(Topic ID: 209975)

Dremmel for contacts

By Metropolis

6 years ago


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  • Latest reply 6 years ago by Stoomer
  • Topic is favorited by 9 Pinsiders

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Post #17 Good explanation of when to use Drexel v file. Thanks Clay Posted by cfh (6 years ago)

Post #24 Part number and link to buy Posted by John_I (6 years ago)

Post #25 Part # and nice list of pros/cons Posted by NicoVolta (6 years ago)

Post #28 Why the blue arc? Posted by MarkG (6 years ago)


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#1 6 years ago

Does anyone have a video of how do do this? I see some love it and some hate it. What's your preference?

#2 6 years ago

I use fine emery board. Fine sandpaper would work too.

Using a motorized tool risks a sharp edge on the blade getting caught and bending or ripping.

#3 6 years ago

Seems like overkill. I use a Revlon nail file. To each their own though..

#4 6 years ago
Quoted from Metropolis:

Does anyone have a video of how do do this? I see some love it and some hate it. What's your preference?

Nothing works better. The bingo pin guys came up with this long ago. I scoffed, then tried it on a few parts relays I had - wow. Nice clean polished look with little to no effort. No filing them crooked. I use a Dremel with a wire brush on all of my EM restorations now. I have used brass & steel brushes and both do a great job. I was concerned about bristles coming loose & causing shorts, but I have yet to run into this problem.
ALWAYS WEAR EYE PROTECTION!!!

#5 6 years ago
Quoted from dasvis:

I use a Dremel with a wire brush on all of my EM restorations now.

Which wire brush attachment do you use?

Thanks!

rd

#6 6 years ago

Dremmel #443 burnishing tool

#7 6 years ago
Quoted from HowardR:

Using a motorized tool risks a sharp edge on the blade getting caught and bending or ripping

Agreed, can get caught and cause damage. I like using the dremel. I always make sure the rotation of the brush is rotating away from the edge not rotating towards it and risk digging in and grabbing it.

#8 6 years ago

Overkill is right!.............. I first read about using just using a business card to clean contacts
I just use the flex stone that PBR sells

#9 6 years ago

I don't doubt the Dremel does a great job. With that said it does make a simple job more time consuming. I'll stick with the flex stone for now. It's never let me down in 14 years. Maybe someday when I have more time and I want that thoroughly detailed look.

#10 6 years ago

I've been playing with the dremel/wire brush thing for some time now.

My conclusion is this... and i have a lot of data points to prove it too....

On coil voltage contacts, the dremel/wire brush thing is USELESS. you're just wasting your time. The reason for this is complicated. But if anyone cares i can type it all out. but that's the bottom line.

On the other hand, using the dremel/wire brush on 6 volt lamp contacts works GREAT. That's where this tool is good.

Also for Jones plug male connectors, the dremel/wire brush works great too.

#11 6 years ago

Yes. I have used the dremel at very low speed with the small, fine grit sanding drum on the lite sockets. they fit inside
the socket perfectly

#12 6 years ago
Quoted from AlexF:

I don't doubt the Dremel does a great job. With that said it does make a simple job more time consuming. I'll stick with the flex stone for now. It's never let me down in 14 years. Maybe someday when I have more time and I want that thoroughly detailed look.

Same here. PBR Flexstone files.

#13 6 years ago
Quoted from cfh:

On coil voltage contacts, the dremel/wire brush thing is USELESS. you're just wasting your time. The reason for this is complicated. But if anyone cares i can type it all out

I'm interested in hearing more please.

#14 6 years ago

DREMEL wire brushes work great for switch contacts! I've been using them for years and would never go back to relying on flexstone cleaners as they aren't as effective and sometimes leave grit behind. I do use flexstones occasionally though when a Dremel tool can't fit in certain tight spaces.

#15 6 years ago

I use the Revlon metal nail file because it does not wear away and leave grit like a flex stone or cheap file. The flatness of the file allows me to place it between the 2 contacts being cleaned and hold the switch closed. I'm cleaning the contacts on the same plane that they function which hopefully means I creating a flat and even surface between the contacts. I'm not sure how this could be done with a dremel. I won't judge though..as long as your games are working.

