Violin Forum/Message Board

[kjb]

I am not quite getting the dimensions put in right

1. when the say the upper corner, is the the corner of the ribs ?
2. C bout is at the widest part?
3. same for the lower corner.

thanks k

[actonern]

You get to decide all those things...

For example, when talking about the c bout, you could choose to plot the arc for the narrowest point of the plate. Or, alternately, you could plot the arc for the midpoint of the instrument.

The software provides 5 (and 6) plots on the assumption that you'll be especially interested in the cross arch at the widest point of the top and bottom bouts, the middle, and the upper and lower corners.

But there's nothing whatever stopping you to plot arches in increments of 1 inch for the entire length of the instrument. Just input the appropriate height and widths and print 'er out!

[kjb]

I must be doing something off, I get lumps and saddles on the long arch?

thanks I will keep hitting at it.

[actonern]

To be honest, I don't use this program at all for the long arch. I do as Michael suggested; take a long radius circle to trace an arc for the back plate and something else for the top.

Then I work the wood till it corresponds to that profile. In other words the long arch is finished to a high degree before moving on.

THEN, I trace pencil lines 90 degrees to the centre joint at all places along the plate that I want a cross profile to be made. I do this on the still-flat back of the plates.

I then take my calipers and measure the height of the plate at the point the cross line intersect the centre line of the plate. That is obviously the hightest point of the arch at that place. Write that height down at each such intersection.

Then I decide where my "minimus" point of the arch will be around the perimiter of the plate... farther in from the edge at the top bouts and closer in for the mid bout... then I measure the widths point to point across the plate between those "minimus" points and input the numbers.

You'll also have to input the thickness of the plate at the "minimus" point, so the software can subtract that thickness from the overall height of the plate. So, for example, if the "minimus point" all around the plate is an even 3.3 mm thickness, and the centre arch in the middle of the plate where measured is 16 mm, the arch profile at that place will be a height of 12.7.

Best regards,

E

[kjb]

thank you for the help, that makes a great deal of sense. k

[kjb]

one more question,
when you measure do you use a flexible rule that conforms to the curves to try to measure straight? thanks again k

[actonern]

If the question was directed at me? I measure the distance across these points on the flat of the back... no arch induced "lengthening" is factored in...

The software seems to work fine doing it that way.

[kjb]

thanks again. k

[John Schmidt]

[kjb]

yes that is the one