proportion question

[wisardd1]

I have plans for a 7 inch clock that has a 4 degree slope on each side. I want to double the height to 14 inches. What proportion should the width be in relation to doubling it like that. It can't be 100%. I am thinking either 1 or 2/3, but I am no good at math at all. Any feedback would be appreciated. Also, attached in a picture.

dale

[Stretch]

If you have plans, and want to double the height and keep all the same proportions, you double every measurement on every piece. The one exception would be that you don't need to double thickness on parts where the thickness doesn't matter.

Edit: The four degree slope on the sides will stay at four degrees.

[wisardd1]

Yea, I guess so because the proportions are already set! duh!

[JBark]

I agree that you need to double everything. In terms of thickness you need to increase the size of the stock you are working. If the top was 1/2" at 7" tall you need to double it to keep all aspects looking proportional.

John

[Ruffnek]

Dale,

By doubling the height, you will only double the portion of the side that angles away from vertical. It won't be a lot and the clock will still be in proportion as you figured out already.

I don't have a scientific calculator with a COS function or I could tell you how much it would widen on each side.

The sketch I drew shows how it stays in proportion and I drew lines on your pic to show the part of the base that would double in width (circled in red).

The inside dimensions do not change because the sides are vertical on the inside.

[wisardd1]

You guys rock!

[rrich]

This may sound strange, but on that clock I would reduce the angle of the taper of the sides of the clock to 2°.

With a 4° taper at 7" high the thickness of the side is about 1/2" at 14" high the thickness would be about an inch. IMHO this might be overwhelming in terms of aesthetics.

[fredbelknap]

Dale when I am in doubt about something like that I do a scale drawing and see how it looks. I was going to build a thing on my roof with a wind vane on top to cover up an ugly cut stone chimney that isn't used anymore and when I scaled it out I didn't like its look so it is on hold for now.

[Mark T]

I also would take Fred's advice, with the exception that I would draw it full size. 14" is not a huge drawing, and it will show all details in real size. I would scale a large piece, however.

I am inclined to agree with Rich as well. I would draw the face profile with both 4 degrees and 2 degrees. The base at four degrees may be rather thick.

On edit- I would actually draw the full size drawing with VARYING degrees of taper. You can eyball it to be as thick as you think it NEEDS to be.

No charge for the opinions.

[Joe Lyddon]

Might not hurt to get some cardboard boxes, cut'em up, glue'em up, to get the dimensions you're thinking about.

Then, you could "see it" better... ;D

(and cardboard, etc. cuts very nicely in the bandsaw)

[wisardd1]

Maybe I will try a cardboard cutout. The stiles in the 7 inch is one inch wide. Therefore, at 14 inches the stiles would be two inches. Two inches at a 4 degree slope might not be that bad. None the less, I will will cut and paste

[admin]

I agree with Joe. Cardboard is normally cheaper than lumber! You can fiddle with the shape and measurements and then commit it to wood if it looks right.