Hook Pivots...?

[Jack Bradshaw]

What is the best design for (or source of) "Lachenal" rod pivots ?? The scrapper for reeds had what looked like simple staples, not the cutout plates that I see in pictures....

 

Jack

[Paul Read]

What is the best design for (or source of) "Lachenal" rod pivots ?? The scrapper for reeds had what looked like simple staples, not the cutout plates that I see in pictures....

 

Jack

I believe the staples were on the cheapest models. You may want to get hold of another scrapper.

[Marien]

I would say staples could play just fine. If staple pins are round, and if the (thicker kind of) crappers would have square edges where it touches the lever, then an action with staples may play better.

[Paul Read]

I would say staples could play just fine. If staple pins are round, and if the (thicker kind of) crappers would have square edges where it touches the lever, then an action with staples may play better.

Edited November 23, 2007 by Paul Read

[Marien]

?

[Pete Dunk]

New Lachenal lever pillars are available direct from C.Wheatstone & Co but they are 65p each. I posted off an order to Steve Dickinson two days ago for a set of wrist straps and fixings and they arrived today! Remarkable service.

[Marien]

David Leese may have original lachenal pillars of different types.

[d.elliott]

What is the best design for (or source of) "Lachenal" rod pivots ?? The scrapper for reeds had what looked like simple staples, not the cutout plates that I see in pictures....

 

Jack

 

Jack,

 

Staple pivot points are quite common, and quite effective. remember that the the key is constrained by the lever arm, its peg and the key hole in the action box cover. There is no detriment to the key's performabce as such even if the arm is a little 'free' as long as it is not too cranked in plan view. The pad is also fairly tollerant in terms of alignment being probably the best part of 2mm (dia) bigger than the pad hole. I would not be in a hurry to start pulling out and replacing pivot posts or staples unless there was a very good reason. The resultant alignment and action inefficiencies could be a nightmare to sort out.

 

Dave

[Jack Bradshaw]

Jack,

 

Staple pivot points are quite common, and quite effective. remember that the the key is constrained by the lever arm, its peg and the key hole in the action box cover. There is no detriment to the key's performabce as such even if the arm is a little 'free' as long as it is not too cranked in plan view. The pad is also fairly tollerant in terms of alignment being probably the best part of 2mm (dia) bigger than the pad hole. I would not be in a hurry to start pulling out and replacing pivot posts or staples unless there was a very good reason. The resultant alignment and action inefficiencies could be a nightmare to sort out.

 

Dave

 

Yes, it does look pretty good as long as the radius on the rod and that on the staple are a good match.......

 

The problem is exactly that.........I need a new action plate...I don't have the tooling Lachenal had to do the staples w/ any sort of accuracy so I keep thinking of threaded studs (slots w/ glass pivot rods ?...again a lot of work) ......one possibility is to use an english plate and do a layout that will use some of the pivots........

 

I don't know exactly how the rods pivot in the punched out type.....I would think (looking at what I have so far) that a wedge in the plate could rock in a radius on the rod (a single axis radius not the compound one on the existing rods)

 

Jack

[d.elliott]

Jack,

 

Staple pivot points are quite common, and quite effective. remember that the the key is constrained by the lever arm, its peg and the key hole in the action box cover. There is no detriment to the key's performabce as such even if the arm is a little 'free' as long as it is not too cranked in plan view. The pad is also fairly tollerant in terms of alignment being probably the best part of 2mm (dia) bigger than the pad hole. I would not be in a hurry to start pulling out and replacing pivot posts or staples unless there was a very good reason. The resultant alignment and action inefficiencies could be a nightmare to sort out.

 

Dave

 

Yes, it does look pretty good as long as the radius on the rod and that on the staple are a good match.......

 

The problem is exactly that.........I need a new action plate...I don't have the tooling Lachenal had to do the staples w/ any sort of accuracy so I keep thinking of threaded studs (slots w/ glass pivot rods ?...again a lot of work) ......one possibility is to use an english plate and do a layout that will use some of the pivots........

