[PigSquealer]

@jth121 if I were doing this I would leave the spring / keycup end alone. Trim the tube on key touch end. Looks close on the overall move. Next cut the tube between the stabilizer post and touch area. Make a sleeve say 1” long to go over the tube. Check the cup to touch positioning. Solder in place.

Another option with the original old part. Cast the additional area with JB weld. Sculpt & finish with dermal tool.

 

[jth121]

Thank You Pig Squealer for this suggestion. Thinking about this last night I had a similar idea. My thoughts were to adjust the key for clearance between this key and the B key to get the measurement needed to the desired spacing to the G# key. Then trim and square the top of the replacement rod accordingly. Since I have both the newer and the existing rods, use the top of the newer rod and the bottom of the existing rod cutting and brazing the rods together for the desired length. The issue with this is that if something goes south, both rods are done and now this project just became more difficult. That is where a sleeve as mentioned above could help out.
Moving the lower post may be easier after adjusting the top of the rod for the desired clearance between the keys. There are 2 other posts in that area and the joint for the bow, and I feel confident that I can do this, but I don't like to solder with so many things in close proximity.
If I knew for sure that I could hammer swage this rod to stretch as turf3 suggested, I would probably go this route. I have never done this before and am unsure how far this can be stretched and what it will look like when finished. Although this horn is not worth a lot, it is clean for its age and I would like to try to do this as clean and original looking as possible.
An observation while looking closer at this is that none of the rod ends on the existing key or the replacement key are square. The plating is not worn from the ends where they meet the posts, so it looks to be this way from factory. Also, one of the lower rod ends is drilled off center, so the cup moves in a slight eccentric movement. Someone at the Martin factory was having an off day 60 years ago.

 

[jth121]

I had a few minutes to mess around with this. This is what it looks like after a bit of adjusting. The .5-.75 mm gap in the rod in at the bottom for the picture and the gap between this key and the G# key is 3 to 3+ mm close to the B key and 1mm above the B key.

 

[turf3]

I'd hammer swage that rod a little longer (so it stays the way you've pushed it up for the picture) and declare victory. That table looks as well aligned as several of my horns that still have all their original parts.

 

[PigSquealer]

Why not use the key cup end of the original part. That new upper section is looking pretty good. With the sleeve you could marry the two. Soft soldering should do.
That little adjustment looks like you’re almost there. Maybe trim half the distance ? Marry the two parts with the sleeve and you’re done.

 

[ptung]

It may or may not be important to make sure your rod doesn't have any up/down play. Sometimes, an imperfect rod doesn't affect pad seating meaningfully, but very often it will, and you're talking about the pad above your low B and Bb, so if it leaks it will probably give you problems on those notes, and having play in the mechanism will invite those problems.

I think you already know and recognize this, jth, but it's worth underlining for people who will hit this thread in the future.

 

[jth121]

I'd hammer swage that rod a little longer (so it stays the way you've pushed it up for the picture) and declare victory. That table looks as well aligned as several of my horns that still have all their original parts.

Well, I tried that today over lunch with the upper part of the existing rod. Tapping lightly with an average size hammer did nothing except mar the finish, it did not get any longer. Using a larger hammer worked and I was able to lengthen the rod about 1.5-2mm as a test, but the finished rod had curved (which could be straightened) with the texture looking something like braided rope. This could be dressed up a bit, but Nope, that will not work for what I would like and I am glad I tried this on the older key first as a test. Heating it to orange color would probably have made this better but having the right tools to do this would have been the way to go.

 

[turf3]

All right, you've got some choices.

1) Lengthen the rod by swaging - rejected after experimentation as described above.
2) Lengthen the rod by cutting in two and inserting a sleeve - will absolutely work, but it will be pretty visible too.
3) Move the lower post (don't need to unsolder, just bend it over a bit)
4) Ream the pivot screw seat on the lower post (might not be enough meat there).

Whatever you do, you'll want to adjust the pivot screw joints for minimal play and no binding.

 

[jth121]

Why not use the key cup end of the original part. That new upper section is looking pretty good. With the sleeve you could marry the two. Soft soldering should do.
That little adjustment looks like you’re almost there. Maybe trim half the distance ? Marry the two parts with the sleeve and you’re done.

Yup, my thoughts also. Either braze the rod directly or solder a sleeve as described. I would have to get some brass tube for a sleeve. The other option is to move the lower post a bit. I need to look and think about this some more.
Thank You all for the great feedback! I will post updates

 

[PigSquealer]

I would rather see the post moved than manipulated/knocked over some. My concern would be the pivot screw is no longer in line with the tube. Potential bind or rapid ware issues.

 

[ptung]

I would rather see the post moved than manipulated/knocked over some. My concern would be the pivot screw is no longer in line with the tube. Potential bind or rapid ware issues.

Exactly. But this is one area where a DIYer can probably do OK with something like "above average intelligence."

You can drill the hole with normal bits and a screwgun, but you need enough foresight to drill it smaller first, and to take into account that you want to do it (as a DIYer -- with better tools this changes slightly) so that the diameter of the hole never is large enough at any point that "matters" such that there is any lateral play when the key is mounted.

