Keyboard axle removal via electricity

[boxplayer4000]

How helpful it is that, from time to time, we come across accordions where keys can be individually removed without disturbing the axle.
I suppose cost was factor against the design being more widely used.

 

[Glug]

How helpful it is that, from time to time, we come across accordions where keys can be individually removed without disturbing the axle.
I suppose cost was factor against the design being more widely used.

My 1959 Hohner Lucia has individually removable keys and it's the nicest keyboard I've got - no defects I can find (except my fingers).
The same mechanism is in the Atlantic and Pirola from that date.

Some people dislike the tone of the Hohner 'metallbauweise' accordions (from 1953) but it's got a good keyboard.

 

[Tom]

689-2RS are very small, lightweight and sealed. a 2mm steel shaft with a bunch of solid brass bearings might actually be heavier. Lube is the only question, and, arguably, pressing new identical bearings in every 40 years is not a very expensive repair. Easier & faster than re-boring for a new axle.

There's a bit of controversy about the 80 years comment, imho. Firstly, if the accordion is played regularly, the bearing & axle wear will happen a lot sooner. My "project" Morino club is 70 years old and it's been played until holes in celluloid. The brass axle was completely chewed by the brass key rods. I say a good 0.2mm wear on the axle & key rod combined, if not more. Secondly, nobody buys a top of the range laptop expecting it to last 80 years. Or car. Or fridge. Or garden shed. So why is it that people want their relatively cheap musical instruments to last for 300 years and play perfectly during all this time?

I would not build a garden shed to last less than 80 years. Just saying.

 

[dak]

So why is it that people want their relatively cheap musical instruments to last for 300 years and play perfectly during all this time?

My relatively cheap violin (at the time of its making) has lasted (admittedly including repairs) for 204 years already. My relatively cheap accordion (at the time of my acquisition) has lasted for 64 years so far. One difference of musical instruments as opposed to appliances like washing machines or vacuum cleaners is that they are items of personal attachment. Nobody tries doing their laundry in their late mother's washing machine in order to pick up and/or honor a fondly remembered tradition. There may be kind of an exception for children-size instruments that are supposed to stay with you only for a short phase of your life, or for cheapest-category instruments that will be an impediment to progress and enjoyment comparatively soon.

 

[dak]

So, what's the difference between replacing a bearing and replacing a rod and some bushings? Since you want to pull up all the keys every 40 years anyway, why go to the trouble of putting a bearing in every key with some mechanism to hang keys individually (how you want to achieve that without introducing a failure point is still unclear to me)? You probably won't get a stuck axle after 40 years anyway, so no advantage for bearings. Also: Brass bushings and a new rod will come way cheaper then 40+ sealed bearings, so your "cheap repair" argument is flawed.

Ball bearings are for significant forces and/or loads. How many ball bearings will you find in clockwork other than a tower clock?

 

[colinm]

Ball bearings are for significant forces and/or loads. How many ball bearings will you find in clockwork other than a tower clock?

Its not often that you are right Dak, and this time you are wrong again.

In instances where high-velocity is a factor, bearings provide a better solution, while bushings respond well to low-speed, heavy load applications.

 

[John Doe]

Virtually all upscale self winding watches use ball bearings for the rotor. Turntables (EG Garrard) use ball bearings for the platter. Other than dime store strollers and wheelbarrows use ball bearings. Bicycle wheels turn at about 160 RPM at 15MPH (a modestly brisk pace)- high load and pretty slow (a small bearing diameter given the size of the wheel (27 inch whee,l about two inch or less bearing diameter)means quite a slow movement rate between the hub bearing and the axle).

Plain bushings mainly respond well to non-demanding operations where ball or roller bearings would be expensive to employ and the plain bearings are quite "good enough" for the requirements. Plain bearings are used on engine crankshafts but the real bearing surface in that case is the film of oil which is force fed twixt the bearing surfaces under pressure during operation. If there's bearing surface to bearing surface contact you'll pull to the side of the road in a cloud of smoke in short order.

I see the real cut point as a requirement for low friction. The four caps on universal joints in a car move a fairly small distance yet have needle bearings fo just that reason. The constant velocity joints in FWD cars also sport ball bearings- minimal friction is the reason. Both are very heavy load applications.

And of course there are the turrets on tanks- as in battle tanks vvs water tanks... Tons of steel rotating on the body of the tank. High speed for a turret slew is just not all that spritely (unless you have the ill judgement to be standing on the deck when the turret slews... They use PDL (pretty darned large) balls. Speed is of course important, but mainly the need for a smooth precise rotation without herky jerky stuttering drives the design.

Of course, for my money the rod and hole drilled through the keys system is quite suitable for accordions. Clarinets/flutes/sax's et al also make do and yes- reboring the hinge tubes and using oversized rods to take up play developed through wear is a requirement every half century or so.

