A smattering of projects
The punch list for the six meter is as long as my arm. But if I think about it, I’ll get all despondent and dreary. No fun there. Much more fun to think about ticking things off the list, and that’s what I did today.
First off the list, the winch post .
I think it looks like a piece of Danish modern furniture. It’s all shiny with its 2nd coat of varnish. It’ll get at least 7 coats before all is said and done.
For those who care about such things, the large blocking in the center of the 2 uprights will back up the winches. There will be a jib halyard winch on the right side of the top block and a main halyard winch on the left side of the lower block. The two smaller blocks are there to help stiffen the whole affair and keep it from twisting from the force of the lines pulling on the winches.
At the base, right next to the post members, you can see two lighter pieces of wood… those are oak braces that go in between the 2 sole bearers. The braces are screwed down to the floor timber below it, and into the sole bearers as well. These are there to brace the post and keep it from racking.
And just to save you a trip to the glossary:
The soles are the floorboards.
The sole bearer is what the sole sits on.
The floor timber connects the frames to the keel.
Ok, tick that off.
Next up, making a new bending jig for the aft cockpit coamings. The original jig seemed good enough at the time,
but the coamings were left on the jig out in the sun and rain while other things took priority.
They didn’t fare well.
We think the break had as much to do with a hard spot (i.e., a too sharp curve in the jig) as being left in the sun. The long checks (the splits running left to right) were probably due to the sun and rain.
The upshot: those coamings are toast, and we’ll need to bend some new ones. We decided to make a new jig, a solid one. It’s possible that the coaming wood failed because the wood ran straight in the spaces between the 2×4’s in the previous jig, and then had to bend sharply when it curved across them. A sold jig provides a continuous bearing surface for the wood to bend against. It’s more trouble to make than the original jig, but it’s close to foolproof.
Mike traced the shape of the cockpit opening, and cut and faired it out to make a pattern.
This is half of the opening where the coaming will go. The cockpit is symmetrical, so you can make both coaming sides from the same pattern.
The bending jig is a positive mold. This means that the wood is bent over it, and the face that contacts the jig is the inner face of the coaming. However, the cockpit butts up against the outer face of the coaming. Here’s a simplified picture in case this seems obtuse.
So, the problem is that we’ve got a pattern based on the edge of the cockpit but the jig has to be based on the inner edge of the coaming. The coaming is 1/2″ thick. Luckily, it’s easy to fix this. Trace the pattern on some stock for the jig, and then, using a small 1/2″ thick block, subtract the coaming thickness by making little marks all around the inside of the tracing.
You can barely see the little tracing I’ve made on the right side of the block.
You end up with a series of dash marks along the inside of the tracing.
Now, just connect them with a flexible batten
and trace the new line from the batten.
That’s the line you cut to. I like to cut close to the line, and then get right on it using a stationary sander. The sander has the advantage of allowing you to fair in your curve a bit more as you make smooth, sweeping motions across the sander.
Once you’ve got this piece done, it becomes your master template. For this jig, we want a final thickness of about 5″. This means we need a stack of about 7 layers of plywood.
I like using a flush-cutting router or shaper bit with a guide bearing to make exact copies from a template like this. The process would be easy if we had a cutter that was tall enough to handle the whole stack at once, but unfortunately, our longest cutter is about 2 1/2″ This means we have to assemble and cut these layers in stages.
First, we trace out the template onto a piece of scrap plywood and cut it out a little big. Here’s a slick trick to cutting out a large shape like this. Put half of the sheet of plywood on a bench, and the other half on a rolling cart just set away from the bench.
Ok, this only works really if your cart fits entirely within the shape of the cutout. In this case, it does. You can barely see the cutout line drawn on wood here.
Then cut your shape out.
Voila! The cart holds it up and nothing falls and binds the blade.
All right, it’s not a huge trick, but it’s handy if you’re working alone.
So, stack up 3 of these guys on your template and screw them all together. With the template on the top of the stack, use a router with a top-mounted guide bearing to flush cut the 2 layers below it. Yes, the 2 layers, because that’s all the router will reach.
We’ll get to that 3rd layer in a minute.
By the way, this goes MUCH FASTER if you use a sharp bit rather than a chewed up dull hunk of junk like I started with. Word to the wise…
So, after you make this cut, stack two more layers on top of your template, and screw them down too.
Now change your router bit to a flush cutting bit with a bottom mounted guide bearing.
Now when you rout, the bearing still rides along the template and cuts the stack above the template. Flip your stack, add one more layer of plywood, and use this router one last time.
In this case, you will be riding on the layers next to the template, rather than the template itself, but if you’ve been careful, it’s all the same. The only problem that may arise is if your plywood has voids… the bearing will dip into them and give you a little dip on your path.
That’s why I always use marine grade plywood for my first pattern if at all possible… no voids.
At the end of it all, you have a thick stack of wood that perfectly follows the shape of your template. A very heavy thick stack of wood.
Now add some holes for the clamps. They don’t go all the way through, they’re just deep enough for the clamps. The other side has a mirror set of holes.
(that clamp is in place to show why the holes are there by the way, it’s not doing anything important like solving world hunger or clamping a right wing talk show host’s mouth shut)
With a two cleats screwed to the bottom of this beast, you can now clamp it to a couple of saw horses.
Here it is, all set up and ready to go. The clamps are hung on the saw horses to that we can pick them up and use then immediately.
The 1/2″ thick mahogany that will be bent on this form will have been in the steamer for about an hour, but will cool very quickly. Thin wood cools almost immediately after coming out of the steam box. This means we’ll have to work very fast, preferably using four people.
It goes like this: take the hot board out of the steamer, put it on the top of the jig, have 2 people bend both sides down immediately and hold it there while the other two start clamping in the middle and then work their way down to the ends. The board has to be held down with one edge running right along one of the jig’s edges to keep it from being bent at an angle. The whole process should take 30 seconds or less if we’re good.
That’s tomorrow’s job. But for now, the jig is ticked off the list.
Tags: jig, coaming, stem bending, winch post