stabilize is a good idea.

i think it has to do with the edge speed of the bit. a wider bit would have a much higher speed (inches/second) than a thinner bit would at the same rpm. usually cutting tools (saw blades, drills, etc) are rated at a certain linear speed for a particular material. you could ask the place you got them what the optimum speed for that particular bit in glass would be.

rosanna gusler · Post by **rosanna gusler** » Thu Dec 18, 2003 9:14 pm

no matter what way you do it.............tie your hair back. beenupclosetoadrillpressgirl

WarmGlass.com

? for Bert Weiss and others

? for Bert Weiss and others

Re: ? for Bert Weiss and others