#16 6 years ago

I use this and love it.

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#17 6 years ago

Here's the skinny on the Dremel and why it's useless for coil voltage switches...

Before i explain the why and how, here's the data points.

Latest example: Gottlieb Mibs.
Problem: It was having a problem resetting the score reels. I could see it trying, the score reels would twitch. But not getting enough pulse strength to make the reels move.

Issue: score motor switch at 1A. This is on the lowest score motor position, and it's a large contact switch. It gets pulsed many times per rotation of the score motor. Switch adjustment was good, narrow gap (as i always do.) But clearly the switch was the issue. How do i know? If i put my big fat finger on the switch contacts, forcing them together with greater pressure, the score reels would easily reset.

This is a clear case of a problem switch. It was adjusted perfectly too, but clearly the contacts are dirty or damaged. So, like i do a lot, break out the dremel with a stainsteel wire brush. Clean the contacts. Re-adjust the contacts (because the wire brush activity always changes their gap.) Restart the game. THE PROBLEM IS WORSE. The twitching is gone, now there's NOTHING.

Fix: break out an automotive gap file and file the contacts. Restart the game. Works perfectly.

Now this isn't just some one-off thing. To prove to myself that the Dremel is only good for selected items (i.e. it's generally just a waste of time), i've been experimenting with this for the last 8 or 9 months. I fix A LOT of Em's, and when i have a problem, my first reach is for the Dremel. And the bottom line is this... on coil contacts, IT'S USELESS. In every single case, it results in no change, or making the problem WORSE.

So why is this? here's where it gets complicated...

when a coil energizes, it's through some switch contact. In the above example, the score motor contact at 1A is pulsing four score reel coils, to get them to "zero". As a (30v or 50v) coil energizes, a magnetic field is created. When the power to the coil is removed, the coil collapses. When this happens, you get an EMF backflow of *twice* the energizing voltage. This is what creates though infamous "blue sparks" inside an EM game.

Note the blue sparks does not happen on light switch contacts. because that's only 6 volts, and it's really not a coil (it's a light bulb), you just don't get that. Also note this is an AC thing. On games that use DC, a coil diode can be implemented. This will stop the back flow and "blue spark" issue. But the number of EM games that use DC voltage is small (though a good deal of Williams/Bally games use DC on pop bumpers, only.)

Now that blue spark thing is important. It's a lot of energy. And the way these games are designed is that if there's a lot of current though the powering switch (either front flow or back flow.) The blue spark is so hot, it can actually deform or pit the switch contact. This is why Gottlieb used Tungsten contacts (instead of silver) on high contact switches. But it still happens, over time (and there's NO em that isn't at least 40 years old!), the coil voltage switch contact deform and wear.

No bring in the Dremel. What does it do? well basically it polishes the contact. But it doesn't fix pitting or deformed contacts. It just can't do it! It's a freaking wire brush!! That's why the dremel is USELESS on this type of switch contact. It may make you feel better, but it's accomplishing nothing beyond that. In fact, it can make things worse. It's easy to make the switch gap adjustment change, and it's also easy to knock off the nylon lifters (as used on score motors.) Basically you're creating more problems than you're solving.

So how do you actually fix the issue. A FILE. frankly i don't care what kind, but a FILE is the only solution. The pits need to be physically removed, and often, the contact re-shaped. A dremel isn't going to do that.

So now now back to light contacts. Why does the dremel work well there??
It's simple really. But let's make it a bit more informational...

In the case of a 6 volt switch, any sort of junk on that controlling switch can easily make a light not work. Look at voltage like water and a funnel. 6 volt switches are a small funnel with a small opening. any junk that falls into the funnel can easily block the output of the funnel. 30 or 50 volt switches on the other hand are larger funnels. It take more "crap" to clog the funnel output. (but when they do get clogged, you need a roto-router to fix it, not a tooth pick!)

