The 3D Printable MCA Joystick project (MCA 3D)

[Syntax]

I'm reposting this for a friend and everyone here as I have always thought the MCA was the king of SHMUPS joysticks.

Hi all,

Thought it was about time to start typing my notes up on this project that a mate and myself have been working on for the past year. Particularly given it's finally getting to a stage of maturity where we can actually show some real examples, gain some important feedback, while we start working on preparing for a public release of the files for both home users and the DIY arcade community!



So without further ado presenting...



The Modern 'Classic Aussie' 3D Joystick ... (or 'MCA 3D')

A modern inspired recreation of the 'Classic Aussie' MCA joystick that can be reproduced using household 3D printing techniques.

The goals of this project was to design a completely new 3d printable joystick that captured as much of the 'look and feel' of classic MCA Aussie joysticks using a combination of commonly available arcade parts (shafts, smaller ball-tops) with customised 3d printable parts. Our intention is to eventually make the 3D printable .stl files publicly available in the spirit of open hardware / open software once we have incorporated further feedback into the designs.

While aiming to preserve this style of joystick, we wanted to provide retro enthusiasts with another accessible pathway to trying out and experiencing a 'spring less' arcade joystick of the 80s and 90s for themselves particularly given were mostly only found around Australia and NZ and maybe difficult to source in other countries.

Important Disclaimer: While we feel we have gotten pretty close to look and feel of the original, to be clear, this is not a 1:1 replica of the original MCA. In part due to the use of different arcade parts such as the JLF shaft and also due to use of 3D printing techniques.

Official Project URL: https://github.com/dekkit/Modern-Classi ... D-Joystick
Official Forum: https://www.aussiearcade.com/topic/1028 ... ct-mca-3d/



Recent 3D Printed Examples



Example Parts

1 x Seimitsu LB-30 Ball Top (Note: 30mm)
1 x Standard JLF Shaft
2 x Shaft Extenders
4 x Micro switches (Lever)
All other parts incorporated into the examples have been 3D printed using either PLA or resin printing techniques, with TPU for the flexible bush.

Further information on assembly can be found on the github referenced in the url above.


Current Status:

We are currently obtaining feedback on few mature prototypes before we finalise and publish the 3d files, if you'd like contribute to the project please get in contact.

Also I am also collating notes in support of the somewhat less glamorous aspects of the project.... the documentation



Acknowledgements

This project would have not been made possible without the excellent initial 3d scanning, 3d design, 3d printing (... so so much printing), guidance and support provided by cm_au to help bring the initial solution ideas and hand-drawings to life! This also gave me time to start skilling up on 3d modelling software so I could further refine the look and feel of the joystick (which was critical after initial play testing and a couple of feedback sessions). I would also like to give a shout out to Monty for sharing his 3D printable MCA bush (see: https://www.aussiearcade.com/topic/5726 ... ick-refurb/) which was also was included in this design with permission.

Also to those of your who provided feedback on the initial prints, helped with play testing and giving quality feedback, and also those who provided chipped in to buy more 3D printer filament!

[emphatic]

This is awesome. I have never heard of nor tried the MCA joystick, at first glance, it looks a lot like the SUZO 500 that is also discontinued. I'm guessing the MCA only came with a rubber grommet, or did a spring loaded version of it co-exist, like for the SUZO 500, that I own both the rare rubber version as well as the spring type one.

I wanted to suggest someone 3D printing a body that would fit with SANWA or Seimitsu shafts but with the feel and characteristics of a SUZO 500 for a while now, but I no longer have my cabinets at home, so I am not very motivated to experiment.

[dekkit]

FYi - 3D printable .stl files now posted on the GitHub (complete with amended assembly instructions).


Thanks for posting above Syntax!

Agree the MCA looks very very similar SUZO 500 - I wouldn't be surprised if the MCA was based off it (to make them locally).

I've used a 30mm balltop in the design (original MCA was 29.5mm) - from a quick Google it looks like the SUZO 500 may have used a 32mm balltop, so you could probably fit that balltop without needing much (if any modification at all) to the shaft cover part of the design. Can you buy 32mm balltops? I wouldnt mind trying it out.

The assembly guide also shows the style of the rubbery bush if you want to compare.

Dek

[Bratwurst]

So this stick was chiefly an Australian exclusive, being a North American I've never heard of it before and the bushing return sounds like it would be fun to play around with. The shaft & dust covers look like they'd benefit from an acetone vape smoothing session if they were printed in ABS, the pieces that the human hand might interface with that is. Has anyone tried that yet?

