Pentagonal box

[White House Workshop]

Started this today from a piece of scrap black walnut - actually salvaged from an old shed where it was one of the wall 'planks' 36" long by 8" wide by 3/4" thick. By the time I'd cleaned it and surface planed it, it was 5/8" thick. Each side of the pentagon is 7" wide by 6 1/2" deep. Inside depth is 6 1/4". The base is oak veneer ply.

The sides are biscuited with size 0 biscuits. It's now glueing up - an interesting problem getting this many clamps across it while ensuring the measurements stay constant...

I'll post more images later as I progress.

 

[Newbie_Neil]

Hi Brian

I'll bet the clamping drove you crazy.

I'm looking forward to the rest of the wip photos.

Cheers,
Neil

 

[devonwoody]

So what were the angle cuts?

 

[Chris Knight]

Here's some fishing tackle
http://www.learning-connections.co.uk/q ... hap01.html

 

[White House Workshop]

The sides were cut at 36 degrees for the 108 degree inside corners (5 inside corners for 360/5 = 72, half it for each piece). I set the biscuit jointer to 54 degrees (half of 180-72=108). Those are the only angles so far.

I'm now thinking about the top. Do I make it out of one piece, or do I make it from five pieces? As the box is quite large (about 12" across the largest dimension) a half degree out on the cut will leave quite a gap, so 5 'slices of cake' may not be the way to go. I may scour my scrap boxes for an interesting piece of wood and exploit the patterns, or I may do something different by using different materials, or maybe even different woodss as I could conceal any minor cutting errors. Glass inlays might be interesting. I have some pieces of aluminium that would polish up nicely. Maybe incorporate some stone or other natural material? Haven't decided. I'll sleep on it while the glue is setting...

Watch this space!

 

[Chris Knight]

Brian,
If you glue up segments, just leave cutting the last till the others are glued up. You may have to cut it a bit shy or fat of the theoretical angle but no-one will notice.

 

[White House Workshop]

Good thinking Chris!

 

[9fingers]

54 degrees for a pentagon

(180-(360/n))/2 where n is the number of sides.

Bob

 

[woodbloke]

The easiest way to pull up this sort of awkward shape is with two or three webbing band cramps. I have a few where there's no give in the nylon band and a lot of pressure can be wound on - Rob

 

[White House Workshop]

I have one webbing band clamp (albeit thin) around the base. Didn't have another one to hand, though, as my others are really big - bought to hold around a 2.5 metre long item. Easier to fiddle with the regular bar clamps.

 

[White House Workshop]

I took the box base out of the clamps and (surprise!) it held it's correct shape to within 1/32" Here it is with one coat of tung oil. I did a number of stained samples for SWMBO to pick her favourite from - deep mahogany, dark oak, dutch walnut, tung oil, lemon oil, natural wax, and she chose the tung oil. It's not very even yet. I think I'll let it soak overnight, rub it down with 0000 wool, apply another coat and see how it looks. When it's all dried I plan to finish with a thin coat of satin lacquer - maybe :wink:

I took Chris' advice and am making the top from 5 'slices'. I've got four cut and am glueing up two halves of two pieces each. When they are dry (tomorrow) I'll dry fit them and mark out the last piece for cutting then glue the 5 pieces. Even though I measured VERY carefully I was almost half a degree out on each cut, which compounded up to a difference of almost half an inch gap at the outer edge on the final piece! :shock: It's truly amazing how those tiny errors compound into something huge. Anyway, here's a dry assembly of the four cut pieces and the fifth waiting for tomorrow.

More later...

 

[devonwoody]

Everything is looking good.
Not a criticism but if I was doing the lid I would liked to have put a contrast beading down each joint line.

 

[White House Workshop]

I would normally agree with you and I do use contrast strips quite often, but this time I wanted to have a more solid look. Depending on how it turns out when glued up I may put a contrasting band around the outside.

 

[Gill]

I'm following this thread with bated breath... it's looking good so far 8) .

Gill

 

[White House Workshop]

Here's the top out of its clamps and with one coat of tung oil. I'm very pleased with the result for a first attempt at putting together all those angles. Many thanks to Chris for the suggestion of leaving the last piece until the others were cut! Looking at how this has come out I'm glad I didn't use contrasting wood spacers this time.

I was just noticing from the photos how unlike black walnut they all look! More like sapele... It does look different in regular daylight - not as red.

Now I have to figure out how to fit it to the box. I'm thinking of a rabbet all round the edges and just sitting it on. The top is exactly 1/8" larger than the box all round, and I could leave the lip or plane it to fit. I'm tempted to leave a lip! Put a nice brass knob in the centre, maybe with a natural stone surround. I'll experiment a bit in the knob and handle box!

I have decided the box itself needs to be lifted on some sort of feet as it looks a bit heavy. I may do something on top and on some feet that 'frame' the whole piece. Not sure yet. I did look at using brass tubes on each of the 5 corners, but that didn't look right. On a recent project I sat the piece on door handles and it looked really amazing. One of the great things about working with wood is it can speak to you as you go along. What starts out one way may end up totally different.

btw, Thanks Gill!

 

[devonwoody]

Very attractive, the photograph also gives the impression of pyramidal shape.

 

[White House Workshop]

OK, so here it is finished. One coat of tung oil and two coats of hard wax. I spent ages looking at different woods to trim the top for a lighter contrasting band, and they made it look like a hat box. In the end I decided to stick with just the walnut and accent it with brass feet and a brass knob to lift off the lid. The lid is located freely on pegs and fits in any of the 5 possible positions with about 1mm of free movement. I put a stone donut as trim on the brass knob - the colour isn't too visible in this picture but it has a nice bit of green in it that really works well with the wood.

SWMBO is really happy with it - black walnut is her favourite wood and she's busy thinking about what to keep in it. My guess is her silk scarves will end up in it once the smell of the oil has all evaporated.

This picture is very close to the true finished colour.

On to the next project...

 

[Gill]

It's lovely. The construction of the lid works particularly well =D> .

Gill

 

[devonwoody]

My compliments also, antd the attachments are very attractive also.

 

[White House Workshop]

TYVM

If you want a closer look I have put a 3 megapixel pic up on my own website -

http://www.managementtectonics.com/woodwork/pentagonbox1.jpg

Not bad for a piece of scrap that I tore out of the wall of an old shed years ago...