The dremel/steel brush arrangement is really good at removing junk. It won't re-shape a contact or remove pitting, but on a light 6 volt switch contact, you don't need that. In fact, you don't want that! that's why the dremel is the ideal tool for this situation. A file can actually make switch contacts that control lights worse, because the contact points can be changed, causing additional problems.

To that point, the dremel does have other good uses. Like on Jones plugs (the male side.) It really does this well (and quick!)

Another thing... be aware that these steel brushes can be contaminated. So if you use the wire brush on say a circuit board, do not use it on an EM game! So buy a lot of brushes is what i'm saying, and don't be afraid to change them often. Otherwise you can bring contaminations from one situation, and spread them onto another game.

#18 6 years ago

I know the dremel is only cleaning contacts, not resurfacing like a file would. But it works on old contacts because, most of the time, that's all they need.

#19 6 years ago
Quoted from cfh:

Here's the skinny on the Dremel and why it's useless for coil voltage switches...
Before i explain the why and how, here's the data points.
Latest example: Gottlieb Mibs.
Problem: It was having a problem resetting the score reels. I could see it trying, the score reels would twitch. But not getting enough pulse strength to make the reels move.
Issue: score motor switch at 1A. This is on the lowest score motor position, and it's a large contact switch. It gets pulsed many times per rotation of the score motor. Switch adjustment was good, narrow gap (as i always do.) But clearly the switch was the issue. How do i know? If i put my big fat finger on the switch contacts, forcing them together with greater pressure, the score reels would easily reset.
This is a clear case of a problem switch. It was adjusted perfectly too, but clearly the contacts are dirty or damaged. So, like i do a lot, break out the dremel with a stainsteel wire brush. Clean the contacts. Re-adjust the contacts (because the wire brush activity always changes their gap.) Restart the game. THE PROBLEM IS WORSE. The twitching is gone, now there's NOTHING.
Fix: break out an automotive gap file and file the contacts. Restart the game. Works perfectly.
Now this isn't just some one-off thing. To prove to myself that the Dremel is only good for selected items (i.e. it's generally just a waste of time), i've been experimenting with this for the last 8 or 9 months. I fix A LOT of Em's, and when i have a problem, my first reach is for the Dremel. And the bottom line is this... on coil contacts, IT'S USELESS. In every single case, it results in no change, or making the problem WORSE.
So why is this? here's where it gets complicated...
when a coil energizes, it's through some switch contact. In the above example, the score motor contact at 1A is pulsing four score reel coils, to get them to "zero". As a (30v or 50v) coil energizes, a magnetic field is created. When the power to the coil is removed, the coil collapses. When this happens, you get an EMF backflow of *twice* the energizing voltage. This is what creates though infamous "blue sparks" inside an EM game.
Note the blue sparks does not happen on light switch contacts. because that's only 6 volts, and it's really not a coil (it's a light bulb), you just don't get that. Also note this is an AC thing. On games that use DC, a coil diode can be implemented. This will stop the back flow and "blue spark" issue. But the number of EM games that use DC voltage is small (though a good deal of Williams/Bally games use DC on pop bumpers, only.)
Now that blue spark thing is important. It's a lot of energy. And the way these games are designed is that if there's a lot of current though the powering switch (either front flow or back flow.) The blue spark is so hot, it can actually deform or pit the switch contact. This is why Gottlieb used Tungsten contacts (instead of silver) on high contact switches. But it still happens, over time (and there's NO em that isn't at least 40 years old!), the coil voltage switch contact deform and wear.
No bring in the Dremel. What does it do? well basically it polishes the contact. But it doesn't fix pitting or deformed contacts. It just can't do it! It's a freaking wire brush!! That's why the dremel is USELESS on this type of switch contact. It may make you feel better, but it's accomplishing nothing beyond that. In fact, it can make things worse. It's easy to make the switch gap adjustment change, and it's also easy to knock off the nylon lifters (as used on score motors.) Basically you're creating more problems than you're solving.
So how do you actually fix the issue. A FILE. frankly i don't care what kind, but a FILE is the only solution. The pits need to be physically removed, and often, the contact re-shaped. A dremel isn't going to do that.
So now now back to light contacts. Why does the dremel work well there??
It's simple really. But let's make it a bit more informational...
In the case of a 6 volt switch, any sort of junk on that controlling switch can easily make a light not work. Look at voltage like water and a funnel. 6 volt switches are a small funnel with a small opening. any junk that falls into the funnel can easily block the output of the funnel. 30 or 50 volt switches on the other hand are larger funnels. It take more "crap" to clog the funnel output. (but when they do get clogged, you need a roto-router to fix it, not a tooth pick!)
The dremel/steel brush arrangement is really good at removing junk. It won't re-shape a contact or remove pitting, but on a light 6 volt switch contact, you don't need that. In fact, you don't want that! that's why the dremel is the ideal tool for this situation. A file can actually make switch contacts that control lights worse, because the contact points can be changed, causing additional problems.
To that point, the dremel does have other good uses. Like on Jones plugs (the male side.) It really does this well (and quick!)
Another thing... be aware that these steel brushes can be contaminated. So if you use the wire brush on say a circuit board, do not use it on an EM game! So buy a lot of brushes is what i'm saying, and don't be afraid to change them often. Otherwise you can bring contaminations from one situation, and spread them onto another game.

