Lachenal 5 1/2" 20 key restoration

[Jon C.]

Hi,

I am restoring a Lachenal 20 key Anglo. The reed pans were shrunk and cracked, so I desided to cut new reed boards. The previous owner, kept the concertina assembled with the screws loose. ( he may have had a few screws loose himself!)

 

Here is a prototype I just finished, it is made out of Bass wood. The finished reed board I plan to make from English Sycamore. It is good to protoype it, as the fit is critical. The whole thing was drawn on AutoCad and cut out with my Taig CNC Micro Mill, takes about 2 hours to cut out. It is amazing how much stuff that can be stuffed into such a small space!

I will probably also rebuild the "potato chip" action board, and maybe modify the linkage, to make it tighter. I will keep the ivory buttons...

Cheers,

Jon

Edited November 8, 2008 by Jon C.

[Jon C.]

Well, I got the left reed pan done. It is made from beautiful quilted English Sycamore, the photo doesn't do the wood justise, very purdy wood. It is amazing how much the original has shrunk, probably 1/2" agianst the grain. I ended up making it to the bellow frame, and it has a nice snug fit now. The spacing between the reeds and baffles, was quite a challange, to stuff everything on the board!

Still will have to get it mated to the action board.

I love how much detail was originally put into writing the serial number, so I endevered to copy that too... Here is a photo of the CNC Micro mill cutting the dovetail slots for the reeds.

 

Here is a photo of it "snug as a bug in a rug"!

Edited November 8, 2008 by Jon C.

[Pete Dunk]

This work is very impressive Jon, You must be getting to the stage where you are thinking about designing and building your own concertina. I presume the mill cut the narrow slots for the chamber walls too? I didn't even realise that sycamore had a 'quilted' variant like maple has, was the timber quarter sawn for stability?

 

Pete.

[Jon C.]

This work is very impressive Jon, You must be getting to the stage where you are thinking about designing and building your own concertina. I presume the mill cut the narrow slots for the chamber walls too? I didn't even realise that sycamore had a 'quilted' variant like maple has, was the timber quarter sawn for stability?

 

Pete.

Hi Pete,

Thanks for the encouragment. Making a concertina from scratch, has crossed my mind. I think the best way to approach it, is to rebuild a basketcase like this, and you get a feel for it. So. I was thinking about disassembling the fret board frame, and insert a new action board. I may make new linkage, similar to the Wheatstone design, that I can cut out of brass on the CNC.The other option would be to make it from round brass stock, pressing it flat for the hinged portion.

Yes, the thin slots were cut, along with the final hexigon profile. The CNC does a very accurate cut, it is a good thing, as there is very little "fudge factor".

Yes, the English Sycamore was quarter sawn, They even had it at the local exotic hardwood shop. Only two stores sell it it in USA (probably the only good reason to live in Los Angeles!) The figuring in the wood comes out when the wood is quarter sawn. The figuring looks like the wood needs to be ironed, when under the right light. The grain is nice and tight, and straight, but It helps to have the baffles. they keep everything in line. The back of the action board on the original had a huge knot in the middle, causing the board to deform into this wavy mess! There was a couple of attempts to get the holes drilled inthe right place, through the frame... You can see how the quality dropped after leaving the quality controlled Wheatstone shop.

One more reed pan to make still, but it is getting a little easier.

Take care,

Jon

[Jon C.]

I disassembled one of the action boards, steamed it with my trusty espresso machine, and clamped the board, to see if I can remove the patato chip warp in it. It was interesting to note that the action board was laminated, the first plywood... I figured it would have been solid wood, the vaneer that would be touching the reed pan had huge knots in it, and the inner laminate was in two pieces, I presume to try to prevent it from warping. I will re-glue the corner blocks, but that won't give it much added stability. Is there anyway to stablize the wood after I get it straightend out? Perhaps there is some chemical that can stabalize the wood?

Take care,

Jon

[RustyH]

I've had a little experience and use quite a lot of potato chip wood as it's fine for turning as long as it's not for spindles or platters.

 

I had planks I was drying/storing for years in a timber press. I decided I'd take them out and build a table. I had them out of the press for a week and no warpage. I ran them through the planer, then went off to my other job. When I got back to the shop the next day to begin work, all the planks had potato chipped, they made great firewood.......

 

I would take from this that the wood is forever under tension if that's it's nature. Forces had stabilized over the course of time as the wood lost it's two types of water (the water the tree uses to feed itself and the chemically bound in the structure itself). When I put it through the planer I upset the tension balance and it potato chipped (too severely to correct).

 

Anyway, this is my guess........

 

I stay away from the chemicals as much as possible. There is a product, PEG (polyethyleneglycol), that you soak it in for months, I don't like it. Then there is the heated pressurized ammonia chamber that will allow you to make wood so flexible you can literally tie it in knots. I'm surprised the ply didn't de-laminate when you steamed it.

 

Any chance you could build one up from a modern ply?

[Jon C.]

I've had a little experience and use quite a lot of potato chip wood as it's fine for turning as long as it's not for spindles or platters.

 

I had planks I was drying/storing for years in a timber press. I decided I'd take them out and build a table. I had them out of the press for a week and no warpage. I ran them through the planer, then went off to my other job. When I got back to the shop the next day to begin work, all the planks had potato chipped, they made great firewood.......

 

I would take from this that the wood is forever under tension if that's it's nature. Forces had stabilized over the course of time as the wood lost it's two types of water (the water the tree uses to feed itself and the chemically bound in the structure itself). When I put it through the planer I upset the tension balance and it potato chipped (too severely to correct).

