3D printed jacks

Due to interest in 3D printing for jacks, I have created this dedicated topic.

Could anyone give an update on the use of 3D printed jacks from personal experience?

Poly-ether-ether-ketone (PEEK), known by the harpsichordmakers as a good jack bristle material, in 0.40 mm filaments, is largely used as 3d printing material (in thicker filaments) and as engineering components material. So its durability and overall characteristics should be excellent.
PEEK, while difficult to find in 0,40 mm thickness, is simple to find as 3d printing material.

I don’t love plastics so I have never tried it, though.


Hi Keith.

I have had some luck 3D printing my own jacks and tongues. I was able to purchase locally two Hubbard French doubles in 2017 and 2018. The first is from 1967, and has hideous adjustment screws on the key ends for all three ranks, instead of in the jack stem (although I fully understand that for purists any adjustment screw as such is highly despicable :wink:), and also the damper has to be glued to the jack’s body. The instrument came with practically no spares (especially tongues, which in that old model have a tendency to split right at the plectrum), Hubbard Inc. was already back then completely unresponsive, and so that’s when I decided to acquire a 3D printer and print my own jacks and tongues. The upper manual of the 1967 instrument has been fully “upgraded” with 3D printed jacks with a damper slot and a screw hole in the stem, so I could do away with the adjustment screws in the key ends. I’ve never gotten the chance of completing the action upgrade to that instrument. The newer instrument (1980) came with a peau-de-buffle rank but no jacks for it, so I had also started printing those out, along with the special tongues they need to insert a leather plectrum. Again, another never completed project… :roll_eyes:


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It is amazingly excellent. I have had it in the jacks of my Italian for over 20 years and have never had any problems with it. Its “springy” properties can only be the result of a lucky coincidence! (I have never had any problems with the fruitwood jacks supplied by ZHI, either.)


@casinir64 what material did you use to print your jacks?

It would be interesting to see some photos.

HI Andrew.

I’ve been using PLA, because when I started doing this that material was the one with the closer specific weight to delrin (ABS is too light, and also more toxic to print in an enclosed environment). In the end, once equipped with the adjustment screw, the weight of the full jack was pretty much spot on with the weight of the Hubbard jacks. I’ll try to dig some old photos, or take some new ones, and post them here.


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Most impressive!

I have moved the 3D printing posts to a dedicated topic, as we have moved away from warping.

If anyone here is in need of spare Hubbard jacks and tongues, and has access to a 3D printer, I’d be happy to share my STL files. Example attached…

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3 posts were merged into an existing topic: Wooden jack replacements

This topic was supposed to be a location for discussion of 3D printed jacks specifically. As you know, I am fussy about thread hijacking. I’ll start a topic for wooden jack replacements.

A post was split to a new topic: Wire suppliers

Hi Robert,

Yes indeed! I’d be pleased to receive your file. We have these HappyLabs here, one close by, where for a membership one can learn IT. Printers and laser cutters too! I took two sessions and then COVID closed it down for 2 years!. Time to go back…

As a way to share something of mine, I’d be happy to send anyone who wishes my trusty Excel files to calculate string tensions based on lengths. Just ask by PM. i don’t suppose one can post an excel file directly to here? TwM

Hello Thomas.

Apologies for the belated reply! Busy week… As I realized when I shared some files with Carey, the Discourse doesn’t allow uploading of STL files, so I’ll need to send them to you via private email. Let me know if the address that shows up under your profile is the one to use, and which models you’d need. I have models for both 4’ and 8’ ranks for the older (symmetric) and newer (asymmetric) Hubbard jacks, as well as the respective tongues. You can also message me privately at my email address.

Question for Andrew: I wonder if the Discourse would support a sharing area where users can download/upload general stuff and share things such as these 3D print designs. If not, I may thing to create a github repo for my Hubbard designs, and post it here, although I’d have to understand whether such a thing would risk to be a patenting or copyrights violation!


Hi Roberto,
while Andrew will address your question, I wish to say there is a simple workaround for uploading “unrecognized” files. You can just zip them and upload the zip file. Sure it is a bit convoluted, but a viable solution.

Hi Domenico.

Thanks for the tip! I do remember seeing the .zip option among the viable ones… I guess that having spent too much time working at a national lab I have inherited a natural aversion to sending zipped files as they are commonly used to smuggle malware! Ci fanno 'na capa tanta where I work, every single year! :wink:


:joy: (a little tongue-in-cheek between Italians…)

Dear All,

I’ve spent some time over the past few days creating new models for both the old- and new-style Hubbard jacks and tongues. These are more faithful to the original Hubbard designs (apart from the added features), since my original models were a bit too customized to my own instruments.

Folllowing Domenico’s suggestion, I prepared a .zip file that contains the STL files of the new designs. I also added a README file that should - obviously - be read first! However, when I try to upload the .zip file, the system still claims it’s not an allowed format… see attached image of the error message. What am I doing wrong?


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Hello @casinir64. Many users of Discourse forums, of which there are thousands (of forums, that is), often request the use of the forums as a file repository and storage mechanism. The Discourse developers stress that Discourse is not a file sharing application and never will be. We allow images - crucial - and audio, but not general files. That’s why zip is not supported. A very good reason for this is disk space. How much space to provide? And it’s never enough. An issue is that add on disk space volumes at most of the cloud services, including one I use (DigitalOcean) have quite high monthly costs, and are most certainly not free.

The standard answer to this is to find a storage service and provide a link there. Dropbox for example is a simple solution. Alternatively, let people PM you if they are interested and you can send them the files.

Some Discourse admins ban PDF uploads (for reasons which are too technical to detail here) but I allow them.