- This topic has 123 replies, 7 voices, and was last updated 2 years, 3 months ago by
.
-
OK, I’m completely gobsmacked. That has to be one of the most idiotic things I’ve ever seen.
1) I was wondering what that steel piece was inside your harp. He intended to fasten the strings to that, then pass them through the soundboard. Without lateral support, it would never hold the tension, and would ultimately be pressing against the board one way of the other anyway.
2) The action of the harp is designed to come into regulation with the board bowed up slightly. It would never be in regulation without that pull-up, especially in the bass, where there is little adjustment available.
3) Plywood of seven layers of veneer, glued with contact cement. Except that right at the center, where the forces are at their strongest, three layers are cut away in the center, leaving two veneer layers top and two bottom. Of those, at least half run grain vertical.
That leaves you with two veneer thicknesses (usually 1/48″) to hold the tension. My 29! string lever harp has string tension near 750 lbs. A pedal harp is around 2000 lbs.
You are looking at the soundboard. Will it support you and four friends standing?
Throw that board away or try finishing what he started if that interests you.
Regarding designing a special stringing, it can be done. You will need string thickness gauge charts for the brand strings you want to use, or charts of standard constructions for types of strings. You will need a thorough understanding of the Mersenne/Taylor equations and how to use them. You will need to understand how a pedal harp is regulated.
Most of all, you will have to know how to evaluate and test the result for success according to your goals for the instrument. There is no simple formula. Saying “tell me how to build a harp” is like saying “tell me how to build an automobile”. Do you want to go fast? Do you want good mileage? How many passengers? How much cargo room?
Wikipedia will get you a start https://en.wikipedia.org/wiki/String_vibration
Sligo harps has information on building and designing harps.
I can send you a stringing calculating spreadsheet. But it only does the tension calculations. It won’t help you decide how to graduate the diameters or choose a stringing material. There is no information available on how to modify the action of a pedal harp to correctly sharpen smaller gauge strings. All of this is all harp design, and is specific to each builder. In this case, you would be the builder.
What you entertain with designing a soundboard, designing a stringing, and making it all work on an existing pedal harp action would be an advanced research design project for ANY harp builder in the world. You should expect to blow a couple of soundboards (or make them too thick) and restring several times before you get it right.
Dear Charles, Balfour, et al: I know I’m going to sound incredibly snotty with what I have to say, but I need to say it. I have read or skimmed over all of the posts in this thread, and this is what happens when well meaning (I think) but totally unknowledgable people(where harps are concerned) try to “repair” harps. Over my career I have, a number of times, had to repair instruments that someone else, who had no knowledge of the harp or harp construction, had worked on. It always involves ripping out everything that they did and then doing the correct surgery that the instrument needed. This instrument is a classic case of this. He had no understanding at all of how the harp has to function, and no knowledge or understanding at all of the stress on the instrument. In addition, he didn’t even know how to take the harp apart. He has destroyed this instrument beyond repair. And he clearly was so sure of himself and confident in his ability that he didn’t even try to consult with anyone who does know this.
Three years ago I decided that I wanted to train several people to repair harps. The first one was a young man(19 at the time) who was in a cabinet making course in Boston. He is now 23 and has more or less completely taken over my business. He is a master craftsman and a far better woodworker than I ever was. I can’t wait to show him this video! He has already had to undo the damage that other people have done to good instruments, and I had warned him early on that my biggest fear was that, if I didn’t train people to do major harp repair, then that would leave the door open for catastrophes like this.
Good to know, that makes life easier! found some images, so there are about 4 different size eyelets, small, medium, large,extra large, ,I found a Harp site that sells them how do I khow many of each size to get? the harp has 40 strings.
Thanks again!
- You must be logged in to reply to this topic.