Thanks for taking the time to write this - lots of info and I will consider what you wrote carefully.

#20 6 years ago
Quoted from cfh:

... and it's also easy to knock off the nylon lifters ...

Yeah what he said.

#21 6 years ago

I would think the effort to get the dremel near the contacts without deforming all the blades would be far more effort and time than simply using a file... which also has the benefit of ensuring the contacts are filed in a way so they sit properly against each other.

to use a file you rarely have to disassemble anything.

#22 6 years ago
Quoted from HowardR:

Yeah what he said.

yea that nylon lifter thing is a bitch. on Gottlieb's it's not so bad, you can buy new lifters from pinball resource. But on bally and williams EMs, the lifters are different. the hole in the blade is bigger, so you can't really use the Gottlieb lifters, the protruding nylon "tit" is too small to fit in bally or williams score motor switch blades! it sucks, because i don't have a source for bally or williams nylon lifters. this is why the dremel in bally or williams score motors is really just an accident waiting to happen...

#23 6 years ago

Anyone ever see if these guys will sell parts? http://www.relayserviceco.com

#24 6 years ago

I use Dremel 538. They clean the switch to look like new. They seem tougher than the metal brushes, clean just as fast and don't shed nearly as much. If they do shed, its not conductive metal! In some placed it is tough to get them in, so I use a flexstone. On really pitted contacts for a flipper I might use a file and then Dremel.

http://a.co/676j4Wo

#25 6 years ago

We all know Clay hates the Dremel. He prefers to sand things, and sometimes, sanding is the way to go. Like when high-current switch contacts become heavily pitted. But other times not... like using sandpaper to “clean” a bakelite full of rivets. Sure, it works, but it roughens up the rivet heads and flattens them out. Which isn’t ideal over the long-term.

Using the alcohol swab/Dremel 443 polish/swab process is a gentle, time-consuming technique which provides the opportunity to:

Examine for loose/floating contacts (filing will not)

Does not introduce any grit or sandpaper dust

Does not change the strike angle of the contact via sanding/reshaping

Does work very well

Encourages full rebuilding of the relay versus “clean and go”

My technique is more oriented towards restorers and hobbyists, which are the vast majority of the EM world today. Clay’s perspective comes from that of an operator who needs to get old games running ASAP. Both methods work... it just depends upon which approach you need.

Personally, whenever I encounter a pitted switch contact (which is uncommon... most switches are smooth/convex even after years of wear) I use a Dremel flapwheel to sand them smooth and then polish with the 443.

However, the notion that using a Dremel to polish contacts is somehow “useless” and “makes things worse” and the “only” solution is to “grind away with a file” is... well... simply not true.

If switch pitting is a problem, doesn’t it make more sense to leave a smooth polished contact behind instead of a filed-down rough surface?

