Drilling a clean entrance & exit hole

[jal]

I need to drill a 3/4 in hole in my boat. I would like to make shure that it is a clean entrance and exit hole. This will be on a curved piece of fiberglass and I am not confident on how to do it. Does anyone have any ideas?
Thanks

 

[chrismarion]

Re: Drilling a clean entrance & exit hole

You could use a hole saw. One with a good drill bit with length. Start on one side till about half way through, bit should exit BEFORE the hole saw blade, and start on the other side where the bit hole is. Perfect alignment and go back the other way, not pushing any frayed wood out.

A dremel with the Carbide cutting bit for Steel ($15 for one) does ETREMELY well on wood and fibreglass. Cuts like butter! I use it alot on my boat. Just some ideas?!:/

 

[Chris1956]

Re: Drilling a clean entrance & exit hole

Jal, Most importantly, do not push hard on the drill. Secondly, drill a 1/8 pilot hole, follow with larger drill sizes. The key is to cut the FG slowly.

 

[iwombat]

Re: Drilling a clean entrance & exit hole

Cover both sides with masking tape before drilling. It'll keep it from chipping out.

 

[ManOfwar690]

Re: Drilling a clean entrance & exit hole

tglad you save me the point womb gj

 

[drewpster]

Re: Drilling a clean entrance & exit hole

I use masking tape for small holes. For larger holes I use a compass with a sharp pick clamped in it to score the gelcoat. I then cut the hole slightly undersized then open it up to full size with a dremel or a router and a side cutting bit. You have to be careful, but I can get perfectly cut holes this way.

 

[kalla man]

Re: Drilling a clean entrance & exit hole

run the hole saw backwards to score the gel/glass to prevent chipping~~~~~~~~~~~~~~~~~
THE PROJECT.......
s99.photobucket.com/albums/l309/kallaman/

 

[Scaaty]

Re: Drilling a clean entrance & exit hole

run the hole saw backwards to score the gel/glass to prevent chipping~~~~~~~~~~~~~~~~~
THE PROJECT.......
s99.photobucket.com/albums/l309/kallaman/

Damn, ya beat me to it...YEP, run the hole saw in reverse from both sides, then normal and go at it.

 

[jal]

Re: Drilling a clean entrance & exit hole

Well, thank you one and all. The backward hole saw it will be. Will also get some tape on it. When the weather gets more reasonalble I will do it and report back on results,
Thanks again