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I don't know if this is a stupid question or not, but could anyone advise how to adjust clock springs on a horn that does not have the external adjusting wheels like on for example an old Kruspe? I would like to lighten the springs a bit.
On a horn with rotary valves and standard, what is is in English?, springs it is easy to adjust, which I did and found that instrument much more fun to play. Now the clock spring instrument is so hard on the springs that it is not possible to play it for more than a short time before resting...
(I did not mention any manufacturer names so this would not qualify as a commercial I hope )

I don't know of a way to 'adjust' clocksprings without removing all of the lever/housing assemblies from the mounting bar. Most of those are built with a square shaft sticking out of the housing that needs to be twisted to the proper tension before remounting it.

If your complaint is that the springs are too hard... chances are this has already been done several times over the years to the point that the springs are nearly 'bottomed-out' and not capable of being tightened much more. In this case, the springs have lost their tension and probably need to be replaced.

This is not really a big job for someone who is used to working on them. The good part is that you would just need to remove the whole paddle assembly from the horn... which is just a matter of taking out a few screws... and send the assembly to a shop instead of having to transport the entire horn.

It is impossible to know the actual condition of the springs until the valve linkage is disassembled. I would suggest taking the entire instrument to a professional repairman, as there may very well be other issues affecting the valve action, too.

The good news is that even antique valve linkage systems can be restored to very nice playability. New replacement springs are still available, and just about any other part can be bought, repaired, or a replacement fabricated.

Thanks for the replies.
So, if I understood it correctly, if the springs are too hard then it _may_ be time to replace them. However, if I take the units away from the mounting bar so I can manipulate each case separately, can I then twist the squared bar, if made that way, without taking the whole spring case apart? And, do I need some special tools to take the cases into pieces, other than the sledge hammer and a screwdriver ? Sorry, if I do not use the correct names in English for this stuff but I think it may be understandable.

The function of the valves is almost perfect in all other ways, tight, fast and quiet, and the same for the linkages. Just that the springs are too hard, which seems to be the case with almost all instruments that comes in my hands. It is a personal feeling I think, so I had to learn how to fix this myself, but have not worked on a clockspring tuba before so I have to learn something new...

If the levers are indivudally mounted and seperated by a stantion screwed to the key rail.. As you take each lever off the spring will loosen in the drum. be careful to control the unwind by holding the square end of the spring shaft with a smooth jaw plier You stand the chance of dislodging the spring from the anchor nib inside the drum. ( often the spring will re-engage as you rewind the shaft) As you reinstall the lever onto the stantion you can twist the shaft more or less and control the spring tension. It takes practice but it works. and should solve your issue

Lingon wrote:... So, if I understood it correctly, if the springs are too hard then it _may_ be time to replace them. However, if I take the units away from the mounting bar so I can manipulate each case separately, can I then twist the squared bar, if made that way, without taking the whole spring case apart? And, do I need some special tools to take the cases into pieces, other than the sledge hammer and a screwdriver ? Sorry, if I do not use the correct names in English for this stuff but I think it may be understandable.

The function of the valves is almost perfect in all other ways, tight, fast and quiet, and the same for the linkages. Just that the springs are too hard, which seems to be the case with almost all instruments that comes in my hands. It is a personal feeling I think, so I had to learn how to fix this myself, but have not worked on a clockspring tuba before so I have to learn something new...

Your springs may just be wound too tightly. It's worth a try to see if they respond more to your liking by changing the tension. As Lee Stofer hinted to... the springs may have been tightened to cover up other problems like worn bearings causing the rotors to drag inside the rotor housings. You can check this first by removing the screw in the stop-arm and checking for side-play in the bearings and seeing if the rotors tend to drag when you put lateral pressure on the rotor shaft. If you find that the bearings have excessive clearance in them.... it's not time to give up. Find a repairman who has the tools to reduce the size of the outer bearings and refit the rotors. This is not something that you should try without experience.

Once you determine the rotors are OK.... you are going the right direction. If you have to get inside the spring housings... the two side parts with the bearing are just pressed into the housing. Generally... you can use a small leather mallet to drive the center shaft one way or the other to pop one of the side pieces out. New springs aren't difficult to make. You can buy spring steel from McMaster-Carr in Chicago or I'm sure there is an industrial suppier where you are that can provide the steel. Once you determine the length you need... you'll need to anneal (soften) about 1/2" of each end of the strip so it can be bent to fit into the center pin and engage the outer housing. These things can be a real bugger to put back in but there are a few 'tricks' you will learn on your own. After rebuilding all four of yours... you'll be an 'expert'. Everything should come apart with minimal force. It's all brass so be careful not to bend anything but the spring!

Thank you so much for these great tips, it is so good to hear that the world will not break down when taking these things apart