I could also argue that filing can change the switch gaps and deform the contact face, depending upon the technique used.

Ultimately, it’s all about the technique and the end result.

#26 6 years ago
Quoted from dr_nybble:

Anyone ever see if these guys will sell parts? http://www.relayserviceco.com

Yes, they do. But the minimum orders mean only to PBR and the like. They used to sell to Bally, Williams etc. who bought for production and service parts which were then sold to distributors. Wico bought direct from them as they bought a lot.

#27 6 years ago

I like the Dremel, it's the way I've gone to most of my work. However, I will admit that it's mainly used when I'm restoring a game, because now I basically go through and disassemble and clean up virtually every relay in the game. For that, the Dremel is really a nice tool.

I understand the lifter issue, just take it slow and hopefully it will not happen. I think that's more likely than mangling a blade with it.

If I'm not doing that kind of a restore, I probably use the flexstone more because the Dremel is harder to use in close quarters. The Dremel is much better with motor boards/light boards/playfields out of the game and on the bench.

I will say I had an issue with a Royal Guard where I had problems with the 1000 point reel rolling over properly. I adjusted and filed all the related contacts and couldn't cure it. Finally I took the motor board out of the game and disassembled everything and used the Dremel. Cured.

I don't think either method should be the rule. There's often no one answer to a situation.

#28 6 years ago

I'd like to offer a little more background into the arcing part of this discussion for anyone who may want to understand why and when it happens.

Solenoids and coils work because passing an electric current through a conductor creates a magnetic field around the wire. When you wrap a wire into a coil the magnetic field from each loop gets combined and concentrated inside the loop which effectively forms a magnet that attracts the armature or plunger towards the center of the coil. (More info and video here: funwithpinball.com/learn/solenoids-relays-and-electromagnetism).

The magnetic field created by passing electric current through the coil is a form of stored energy analogous to the voltage stored in a capacitor. And just like a capacitor where the voltage can't change instantly (it needs to drain over a short period of time) the current through a coil of wire can't change instantly either. Think of the stored energy as a flywheel that can't be started or stopped instantly; you need to overcome its inertia.

When you open a switch that has been supplying current to a coil you open the circuit leaving the current through the coil with nowhere to go. Since the current through the coil can't change instantly, it continues to flow for a short time after the switch opens, effectively piling up charge or voltage on one side of the switch relative to the other side. This is called the back electromotive force (EMF). If enough current flows from the collapsing magnetic field in the coil to one side of the switch the voltage climbs to a point where it can break down and jump across the air gap of the switch causing the arcing and pitting in the contacts.

Air generally requires about 3000 volts per millimeter to break down and arc so the voltages required to arc across switch contacts are likely in the 1000s of volts. About the same as shuffling across a carpet and touching a metal object, BTW.

DC solenoids generally have a diode (which only conducts current in one direction) across their solder lugs to prevent arcing across the switch contacts, or inside the drivers on solid state games. The diode doesn't prevent the back EMF, it just provides a closed loop for the current to flow through when it does happen. The current flows from the coil through the diode and back through the coil until it eventually decays.

AC solenoids don't have diodes because the current changes direction constantly. A diode would provide a short circuit across the coil half the time. But AC coils don't arc every time a switch opens either. Since the current changes direction, the magnitude of the current decreases from the maximum in one direction to zero then increases to the maximum in the other direction before decreasing and going through zero again. If the switch happens to open when the current through the coil is close to zero, there won't be enough back EMF or accumulated voltage to arc across the switch.

/Mark

#29 6 years ago

I use a Flexstone file from PBR for the low voltage small contacts and a metal ignition file for the high current large contacts. After I either wipe down with alcohol and a cotton swab or if it is a tight clearance between contacts blowout with compressed air (can or compressor). For Steppers I use the green Scotchbrite pad, mean green (if super dirty) and alcohol and wipe with a paper towel. I don't do a lot of restorations or repairs like being on the clock, but if I did repairs for others then I would consider a Dremel in the arsenal as it is just another tool to help get a job done.