My back's durability vs the durability of the rod/keys in my accordions is pretty much a dead heat.

 

[tcabot]

Agreed, with proper maintanance things can be made to work a lot longer than expected.

 

[tcabot]

Back on planet Earth.

A bag with a 100 "689-2RS" type ball bearings comes in at 43 grams. Ouch! I better hit the gym so I can use this monster accordion and remember to lift with my legs, not my back. I mean who would want to add 43g to the weight of their 12 kg box?!

The said bag costs £15 retail including shipping from China. Wowzer. Time to re-mortgage the house to afford this luxury. Good enough quality without any noticeable play (we are not putting any load on them at all) - in any case, a lot less play than the single-axle through holes set up. Good luck getting a 100 brass bushing pairs made to extremely tight tolerances to achieve the same level of smoothness. You can add a zero to that price and not get what you want.

Ball bearing in this case will be extremely forgiving for push-fit and being riveted onto its post.

I'm not at any point suggesting there's a need for ball bearings in this application, but in this particular case they do offer a very easy and very cheap solution, probably more lightweight than a full length axle, with grease/oil/whatever they put in them these days gunking up being the major concern for me.

Don't know much about tower clocks, sorry.

 

[dak]

I'm not at any point suggesting there's a need for ball bearings in this application, but in this particular case they do offer a very easy and very cheap solution,

Apart from the issue of them being available in a standard accordion shop for centuries to come, I have the suspicion that they'd feel awkward. Ball bearings don't really differentiate between holding and moving resistance (straight contact has about half the moving resistance to the holding resistance). Also the lubrication has a more limited lifetime than contact bearings under small loads and small movements.

Whether those suspicions bear any substance (or indeed it would be an improvement) is anybody's guess. Accordion manufacture has had its stories of setbacks. It also had a share of innovations that got pushed under the bus, like keyboard and case constructions and innovation by Hohner that went the way of the dodo when Hohner offloaded much of its manufacture to third parties with their own methods of production.

 

[Snoopz]

A bag with a 100 "689-2RS" type ball bearings comes in at 43 grams.

Interesting, that would mean less than a gram per bearing. Not very likely imho. Far more likely is the answer I got from google asking for the weight of said bearing, coming out at 7g/unit, meaning more than 300g just for the bearings on a full size instrument. Not measuring the additional weight for single hangings compared to a brass rod for all keys.

 

[Glug]

Bearings Online

Buy 689 2RS Ceramic Hybrid Ball Bearing 9x17x5 online today at Bearings Online! We stock a range of quality bearings and transmission products by premium brands.

www.bearings-online.co.uk

Dimensions​

Dimension Bore: 9

Dimension OD: 17

Dimension Width: 5

Weight: 5g

 

[Glug]

Apparently 689-2RS are ceramic with stainless steel races and 9mm bore x 15mm OD x 5mm thickness.
You can also get really small bearings:

SMB Bearings

Chrome steel miniature bearings for shaft sizes from 1.5mm to 9mmDimensions and technical drawings are shown in the product tables belowSee Products V

www.smbbearings.com

Something like 2.5mm bore x 6mm OD x 1.8mm width may be about the right size.
Can't see what they weigh though

https://www.smbbearings.com/firebrick/ckeditor/plugins/upload/Uploads/Documents/bearingpdfs/682X-miniature-bearing-2.5x6x1.8mm.pdf

And they are oiled.

There's also 3mm bore x 10mm OD x 4mm width sealed

Bearingboys

Online

www.bearingboys.co.uk

It's not something I've ever thought about, but it's quite amazing how small ball bearings can be


Edit: Here's a great chart https://iskbearing.com/news/knowled...rings-a-comprehensive-chart-for-ball-bearings

eg. 602X 2.5mm bore x 8mm OD x 2.8mm width 0.61g

 

[JKJ]

I've built a number of things from wood and installed ball bearings. Ball bearings are generally are for things that needed to turn rapidly and/or with little friction. This doesn't seem to be the case for the pivot of a key.

Bushings, however, made from brass, hdpe plastic, teflon, or some other material would be a lot easier to install and work for a lifetime at the motions and forces involved in an accordion. I particularly like brass bushings used with a steel axle. Bushings are easy to make and easy to install.

But of course none of this matters if the axle rod can't be removed gracefully. I haven't read all the posts so I don't know if the poster was successful or still trying.

 

[kimric]

I have done this trick at least ten times over the years and there a couple of things that are really important to get it to work.
The battery needs to be at least the size of the ones used on wheelchairs. You will be drawing at least 20 amps at 12 volts.
Your wires from the battery need to be a LOT thicker than the rod so that they don't become the point of resistance and get hot (and melt off the insulation) , you only want the rod to get hot.
Do not apply the power for more than a second or so at a time, you just want to heat up the rod enough to get it to loosen or soften what is sticking it. Apply the power in pulses so it heats up evenly (sometimes you can hear it clicking as it expands). If you can get it to the point where it will rotate, chuck it in a small cordless grill and keep it spinning as you draw it out, the friction will keep the axel hot and it also makes it much easier to draw out.

