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Replacing Lachenal lever arms


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The 30 key Lachenal anglo I am renovating has a number of lever arms where the pad ends have rusted away to nothing - the pads were only held on by the rust. So they are too short to re-use. The arms are flat profile, 1mm by 2.5mm going through a slot in the post.

 

Do you think it would be possible to lengthen lhem by soldering some wire of the correct profile to the end? If so. does anyone know a source for such wire?

 

Or remake them, from wire or plate?

 

Has anyone ever done this?

 

Regards

Rod

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I have never tried to extend arms as you suggest, It sounds like you have the ferrous type of arms rather than the more common brass, that will make soldering even more problematical. I would use salvaged brass arms as I have many times before. Which type of pivot have you got, staple or aperture? and what state are they in?  one concern might be that the wearing portion of the pivot post's inner face may be damaged and that the new or reclaimed arm my not be held true and thus be unstable. This in turn can give problems with the pads.

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If Mike's offer doesn't work out, you can get brass rod from a hobby shop. Instead of relying on just a solder joint, you may be able to cut away some of the corroded arm and use the appropriate diameter of brass rod linked together to what is left of the arm using a short length of brass tubing with a drop of solder so it does not come apart

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4 hours ago, Mike Acott said:

What length levers sre you seking? I may have some. 

Mike Acott

Mike

I have 12 arms that are corroded, but as some are short and some long I can salvage some of the long ones to satisfy the short ones. I will send you a pm with the 6 sizes I need to replace.

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3 hours ago, d.elliott said:

I have never tried to extend arms as you suggest, It sounds like you have the ferrous type of arms rather than the more common brass, that will make soldering even more problematical. I would use salvaged brass arms as I have many times before. Which type of pivot have you got, staple or aperture? and what state are they in?  one concern might be that the wearing portion of the pivot post's inner face may be damaged and that the new or reclaimed arm my not be held true and thus be unstable. This in turn can give problems with the pads.

Dave

Thanks for your reply. I'm not sure what the difference is between staple and aperture. The pivot is like a solid piece of metal (brass?) with a slot cut through it - as in the eye of a needle. They all seem in good condition. The arms seem to move freely in all of them, so hopefully they do not need to be replaced.

 

3 hours ago, Frank Edgley said:

If Mike's offer doesn't work out, you can get brass rod from a hobby shop. Instead of relying on just a solder joint, you may be able to cut away some of the corroded arm and use the appropriate diameter of brass rod linked together to what is left of the arm using a short length of brass tubing with a drop of solder so it does not come apart

.

Frank

Thanks for that. If all else fails I will look into your suggestions. I didn't think of using brass tubing!

😊

 

2 hours ago, Jake Middleton-Metcalfe said:

you could always get in touch with steve dickinson at c.wheatstone and co. He has the tools to make those parts left over from when wheatstone bought lachenal.

 

Jake

 

Thanks for your suggestion. Didn't think of that either!

😊

 

Thank you all for taking the time to reply.

 

Rod

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Rod, that is what I think of as an aperture or window, some instruments had a piece of rod bent into a 'U' shape, inverted then both legs cut sharp. These are then pushed/ hammered? into the action board for the lever arms to hook under. 

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Hi All,

 

I think this is a fascinating topic. I assumed the levers on Lachenal's were round rod/wire stock bent to form the correct kinked profile and then press or rolled. I imagine this flattening gave better stiffness in the direction of action, but perhaps work hardened the metal some as well? It would be interesting to know what equipment has been preserved by Wheatstone from the Lachenal acquisition. I'd be curious if anyone knows more about the process or the rationale.

 

I know the levers can also be replaced with riveted action constructed de novo, but it is interesting to know how one would at least try to restore to original condition, especially if you plan to keep the levers that still work in place.

 

I have a similar challenge with an old Crabb that has some missing rivited levers. These are round profile, flattened only where the rivet attaches, and I have gone to great pains to acquire brass rod of a similar diameters. I used an arbor press to flatten the section for the rivet, and had to tinker with filing hardened steel to get the correct profile. The posts will not be easy to match, as they appear to be stamped out of thick sheet and filed to a point. I only need a few, so just plan to get as close as I can with filing/grinding down some bits of flat stock.

 

It's all a bit more work than one should spend to get a workable lever, but you do gain some insights into the process used over 100 years ago, which is kind of fun. We all know you can't get modern threads to match the old end bolts, but it seems that the rod diameter used back then was not a gauge that is currently made in any system of units either! (or perhaps the tolerance was just poor and there was lots of variation.)

 

Jeremy

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  • 2 weeks later...
On 12/4/2020 at 5:29 PM, Jake Middleton-Metcalfe said:

you could always get in touch with steve dickinson at c.wheatstone and co. He has the tools to make those parts left over from when wheatstone bought lachenal.

Jake

Thank you for the tip. I have just taken delivery of 30 'new' brass levers courtesy of Steve, so I can replace all levers and know they are all of the best standard. Steve was able to supply them from unused Lachenal stock.

 

Regards

Rod

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3 hours ago, Rod Pearce said:

Jake

Thank you for the tip. I have just taken delivery of 30 'new' brass levers courtesy of Steve, so I can replace all levers and know they are all of the best standard. Steve was able to supply them from unused Lachenal stock.

 

Regards

Rod

 

ah great. I knew he had the tools, I didn't realise he had a lot of them stored as well. He used to make a cheaper version of his instruments which used those parts.

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