#30 6 years ago

I have not used the Dremel (yet) but respect those who do. An ignition file, 220 sandpaper or finer, a lot of alcohol - laden paper strips (I like to cut non-coated paper plates into strips) works for me, they all play without issue. I am extremely light-handed when using these, I am more concerned with cleaning then changing contact angles. Would worry about dislodging a soldered contact, even though I keep a bag of new replacements.
I purchased a new Dremel and like many started looking for ways to use it, maybe this is one.

#31 6 years ago

The dremel has its uses, but in my opinion, in the case of coil voltage contacts, it just makes people feel better and makes things *look* better. i've really been trying it in situations where i can actually prove the dremel/wheel technique makes a valuable difference. Again, in coil voltage switch, it's useless. It doesn't cut the cheese. But in the case of light voltage contacts, it's pretty damn awesome. And on male jones plugs too. light sockets it's great too. It has its uses, but it's not a silver bullet that some proclaim it to be.

We've been using it on stepper units too at the VFW. but frankly, i'm just not impressed. Almost always, after Brian goes over the steppers with the dremel, things still don't work. I almost always have to go back and use 400 grit sand paper to get things to work right. So we've just stopped using the Dremel on stepper units, because it accomplishes next to nothing, and we have to re-do the work (with more conventional tools.)

#32 6 years ago

As far as I know, there is not a single video on when/where/how to use the Dremel correctly on pins. Looking forward to viewing one someday

#33 6 years ago
Quoted from cfh:

We've been using it on stepper units too at the VFW. but frankly, i'm just not impressed. Almost always, after Brian goes over the steppers with the dremel, things still don't work. I almost always have to go back and use 400 grit sand paper to get things to work right. So we've just stopped using the Dremel on stepper units, because it accomplishes next to nothing, and we have to re-do the work (with more conventional tools.)

Mothers metal polish has typically worked great for me on the bakelite disc contacts on stepper units.

#34 6 years ago
Quoted from Tuna_Delight:

Mothers metal polish has typically worked great for me on the bakelite disk contacts on stepper units.

Ideal for Bally flat rivets especially!

#35 6 years ago
Quoted from NicoVolta:

We all know Clay hates the Dremel. He prefers to sand things, and sometimes, sanding is the way to go. Like when high-current switch contacts become heavily pitted. But other times not... like using sandpaper to “clean” a bakelite full of rivets. Sure, it works, but it roughens up the rivet heads and flattens them out. Which isn’t ideal over the long-term.

Green pad scotchBrite works well for these. No rough edges. Just cut into squtes.

Using the alcohol swab/Dremel 443 polish/swab process is a gentle, time-consuming technique which provides the opportunity to:
Examine for loose/floating contacts (filing will not)
Does not introduce any grit or sandpaper dust
Does not change the strike angle of the contact via sanding/reshaping
Does work very well
Encourages full rebuilding of the relay versus “clean and go”
My technique is more oriented towards restorers and hobbyists, which are the vast majority of the EM world today. Clay’s perspective comes from that of an operator who needs to get old games running ASAP. Both methods work... it just depends upon which approach you need.
Personally, whenever I encounter a pitted switch contact (which is uncommon... most switches are smooth/convex even after years of wear) I use a Dremel flapwheel to sand them smooth and then polish with the 443.
However, the notion that using a Dremel to polish contacts is somehow “useless” and “makes things worse” and the “only” solution is to “grind away with a file” is... well... simply not true.
If switch pitting is a problem, doesn’t it make more sense to leave a smooth polished contact behind instead of a filed-down rough surface?
I could also argue that filing can change the switch gaps and deform the contact face, depending upon the technique used.
Ultimately, it’s all about the technique and the end result.
Some are Pinball Ninja, and some are Pinball Jedi... but whichever your path may the Force of the Gleaming Contacts be with you.

