A blog about SCAMP (Small Craft Advisor Magazine Project) boats. Covering the build, sailing the boat and the scamp community that has formed around this little portly boat.

Sunday, October 5, 2014

Centerboard drilling

This post is about drilling the centerboard. Both the perpendicular hole and the hole through the centerboard trunk.

I was very nervous about the perpendicular hole through the centerboard. It needed to be perfectly perpendicular or the centerboard would have a wobble and that would be bad. Let's cover that first.
I had already painted it with epoxy and then filled the oversize hole. The oversize hole didn't matter if it wasn't perfectly perpendicular as long as I didn't hit any wood when drilling my perpendicular hole.
I have a drill press, but the centerboard is very heavy and I would have to support it with something. And my forstner bits are not very long, so I had limited play in the table of the drill press.

After futzing about with it for awhile, I remembered my angle meter. I pulled it out discovered that again, it's batteries were dead. I think the little soft buttons are too easy to push. A cr2025 later and I was measuring and making sure that the angles were all correct. Then I drilled. At this point, I had only graphite powdered the other side, not this side.
Finding 90
Here's the result. Not too bad.
Resultant hole.
After that was done, I switched to drilling out the centerboard trunk hole.
This was nerve racking because I had a plan (see the earlier post), but had never done anything quite that complicated. I took lots of shots.
Here is the 1/2" hole centered.

I put tape on it to hold it still.
Then drilled the holes into the centerboard sides. (note the tape to make sure I don't drill too deep.

Take the plat off and now I can put any plate on there.

Now take the pin out and put it in on this side

And you get a pin out the inside.

Now to do the same thing on the outside of the boat. Unfortunately, the planks are on the boat. That makes it harder because you can't fit a drill in very well. I have a right angle drill, but it's still a bit too big with the forstner bit in there.
I was ably get 3 of the holes drilled, which is enough.
Now that I had both sides drilled and ready to accept any of my plates, I wanted to drill out the hole to a larger size with the 7/8" hole guide.
Unfortunately, I didn't want any rip out inside the centerboard trunk because it would be very difficult to repair, so that means I had to stick a chunk of wood in the trunk. But how could I get it back out again? I happened to have a spare chunk of white oak that fit just perfectly and was nice and hard. I screwed a chunk of plywood to it to push it in and out.
Useful chunk

 I shoved that down through the centerboard and left it in place while I drilled with the 7/8" forester bit.
Stuck down the centerboard trunk.
Now the 7/8" plate is on and you can see the 1/2" hole just a bit.

I drilled with the 7/8" forsner.
I put packing tape on the stick and put it back down.

Then I filled the hole with epoxy, microballons and silica.
That was very nerve wracking, but it was done. It felt good to have it done.

I still had a bit more to do, though. Since I had some glue mixed up, I wanted to glue in the bushings. I scratched them up for adhesion, then put them in with glue.
Bushings before gluing
And I still had some glue, so I glued up the pieces I had cut for the rudder top. I had dry fit it earlier, and I didn't like it because the fit was just too tight. So I added a 5.2mm chunk of oak plywood in the middle.

Rudder top

rudder bottom
I have a plan to get a copper pipe in there for the up haul an downhaul lines. That will be another post.

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