Sunday, 20 September 2015

Renaissance Lute, chapter 7 - Bracing

April 2012

The bars in a lute are shaped, sized and placed according to magical rules that go somewhat beyond my understanding. I would be quite interested in learning how much the bracing affects the sound and how the optimal shape has been devised by the ancient makers. And I should re-read Lundberg.

For now, I'm just following the plan. I got some very nice quarter-sawn spruce from the local DIY shop with tight rings. The bars are cut and shaped as indicated. Simple.

Now the glueing. Luckily in april the apartment was still at a very low humidity level, around 34%, and not likely to dive much beyond that point, relieving me from the necessity to organise a heating system to bring it down even more artificially.

But then I had to build a go-bar box. I thought a second table, stacked on top of the other would easily do the trick, so I wouldn't have to bother building said box, not to mention storing it somewhere for later use.

I didn't do a proper full size dry run, I would have learned that all bars, under tension, can easily lift the table while standing on top of the bars, themselves standing on their narrow side! Anyway I managed to throw a couple of spanset around both tables to get things tight and get myself back to non-sweating.

A day or two after, with the glue dry, the bars are trimmed and planed, according to plan.

Once the bars are trimmed, the "box" can finally be closed! (Just for fit check). It starts to look like an instrument. One can see the slight gap between the shell and the soundboard, that will produce, once glued, the concave arching of the latter.

Monday, 31 August 2015

Renaissance Lute, chapter 6 - The rose

March - April 2012

Ah, finally, cutting the rose. I've been looking forward to that, having come to woodworking through woodcarving. And it makes a welcomed change from the work on the bowl and the planing of the soundboard.

I chose the Venere rose from the provided designs and got started on the offcut with a narrow gouge that I already owned.

The tool felt a little too wide so I turned to a thinner tool, an ex-acto scalpel which I reground into a chisel shape.
My fingers felt sore pretty soon so I added a wooden grip to help push it down into the wood.

The paper with the pattern is then removed.

Enough practicing, let's move to the real one. To prevent staining the soundboard with my filthy paws and sweat, I covered it with some paper and to avoid having little offcuts creeping between paper and wood, I sealed the whole with tape.

Then, the profile carving.

The last step is the pattern on the circle, for which I prepared a sheet of tracing paper with lines each 3° step to help with regularity. I could then just punch through, diagonally.

Finished !

Read next post : Bracing

Friday, 28 August 2015

Renaissance Lute, chapter 5 - The soundboard

March 2012

Things are getting serious now, time to work on the actual sound-producing part...
I ordered some nice spruce online, coming from the french Jura mounts.
It's a special thing to count the growth rings on one of the two thin planks.
Even with the sides cut straight, the number was about two hundred...

It's time to spread out the plan.

The two planks are roughly planed to get to the same thickness. It seems to make the glueing alignment easier.

The join is prepared. Yes, that's a brick, I don't have a proper bench with holdfasts...

The excess is cut off.

So, the two parts are joined using the "nail" technique. The nails are to be oriented with the head pointing towards the center, don't ask how I found out... 

I'm using the drawers of my black chest (in the background) to press down while the glue sets.

Now the planing of the outer surface can be done.

And that's the (bad) result that I managed to get with my smoother plane -- I've learned since then, that a low angle block plane is much better for the task...

So I turned to dusting sanding.

Aaaaaah... much better.

On the inner side, the board is thinned to the approximate final thickness. I keep track with caballistic signs of how much is yet to be removed.

It's surprising how much space the shavings quickly take.

Cut to the pear shape, now it's looking like something...

And the box is (temporarily) closed !

And that's how thin it gets...

Ready for the next step, with the reinforcement paper glued on the rose underside, and the same paper on an offcut for rose cutting practicing...

Next post : Carving the rose

Thursday, 27 August 2015

Renaissance Lute, chapter 4 - Cleanup & reinforcement

February - March 2012

When the happiness of having completed the bowl assembly has settled, work can move on.
The next steps take the bowl to a more presentable robust state. The sellotape is removed, glue excess is washed away, the spacers are scraped flush, the false soundboard is cut and a set of clamps for the endliner are prepared. The endliner is also made and glued to the bowl.


I found it handy to actually use the planing desk to cut the edge of the bowl to its final line. By pressing the sides, the bowl takes up a different shape that allows to plane the slight recess that eventually causes the soundboard to be cupped longitudinally.

 When all of that is done, the reinforcement stripes of paper are glued on the inside.

Finally the endclasp can be cut, bent and glued to the bowl. Some little adjustments must be done to close all the little gaps that can remain. The travel iron is the right tool for that.

I decided to add an extra fillet to the endclasp, for a nice contrast and to conceal the little gaps that would not go away, even when asked politely. I bent the fillets over a soldering iron.

Read next post : The soundboard