You don't want to get it so hot that it chars the wood, if you do you will need to rebore the keyboard and keys for a larger rod.

I have had luck shoving a piece of brass between the keys on the far end of the keyboard to make contact without boring into the keyboard to get at the far end of the rod.

 

[Dingo40]

I have done this trick at least ten times over the years and there a couple of things that are really important to get it to work.

Thanks very much for sharing your experiences with this technique!

 

[Mr Mark]

I have done this trick at least ten times over the years and there a couple of things that are really important to get it to work.
The battery needs to be at least the size of the ones used on wheelchairs. You will be drawing at least 20 amps at 12 volts.
Your wires from the battery need to be a LOT thicker than the rod so that they don't become the point of resistance and get hot (and melt off the insulation) , you only want the rod to get hot.
Do not apply the power for more than a second or so at a time, you just want to heat up the rod enough to get it to loosen or soften what is sticking it. Apply the power in pulses so it heats up evenly (sometimes you can hear it clicking as it expands). If you can get it to the point where it will rotate, chuck it in a small cordless grill and keep it spinning as you draw it out, the friction will keep the axel hot and it also makes it much easier to draw out.

You don't want to get it so hot that it chars the wood, if you do you will need to rebore the keyboard and keys for a larger rod.

I have had luck shoving a piece of brass between the keys on the far end of the keyboard to make contact without boring into the keyboard to get at the far end of the rod.

Great, thanks for sharing the experiential expertise!

I'm pretty sure I used actual booster cables with large nails clamped by the jaws last time - reasoning that in doing so the smaller diameter brass rod would take the heat first. Seemed to work, the problem was applying it too long, as you mentioned the holes got bigger pretty fast. The smell of wood burning and the little wisps of smoke definitely clued me in that was long enough. 2 or maybe 3 seconds was all. Which is to say 1 or 2 seconds too long. Like many things less is more.

The tidbit of brass without bore is the golden nugget here. Thank you!

 

[Mr Mark]

I'm happy to report that I have at long last freed the axle from it's snugly and dusty little home. I'm not sure what entirely did the trick but two things happened.

1) The CLP I ordered arrived today (thanks Paul!), I went through with the needle applicator to every gap. I didn't quite get all the way with some looking at the stains on the wood after but at least half got the works.

2) I had to bend the pulling end over so I could play the instrument without ripping my pants (the eyelet had long since given out - but hadn't broken so was sticking out about 1/4") for a bit. Today I had to straighten it with a screwdriver hammered into it from the side (best means of leverage all options considered), just to get the rod tool on it. when I did that, it turned slightly so I knew it was turning.

From there I used the rod tool I bought, and with a lot of elbow grease was able to pull and turn until I could get a drill on it. From there it was about an hour of taking the keys out, dedusting, then applying new keyboard felt. I actually doubled up over the existing felt with a really soft weather stripping as the specific keyboard felt I had acquired somewhere along the way was really tough and likely to reproduce the great clacking this whole ordeal was meant to address in the first place. It did reduce the valves opening but it has turned out to open just enough air, so the added bonus is much reduced keyboard travel - an issue on these older boxes for sure.

Everything is back together and playing wonderfully. The axle is solid and I'm very happy not to have had an electricity gone awry (although I'm sure it would have been fine).

My 1959 Hohner Lucia has individually removable keys and it's the nicest keyboard I've got - no defects I can find (except my fingers).
The same mechanism is in the Atlantic and Pirola from that date.

Some people dislike the tone of the Hohner 'metallbauweise' accordions (from 1953) but it's got a good keyboard.

I too own a Lucia and this is definitely one of the nicer features of this instrument!

The tone is definitely different than my Tango but a lot of the construction is completely different so hard to realistically compare - but nothing I had a problem with.


Very interesting discussion on all the ball bearings and such. I guess at the end of the day the rod in the wood seems to be about as good as the day it went in there all those years ago - so kudos to them for getting that right. I think that better access to the rod with a drill and this would be a lot easier to begin with (more to grab onto). I wonder what they would have used to tool it in there in the first place. What would they have grabbed the eyelet with to put it in?


Thanks for all the suggestions and help on this!

 

[Dingo40]

. I wonder what they would have used to tool it in there in the first place. W

This is how they did it at the Alessandrini works:

And at Dallapé:

 

[Mr Mark]

From what I can see in that first video - that rod goes in a lot easier than on mine - twas super snug to say the least! Using the rod tool made that process a whole lot easier for sure, I can see them using one in the second video. Looks like they’re greasing everything that moves, I’m sure the dust bunnies will love this !