Wednesday, July 9, 2014

Back boatbuilding again.

Back to work on SEI.

With the bottom panel all scarfed up and the edges faired off with a hand plane it was time to cut the daggerboard case slot and fit it to the framing.

I measured the frame to get the “case” position, then the width and such, drew the ‘case” shape out and drilled a couple of holes big enough to take the jigsaw blade.

Off topic for a moment, I regularly get people asking about jigsaw blades, and why theirs make such a splintery mess of their plywood and mine don’t.
I use hollow ground veneer blade, in Makita these are number 10s, they have not got the wavy “set” that the usual blades have on the teeth in order to give the blade clearance in damp or resinous wood, rather they are shiny ground on the sides, have seriously shark like teeth which are straight, not bent outward like  a handsaw blade and cut on the up stroke.  The downstroke veneer blades look similar but are not what you want at all.
Most major brands supply an equivalent, as do most of the specialist manufacturers of jigsaw blades, they are used by cabinet makers and those odd types who putter around in their garages building plywood boats.

Back to our topic.
After cutting the case slot and dry fitting the 9mm plywood bottom, I reached in underneath with a pencil and traced off all of the frames onto the plywood bottom panel.  I then lifted the bottom off, flipped it over working from the outside drilled pilot holes and countersinks for all the screws.
This procedure meant that all of the screws hit their target when driven through from outside.
I masked up the few places where I did not want the glue to stick, temporary cross members in the main and I was ready to make it permanent.

Mixed up the system 3 epoxy glue, applied just enough to make sure it all stays where I want it to until the boat is all planked up and seams taped, the boat then being ready for the interior to be filleted, then fitted the bottom to the boat with screws driven in.
It’s a big step, takes her from just “bones” to, well, not a boat really but a bit different from what she was.  Visible progress.

 Sorry about the light, it was late on a very gloomy day, and my camera insisted that the light outside was nicer than the gloom inside.
You'll get more in a few days, but this will show you where I'm up to.
The next job is to hotmelt glue a spiling plank together out of MDF door skin strips and work out the shape of the garboard plank.
Sunday! I'm out of action tomorrow through Saturday.

One of the reasons for the progress in the shop today is that its blowing like stink here, again!  The weatherman says it may be the worst storm in a decade!  The nowcasting buoy off the river mouth is reporting gusts of 60 knots.  That’s better than it was a couple of hours ago! The trouble is that its blowing straight down the estuary so its much rougher in here than it would usually be, “the ship” is beig bounced around enough to make work at the drawing board quite uncomfortable so it’s been a workshop day.

Out in the workshop is nice, gave me a chance to do some comparison between the new sample Blu-Mol drill set that I had handed to me a few weeks ago.

 This shows the inside of the bottom panel, all pencil marked and drilled, the case slot cut and test fitted, and I"m ready to flip it over and drill the countersinks with my nice new Blu-Mol drill bits.  

These have whats known as a “split point” configuration on the point, plus are ground for more clearance angle than is usual in an engineering twist drill (the kind that we almost invariably use in our smaller sizes).  Breakout is an issue with most drill bits, as is clogging when pushing into a deep hole.
These new drill bits are made by (or for) the old Disston company under their Blu-Mol brand.  I’ve come across these in their holesaws which are pretty good tools, and was keen to see how these drill bits worked out so asked the distributors for a sample set so I could put my impressions up here.
( thanks guys,)
These are impressive drill bits. On metals they work really well, cutting cleanly and smoothly in mild steel, cast iron and aluminium. Sizing is accurate, they don’t vibrate in the cut and they clear well.
Not good on thin sheet metal though, but then, not many drill bits are.
When drilling wood or plywood they are significantly better in terms of surface breakout around the holes, and seem able to go further in without clogging the flutes up than a conventional  drill bit. The extra clearance behind the cutting edge down the flute makes it possible to cut laterally if you are careful, not like a router bit of course but it will cut an oval or enlarged hole for you.
They seem to cut faster as well, always helpful.
The drill set is housed in a very nice case, that case has drills from 1.5mm to 10 mm ( I am told that there are imperial sets available in the USA ) and has two extended driver bits in it as well. In this case a pair of number 2 square drives.
Points? Say 8/10 where a normal engineering twistdrill set in their usual plastic case scores 6/10.  I like them, will be looking to get them in preference to the usual ones in future.

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