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Parts, Service, Maintenance & Repairs / Re: Mk2 Plastic Balance Rail Replacement... thoughts?
« on: December 24, 2020, 02:49:49 AM »
As a fellow tinkerer, I can get behind this little endeavor. Totally not practical and probably not worth it but hey why not lol. I just recently restored an '82 suitcase with plastic keys and while cleaning all the balance rail pieces I had the exact same thought...what if the posts were aluminum and screwed into the base so they could be replaced at some point.
I did wonder if the plastic on plastic motion is causing a bit of the clickity clack and if so...could the posts be a little thinner like the wood models and could we add some type of insert into the key to mate it to the post. That way you'd have the material stability and precision of the plastic key but with the softer dampening and structure of the wood key. However there's the front posts also that are plastic on plastic so they would probably need to be replaced also to totally minimize the clack.
For your design, it's not clear if you mean to have the base machined out of aluminum or somehow make it plastic again. If you're going to have that machined then I'd look into simplifying the base overall. Seems like it would only need 2 holes to mount to the wood shell, and could probably lose the front/back bevel and the four corner fillets. Now I'm wondering if the base could be 3d printed with female brass inserts installed for the posts...or maybe capture nuts. Tricky part is the precision placement but a well-calibrated printer and maybe an alignment jig could help with installing the inserts.
Then you just have to worry about the posts. If there isn't something off the shelf, which seems like there would exist something already with like 5 to 10 mm of thread and smooth for the rest of the post. Or maybe a thinner, fully threaded post where you then fit some kind of sleeve over it so the key mates snugly.
Along similar lines of tinkering for tinkering's sake...I ended up modeling the dowel holder in the back and printing that in PETG. Also replaced the front rail felt with TPU pieces that match up with each front rail since the felt seemed like a nasty/dirty solution. The keys aren't really supposed to come in contact with the felt in any case. Attached images of what I'm talking about.
For the key bounce - I built a new wood shell for the top and did not groove out a strip for the back felt. I just put the correct replacement felt right on the layer and that seems to have helped a bit with the action. After all my tweaking I feel like I'm in a good place. The plastic keys get a bit of a bad rap but as someone in a high-humidity location they actually are a good choice for me.
I did wonder if the plastic on plastic motion is causing a bit of the clickity clack and if so...could the posts be a little thinner like the wood models and could we add some type of insert into the key to mate it to the post. That way you'd have the material stability and precision of the plastic key but with the softer dampening and structure of the wood key. However there's the front posts also that are plastic on plastic so they would probably need to be replaced also to totally minimize the clack.
For your design, it's not clear if you mean to have the base machined out of aluminum or somehow make it plastic again. If you're going to have that machined then I'd look into simplifying the base overall. Seems like it would only need 2 holes to mount to the wood shell, and could probably lose the front/back bevel and the four corner fillets. Now I'm wondering if the base could be 3d printed with female brass inserts installed for the posts...or maybe capture nuts. Tricky part is the precision placement but a well-calibrated printer and maybe an alignment jig could help with installing the inserts.
Then you just have to worry about the posts. If there isn't something off the shelf, which seems like there would exist something already with like 5 to 10 mm of thread and smooth for the rest of the post. Or maybe a thinner, fully threaded post where you then fit some kind of sleeve over it so the key mates snugly.
Along similar lines of tinkering for tinkering's sake...I ended up modeling the dowel holder in the back and printing that in PETG. Also replaced the front rail felt with TPU pieces that match up with each front rail since the felt seemed like a nasty/dirty solution. The keys aren't really supposed to come in contact with the felt in any case. Attached images of what I'm talking about.
For the key bounce - I built a new wood shell for the top and did not groove out a strip for the back felt. I just put the correct replacement felt right on the layer and that seems to have helped a bit with the action. After all my tweaking I feel like I'm in a good place. The plastic keys get a bit of a bad rap but as someone in a high-humidity location they actually are a good choice for me.