#36 6 years ago

The bottom line, and a point that you guys seem to all be missing is this. For the last 40 to 80 years all these stepper units have done nothing but reshape themselves. All the stuff was designed for five year life cycle. Stepper rivets are not made of tungsten or hardened steel. They’re fairly soft. They’ve been reshaping themselves, all by themselves, throughout their history. So to think that you could just take a Dremel and clean them is just BS. It’s just not gonna work. These things need to be sanded. Otherwise you’re just propagating the problem that they’ve created all by themselves over the last zillion years

The dremel is a good tool for some things. But for a lot of things it’s just not the proper tool. And someone that thinks that the Dremel is a magic silver for every problem it’s just either inexperienced or in denial

#37 6 years ago
Quoted from cfh:

The bottom line, and a point that you guys seem to all be missing is this. For the last 40 to 80 years all these stepper units have done nothing but reshape themselves. All the stuff was designed for five year life cycle. Stepper rivets are not made of tungsten or hardened steel. They’re fairly soft. They’ve been reshaping themselves, all by themselves, throughout their history. So to think that you could just take a Dremel and clean them is just BS. It’s just not gonna work. These things need to be sanded. Otherwise you’re just propagating the problem that they’ve created all by themselves over the last zillion years
The dremel is a good tool for some things. But for a lot of things it’s just not the proper tool. And someone that thinks that the Dremel is a magic silver for every problem it’s just either inexperienced or in denial

Cool down Clay, it's just pinball dude.

#38 6 years ago
Quoted from cfh:

The bottom line, and a point that you guys seem to all be missing is this. For the last 40 to 80 years all these stepper units have done nothing but reshape themselves. All the stuff was designed for five year life cycle. Stepper rivets are not made of tungsten or hardened steel. They’re fairly soft. They’ve been reshaping themselves, all by themselves, throughout their history. So to think that you could just take a Dremel and clean them is just BS. It’s just not gonna work. These things need to be sanded. Otherwise you’re just propagating the problem that they’ve created all by themselves over the last zillion years
The dremel is a good tool for some things. But for a lot of things it’s just not the proper tool. And someone that thinks that the Dremel is a magic silver for every problem it’s just either inexperienced or in denial

Sanding rivets doesn't make sense unless they are in such horrible shape that they need the sharp worn edges smoothed off. Even then, it's a matter of sanding "to the round" rather than across the top. After which, I'll always follow with the 443 regardless for maximum smoothness.

Gottlieb rivets are truss head rivets. The rounded surface is supposed to facilitate smooth travel. The wipers are also rounded where they meet the rivet. The two rounded surfaces should thus glide up and down gracefully as the mechanism travels.

By sanding and roughening the surface, you are simultaneously increasing drag and creating an uneven glide path... which, in time, will lead to further degradation and wear across the rivets.

Now, if a rivet has a worn track within it, those must be sanded out or re-riveted. We don't want the wiper sticking in the groove. But this is uncommon to find.

I don't understand why polishing the rivets "isn't making the steppers work" for your volunteer crew. Perhaps the wipers and springs are not also being cleaned? Or the flexy-wire is creating tension?

Frankly, after hitting Gottlieb rivets with the 443 and adding a light swish of PBR grease, I have yet to see a single failure. I've taken the same game to at least two festivals at TPF and several tournaments in between and it still runs like a Swiss watch. One of hundreds I’ve rebuilt this way.

In general, I see sanding as a last resort. It is a destructive process which removes metal. Unless, as mentioned previously, it is to correct pitting or misshapen contacts/plunger wear... but this is more often the exception than the rule. Or, if there is simply no time to do anything else.

#39 6 years ago
Quoted from Tuna_Delight:

Mothers metal polish has typically worked great for me on the bakelite disc contacts on stepper units.

The Tim Meighan method -- I use it too! Works great.

#40 6 years ago
Quoted from goldenboy232:

The Tim Meighan method -- I use it too! Works great.

Tim Meighan has my full respect. His games play perfectly... he's also a meticulous rebuilder and it shows. Was great to meet him on the pinball tour.

Go to the next NWPAS if you can. He brings a lot of his personal EM's to the show and they play great!

#41 6 years ago
Quoted from NicoVolta:

Tim Meighan has my full respect. His games play perfectly... he's also a meticulous rebuilder and it shows. Was great to meet him on the pinball tour.
Go to the next NWPAS if you can. He brings a lot of his personal EM's to the show and they play great!

