bobl

Does anyone have a good way to drill the transom for angled exhaust tips? How do you get the correct angle and not screw it up? I remember reading some discussion in an old thread, but I can't find it.

Bob

Kanookstr

I have done 2 , And I always use a Hole saw. But first I Measure from the center of the out drive on the inside. to the center of the riser pipe. Then I re measure that demention on the outside. I then use a small drill bit,(1/8") and drill at the angle of the tip. Then go inside and see if you are in the center of the riser pipe. If you are, Now use the hole saw. If not, try another pilot hole till you get in the center of the riser pipe. Don't worry about the wrong pilot holes. you will be cutting them out when you cut the 4" bigger hole. Your first 1/8" of the hole saw hole should be done with the drill in reverse. This way you won't chip the jelcoat. then switch to forward and finish cutting.
Take your time, And measure 10 times!!!
Good luck,

Mr Gadgets

bobl,
If you are concerned about going thru the transom parallel and keep the drill bit at a 90 degree angle, I use a jig I bought from Sears several years back. Mounts a drill motor and has a platform and two slide posts. You can cut your pilot holes with that as Kanookstr said then go after it with the hole saw. I use duct tape to protect the gelcoat when drilling, just tape off the whole area.. and go for it.

Good luck.

Dick

[ 01-14-2002: Message edited by: Mr. Gadgets ]

puder

you coudl also try a rotozip to amke ita nice round hole. you can use rotozip blades/bits in a dremel then you can use dremel sanding drum to smooth it out and makeit nice and round. Might be easier than a hole saw. they can be apain in the ass and do some serious damage if you aren;t careful.

bobl

Thanks guys, but what I need to do is drill the holes at an angle(not 90 degrees to the transom). I think the flanges on the tips are at a 12 degree angle. I'm thinking I could drill a 1/4" pilot hole all the way through at the appropriate angle and then use the hole saw. I've never tried to use a hole saw at an angle before. Any thoughts?

timewarp

The only advice I can think of is that you can put alonger drill bit in the hole saw so that when you go into the pilothole and the saw is at an angle you have alot of bit in the pilot hole.
Caleb

laster

If you are going to try it free hand with a hole saw timewarp is on the right track but instead of a longer drill bit, after you drill the pilot hole replace the drill bit in the hole saw with a 1/4" steel rod. It can be any length you need and won't have the tendency to cut sideways in its hole from the force of the holesaw like a drill bit would.

Audiofn

Laster had the correct answer. Some times the transom can be so thick that the hole saw will not go through you have to break up the stuff in th middle to keep going or if you can get at it from the inside you can then go from the inside out and the outside in. If you put tape on the outside gell coat it actually helps with chipping

Jon

DanL

We had this conversation when I had to make my 4.5 inch holes larger and slighly off the centerline on the race boat. I cut and glued plywood patches over the holes, drilled a pilot hole and put a long piece of rod in the place of the bit in the hole saw as a guide. Worked perfectly.

BadDog

Bobl,
Use a band saw and slice a piece of wood in a wedge shape of the correct angle and center to center measurement. Then use a drill press with the bed tilted so that the face is 90 degrees to the surface of the wedge and cut your 4” in holes into the wedge. Temporarily affix this wedge to the transom and put the hole saw into the hole of the wedge. Once the hole saw is inserted into the wedge it will act as your guide for the bit. Use a long bit but don't clamp it into the hole saw and run it through until it cuts into the inside. You can now check the inside for positioning.

If your wedge is cut into a nice rectangle and you mark where it is located on the outside up and down and left to right then you can adjust it's position to compensate for the amount you are off on the inside. The lower edge of the wedge will need to be the same depth as the hole saw so it acts as guide for the hole saw. Use tape to mark the position of the wedge on the outside. Once you have it positioned scribe the inside of the hole (which will be the outside of the transom) with a marker and carefully etch the gel coat. Now lay some tape over the holes outline to help prevent chipping. You may consider attaching the wedge with a light bonding agent such as silicone to prevent it from moving around. The cheap silicone will allow you to remove the wedge, something like a latex caulk applied at the corners of the wedge.

Now that you are all ready to go you only need to worry about maintaining the hole saw in the wedge square. Take a second board say a 2x4 with the correct angle and width pilot holes and affix it to the inside. In the hole saw use a rod that will extend all the way through this inside board. Now you have a guide on the outside to get you started and a guide on the inside so you should stay straight.

This method or a six pack and a SawZall will work. Just take your time and think about it.
Tim T.

[ 01-16-2002: Message edited by: cpqtim ]