If the pivot were shouldered (it probably isn't, but if it were) a normal and a fine (latter meaning smaller diameter) set of hand files -- there is a name for the set that escapes me now, but the type that are used in mouthpiece work, for example -- can do what's necessary, used carefully and wisely (again in a way that avoids lateral play/looseness) in the final mounted position.

If you want consistent seating, lack of play/looseness to the greatest degree possible is of course the goal. Some horns with loose/sloppy mechanisms still play (because they manage to still seat) well. Others won't. Accidents of player technique no doubt have a role to play there, but obviously the goal is the smoothest operation possible without inconsistent movement.

 

[jth121]

I did more shoveling snow and painting than working on this over the weekend, but here is what I did do. To reduce the gap between this C# key and the G# key, I started trimming the top of the rod. I did notice that as this gap was getting closer, at the lower end, the arm to the cup was getting closer to the post for the B/Bb keys. I kept trimming the top of the rod until it was almost hitting this lower post and there was still 2mm between the C# and G# key. The gap at the bottom between the rod and post was now 3mm. I was planning on soldering an Extension on the lower rod from the existing rod to eliminate this gap. I tried bending the cup arm for more clearance, even building a jig to keep the rod from bending, but could not bend the cup arm without bending the small stub of a rod at the lower post. I tried heating it to bend to arm, but all this did was show silver at the braze joint where the arm meets the rod. At that point, with a 3mm gap at the bottom and unable to bend the cup arm the way I would have liked to, I heated and removed the arm and cup and went back up top and finished trimming the post so that the tops of the B and C# to G# keys were both 1mm. This looks good up top. My thoughts are now to use the top of the newer rod and the bottom of the existing rod with a joint somewhere in the middle. My choices are to braze a butt joint with silver or to solder with a brass sleeve. Either will be clearly seen. The sleeve would help with alignment and soldering may be cleaner, although I have no experience soldering onto nickel plating. Looking it up online there is a lot of conflicting information, no surprise there. Can I solder a brass sleeve to nickel or should the plating be removed first? If so, do I need a special flux and solder?

 

[jth121]

Looking at this a bit more since the previous post, I may be able to move the cup arm down the rod a bit more to clear the other post and braze it back on in the proper orientation. Then possibly solder the rod extension on the bottom to add length to the rod. I need to look into this a bit more.

 

[ptung]

Looking at this a bit more since the previous post, I may be able to move the cup arm down the rod a bit more to clear the other post and braze it back on in the proper orientation. Then possibly solder the rod extension on the bottom to add length to the rod. I need to look into this a bit more.

Please forgive me for just looking at the 1st two photos, and not yet reading posts in full (limited time at this moment/second). It looks like you're fine (good, really) and all you need to do is (1) alter the rod at the bottom, straighten the bends in the keyarm a bit overall -- which will lengthen it -- while repositioning things slightly to pass the other post and center the cup over the tonehole; or (2) move the post and then do the same second part. This is just based on those two photos, really, but that's all I need to see, personally.

 

[PigSquealer]

@jth121 when in doubt test bonding on old parts. I think you will be fine. I would even consider using superglue and making it a cold joint. The issue is the working time. Don’t blink.

I haven’t looked but nickel plated brass tubing may be available.

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[whaler]

If you need another Imperial, let me know $50 plus shipping. No case.

 

[jth121]

This Project is now complete. I definitely took the long way around to get this done. I ended up moving the arm/cup lower on the rod from the replacement part off of the Imperial. I had to make a jig to get the key/cup orientation right and then brazed this together. Then I soldered a 3mm extension at the lower end of the rod to make up for the shorter rod due to trimming the rod at the top for the desired key clearances. I already had a new pad and spring to finish this. I must have overheated the end of the spring to flatten the end as when I tapped it with the hammer, the end broke into pieces and was then too short. I needed a longer spring from the original due to trimming the top and moving everything up. I used a lighter spring with more bend to get playing again until I can get the correct spring. I am pretty happy with the results and the transition between Bb and C# is so much nicer. If I had to do this again, I would use the original rod, arm and cup, and remove the key and braze the replacement key off the Imperial at the correct position. Thanks to all for the comments and suggestions.

 

[PigSquealer]

Looks really good ! Nice work making it happen
Springs will do that if you just heat it and hit it.
I heat the spring and let it cool. Soften.
Heat cherry red again and hit it. Check fit.
Heat even and dunk in oil. Let cool. Hard and brittle
Then temper by slowly heating until the metal blues again. That way it’s not brittle.
put to use

 

[jth121]

I have been playing this for a week now and really like the results from this project, it is a much easier transition between these keys. I ordered the correct replacement spring and am waiting for that to arrive to install. I overheated the first replacement spring with my torch making it brittle. Thanks PigSquealer for sharing your procedure on doing this.

 

[PigSquealer]

That’s great you got the results you were after. Definitely looks like a nice upgrade. I found a video on YouTube on conditioning Springs. Although this is for flat Springs it’s the same technique.