 

Anyway, this is my guess........

 

I stay away from the chemicals as much as possible. There is a product, PEG (polyethyleneglycol), that you soak it in for months, I don't like it. Then there is the heated pressurized ammonia chamber that will allow you to make wood so flexible you can literally tie it in knots. I'm surprised the ply didn't de-laminate when you steamed it.

 

Any chance you could build one up from a modern ply?

Thanks for the information. Actually, that was my original intent, steam the joints, and disessemble the whole thing and replace with new birch plywood. But when the wood got all plyable, I thought I would try clamping it and see if it would stay put. Well it did for a couple of days, I took it out of the clamps, and secured it back on the concertina, (proud of myself) that I had solved the problem. Well, today I took it apart and it looks like a Lays potato chip again! I guess I will get to re-make that action board after all.

Take care,

Jon

[Jon C.]

Hi,

Here is a photo of my new action linkage. I I went with the Wheatstone design hinge pin. The key is now very smooth and quite, with out the wobbly side to side movement. I copied the contour of the original Lachenal key, to get the proper lenght and offset. Took about 4 hours to cut all the parts out with my CNC, the board overheated on the last cut, a little to much for the little guy... But now I have to wait on essembly, until I rebuild the action board. Work in progress...

Jon

[Dieppe]

(probably the only good reason to live in Los Angeles!)

 

Awww now, there's other good reasons I'm sure...

[Greg Jowaisas]

Jon,

You are doing good work! Keep it up.

 

One sugestion: Make sure your lever pivot post has some right angle purchase with the action board surface. You will want to eliminate any chance of the lever rocking motion being transfered to the pivot post anchor tang.

 

Best of luck,

 

Greg

[Jon C.]

Jon,

You are doing good work! Keep it up.

 

One sugestion: Make sure your lever pivot post has some right angle purchase with the action board surface. You will want to eliminate any chance of the lever rocking motion being transfered to the pivot post anchor tang.

 

Best of luck,

 

Greg

Hi,

yes, I can see that now, it would give more stability. I have to re-cut the posts anyway, as the work shifted, and the wholes got off center on the posts.

Thanks for the input,

Jon

[Richard Morse]

Yes, the English Sycamore was quarter sawn, They even had it at the local exotic hardwood shop. Only two stores sell it it in USA

I don't think that's correct.... It seems that few people know that English Sycamore is the same tree as the American Maple. They're both Acer Pseudoplatanus, just their "familiar" names are different across the ocean. Maples are one of the most common trees in the US and widely available in quartersawn. Sycamore trees (Platanus species) in the US are called Plane trees in England, and are considerably different from the Acer Pseudoplatanus.

 

-- Rich --

[Paul Groff]

Yes, the English Sycamore was quarter sawn, They even had it at the local exotic hardwood shop. Only two stores sell it it in USA

I don't think that's correct.... It seems that few people know that English Sycamore is the same tree as the American Maple. They're both Acer Pseudoplatanus, just their "familiar" names are different across the ocean. Maples are one of the most common trees in the US and widely available in quartersawn. Sycamore trees (Platanus species) in the US are called Plane trees in England, and are considerably different from the Acer Pseudoplatanus.

 

-- Rich --

 

Hi Rich,

 

True that english "sycamore" is a species of the genus Acer (often called "maples"), but this species is not one of the common, native, "American Maples" as you suggest.

 

Common names of plants are not standardized in the way ornithologists have tried to standardize bird names. "Cedar" or "pine" as well as "sycamore" can mean many different species. That's why it can be very helpful to determine the "scientific name" as a link to accurate technical information about a plant species and its characteristics (including wood properties and availability). But important to have the right scientific name.

 

Here is a good source of links to information about Acer pseudoplatanus (called "sycamore" in England and sometimes called "sycamore maple" in the US), as it occurs in the US:

 

http://plants.usda.gov/java/nameSearch?key...amp;submit.y=11

 

And here is more general information about the various species of the genus Acer in the US:

 

http://plants.usda.gov/java/profile?symbol=ACER

 

As well as the Platanus species that are called "sycamore" in the US, there are also species not in the genus Acer that sometimes have "maple" in their common name.

 

I would think most people mean Acer saccharum (commonest common name, "sugar maple") when talking about "American maple." Actually, however, many different native American species of Acer have useable wood as does the non-native, introduced "sycamore maple."

 

PG

Edited December 8, 2008 by Paul Groff

[Henrik Müller]

...

and cut out with my Taig CNC Micro Mill

...

Hi, Jon - good stuff!

One question immediately comes to my mind when I see this:

 

What is the diameter of the dovetail router bit?

 

/Henrik

[Jon C.]

...

and cut out with my Taig CNC Micro Mill

...

Hi, Jon - good stuff!

One question immediately comes to my mind when I see this:

 

What is the diameter of the dovetail router bit?

 

/Henrik

I am using a 1/4" dovetail router bit, with a 7 deg pitch. I cut a inside profile, you have to make sure that the bit enters and leaves outside of the pocket.

Cheers,

Jon

[Henrik Müller]

...

and cut out with my Taig CNC Micro Mill

...

Hi, Jon - good stuff!

One question immediately comes to my mind when I see this:

 

What is the diameter of the dovetail router bit?

 

/Henrik

...

I am using a 1/4" dovetail router bit, with a 7 deg pitch

...

Good - my guess exactly

/Henrik