Weltmeister Supita Keys

[Mito44]

Dear colleagues,

I tried to find some relevant info but I couldn’t so I decided to start a new thread.

Some of this Weltmeister Supita Keys have a small movement left and right and after I remove all the keys I figured out that this is due to this little black plastic hole.

Due to usage this is not fit anymore so could you please help me with some advise how can I solve this problem ?

Thanks in advance

 

[Ventura]

i am sorry to say this, Mito, but this plastic bushing system
suggests that Weltmeister did not intend this model to last
a long time., but only to last so long then discarded

you could attempt to re-engineer the axle and pivot for
the entire keyboard.. for example removing all the plastic
bushings and finding a new axle rod the same size as the
wood holes

or replacing the plastics with nicely machined brass bushings

or wood dowels and re-drill new holes for the axle

but if they designed the accordion to only last so long,
then the rest of the accordion may also be close to end-of-life

do you have better accordions to consider for re-building ?

good luck

 

[tcabot]

do you have better accordions to consider for re-building ?

What, Supita not good enough to do a repair for folks these days .

@Mito44 Several options here.
1) If the wear is not too bad, just ignore it.
2) Install a larger diameter axle. This is the usual response to a worn key axle hole.
If the axle is housed in a wooden comb, you can do the following:
- get the new rod (stainless steel preferred) that's larger than original;
- hammer one of the ends on an anvil to flatten it very slightly - we're talking 0.1mm larger than the rod diameter.
- file a spear point on it. Now you have an improvised reamer with the cutting head 0.1mm wider than the new axle.
- Chuck the other end in a hand drill, wax the rod and ream out the existing comb holes for the larger axle. The existing holes help guide the spear point and keep it perfectly on track.
- Ream out the key holes. You can do it on a pillar drill with a reamer of the right diameter (you can get HSS machine reamers in 0.1mm steps from china for about $5 a piece), but the result might not be very precise in the end. Alternatively, ream them one key at a time straight in the keyboard. hold them tightly in place in the comb, insert the axle reamer into the comb and ream out this way.
- Cut off the spear point, cut the axle to size.
3) Try to find plastic inserts in the right size (both OD and ID) and replace the worn ones, or, maybe, buy some PTFE rod with correct OD, drill out the old plastic out of the wooden keys, install the PTFE and then drill & ream. PTFE can be glued into wood with CA glue as long as you file some notches on its sides for the CA to flow in there, harden and form an excellent bond.
Nicely machined brass bushings would be ideal, but there's a lot of problems with this approach. Precise engineering costs money. A lot of it. Getting a set of custom-made bushings will be very expensive. More importantly, you cannot guarantee that you will press them in the wooden keys perfectly, Even a small off-axle variance in bushing placement will make your keys rub against each other or against the comb! So you can get the world's best engineers to make you the bushings, but if you can't fit them with sufficient tolerance, they are useless. If you replace the bushings with PTFE and ream then in place in the comb, it should give you better results, but it's quite an advanced repair!

Option 1 is preferable.
Option 3 is the most complex to execute and only relevant if you have good tools & know how to use them. Unless you have a lot of time to practice this on sacrificial squeezeboxes, I recommend avoiding it.
Option 2 is hard, but with a bit of practice (get some old worthless box from the tip) can be done, especially if you keep the increase in axle diameter to the minimum. Can you get away by installing an axle that's just 0.2mm bigger? The result won't be 100%, but it should be playable.
E.g. If original axle is 2.0mm, get an axle that's 2.2mm, expand the spear point to 2.3mm, do all the reaming (Beware of the axle overheating when it's rotating in a wooden comb!!! You can do some serious damage here, especially if you haven't done this before!)

Only if the keyboard is worn completely beyond playable, I'd consider options 2 & 3. If worn keys are a minor inconvenience, don't fix what ain't completely broken.

 

[tcabot]

If you decide to follow Ventura's advice, you can always send the Supita to me to dispose it for you. I'll do it for free and even pay for the postage

 

[debra]

Dear colleagues,

I tried to find some relevant info but I couldn’t so I decided to start a new thread.

Some of this Weltmeister Supita Keys have a small movement left and right and after I remove all the keys I figured out that this is due to this little black plastic hole.

Due to usage this is not fit anymore so could you please help me with some advise how can I solve this problem ?

Thanks in advance

The slight room for movement at the axle is something you could easily ignore.
The sideways movement of keys is mostly restricted by the "guide pin" at the other end of the key. That pin fits in a comb and the pim should be just wide enough to go through the comb smoothly (frictionless) without having any extra room.

 

[Mito44]

i am sorry to say this, Mito, but this plastic bushing system
suggests that Weltmeister did not intend this model to last
a long time., but only to last so long then discarded

you could attempt to re-engineer the axle and pivot for
the entire keyboard.. for example removing all the plastic
bushings and finding a new axle rod the same size as the
wood holes

or replacing the plastics with nicely machined brass bushings

or wood dowels and re-drill new holes for the axle

but if they designed the accordion to only last so long,
then the rest of the accordion may also be close to end-of-life

do you have better accordions to consider for re-building ?

good luck

Hello Ventura, I like this model of Weltmeister for it’s sound. For the moment I would like to get to end with this project!

 

[Mito44]

What, Supita not good enough to do a repair for folks these days .

