Cutting drain holes in sinks

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Greg Rawls
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Cutting drain holes in sinks

Post by Greg Rawls »

I've got the chance for a commission to make a sink. I figure that I could make a bowl and some how cut the drain hole. Any ideas? Where can I get a bit large enough? How do I keep it wet during drilling? Thanks in advance1
Greg
Dick Kolpack
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Post by Dick Kolpack »

Mask and sandblast.

Dick
Tom White
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Post by Tom White »

I have drilled a drain hole in a bowl formed from about 3/4" thick System 96 glass by using a 1 1/2" carbide grit core drill from Home Depot in my drill press. I placed on the drill press table a shallow container large enough to hold a piece of 3/4" plywood slightly larger than the bottom of the slumped bowl, 3/4" plywood piece and the slumped bowl with the center of the desired hole marked on the inside of the bowl. After adjusting the height of the table to assure I could drill completely through the bowl I positioned the point of the pilot drill over the center mark then poured about an inch of water into the bowl. I drilled with the typical up and down motion I use when drilling any glass with an abrasive core drill. I started with moderate pressure and finished with lighter pressure as I neared the bottom of the hole. When the water drained from the bowl into the container below I knew the hole was completely through the glass. The plywood piece cushioned the bottom of the bowl and accepted the 3/8" of the pilot drill as it came through the glass first. Using light pressure at the end of the hole resulted in minimal chipping on the bottom of the bowl when the drill broke through.

Best wishes,
Tom in Texas
Bert Weiss
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Re: Cutting drain holes in sinks

Post by Bert Weiss »

Greg Rawls wrote:I've got the chance for a commission to make a sink. I figure that I could make a bowl and some how cut the drain hole. Any ideas? Where can I get a bit large enough? How do I keep it wet during drilling? Thanks in advance1
Greg

I use diamond core drills that I buy from CR Laurence. a 1.5" drull bit does the job. I drill bottom up. I first make a dam using Mortite or modeling clay. Once the drill bit is placed right, I fill the dam with water. It doesn't take much to do the job. Duck tape the glass under the hole. I sometimes suoport the bowl with clay on a board or brick so that it is pushing back up on the drill. This will minimize chipping.

There are 3 ways you can drill. I use a tripod glass drill which is, in my estimation, the best tool for the job. Next, you can use a drill press as long as it has a long enough arm to get you to the middle of the bowl. In a pinch, you can use a hand drill. The problem is that once you start drilling, the water clouds up and you can't see. The bits last longer when used in a drill press of some sort. The cheapest bits don't last very long. Eventually it takes a long tome to get through.

Once I have drilled through, I sandblast a dent for the drain to set down in to, so it sits flush after beiing puttied in.

BTW make your glass 3/4" thick.
Bert

Bert Weiss Art Glass*
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Val
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Post by Val »

Bert,

I've never heard of a tripod glass drill where can you get one or is there a website I can see one.

Val
Annah James
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Post by Annah James »

I don't drill them, I have a guy sandblast the holes for me. That way, he can make the countersink for the hardware as well. I thought about doing the drilling thing, and it just stressed me too much. A good friend, though, bought a drill press and does the dam-thing with clay. He puts a sandbag under the glass to hold it securely, since often the pieces are not totally even.

I still feel safer with the sandblasting. It's also worth it to pay for someone else to do it, at least so far. I guess that it's one area that I am not that interested in the actual production. Good luck!
-Annah
Bert Weiss
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Post by Bert Weiss »

Val wrote:Bert,

I've never heard of a tripod glass drill where can you get one or is there a website I can see one.

Val
Val

Both CR Laurence and Somer & Maca sell the tripid and various suction cup glass drills. The tripod is the most usefull for is as it doesn't require a flat spot to work.

http://www.crlaurence.com/ProductPages/ ... 49&Origin=

Somaca.com did not give me a picture without a login.

CR Lauremce sells everything for a glass shop but glass. It is a very important resource for tools and supplies. They sell the pro tools as opposed to stained glass shops that sell hobbyist tools.
Bert

Bert Weiss Art Glass*
http://www.customartglass.com
Furniture Lighting Sculpture Tableware
Architectural Commissions
Greg Rawls
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Post by Greg Rawls »

Thanks folks! Lots of good information here.

My drill press is small so I'll have to use a hand drill, if that's the way I go. I could sand blast, but I have a siphon system. Maybe I'll check and see if I can hire someone to do it.

I'll let you know how it turns out.
Greg
Bert Weiss
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Post by Bert Weiss »

Greg Rawls wrote:Thanks folks! Lots of good information here.

My drill press is small so I'll have to use a hand drill, if that's the way I go. I could sand blast, but I have a siphon system. Maybe I'll check and see if I can hire someone to do it.

I'll let you know how it turns out.
Greg

The hand drill is tricky because you can't see where to replace the drill bit once you have started drilling. The drilling technique is to drill for about 10 seconds and back off to let the water in to the hole. One solution that you could try is to get somebody else to spray the water right at your drill bit while you work, instead of using a dam. This will be messy, but the idea is to keep the bit cool one way or another. The other factor to worry about is that a spinning drilll bit can be hazardous to the glass if it is contacted at a funny angle. The drilll press always approaches the glass at the same angle. With care it can be done. The other down side to hand drilling is that the bits seem to wear faster and they are not cheap.

When you buy your bit, it will come with paper work that will specify the best rotation speed. While thiis is NOT a critical spec, you want to try and come close.
Bert

Bert Weiss Art Glass*
http://www.customartglass.com
Furniture Lighting Sculpture Tableware
Architectural Commissions
Val
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Post by Val »

Thanks Bert,
I took a look at the website and they have some very interesting things.

Val
Tony Serviente
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Post by Tony Serviente »

Greg-I just drilled a 1" thick sink a couple of months ago. It was too big for the drill press so I did it by hand with my porta cable 1/2" drill, and a core bit. These drills are relatively low rpm, but with high torque, so one must be very careful about the angle of approach. I started from inside with water sitting in the bottom of the sink, and when I got about 90% through I flipped it over and met the hole from the other side. You get no chipping this way, but you have to be careful to align the holes carefully. Took about 15 minutes total. Now if you know someone with a water jet cutter... Good luck.
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