Shock Mount

ArcadeTechGW

Well-known member

Donor 5 years: 2012, 2022-2025
Joined
Apr 16, 2012
Messages
25,896
Reaction score
12,997
Folks,

When I saw the pictures of the "grommets", a light went on in my head.

BING! I work in nuclear power, aviation, and arcade stuff - this is a cross-over to aviation.

Go to the following website: www.aircraftspruce.com

In the search field, type SHOCK MOUNT

You'll get several different mounts, ranging in price from $7 to $17, of things that look just like the "grommets".

Description:
1" Square Plate Type Lord Mounts, 6 lb. rating. Monel mounting plate. Base holes .141" dia. for 6-32 screws. Center hole .166" dia. for 8-32 screw. New surplus item - like new mfg.

Description:
2" Square Plate Type Lord Mounts, 35 lb. rating. Steel mounting plate. Base holes .196" dia. for 10-32 screw. Center hole .391" dia. for AN6 bolt. New surplus item. 200P-35

10-00034.jpg


These things are used to shock mount aircraft instrument panels. They have the same problem by the way - the rubber cracks after years of service.

You can also cross-check them by make / model - Piper, Beech, Cessna - if you have an avionics shop nearby, you can bring them your old one, and they might be able to match it.

I hope this helps.
 
Other grommet retrofit ideas

Note: This is a Non-Reversible Change - Read the WHOLE POST please or risk making a hard to reverse mistake.

For shafts that are too large only for their grommet:

Remove the ball

Tape the shaft with 1 layer of electrical tape (no overlap)

Chuck up the shaft gently in a good drill.

Turning the drill on slowly, apply the shaft that is too big to a flat fine mill file, and carefully machine off an even layer. Test the grommet at each 3 to 5 revolutions on the file.

If you want to be extra careful, you can use crocus cloth.

Clean the file frequently. This should give those of you without a lathe a simple way to use household tools to mill down your shafts (if desired - note: this is NOT reversible) to use the new (or alternate) grommets.

Given that it is unlikely that a vendor will make new grommets for an old game that "nobody cares about," it may be desirable to go this route.

Similarly, you can also either carefully drill or file out the grommet to get to your shaft size.

If you have a micrometer and know what to shoot for, you can slowly remove material and measure to get an interference fit that will give you years of joy.

When doing this, GO SLOW - Don't apply a lot of pressure. Once removed, you can't put the metal back on.

For those with shafts that are too small....

Another option for those people who have access or know "a guy who knows a guy" is remove the stick, have someone who is good with TIG put a layer of material on the shaft, and then turn the material down to your grommet spec on a lathe. They can get you an interference fit. Remember, "0's" count here folks - if you have a grommet with a 0.391" hole, your shaft needs to be in at 0.391" with a tolerance of +0,to -0.002.
 
Business and Wisdom

You offer a good comment.

I spoke to a fellow from NASA a few years ago. He was bubbling about how NASA invented a way to weld a 6" thick steel cylinder to use as the lift mass for the Constellation Test.

I asked him: "Have you ever visited the Naval Shipyards at Groton?"

He answered: Nope.

I asked "How about viewed a video on Nuclear Power, where reactors are 6 inches thick or more, and are welded to maintain pressures between 1500 and 2500 pounds or more?"

He answered again: Nope.

The moral of this story is three-fold:
1. NASA is great about telling everyone what they have created as part of the Space Program. They aren't so good about thinking about what other people have done.
2. Alternative suppliers for these "grommets" - where do you think the manufacturers got them from in the first place? They didn't invent these things - they re-purposed them for their needs.
3. The gentleman who developed these grommets has one that works (at the present time) for a specific, finite group of games. Don't we as members have a duty to help those other folks (e.g., THESE DO NOT WORK ON TRON!!!!) find grommets that can help restore their games?

I'm just saying - me thinks thou doth protesth too much.
 
I am leaving this in general because the (now) op only has 91 posts and wouldnt be able to see it in the dealer forum.

#brainhurts
 
Interesting observation. Its always cool to find out that what appeared to be a custom thing is actually standard part (in another industry).

Unfortunately, none of these look like Battlezone's rubber joystick centering spring... so alas it may have actually been custom molded.

In any case, I'm going to measure up a couple of the other rubber NOS parts I've got here, and see if there's a standard "instrument panel" mount with the same dimensions.
 
Actually, I noticed the same thing earlier this year when I was going through some stuff that we were throwing out at work. I initially thought "Wow, why do we have joystick grommets here???" Then I read the box and saw it was labeled "Shock Mounts".

They got them from McMaster Carr... and while I thought they were identical, I gave one to someone locally to replace a Pac-Man grommet, and he told me that they didn't quite fit, and that one end is actually slightly tapered... so he had to drill it out a little bit to make the joystick fit. I never got around to looking into it again since I don't have any joysticks that need a replacement grommet.

DogP
 
In any case, I'm going to measure up a couple of the other rubber NOS parts I've got here, and see if there's a standard "instrument panel" mount with the same dimensions.

They got them from McMaster Carr.

I just compared a part I got from Bob Roberts some time ago (few years?) with the dimensions of McMaster-Carr P/N 6008K14, and everything seems to match up. Next time I order fomr McMaster, I'm going to add one of these to my order and compare them more closely (one only costs $6.24).
 
