Author: JTJC
Date: 2020-04-12 19:41
3D Printing a Basset Horn Crook
I have a Buffet Prestige Basset Horn and I find I have to have the main body of the instrument quite far away from my body in order to have the mouthpiece at a comfortable angle. This also means I have to have the spike fully extended but it’s not quite long enough. What I need is a crook with a tighter radius in the bend to bring the instrument into a more vertical position. The bend on the crook original has a radius of about 20cm, so one half that might be what I’m looking for.
I’m thinking of creating a 3D design of a crook of the required dimensions in something like Fusion 360 and have it 3D printed by a specialist firm. This is a relatively small, uncomplicated part and looks as if it would cost around £20 to £40, plus usual extras to have it printed, depending on the material used. Before embarking on the design, and not having used a 3D design/print before, I have a few questions which those with some experience in this area can probably help me with.
Strength of the material.
The thinnest part of the metal crook (the tenon that goes into the top joint) is about 1.0 to 1.1mm thick. This is dictated by the difference in size between the tenon socket on the top joint and the size bore of the instrument at that point. The original crook is metal (plated copper?) and appears to have sufficient strength for its job as it doesn’t flex. There is also a threaded collar at the top of the tenon on the crook. This can be turned to draw the crook out of the instrument if you need to lower the pitch and acts as a marker for how far out you’ve pulled. I think this collar may also be there to help support the crook at the point, where it is under most stress. I’m wondering whether the moveable collar is not there just as an aid to tuning, but in fact necessary due to the thinness of the material (1.1mm) - it gives additional strength. However, I wasn’t thinking of putting the collar in my design as it would probably be too difficult, I’m only experimenting. That means my 3D crook would be 1.1mm thick to the depth of the tenon. The question is, is it likely that a 3D printing material would be strong enough for this job if it was only 1.1mm thick? If so, which material(s) would that be? Something metallic would be nice, but it’s not essential. Another concern here is that I’d need to have a recess/rebate in the tenon so I could cork it, to give an airtight seal. In some areas the tenon will be less than 1.1mm thick, but all the corked area of the crook would be within the tenon socket when playing.
Accuracy
Would I be expecting too much from 3D printers, or the materials they use, in designing something 1.1mm thick, or less? I’m not sure how accurate the bore of a Basset Horn crook needs to be (as for barrels ?), but can I expect to print something with a consistent bore of 17.3mm? Don’t forget this will be printed on a professional/manufacturing level printer.
Porosity.
I hear some 3D printing materials are porous. I’m not sure whether that’s only to moisture or to air as well, or are they the same (? hot, moist air!). Is this characteristic of the material dependent upon thickness? Virtually all the 3D printed clarinet parts I’ve seen, barrels/bells, are much thicker than 1mm so this may not be a concern when printing those parts.
Finish.
I’m not too worried about cosmetics but I would want at least the bore of my printed crook to be of the requisite degree of smoothness/polish. Are there some 3D materials that have the necessary strength for this job but that could not be given the necessary surface finish (on the inside particularly)?
Any help or advice gratefully received, even if it’s a no go.
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