What Kind Of Drill Bit To Use?

[Jeff T]

What kind of drill bit do I need to drill through the gunwale? I will be starting the stereo install next week, at which point I will need to drill through the deck (under the tower mount) to run speaker wire up through the tower. Also, and size recommendation is appreciated.

[chpthril]

What kind of drill bit do I need to drill through the gunwale? I will be starting the stereo install next week, at which point I will need to drill through the deck (under the tower mount) to run speaker wire up through the tower. Also, and size recommendation is appreciated.

Hi-speed steel resist biting/chipping the most. Go slow w/lite pressure. It will go though the figerglass real easy but will want to grab when it hits the reinforcement plate.

Start with 1/8th and slowly work your way up.

I think that 7/16 will be just right for 2 wires.

[spharis]

Drill in reverse.

[Jeff T]

So just a regular straight bit? I'm looking for bit type. Chp-start with a smaller bit first and then get bigger?

[spharis]

No need to start small. Regular general purpose straight bit. Drill in reverse, use masking tape, and chamfer the gel by either turning a bit by hand over it, or using a chamer bit in reverse on a low setting. This is what I did, and my holes were perfect with no chips on very old gelcoat.

[Razzman]

I used a forstner bit the exact size i needed, they're extremely sharp. Like the others said, drill in reverse 'till you're through the gelcoat.

[xpjim1]

I concur. Drill in reverse thru the gel coat. Then you can drill forward. No chipping what so ever.

[Jeff T]

Thanks. I do not mean to be a ingorant pest, but I do not know what "chamer" or "forstner" bit is.

[Razzman]

Here's a forstner bit, it's a combination of a hole saw and precision drill bit. The nice thing is that they come in virtually every size. I got mine at Home Depot for $8 if i remember right.

[Razzman]

Bigger pic showing the design...

[chpthril]

Thanks. I do not mean to be a ingorant pest, but I do not know what "chamer" or "forstner" bit is.

A chamfer is a beveled edge in the gel coat that will help prevent spider cracks.

A forstner bit is a wood cutting bit. Would probably work good if just drilling through gel and fiberglass, but will not drill through the metal plate that is glassed in

The reason I suggested to start small and slowly work your way up was the metal plate itself. It will be much easier (IMHO as I don't have a degree in holeddrillology) to enlarge a pilot hole in the plate than trying to drill a single 7/16 hole. You would probably ruin the bit by time you got through the metal reinforcing plate.

Good luck

[spharis]

Chamfer bit looks like this; this one is for a router, but they are available for hand drills as well.

[Razzman]

A chamfer is a beveled edge in the gel coat that will help prevent spider cracks.

A forstner bit is a wood cutting bit. Would probably work good if just drilling through gel and fiberglass, but will not drill through the metal plate that is glassed in

The reason I suggested to start small and slowly work your way up was the metal plate itself. It will be much easier (IMHO as I don't have a degree in holeddrillology) to enlarge a pilot hole in the plate than trying to drill a single 7/16 hole. You would probably ruin the bit by time you got through the metal reinforcing plate.

Good luck

What metal plate you talking about? The only metal plate i have is in my head.

[Jeff T]

I took a peek at the hole that was driilled in BD's 06ve and I did not see a metal plate either. Doesn't mean it wasn't there...just that I didn't see it.

[anhaney]

Once you are through the gel coat you need to take some 1500 wet or dry sand paper and sand around the edges of the hole. If not in a year or so you MAY regret that you didn't. This was not done on my boat but thankfully for me when I got spider cracks a year later the dealer accepted responsibility for it and took care of the issues since they did the install work. $3600.00 later spider cracks were gone. Just my two cents worth.