Thanks Mods.

Well it looks like someone else had the same opinion on the placement of your post. Glad to see its been moved, as it doesn't help the seller recoup his investment in repro parts for the community. It's also not cool to kick a guy when he's down.

By the way, I've been to Electric Boat in Groton CT.. Also have toured many Nuclear power plants over the years.. Have a close group of friends whom are electrical and chemical engineers.. Also a couple nuke buddies.. So I get where you were going with your "NASA" story, but it still doesn't make any difference that it was poor judgement on your side with posting in someone's sales thread.

You've got some good info, just post it in the correct thread. As its hard enough getting people to pick up projects on their own dime for a very limited market. With all of your knowledge, maybe you should start reproducing parts for us? We could use all the help we can get.
 
I just compared a part I got from Bob Roberts some time ago (few years?) with the dimensions of McMaster-Carr P/N 6008K14, and everything seems to match up. Next time I order fomr McMaster, I'm going to add one of these to my order and compare them more closely (one only costs $6.24).

I just checked... the part I have is manufactured by Lord, P/N 150P-12.

Measuring with the calipers it looks to be the same all the way through, but this is what the guy said when he tried to use it: "I put the shaft in the grommet, but it wont go all the way through...so I flip the grommet and i cant even get the shaft in on the other side." He said he eventually got it to work by drilling it out a little bit.

So... I dunno. :p I didn't want to crap on the other guy's thread by posting about them, especially if they don't work.

DogP
 
Take a little off

All,

If you take a little off the inside of the grommet to allow a fit, you know how much it will affect game play?

Not at all.

Why are the grommets inconsistent? Because they are repurposed - the ID isn't a critical parameter - as long as it passes the right size AN bolt (aviation grade), everyone is happy.

There is no harm in taking off a skim cut on the ID of the steel in the center to get your joystick to fit properly. None at all.

Some caveats: the rubber material around the steel in the center is either Buna-N or EPDM, so you don't want to run a high speed drill through it. Gently grip the tip of the bushing in a vise, and work it with a drill, a small rat tail file, or crocus cloth to get the profile you need. File / drill / sand a little, test the fit, and repeat until you get the right fit.

You aren't going to crack the bushing taking a skim cut of a few thousanths of an inch. Really. The hoop strength of the cylinder is impressive.

If someone wants me to go grab my calc book, I can tell you what the approximate hoop strength is (which is more than you can imagine), and since the grommet is centered in Buna-N or EPDM, (barring a well-motivated idiot) you can't get enough force on the darn thing to damage the little steel cylinder in the middle. The rubber will fail long before you'll crack the steel in the center.
 
Last edited:
I don't think anyone is worried about damaging the grommet with a drill... I'm guessing it's more that you can get the shock mount for $7, and maybe have to drill it, or get a grommet that's known to work for $10.

Maybe the $3 is worth it to some people (or someone looking to buy a bunch), but there are probably a lot of people that'd gladly pay $3 more to not have to mess with it, or for people that don't have a drill press, a bunch of drill bits, etc.

And I'm only going by second-hand experience about drilling... I've never personally tried these grommets, and even so... there may be sizes that are an exact fit.

DogP
 
I gave one to someone locally to replace a Pac-Man grommet, and he told me that they didn't quite fit, and that one end is actually slightly tapered... so he had to drill it out a little bit to make the joystick fit.
DogP

It was me :)

Yea...i was all excited to try out the new grommet in my at the time recently acquired Pac-man. I took apart the joystick, and i couldnt get the old grommet off so I ripped it hell, tried to cut it off and ended up messing up the shaft. I still tried to put the new grommet on so I could tell DogP if it worked or not. I could get the joystick in, but not all the way through so I flipped it over and I couldnt get it in at all. I went ahead and replaced my joystick shaft since I screwed mine up, and when the new one came, same problem. so I took my drill and just kept drilling and spinning the grommet until I was able to fit the shaft in. I took a little too much off and the joystick was loose in the grommet but I was able to fix the issue by wrapping the shaft in a layer of electrical tape. You cant see it and its snug in the grommet now and the joystick works great!

Short version....it can be a pain, but the grommet works fine once you get the joystick to fit.
 
Heh, yeah... getting the old one off can definitely be a problem. The metal insert really likes to rust itself to the joystick shaft.

DogP
 
Rust-Busters

You can use Sea-Foam or Kroil to help penetrate / break up rust. You apply the stuff and let it sit overnight. It does a pretty good job of penetrating and loosening up rust.

It works great to remove Oxygen sensors that are rusted into an exhaust pipe as well.
 
I destroyed a mint pacman stick not to long ago because of a stuck grommet :(
Soaked it for day's in a few different chemicals.. No luck, it was fused onto the grommet.. Tried cutting it off with my dremel and ended up cutting the shaft badly.. Totally sucked.. As the stick looked almost new.

So, if you still have an intact grommet.. Keep it on! Heh
 
My Ms. Pac's grommet was not hard to get off at all. A few quick squirts and it came off like butter with no rust.
 
Yea...mine didn't look like it had much rust, it almost looked like the grommet was welded...but oh well the one DogP sent me worked on the new stick after drilling and the game is working now
 
Back
Top Bottom