 The Clarinet BBoard
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Author: shmuelyosef
Date: 2017-09-27 23:13
Attachment: LH_ring_finger_hole.jpg (171k)
I have here a Vito V40 in exceptional condition that is barely played and mostly just needs pads, corks and some regulation; everything is tight, but the soft materials are dead.
Likely the reason it was not played is that the LH ring finger tonehole was badly drilled; looks like a dull drill pushed too fast. The rim is slightly melted and pushed up and there are a couple of tiny chips...picture attached.
My first reaction was to just use a tonehole dresser to clean it up like I might on an older clarinet, although I have never had an issue with the plain 'bored' hole. The hole is 5/16" diameter and the biggest dressing tool I have is a 3/8", which would put a steep edge on the hole. Would it be better to get a larger dressing tool?
Alternatively, I could sand off the raised bits and patch the chips with some epoxy loaded with carbon black and then file it back to shape; more work, but maybe better?
Given the value of the clarinet (despite the fact that these are very nice) I am resisting the option of machining a thinwall insert and filing that down...way too much work...in many ways it is easier to fix/replace a ring or padded tonehole!
Curious if anyone has a better idea.
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Author: Caroline Smale
Date: 2017-09-27 23:46
you can gently reshape plastic with a heated rod of appropriate diameter (e.g. an old drill bit) then use a simple hand countersink tool to clean up and bevel the edges,
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Author: shmuelyosef
Date: 2017-09-28 02:11
That seems a little scary as it needs very delicate reshaping. Any tips on how to control the temperature?
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Author: Matt74
Date: 2017-09-28 03:24
I think machining a new hole would be awesome. That said...
Epoxy would probably work. If the epoxy is a DIFFERENT color than the plastic (and softer), it will be easier to remove the excess accurately. I did this a lot in picture frame restoration, with gesso and other materials. (For example, JB Weld is grey, and is easy to cut before it hardens completely. I imagine you could color it when dry. I don't know how well it would bond to resin.)
Would it be possible to do the reverse of undercutting? Assuming the hole is the correct size where it meets the bore, you could leave that exactly the way it is. Then, remove material from the outside with a taper, making the hole on the outside bigger but round and sharp. If you only tapered the outer 1/2 of the tone hole it might not change the intonation too much. I would think a larger hole that is sharp would be preferrabe to one that is beveled.
You could do both. Fill the worst and ream what's left. It would enlarge the hole less, and make finishing the unhardened epoxy fill super easy.
- Matthew Simington
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Author: Chris P
Date: 2017-09-28 04:24
If it's just the raised burr, then you could always countersink the extreme edge to remove the burr - a hand-held spherical reamer will do this, but it will leave an elliptical countersink due to the curvature of the surface if you go straight in and ream perpendicular to the bore, but you can run it around just the edges to get a more even finish.
You should be able to do a better and more uniform job running a deburring tool all the way around the edge and take your time over it as well as gently so the deburring tool doesn't catch and dig into the plastic.
If you choose to fit a raised tonehole insert/chimney that sits around 1mm above the joint surface, then the diameter of the D/A tonehole will need to be made larger by between 0.5mm to 1mm than the existing plain tonehole to bring the D and upper register A up to pitch.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: clarnibass
Date: 2017-09-28 07:20
A regular countersink/chamfer tool would be more at the North and South because it is curved (North being the mouthpiece end).
It looks like there's very little that needs to be "dressed" so I'll likely use a dental micromotor with either a deburring bit (tapered shape) or even just several grits of polishing rubber cone bits.
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Author: Tony F
Date: 2017-09-28 12:23
I'd suspect that somebody has tried to clean up the hole or possibly attempt to undercut it using a cylindrical or rat-tail file.
Tony F.
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Author: Chris P
Date: 2017-09-28 12:32
I only hope they didn't muck around with that tonehole to mistakenly try to cure a flat or stuffy C or G!
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: shmuelyosef
Date: 2017-09-29 07:26
the clarinet main bore is clean and flat at the end of the tonehole, so I don't think anyone tried to undercut. It does seem like the hole was raised and someone took a couple of cuts at the top, but the ID of the tonehole itself is clean. I don't have small rubber polishers...just the discs. Never seen them...any of the repair suppliers carry these?
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Author: tictactux ★2017
Date: 2017-09-29 13:18
I'd take a countersink and wouldn't worry too much about the elliptical result as the player's finger is likely to be somewhat spherical too.
--
Ben
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Author: shmuelyosef
Date: 2018-06-13 01:28
I used a spherical polishing head with some Flitz...came out so nice I 'touched' the harsh edge on the tonehole chimneys as well (polished the insides as well); it's all finished and plays much better than the typical 7212 or 7214.
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