 The Clarinet BBoard
|
Author: stebinus2
Date: 2009-03-20 14:33
Got an Evette with those tiny pivot srews and the slots are half or all broken off. If I drill a little hole in there can I use a left handed drill bit on a pin vise to get in and turn it out? EZouts don't seem to come small enough. Any other hints or methods to get these out?
|
|
Reply To Message
|
|
Author: clarnibass
Date: 2009-03-20 15:03
It depends if it is just the head that is ruined, or the screw is also stuck very hard inside the post or key, for example because it rusted, etc.
If it is just the head you might get away even with a regular drill with reversed direction, but maybe not even if the screw is tightened very hard.
A left hand drill might work if it is stuck but I don't know since I've never had to resort to this for a rod screw.
If the screws are really stuck hard, do you know if the screw is stuck in the posts or in the key?
How good are your screwdrivers?
You can use penetrating oil and heat and it helps a lot sometimes. This might be a problem for example on plastic instruments, which might be too sensitive for the heat needed? This also can take time and you might have to leave with the oil and add more plus heating it occasionally. I've heard that sometimes this can take days (haven't had one this slow personally).
But after this you still have to remove it, so you can use the drill, or something like an EZout (if small enough). An alternative is:
If you have the tools, to cut a new slot in the screw while it is still in the post, without damaging anything (the post). I use a micromotor. Then screw it out with a GOOD(!) screwdriver.
Worst case scenario: Assuming you can screw (or rotate) posts, cut the hinge tube (with thinnest way you can) right next to the post. Then rotate the post and the key might move out of the other post relatively easily (hopfeully). Or screw the post (if possible) all the way out and try to remove the key from it. Then you can also can soak it (was recommended alum in boiling water, never tried it though). If the screw is stuck in the posts too it's harder but you can probably figure out what to do. I've only had to resort to this last option one time, before having the tools for the above.
|
|
Reply To Message
|
|
Author: stebinus2
Date: 2009-03-20 19:11
Thanks so much! The screws are evidently stuck in the post since the keys move freely. My screwdrivers are uh... utilitarian, but I have 2 sets so I have done some modification of tips to fit a variety of slots. One more little question: I see Ferrees has "old" and "new" Buffet pivot screws. I'm assuming the little ones I'm looking for are the "old", right?
|
|
Reply To Message
|
|
Author: Chris P
Date: 2009-03-20 19:14
Have they got a blob of bright blue stuff on the threads?
If so, then that's the old (headless) style.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
|
|
Reply To Message
|
|
Author: Caroline Smale
Date: 2009-03-20 19:35
Do not assume the rod is stuck in the post. Operate the affected key and look very closely at the (damaged) head, does it move? because a key can move freely when the rod is jammed into the key by the rod rotating in the thread and the other pillar. This is quite common.
|
|
Reply To Message
|
|
Author: tictactux ★2017
Date: 2009-03-20 19:40
Norman Smale wrote:
> Do not assume the rod is stuck in the post. Operate the
> affected key and look very closely at the (damaged) head, does
> it move? because a key can move freely when the rod is jammed
> into the key by the rod rotating in the thread and the other
> pillar. This is quite common.
Now I am confused - the subject says "pivot screw", so there's no rod, right?
(edit:typo)
--
Ben
Post Edited (2009-03-20 19:45)
|
|
Reply To Message
|
|
Author: clarnibass
Date: 2009-03-21 05:17
I accidently also thought about a rod screw in my reply. Most of what I wrote is the same anyway, and a few things are more for rod screws but I think you can figure out the ideas for pivot screws (for example cutting is less likely for pivot screws).
I just checked old and new Buffet pivot screws, and the difference is the new ones have that plastic on them. But these are for RC/R13/etc. models. Also possible that at some point Buffet changed the screws, before adding that plastic (but I'm really not sure about this).
Are these pivot screws with heads or headless? The replacement Buffet screws are with head. Considering when an Evette is from, I assume the old Buffet screws, but maybe ask Ferree's if they fit this model?
Edit: I just noticed one supplier says new Buffet pivot screw have M2.0x0.4 threads, and the old ones have M2.1x0.35 thread. I checked mine and new are correct, but my old(?) ones are definitely not 0.35 threads. 0.4 seems closest but also American 64 seems pretty much the same (I assume it's the mm measurement though). This is why I think it's likely there is old without plastic but also old with a different thread.
If there is at least one that isn't stuck maybe you can measure?
Post Edited (2009-03-21 05:21)
|
|
Reply To Message
|
|
Author: Gordon (NZ)
Date: 2009-03-21 14:55
Clarnibass, you are too young! :-)
The 'old" ones are 3.1 x 0.35 mm.
The "new" ones are 2 x 0.4 mm.
The silly newER ones have the squishable plastic stuff under the head.
Stebinus, to be sure which you have, you need to measure the pitch of the thread of one of the screws, with a thread gauge.
BTW, are you aware that you will likely need to fit the key &/or post to the screw dimensions? Each batch of screws is slightly different. This requires specialised tools.
For point screws with broken heads (most likely because a substandard screw driver had been used), I have sometimes carefully drilled right through the middle of the screw, then used a small inverted cone bur to widen the base of that screw until the steel was sufficiently removed for the key to come free.
There is also a specialised tool that cuts into a slot-less head in an anticlockwise direction, to grip it and turn it out.
For a long key, it may be possible to bend the key, and slightly unscrew the post, to free the key. If a key is removed, then you can work on the screw from the point end, perhaps cutting off the point and drilling part into the remaining screw, which usually frees it, from the heat, torque and pressure (in the ASSISTING direction) generated all at once.
Hot, strong, alum solution gradually dissolves steel without attacking key metal.
There are many 'tricks' that resourceful technicians have that are possibly not accessible to the DIY guy. This sort of work is where a good technician can be indispensible.
|
|
Reply To Message
|
|
The Clarinet Pages
|
 |
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
