Tuesday, July 14, 2015

Treasure chest with curved lid part 7, the lid

After the glue had dried I decided that it didn't look right if I'd led the inside stay as it was with flat boards forming the surface.
I adjusted the scrub iron in the plane, so it was able to take a bit of a cut even when only the sides of the plane were riding on high spots. It was far from ideal, but I managed to get the inside to form some sort of a curve instead.
There were a few places I wasn't able to reach, so I took the iron out of the plane and used it as a scraper. Again it is not an efficient trick that will make your friends gaze in awe, but it helped me git a bit closer to a decent shape.

The surface looked like crap after my exploits with the scrub plane and the scraping experiments, but I found some 60 grit sand paper in the deck workshop, and then I just started sanding away.

After quite some time I was satisfied with the way things were looking, and I was ready to move on to attaching the ends.

Originally my plan was to make the ends straight down, but for some reason I decided that it would probably be too easy, and that I should challenge myself a bit more.
Therefore I decided to make slanted ends.

I immediately sawed the ends of the lid so they were slanting. Then I "squared" things up the best I could using the smoothing iron in the plane.

I am getting used to making angled dovetail joints on flat boards, so I guessed that this wouldn't be
much different.
Guess I was wrong.
It really is a lot more difficult to make dovetails that will connect a semicircular flat board at an angle to a less than perfect half cylinder shaped object.

At first I marked out the tails on the end boards and cut them, I even made sure to take into account that the cut had to be deeper on one side than the other. It looked fine until I tried to put them on the lid itself for marking out the pins.
Even I could see that there were no way I would ever be able to make some pins that would allow that tail board to go on. The tails had to have different angles depending on if they were placed on the side part of the ends or on the top part of the ends. I realized that this slanted end challenge was going to be a lot more difficult than I had imagined.

I spent some time trying to figure out how I was supposed to mark out the dovetails, and ended up making the pins first.
I could use a compass to step them of, but since the reference side was curved I didn't have a system for marking out the angle of the pin. My solution was to cut a small dovetail marker that looked like a triangle, and then I placed it so it looked fair to me. At least I knew that the slopes would be the same.

Marking the depth of the tail was done using my marking gauge. Next came the problem concerning how to mark out the direction of what would be the sides of the pins. Normally I use a small square in form of a piece of cardboard. But a square is best if it has got some sort of reference edge that you can measure from.
I tried various ideas before settling on simply eye balling the lines. For that I used the back of the panel saw that we have on board. I positioned it at the pin markings and tried to make it follow the length of the lid as well as I could.

Once all the markings had been taken care of, I sawed and chiseled out the waste between the pins.
Normally I like to undercut my waste area, but I figured that it would end up showing when I get to the point where I can plane the outside of the lid to the final shape.
So the waste area was finally cleaned up using a coarse file (we haven't got any rasps out here).

I made a couple of new end boards instead of the ones with the faulty tails on them, and after a lot of fiddling I managed to mark out the tails and cut them too.
This involved some guessing regarding where to stop the cut on one side, and then just hoping that it was the correct place when I placed the chisel to remove the waste.

I dry tested the end boards, and they seemed nice and tight. When I tried to gently remove them to be able to add some glue, both top pieces broke off.
I simply glued the pieces back on and then trimmed the pins for those areas a bit more.

Finally I glued on the ends. And I pretty much immediately regretted not undercutting between the pins because there were gaps on the outside of the chest. I am afraid that these gaps will be more visible than any undercutting I could have dished up with.

The end with faulty dovetails.

Marking out for the slanted cut.

Sawing, the line from the bucket wasn't completely straight after all.
The glued up lid.


  1. Yikes, you sure complicated your life on that one :-)
    But I'm sure you learned a lot from this, and that is the fun part isn't it?

    Note to myself, when trying that project, keep the sides of the lid straight :-)
    I never tried sloped dovetails before sound interesting to say the least


    1. Hi Bob
      In hindsight the idea wasn't very good.
      But on the other hand, I had to try it - so now was a good a time as any.

      My original sketch of the chest was made with straight ends, and that looked really fine as well. So I should probably have stuck with that plan.


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  3. It's been my experience that scraping pine or other softwoods is not easy to do. Even with incredibly sharp scrapers I get less than acceptable results.
    You have made me doing angled dovetails a must do. It was interesting reading how you dealt with the slanted lid ones. It boggles my mind that you do this at sea - try that you land lubbers.

    1. Hi Ralph.
      It is strange with the surface of pine and spruce. It planes like crazy and looks like a million even with a not perfect plane, but the scraping like you say is not the way to go.
      I did it to get an acceptable shape, and that was actually the only thing I got. I took a picture of it, but it looked so fuzzy that I decided not to publish it.

      I have to admit that i used a few cuss words during the process. My biggest problem is the very limited space and the close to non existing work holding capabilities.
      On a decent work bench I think you have a better chance of success.

      Angled dovetails aren't hard to do. I normally do the "cheap" version, where I just mark out the dovetails as if the piece was straight. It works because my angles of the boards are perhaps just 80 degrees.

      Another way to do it is to make sure the dovetails are still "level" with the floor. By doing that you need to mark out the dovetails with reference to the original square end, or you can make a "dummy" reference consisting of a line drawn at a 90 degree angle to the bottom. It is a bit difficult to explain, but I can make a sketch of it some time.

      Thanks for your support :-)