[dekkit]

We havent done the vape thing (either me or my mate) but had entertained it. Its actually pretty smooth without it.

We trialled using resin prints which worked really well for a near perfect plastic feel (I had a few shaft parts made). The issue was the limitation of what colors you can use (black, white, greenish).

Hopefully over time, 3d printing will get smoother too.

Yes these joysticks were primarily used in Australia /NZ cabinets - so not as popular and cloned like sanwas etc and it's why went the DIY / 3D route to see if it would work.

Its now entirely possible to bring back other old joystick designs using similar approaches - it's also why we released the files publicly.

[Bratwurst]

Do you have a recommendation for a TPU filament brand?

[dekkit]

Mate (Cm_au) used : TPU Overture 85

You can substitute other brands and types - but it needs to be able to flex and return to shape.

There is a forum post on Aussie arcade that talks about what settings people have used to get their prints right for the bush:

https://www.aussiearcade.com/topic/5726 ... ck-refurb/

This bush part referenced above fits in original MCA joysticks as well (ie can use in either original or the 3d printed MCA joystick)

[dekkit]

Also here is an example of how amazingly good resin printing can be:

https://github.com/dekkit/Modern-Classi ... k/issues/1

Its very close in look and smooth feel of traditional plastic approaches.

Note: Used JLCPCB 's 3d printing service for those 2 x parts using their smoothest resin print option.

[Bratwurst]

Since I've received a sample stick and bushings from dekkit the other day here are some thoughts:



This is a cross-cut of the present bushing design. Of the samples I received they were really stiff, though not unusable. By adjusting shell/wall thickness, not just infill we can make a piece significantly more yielding without sacrificing spring/return. Even then I think there's room for improvement by considering 3D printing's characteristics and limitations; because printing with TPU is a different method of fabrication and especially material than the original rubber, straying from the original shape is going to be necessary to better explore mechanical properties. Initially I thought turning the bushing into something more like a wagon wheel with spokes would help but that actually added more surface area (shell) which stiffened things up.



My proposed design revision reduces the floor of the bushing by 50%, cutting out 4.25mm. This is the mechanical crux of the centering mechanism I think- increasing the pivot potential of the tube that holds the joystick shaft against the perimeter of the bushing by giving it less to fight against. Printing with 95A shore TPU at 220C on a 50C bed, shell/wall thickness was kept to 0.9mm with infill set to 5% to 10% lines pattern. I also made use of my machine's ironing function to smear the hotend over the top of all flat surfaces to help bond the layers and give the print more resilience. 5% infill produced a very light-touch but the striations in the hard plastic parts, the dustcap and shaft cover, sometimes kept the actuator from uncoupling from a switch completely. 10% infill bushings overcame that while still feeling satisfyingly light, but this leads to my next observation...



The center black piece is untreated Atomic Filament ABS and the black shaft cover adjacent has been acetone vapor smoothed for 1 hour in a 200mm cube HDPE container. I did this with the wide end of the shaft cover facing up, exposed, so the interior curve that mates with the dust cover dome also smooths over. After curing, all ABS pieces given the vapor treatment completely lose their print striations and become glassy smooth, and the 5% infill bushing no longer snags on switch actuation. I strongly recommend smoothing the shaft cover, dust cover and the actuator, the rest of the joystick assembly isn't necessary since those parts are not rubbing against anything.

I'll take a video sometime soon if anyone's interested.

[dekkit]

Thank you, that's really awesome work there. That vapor approach looks incredible - do you have a pic of the setup you used to do that.

Also dont forget you can soften TPU in boiling water to avoid throwing out prints.

[Bratwurst]

The setup here is a plastic ice cream container (they usually have an HDPE recycle mark on the underside) with a ceramic floor tile anchoring folded over paper towels. I use a pipette to soak the paper with acetone to avoid getting any on the tile, place the ABS pieces and then close the lid. After an hour I gently pry open the lid to avoid jostling the container and let it air out for 24 hours before handling the prints. Sometimes they cure in 12 hours but it's crucial you don't touch them until the acetone's fully evaporated because they will deform from handling if they're still soft, so better to exercise caution. You'll have to experiment to get a feel for acetone volume/time duration.

You can use pyrex or glass casserole dishes with a lid too, and a small dinner plate you don't care about to hold the paper towels in place while giving the pieces something to sit on, but you'll have to seal off the lids with masking tape to keep the vapors in.

And yes I've set aside the orange bushings you've sent me to give boiling a try, though I'm really satisfied with my revision. Time will tell on the durability aspect once I start playing with the stick in earnest.