Hinge Tube Longer

[soruyo]

Hi guys

How do you make a hinge tube longer? I can´t swedge this one because of the pivot screws at the edges. I have this play on the Bb (middle) key, and can´t get rid of it unless I make the tube longer.

Thanks!

[Gordon (NZ)]

Swedge it away from the ends, with a narrow-blade, pliers-type swedging tool.

[TenTenTooter]

-If the hinge tube is solid you can stretch it.
-You can counter sink the post so the pivot screw goes in further.
-Depending on whether the post is attached to a rib or mounted individually (and the condition of the finish of the horn), you can un-solder/move the post slightly.
-Solder an extension to the existing tube and ream it to match the pivot screw.

[soruyo]

Swedge it away from the ends, with a narrow-blade, pliers-type swedging tool.

I have swedging pliers from music medic, but I thought they were only to swedge tubes which use rods passing thru. Can I use them in this case too?

[BOPITY FUNK]

Yes you can swedge tubes for pivot screws, trouble is though you can end up with a 'raggedy' end.
Counter boring the post might be better or even drilling the rod to take a bushing of smaller diameter tube.

[Gordon (NZ)]

I have swedging pliers from music medic, but I thought they were only to swedge tubes which use rods passing thru. Can I use them in this case too?

Yes, swedging piers can stretch solid rod. (If the diameter is reduced, and material is not actually removed, then it has to get longer.)
But best to keep away from the ends, unless you want to re-fit the hole in the end to the pivot screw.

[slausonm]

There are many methods of making hinge rods and hinge tubes longer. If the needed additional length is rather short, a mm or so then swedging is a good method. There are multiple ways to swedge including pliers, rollers and swedging dies. If longer extensions are needed then grafting material on to the end is possible as well. You need silver soldering equipment and a means of fabricating the end of the rod or tube. A lathe is helpful for this but it can also be done in a bench motor.

[abadcliche]

I was asked this question by email earlier today, so pardon the formatting and grammer cause I'm gonna be lazy and just paste it:

"...you can use some sort of extrusion method to swedge it and make it longer, then re-ream the pivot screw receiver in the key. You can make a pivot screw exact shape reamer from an extra pivot screw of the same type. The shape needs to be exact!

Also it will take forever, but you can use regular swedging pliers to lengthen a solid key.

The Ferree's neck expander has a key swedging/extruding attachment. It works well, but puts a slight bend in the key you have to fix.

http://www.ferreestools.com/h59_canopener.htm

I recall seeing another swedging/extruder for solid keys for sale somewhere recently (thought it was JL Smith?) but I can't find it now."

Extrusion swedging of solid keys is to be used only when necessary- which is not that often- in conjunction with the main method of fitting pivot keys by counterboring the pivot screws and reaming the pivot screw receivers for an exact fit during keyworking.

[slausonm]

... You can make a pivot screw exact shape reamer from an extra pivot screw of the same type. The shape needs to be exact!...

While it is true that most of us that do this sort of thing try to make the (conical) pivot screw receiver as precise a fit as possible to the (conical) pivot screw end, in practice the pivot screw surface needs to fit at least tangent to the surface of the pivot screw receiver. It does not have to fit "exact" to function properly. Having the two contours match as precisely as possible will help with the longevity of the key fit.