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Double Bass Constructing an electric upright bass
- Thread starter P John Mathew
- Start date
Hello !!! Could i send you a PDF of the final dimensions of my eub project and could you please tell me if there are any obvious or potential faults / pitfalls ahead? My email id is [email protected]
Thank you so much Jay !!!! The video is clear and lucid. Question : what are the dimensions of the triangular wedge like panel based on? Must have something to do with the radii ?? And what are the radii that works best for the nut end and bridge end ??
Thanks so much again , Jay !!!
Thanks so much again , Jay !!!
I observe that you have a hinge on the triangular pane...Where on the panel do you located the hinge?
I've been following this thread. Unfortunately I cannot access the files, I wonder if it's because I use Android.
I'll do another attempt later on.
I'll do another attempt later on.
1. Re the hinge. It doesn't matter what sort of hinges you use or where they are attached along the bottom edge of the triangular panel. The important thing is that they are exactly lined up with each other and they firmly attach the triangular panel to the bench. You could use piano hinge all the way along the bottom edge.
2. Radius. The height of the triangular panel is dictated exactly by the required radius and its length should be a bit longer than the fingerboard. A 3/4 scale bass has a string length of 1053 mm, a radius at the nut of 250mm, and radius at the bridge 76mm. These radiuses can be visualised as a cone. The tip of the router bit must be the required radius from the hinge axis at each end of the fingerboard. Because my fingerboard is 850mm long, by simple geometry the radius at the bottom end of the fingerboard works out to 109mm. So when the blank to be machined is attached to the top of the triangular panel, and the hinges attached to the bottom of the panel, and the hinges firmly anchored to the bench, the router cutting bit is:
250mm from the hinge axis at the top end of the fingerboard.
and
109mm from the hinge axis at the lower end.
3. The panel itself is obviously a bit smaller than these measurements because there are hinges on the bottom and the thickness of the fingerboard blank on top.
4 If you were very precise (I wasn't) you could correct the radiuses slightly to account for string height. For example the string height at the nut is only about 1mm, but it is about 5mm at the end of the fingerboard, and 0mm at the bridge. It got too hard for me!!
Hope that helps. Let us know how you go.
If you already have a woodshop or access to a few simple hand tools you can shape the fingerboard by hand in a couple of hours. It is a simple cone with a slight relief- not too much for anyone with basic woodworking skills. A sharp edge and a bit of patience will go a long ways. Save the jig making for when you want to startup a large production run.....
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From what's been said earlier in this thread, the radius varies along the length of the fingerboard. So it's a cone, not a cylinder.
How can we see this as a "cylinder with a slight relief"? What do you mean by relief? I'd like to understand this if it makes things simpler.
Thanks James for your comment. While i do own a furniture manufacturing facility , my hand skills while not bad are not so great either. A jig would make life simpler for me and not such a big deal or expense to build. A luthier friend of mine told me that scrapping an ebony fingerboard could be very very tedious...,.,.so ; thanks for the confidence though....
Thanks Jay , thats pretty instructive. let me try what you said with some blanks and tell you how it went. Thanks so much Jay !!!
Hi Jay ,
I have just uploaded a schematic of the Jig front view . Does this look about right ?? The triangular panel is longer than the fb and the heights under the fb ends are 250mm and 76mm. The template is mounted to mirrored triangular mounting plate where the hinges are and the mounting plate is in turn secured to the worktable ? The router would be mounted on slider channels above the whole jig.
I have just uploaded a schematic of the Jig front view . Does this look about right ?? The triangular panel is longer than the fb and the heights under the fb ends are 250mm and 76mm. The template is mounted to mirrored triangular mounting plate where the hinges are and the mounting plate is in turn secured to the worktable ? The router would be mounted on slider channels above the whole jig.
That looks perfect! Great diagram! As long as the mounting plate is very firm and you put the router on its highest speed to avoid vibrations, you're good to go.
Note that there are two ways of cutting: (I used the first)
1. clamp radius template and run the router along its full travel. Move radius template slightly. Clamp. Repeat.
2. clamp the router and swing the radius template. Move router along rails slightly. Clamp. Repeat.
Either way everything will need to be very solid to avoid the possibility of the FB blank moving or vibrating during cutting.
So glad you're doing this. Keep up the good work
Thanks Jay . Thats very encouraging. I think I will prefer the first method as the cutting will happen along grain direction and the latter is across grain? Will a 12mm router bit do or better to go for smaller bit diameter? was thinking of screwing down the fb blank to the radius template from below....to avoid any inadvertent shifting.... Did your bridge end fb radius of 109mm .. instead of 76 mm affect your playing in any way ? I have seen tell of going deeper towards center of fb in some cases. Does this prevent string buzz or what? Anyway wasnt planning to do that ....too iffy ??
Thanks again , Jay will keep you updated on my progress.....
Thanks again , Jay will keep you updated on my progress.....
