[Jennifer]

How do you stabilize the glass pane while drilling a hole in it? I was thinking of putting the pane on a table with a piece of plywood or something under it and then clamping them together on the table?

 

[Chris S]

How do you stabilize the glass pane while drilling a hole in it? I was thinking of putting the pane on a table with a piece of plywood or something under it and then clamping them together on the table?

That works, or a couple scrap pieces of 2x4 underneath to give it lift.. I've found the pressure of my hand holding it down is enough, if even needed. The drill/drill bit itself should not be moving the glass around - it should be just grinding out the hole. You don't need to put pressure on the drill while drilling (and shouldn't). Let the bit do the work.

 

[Jennifer]

That works, or a couple scrap pieces of 2x4 underneath to give it lift.. I've found the pressure of my hand holding it down is enough, if even needed. The drill/drill bit itself should not be moving the glass around - it should be just grinding out the hole. You don't need to put pressure on the drill while drilling (and shouldn't). Let the bit do the work.

And then I suppose the area under where you’re drilling would just be open if propping it up with 2x4s right? I like that idea better than resting my working area directly on wood. Thanks!

 

[Chris S]

And then I suppose the area under where you’re drilling would just be open if propping it up with 2x4s right? I like that idea better than resting my working area directly on wood. Thanks!

Correct, keep it open. I typically use painters tape on the bottom half of the glass as well, so the glass piece does not fall, but rather just seperates and remains stuck to the glass/tape. Keep it wet while drilling as well.

 

[Socratic Monologue]

I drill with the pane flat on a sacrificial board -- no lift, since the hole will tear out the back side more if there is no support directly under it. The tape trick helps, but both tape and a flat surface is even better.

If the glass is moving around, you're using too much pressure. Only the weight of the drill, if that much, should be applied.

 

[bulbophyllum]

Definitely use a backer piece while drilling glass. The tear out on the exiting side will be less. I also like to lightly clamp the glass in place.

If you can get access to a drill press or one of those peel and stick guide things all the better.

I have had to drill a lot of tile and those peel and stick guides are pretty cool if you can find on for your size bit. Rubi 1/4 in. and 3/8 in. Drill Bit Kit-04909 - The Home Depot

 

[Jennifer]

Definitely use a backer piece while drilling glass. The tear out on the exiting side will be less. I also like to lightly clamp the glass in place.

If you can get access to a drill press or one of those peel and stick guide things all the better.

I have had to drill a lot of tile and those peel and stick guides are pretty cool if you can find on for your size bit. Rubi 1/4 in. and 3/8 in. Drill Bit Kit-04909 - The Home Depot

Didn’t even know those existed! Thanks so much for the tips!!!

 

[Socratic Monologue]

I forgot I own a drill guide. I have this one:

DRILAX Drill Bit Hole Saw Guide Jig Fixture Vacuum Suction Base with Water Coolant Hole: Amazon.com: Industrial & Scientific

DRILAX Drill Bit Hole Saw Guide Jig Fixture Vacuum Suction Base with Water Coolant Hole: Amazon.com: Industrial & Scientific

www.amazon.com

Works fine, but it is too difficult to build a plumber's putty water moat when using a guide, so I just freehand it.

 

[Jennifer]

I forgot I own a drill guide. I have this one:

DRILAX Drill Bit Hole Saw Guide Jig Fixture Vacuum Suction Base with Water Coolant Hole: Amazon.com: Industrial & Scientific

DRILAX Drill Bit Hole Saw Guide Jig Fixture Vacuum Suction Base with Water Coolant Hole: Amazon.com: Industrial & Scientific

www.amazon.com

Works fine, but it is too difficult to build a plumber's putty water moat when using a guide, so I just freehand it.

That thing looks awesome. I’m getting it!

 

[NateDawg]

Definitely helps to have the area your drilling supported, less blowout the backand less chance of cracking the glass. And if you end up not using a press/guide, start the drill bit at an angle and slowly shift it strait up and down. This will help seat the bit into the glass so it doesn't run away from you. Also, I'm sure you've already checked for this but make sure the glass isnt tempered or you'll end up with a 1000 little pieces of glass the second the diamond bit touches the glass.

 

[fishingguy12345]

I made a template that I use to stabilize the drill bit. Took a spare piece of wood and drilled a hole in it to act as the guide.

 

[Jennifer]

I made a template that I use to stabilize the drill bit. Took a spare piece of wood and drilled a hole in it to act as the guide.

That’s a good idea...but how did you start the drilling at a 45 degree angle then? And how did you keep water over the drilling site?

 

[fishingguy12345]

That’s a good idea...but how did you start the drilling at a 45 degree angle then? And how did you keep water over the drilling site?

The template means I don't need to start at an angle because it holds the bit against the glass.

I pour water into the template and into the center of the drill bit too help keep things cool.

 

[Jennifer]

The template means I don't need to start at an angle because it holds the bit against the glass.

I pour water into the template and into the center of the drill bit too help keep things cool.

Ah that makes sense. Seems like a great idea. Thanks!

 

[Fresh2O]

Good info in this thread. I just drilled holes for 1/2” and 3/4” bulkheads today. I used a template as mentioned in post #11 and for one of the holes I was able to use a board on the opposite side of the glass. Hole was clean (required some wet sanding). The other hole had no support so I used duct tape. Hole was not as clean as the supported one.
It took quite a while to cut each hole. The noise of the bit grinding would change as it got deeper into the glass. It actually got loud. I would stop every few minutes to blot out the water, check the depth, and add more water.
I think a press would have given better control. I applied little to no pressure; just did my best to stabilize the drill and keep it straight.
I’m not sure this is by design (or cheap equipment) but the the stems on the two bits I used appeared to be “off”. As the cutter would rotate, there was a noticeable wobble. I did not see this with the smaller bits.

 

[Jennifer]

Good info in this thread. I just drilled holes for 1/2” and 3/4” bulkheads today. I used a template as mentioned in post #11 and for one of the holes I was able to use a board on the opposite side of the glass. Hole was clean (required some wet sanding). The other hole had no support so I used duct tape. Hole was not as clean as the supported one.
It took quite a while to cut each hole. The noise of the bit grinding would change as it got deeper into the glass. It actually got loud. I would stop every few minutes to blot out the water, check the depth, and add more water.
I think a press would have given better control. I applied little to no pressure; just did my best to stabilize the drill and keep it straight.
I’m not sure this is by design (or cheap equipment) but the the stems on the two bits I used appeared to be “off”. As the cutter would rotate, there was a noticeable wobble. I did not see this with the smaller bits.

Thanks for the info here. I can assume, but what exactly is wet sanding??

 

[Fresh2O]

Thanks for the info here. I can assume, but what exactly is wet sanding??

Just wet sand paper. Which does not hold up very well (backing gets soggy). I think there are other types of sand paper that holds up better when wet.
One thing I noticed is that when after I cut the template, once the wood got wet I think it swole up and made the hole smaller. I wrapped one of the smaller bits in sandpaper and used the drill to route the hole. I’m going to save the template for future projects. Going to label the hole size and coat it with sealant.

 

[Socratic Monologue]

Just wet sand paper. Which does not hold up very well (backing gets soggy). I think there are other types of sand paper that holds up better when wet.

You can either use waterproof sandpaper, or sand it dry. Wrapping any type of sandpaper around a dowel that is smaller than the hole makes the job easier. If a bulkhead is going in the hole, you really don't need to sand it at all, but for vent holes it is a good idea to remove any sharp edges.