Drill guides?

[Ratpack]

Just wondering if any has any good ideas to make a drilling guide to use while drilling my tank? I know you can just start at an angle, but I would really prefer a guide I can clamp down and let it hold the hole saw in place. I thought of plywood, but will it hurt my diamond bits to drill the plywood first? I think I would need to do that to ensure the hole in the plywood or whatever is the same as the holesaw. Any thoughts?

[hllywd]

The diamond bit will fry before it cuts through wood... bad idea.

I use the inside corner of an aluminum framing square. A lot of times the spacing works out so the square can sit on or against the plastic trim. Space the square up 1/4" so the diamond filled portion of the saw doesn't hit the square and drill away.

Tim

[tedu]

Just use a standard hole saw to drill in the plywood then clamp / drill as you proposed.

[scaast]

I planned on using 1/4 acrilyc with guide holes cut and then a another solid piece of acrylic clamped on the other side of the glass to prevent chipping on the backside.

[jubjubrsx]

i just did the angle trick worked fine when i did mine...(first onei would do it again, just go slow until you get a little groove..)

[Ratpack]

Originally posted by tedu
Just use a standard hole saw to drill in the plywood then clamp / drill as you proposed.

I would do this, but that means buying about $60 worth of holesaws.

I think I will do the angle thing. I have a piece of starboard laying around. Perhaps I can cut an inside 90 in it and use that. That way I can bevel the under side edge to not hit the diamond coat. I'll give that a try and see how that works. I have oneof oursuppliers bringing me some 3/8" thick glass tomorrow to try and practice on before doing my tank.

[miwoodar]

I use the bottom of a cottage cheese container. I cut a hole that matches the size of the diamond bit. I then use grey tape to attach the base of the container to the tank. No wobble and it provides a place for the cooling water.

[hllywd]

Originally posted by Ratpack
I would do this, but that means buying about $60 worth of holesaws.

I think I will do the angle thing. I have a piece of starboard laying around. Perhaps I can cut an inside 90 in it and use that. That way I can bevel the under side edge to not hit the diamond coat. I'll give that a try and see how that works. I have oneof oursuppliers bringing me some 3/8" thick glass tomorrow to try and practice on before doing my tank.

That doesn't sound like a bad idea other than the possibility of the starboard may be a little sticky against the hole saw and make it want to walk. That may even be a non issue with the back side beveled.

Tim

[woodwonders]

I made this simple jig. It did require standard hole saws to drill the plywood but I already had those. I had the suction cups laying around. They were dirt cheap at Harbor Freight. I also found duct seal (used by electricians) worked great for making a dam to hold water.

[funman1]

Here's my video on drilling.
I just use the angle method, and it works VERY well.

http://www.youtube.com/watch?v=ZMctXz7GraU

[Ratpack]

Steve, watched the video and that was fast. Hope all mine go that easy.

I have also heard of people using the foam insulation sheet from Lowes as a guide as well as template. Cut it to fit, mark and cut out the holes you want, then tape it to the tank. Then use that to guide the bit and you know where you want your holes. What do you all think?

I also plan to drill from the inside so that any chipping will be on the outside surface so that the bulkhead has a better surface to seal to on the inside. Good idea or not?

[funman1]

Originally posted by Ratpack
I also plan to drill from the inside so that any chipping will be on the outside surface so that the bulkhead has a better surface to seal to on the inside. Good idea or not?

Sounds like a good idea, but I think that would be pretty hard drilling like that..