Took me a little while to do the steel work on the jig.
Have to make the somewhat C-clamp with push block. Cutting threaded bars and looking for the nuts. Shaping the push blocks (made from ebony) become tiresome after making 16 pieces. These are made from scraps.
Here are some self explanatory photos… I give notes on some important aspects and ideas that you can grab suited for your project and availability of materials:
Notes:
1) The piece that was bended was narra ripped by handsaw with vertical grain orientation; sanded to the final thickness of 1 mm thick. I tried the longitudinal way (horizontal grain orientation) but it splits because narra is medium hard wood and brittle. On vertical grain orientation, the grain has strong quality vertically and during the bending, some portion (specially those in the sharp curve) it splits but can still be recovered by gluing. I need the vertical strength for the violin ribs because it supports both the back and front plate. The secret of bending this Narra wood is boiling it directly in contact with water. If you just steam it… the hotness will not be enough as the steam quickly dries up and easily cool down and the narra regains its brittleness quickly as it dries. (I never tried heating it with the electric heaters.)
2) I underestimated the length of the C-clamp (not all but few). It was too close that I could not insert the rib plus the wood strip and the vinyl retainer into the jig and push block. The solution was to reduce the diameter of the crossing pin. You can visibly see at above picture that one c-clamp is using an old concrete drill as the pin. It works with a little bit of idea… GOOD THINKING.
3) Another point is the length of the wood strips. In this design, I have no idea how long it will be so I made the upper rib longer. This protrusion on the corners made it so difficult to insert the C-rib on the jig. There is no solution but to cut it in place. This has resulted into a damage to one corner (split and crack). THIS IS THE REASON why those professional VIOLIN maker uses a CORNER POST instead of the one above that the ribs are joint end to end at the corners. Well this is the challenge I got… Anyway, the violin I am restoring is a vintage one not the modern one.
LEARNING IDEA: The planning was there but none was done on the sketches. The available materials are just leftover and scrap… TARGET is to build a jig at low cost. PROTOTYPE must be considered as PRECIOUS as it will become the ORIGINAL. In my case, the idea was only to build what I need for the restoration of my violin, but in the later end… this become a promising jig for making more violins in the future. Notice that I used EBONY push blocks to have a lasting jig and I was rewarded by it with each strength… the bolts that pushes the blocks did not even punctured the ebony.
Another close up look on the C-rib clamped on the jig.
Here is the amazing way I discovered. The retainer piece I use is vinyl and boiled them together with the rib and the push block. Then while hot, just bend to shape. Quite easy. When the vinyl cools down, it retained the shape. I clamp the edges to the vise to prevent spring-back while cooling.
LEARNING IDEA: The point of thinking is boundless. Though this is small size, but a controlled automatic steamer or boiler like this is the one that will solve my bending problem. This is an actual sterilizer. This is were I dipped those ribs..
Meantime while the ribs are clamped and still wet, I have to regroove the plates…
I found that the grooves are dirty and I used the dremel to clean it and widen it a bit just enough to hold the ribs.
LESSON LEARNED: The error most of the time is trying to force something that will not fit. Cleaning and rework are the things that should be done rather than consuming a lot of time trying the impossible thing.
THE RIBS STAYED in form overnight… Early morning last Sunday, I was surprise of the success.. Took out the clams and here it is after fitting it to the plate..
FITTING BOTH PLATES without glue….Here are photos that I fitted both front and bottom plate….
SO, Until then. As you can see, nothing is unusual that I will back out from it. So life must go on
NEXT will be the hardest of them all….
HOW WILL YOU CLAMP BOTH PLATES WITH THE RIBS IN BETWEEN?
Hope you enjoy this portion, as this is the real part of the game in making the ribs of the violin and the jig in action.
Have a nice day!
Thanks,