 

I don't know exactly how the rods pivot in the punched out type.....I would think (looking at what I have so far) that a wedge in the plate could rock in a radius on the rod (a single axis radius not the compound one on the existing rods)

 

Jack

 

 

Jack,

 

any chance of a photo so we can see what you are facing?

 

Dave

[Jack Bradshaw]

I'll see what I can do about getting some actual pics...in the meantime, the staples look a lot like the pivot shown in the bottom left of the photo

 

 

The rods are flattened brass rod (easy to make) w/ two "v"'s as opposed to the Aluminium ones in the photo....the scrapper had parallel reeds.....

 

The rods look like these

 

Edited November 26, 2007 by Jack Bradshaw

[d.elliott]

I'll see what I can do about getting some actual pics...in the meantime, the staples look a lot like the pivot shown in the bottom left of the photo

 

 

 

These are the standard staple type pivot, so why do you need to change the action plate?, That's why I suggested photographs.

 

It is easier to repair the actionplate by inlaying wood into damaged areas, than it is to peel it off the plate without structural damage to the padboard and its case!

 

Dave

[Jack Bradshaw]

Ahhh...well, the junker actions are/were 20 button Lachenal Anglo......pretty sad.(worse).....just scavaging parts to build up a 30+......the pivots are just a bent piece of wire, "U" shape stapled into the plate.

 

(The old Bastari...learning curve unit has been relegated to making a MIDI controller.....)

[Pete Dunk]

This is where I have a problem with terminology. A 'staple' to me is simply a piece of round wire bent into a 'u' shape and I have seen a concertina (a Wheatstone in fact) with just such an action. Lachenal's 'standard' slotted pillars, whilst not being ideal, are much more sophisticated - but I guess it would take an engineer to say if the degree of sophistication had any material effect compared to a simple piece of bent wire.

 

The point is that the action you have is just about as good as Lachenal ever got so unless you want to go down the road of fitting a complete replacement riveted action (expensive!) there isn't much you can do other than a straight replacement if the existing action is so badly worn.

[Jack Bradshaw]

It's not so much that it's worn or that a "staple" action couldn't be good (although the wear marks on the rods would seem to suggest that it wasn't the optimum fit) as that it's the wrong action plate (just what I could find as junk)

 

I'm not convinced that "riveted" is necessarily the best action either.....(instrumentation background)...hence this topic.....

 

Come to think of it...and I just thought of (remembered) it....years ago, when I was making microindentors, we used "spring pivots" ....which combined both functions...I'll dig that up .....

 

Jack

[Chris Ghent]

Riveting has the advantage it can be done successfully from a low industrial base, other methods require an intermediate forming tool or two. It seems to last adequately...

 

Chris

[d.elliott]

What is the best design for (or source of) "Lachenal" rod pivots ?? The scrapper for reeds had what looked like simple staples, not the cutout plates that I see in pictures....

 

Jack

 

Er, Jack, what is the objective here?

 

1. to refurb a damaged action plate?

 

2. to refurb a damaged pivot post or two?

 

3. to re-develop a concertina with different fingering etc? more keys or what ever.

 

Dave E

[d.elliott]

This is where I have a problem with terminology. A 'staple' to me is simply a piece of round wire bent into a 'u' shape and I have seen a concertina (a Wheatstone in fact) with just such an action. Lachenal's 'standard' slotted pillars, whilst not being ideal, are much more sophisticated - but I guess it would take an engineer to say if the degree of sophistication had any material effect compared to a simple piece of bent wire.

 

The point is that the action you have is just about as good as Lachenal ever got so unless you want to go down the road of fitting a complete replacement riveted action (expensive!) there isn't much you can do other than a straight replacement if the existing action is so badly worn.

 

The main issue between the Lachenal 'window frame' post and the staple is the lever arm's flank support where the arm is subject to axial turning moments. These situations only become a problem:

 

a, if the lever arm is in anyway cranked,

 

and

 

b, the legs of the staple are splayed.

 

The resultant problem will be the same as the 'Edeophone Cranked Arm Syndrome' previously discussed on this site.

 

Dave E