Man, his Top card is NICE!

#42 6 years ago

This is turning out to be a good thread with many experienced pinsiders chiming in. Even though not everyone agrees, I think it's through discussions like this that even better and more refined techniques emerge over time. Science works like this too so I have learned to appreciate disagreement more.

#43 6 years ago
Quoted from goldenboy232:

The Tim Meighan method -- I use it too! Works great.

Yep. In addition to Clay's guides and videos, I obtained the bulk of my EM repair and restoration knowledge from fellow-Seattleite Tim Meighan ("TimMe" on RGP and Pinside). Tim is a big proponent of the use of Dremel wire brushes and Mothers metal polish for cleaning switch contacts and metal components respectively.

That said though, I know that Tim would agree that, as has already been stated in this thread, there is no single correct method to properly clean EM components. Like the often touchy subject of how much lube to use in pinball games, there is no shortage of opinions on the matter as well.

#44 6 years ago

For those of you that use the Dremel, and assuming the bottom board is pulled from the cab, how do you go about cleaning all switches on the score motor?

#45 6 years ago
Quoted from spinal:

For those of you that use the Dremel, and assuming the bottom board is pulled from the cab, how do you go about cleaning all switches on the score motor?

On restorations, I typically disassemble the switch stacks and give the entire score motor unit a thorough cleaning as well as the switches (using a DREMEL wire brush on the latter).

If I'm only looking to clean selective score motor switches, I'll often resort to using a flexstone as a DREMEL brush can't access many score motor switches (on Gottliebs anyway) adequately without disassembling the stacks.

#46 6 years ago
Quoted from cfh:

The bottom line, and a point that you guys seem to all be missing is this.....

I stopped by the VFW this morning and caught Clay working on a stepper unit. He said he was in a hurry

Doug D.

Clay stepper a (resized).jpgClay stepper a (resized).jpg

#47 6 years ago

...and here's Blake touching up an AX-BX relay...

Blake stepper a (resized).jpgBlake stepper a (resized).jpg

#48 6 years ago
Quoted from nsduprr:

I stopped by the VFW this morning and caught Clay working on a stepper unit. He said he was in a hurry

Doug D.

Glad I wasn't drinking my coffee when I saw this. LOL!

#49 6 years ago
Quoted from Tuna_Delight:

Yep. In addition to Clay's guides and videos, I obtained the bulk of my EM repair and restoration knowledge from fellow-Seattleite Tim Meighan ("TimMe" on RGP and Pinside). Tim is a big proponent of the use of Dremel wire brushes and Mothers metal polish for cleaning switch contacts and metal components respectively.
That said though, I know that Tim would agree that, as has already been stated in this thread, there is no single correct method to properly clean EM components. Like the often touchy subject of how much lube to use in pinball games, there is no shortage of opinions on the matter as well.

As did I, when I lived there, Nico! Tim was gracious enough to take me under his wing (and into his workshop) when I was a newbie and taught me a ton. I loved the Northwest Pinball show when I lived there, and miss it. Hope to start coming to the Texas show next year.

#50 6 years ago
Quoted from dasvis:

Man, his Top card is NICE!

But the way he has it set up, it will kick you A$$ every time (at least for me). The one show I attended up there, I kept going back to Top Card all weekend. That, and someone's Big Shot!

To stay on topic. No dremel for me yet. No flex stones, no sand paper (400 grit seems awfully aggressive?)

Metal ignition file for all points. Dremel and flat grinding wheel discs to resurface tungsten points used on DC pop bumpers and flippers. Or disassembled and take to the bench grinder. Metal polishing pads (like 3M scotchbrite) for stepper boards and file again to resurface wiper blades (or replace if too far gone).

I already use Front line dry Teflon lube for other purposes and will start using it on stepers instead of the sticky super lube (finally running out of my MBI machine instrument lube). And will add Mothers to the arsenal too.

Oh, and I do pull out a piece of 1000 grit wet sand paper now and then (used dry).

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