Low Force Joystick Grommets

Thanks for all the interest in the Atari BZ/FF grommets. After playing around with the first prototype for a few days, I feel it needs some (relatively minor) changes to be solid enough to send out. Will update soon.
 
OK, maybe a bit more than minor changes...

After testing this design for a few days, it was clear it wasn't strong enough. The rings were too thin and cracked easily.

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So, I made several major changes this time around:
- Thicker rings for more strength.
- To prevent / improve dead zone slop, I made the inner bearing deeper to grab ahold of the stick better.
- The flex member bows upward rather than downward now. Given how the stick moves relative to this grommet, I thought this made more sense.

The new ring designs are shown below. Both have more depth now. The walls are thicker as well. The anchor points in the outer ring are now recessed to avoid interference with the inner ring during displacement.

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Complete assembly:

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The mold process is shown below. As before, the rings are molded 'in situ' so the silicone cures all the pieces together.

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Finished result:

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These seem to work well. They seem to have plenty of displacement available.

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Fitment in the Battlezone stick housing is fine. Play action is pretty good.

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I don't have a Food Fight joystick, so I sent a few of these to another member to test in theirs. Hopefully these changes will still work in that joystick too.
 
OK, maybe a bit more than minor changes...

After testing this design for a few days, it was clear it wasn't strong enough. The rings were too thin and cracked easily.

full


So, I made several major changes this time around:
- Thicker rings for more strength.
- To prevent / improve dead zone slop, I made the inner bearing deeper to grab ahold of the stick better.
- The flex member bows upward rather than downward now. Given how the stick moves relative to this grommet, I thought this made more sense.

The new ring designs are shown below. Both have more depth now. The walls are thicker as well. The anchor points in the outer ring are now recessed to avoid interference with the inner ring during displacement.

full


Complete assembly:

full


The mold process is shown below. As before, the rings are molded 'in situ' so the silicone cures all the pieces together.

full


Finished result:

full


These seem to work well. They seem to have plenty of displacement available.

full


Fitment in the Battlezone stick housing is fine. Play action is pretty good.

full


I don't have a Food Fight joystick, so I sent a few of these to another member to test in theirs. Hopefully these changes will still work in that joystick too.
How much for the Food Fight grommet? I have an old FF Joystick that needs a few updated parts.
Thanks.
-bc
 
Report: Food Fight grommet installation from jlpmauldin

-Drop in fit.
-Working great so far and will keep playing.

I have a Food Fight cocktail game and so I installed one of the new grommets on player 2 side to compare to an original. So far I've found the performance to be really nice. It seems a bit of a softer feel than the original grommet (which I like), though I believe that can have some to do with the type of grease (and viscosity it has) applied in the joints of the two joysticks and what kind of dampening effect that has. I do need to get either some nyogel or similar silicone grease and I'll play through more after adding fresh lubrication to both.

Otherwise the design is a drop in fit and was pretty easy to do once I knew what I was doing. It doesn't even require taking the joystick off.

A few photos attached showing the original worn grommet and the replacement, and a bit of start of game play.
 

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I am so glad these fit and work OK in a FF.

Thanks so much the help. Waffel essen!
 
Hi,
Are your Defender joystick rebuild kits for sale?
Thanks,
—Rich

Yes. Will send you a PM.

I hope you guys beat the shit out of them. I still have to drop in my robo ones, but i shake the shit out of that machine! Put em to the test!

Reliability is a definitely a legit question. I've wondered about it. What's a good metric? Number of successful moves? Force required to make a move? Re-centering speed? Unbroken parts? Can I pick the cab up by the joystick and not break it?

This makes me wonder how many total moves (moving and shooting) are in one typical game of Robotron (~500k score).

The biggest concern for me is the mounting plate. I suppose it's possible to break the bearing as well (less likely).

The silicone is a big question mark for me too. No idea on that. Does it just turn to dust one day, or will it out live me? Does it get less pliable? The only data I found listed it's usable life in years. Do environmental factors (temperature, humidity) make any difference?

You can actually use an old OG metal mounting plate with these. Just scrape off the dried up old grommet material first.

The latest rev has done pretty well in the field (feedback has been a great help). I think they're solid for collector home arcades. All the ones I installed in my games are OK (I try to play Robo a few times a week at least). Would they hold up in a busy arcade in the 80's? Not so sure.

I figure for $7.50, and the few minutes needed to install it, if it lasts a few years that's good. Especially if it makes an unplayable game fun again.
 
Update on grommet on Food Fight:

I applied some dialectic silicone grease (2.99 at O'Reileys) today and also installed some NOS orange e-clip buttons on the machine and I about doubled my high score.

Obviously the grommets are working well, and I'll keep playing on them. Even if they are 1/3 or 1/10 the durability of the originals (and this is near 40 years and one of my original grommets is still fine) it seems like a great option to me. I prefer the feeling of these to an original (who knows if maybe the original was looser or tighter and has aged) in its present state, and they are quite easy to install (easier than in a Wico I think).

Thinking they will have some good durability too.
 
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Got my grommets today. My frogger joystick had so much slop even with a new AS grommet, I had replaced it with a Pac Pro stick with a long shaft to approximate the original. The new grommet has 0 slop and the stick feels great! Time for it to go back home :D

Some unscientific video proof: Before and After
 
Received 3/8" grommets for my Robotron cab and I give them a 10/10. Very well made product, replaced the stock grommets on repro 4" wico sticks that were just too stiff. These are just right and similar to how the original arcades played. It's not too loose, but smooth, just the right amount of resistance. I can rest side of my hands on the panel and control with my fingers easily. Installation was a breeze and better than the stock grommets that were a little too thick and near impossible to attach the e-clips. These installed in less than 5 minutes. Do not hesitate to buy these, and order some spares while you're at it.
 
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I have not. The blue stuff actually has a lower durometer than the green. So, maybe too wimpy. There are some stiffer silicones that may be OK. I need to get one into a game and see how it plays, and my only opto stick game (Joust) is down at the moment.



I think you are correct. At least about the rotation rods. I think the leaf actuator rod is not subjected to much force and should be OK. I decided to fall back to the older design and use 1/4" bolts that screw in to nuts captured in the actuator body:
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I'm sure some appropriately sized rods pressed into the actuator would work too. But, they need to be the right length, and I'm trying to minimize fabricated pieces.

Since I don't want to require any permanent modification of the housing, I placed an additional bearing outside the joystick frame to allow the bolt head to rotate freely:
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Assembly was completed in a few minutes with a screwdriver and some pliers to tighten the nuts:
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This assembly feels solid with no slop. Better than the plastic rod version. Pretty strong.

My defender needs this mod. I'm going to try it and see how it holds up.

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I should be putting 2 of these in ICB shortly.
Looking forward to getting it going again.
@jlpmauldin - another great idea
 
Hi. Wanted to add my own experience in rebuilding a pair of Wico rotaries with these replacement grommets.
Compared to the NOS rubber ones I picked up before, I am moving the joystick and not the entire cabinet now.

Very nicely designed and great feel to them.

Cheers!
 
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