@Mito44 Several options here.
1) If the wear is not too bad, just ignore it.
2) Install a larger diameter axle. This is the usual response to a worn key axle hole.
If the axle is housed in a wooden comb, you can do the following:
- get the new rod (stainless steel preferred) that's larger than original;
- hammer one of the ends on an anvil to flatten it very slightly - we're talking 0.1mm larger than the rod diameter.
- file a spear point on it. Now you have an improvised reamer with the cutting head 0.1mm wider than the new axle.
- Chuck the other end in a hand drill, wax the rod and ream out the existing comb holes for the larger axle. The existing holes help guide the spear point and keep it perfectly on track.
- Ream out the key holes. You can do it on a pillar drill with a reamer of the right diameter (you can get HSS machine reamers in 0.1mm steps from china for about $5 a piece), but the result might not be very precise in the end. Alternatively, ream them one key at a time straight in the keyboard. hold them tightly in place in the comb, insert the axle reamer into the comb and ream out this way.
- Cut off the spear point, cut the axle to size.
3) Try to find plastic inserts in the right size (both OD and ID) and replace the worn ones, or, maybe, buy some PTFE rod with correct OD, drill out the old plastic out of the wooden keys, install the PTFE and then drill & ream. PTFE can be glued into wood with CA glue as long as you file some notches on its sides for the CA to flow in there, harden and form an excellent bond.
Nicely machined brass bushings would be ideal, but there's a lot of problems with this approach. Precise engineering costs money. A lot of it. Getting a set of custom-made bushings will be very expensive. More importantly, you cannot guarantee that you will press them in the wooden keys perfectly, Even a small off-axle variance in bushing placement will make your keys rub against each other or against the comb! So you can get the world's best engineers to make you the bushings, but if you can't fit them with sufficient tolerance, they are useless. If you replace the bushings with PTFE and ream then in place in the comb, it should give you better results, but it's quite an advanced repair!

Option 1 is preferable.
Option 3 is the most complex to execute and only relevant if you have good tools & know how to use them. Unless you have a lot of time to practice this on sacrificial squeezeboxes, I recommend avoiding it.
Option 2 is hard, but with a bit of practice (get some old worthless box from the tip) can be done, especially if you keep the increase in axle diameter to the minimum. Can you get away by installing an axle that's just 0.2mm bigger? The result won't be 100%, but it should be playable.
E.g. If original axle is 2.0mm, get an axle that's 2.2mm, expand the spear point to 2.3mm, do all the reaming (Beware of the axle overheating when it's rotating in a wooden comb!!! You can do some serious damage here, especially if you haven't done this before!)

Only if the keyboard is worn completely beyond playable, I'd consider options 2 & 3. If worn keys are a minor inconvenience, don't fix what ain't completely broken.

Hello tcabot,

Thanks a lot for your detailed answer, I think I will go with option 1 because we are talking about 5 or 6 keys, mostly the middle ones.
I need some precision tools for option 2 and 3 which currently do not have because the alignment needs to be perfect!

When I will have a new garage completely equipped I will consider other 2 options

But thanks a lot !

 

[Mito44]

If you decide to follow Ventura's advice, you can always send the Supita to me to dispose it for you. I'll do it for free and even pay for the postage

Hahahhaha! ))

 

[Ventura]

i wish you luck whatever you attempt, and hope
it keeps playing for awhile longer for you (op 1)
but
i fear for using typical repair methods, because it
seems to me the plastic bushings are more likely to be
be turning and wearing and loose between the plastic
and the wood, while usually in normal italian accordions
the wear is in the hole itself after 100 years or so

the plastic bushing required a large hole through the key
to fit the plastic, and eliminated the need to make precision
holes through the wood, or of using wood strong enough
to allow simply not using any bushing at all (during manufacture)
which is the logic that i am using to be saddened by this
choice Weltmeister made

trying to drill larger holes through the plastic and using a
larger axle rod, i fear, will simply cause all the plastics to
come completely loose and spin in the wood and make things worse

good luck.. i still hope for nicer accordions to come into
your life

 

[Mito44]

One of the causes which led to the movement of the keys was the T shape plastic under the key, which was missing.

I made a handmade replacement and I am eager to add the key to the keyboard to see the result

 

[Mito44]

Dear colleagues,

I find a way to deal with the annoying key movement.

I found in an electrical store some pins with a diameter close to the axis of the key. It is made of copper material and I think it is more durable than plastic rings.

I cut a small line and pressed it into the plastic ring.

It was a very painstaking job, but it was a succes!

It works perfectly now, so if anyone has this problem, it works!

Thanks for all your help. I love this community!

 

[Ventura]

excellent

you have made this weltmeister better than original design

 

[Mito44]

excellent

you have made this weltmeister better than original design

Hahaha.

Not really, I think they are excelent instruments but for the SH instruments it depends a lot of how much respect the owner have to them.

But yes I am glad that I found a formula that works because I was stressing my brain some nights ))

All the best!

 

[PhiliGol]

Great job Mito.
Amazing you discovered that wire end ferrules just are perfect fit.

 

[debra]

One of the causes which led to the movement of the keys was the T shape plastic under the key, which was missing.

I made a handmade replacement and I am eager to add the key to the keyboard to see the result

That's what I said: the guide pin at the end of the keys needs to go into a "slot" to keep it from moving sideways. Glad you could make suitable replacements for these "slots".