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Flipper Assembly Basics

Jersey Jack Pinball·video·25m 13s·analyzed·Jan 15, 2019
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claude-haiku-4-5-20251001 · $0.020

TL;DR

Jersey Jack Pinball technical guide to flipper assembly adjustment, maintenance, and wear parts.

Summary

Butch P from Jersey Jack Pinball delivers an in-depth technical tutorial on flipper assembly adjustment, maintenance, and wear parts using The Wizard of Oz as a demonstration machine. The video covers end-of-stroke switch adjustment, flipper button cabinet switches, flipper bushing alignment, and common wear patterns that require periodic replacement or rebuild. Key emphasis is placed on proper gap settings, avoiding overtightening, electrical verification, and safety precautions when working on energized machines.

Key Claims

  • The coil in a pinball flipper assembly carries 70 volts across three lugs when power is on and the coin door is closed, posing electrical shock risk.

    high confidence · Butch P, safety section early in video

  • Leaf switch blades on end-of-stroke switches should be bent slightly outward as close to the attachment stack as possible to reduce stress and prevent blade snapping over time.

    high confidence · Butch P, detailed EOS adjustment section

  • Flipper bushings require a small gap to prevent binding; the flipper bat and shaft must have freedom of movement within the nylon bushing.

    high confidence · Butch P, bushing alignment section

  • The crank-to-shaft connection should never be tightened so tight that the gap completely closes, as this makes the piece a one-use item that cannot be re-tightened.

    high confidence · Butch P, crank tightening section

  • Worn flipper parts (coil stop, plunger/link assembly) develop mushrooming and dimpling that creates resistance and weak flippers.

    high confidence · Butch P, wear parts section with visual comparison

  • Williams flipper rebuild kits are compatible with Jersey Jack pinball machines and can be purchased online from multiple retailers.

    medium confidence · Butch P, flipper rebuild section

  • Loose nut connections on the elbow joint cause wear that makes the joint oblong and creates significant play, weakening the flipper.

    high confidence · Butch P, wear analysis of elbow joint with visual demonstration

  • The Wizard of Oz has multiple flipper assemblies throughout the underside of the playfield.

    high confidence · Butch P, opening statement about the game

Notable Quotes

  • “so when you touch those you will know it whether it be your knuckle or your finger or someone bystander just helping you something like that they're going to know it if they touch those lugs those are energized”

    Butch P@ 2:06 — Critical safety warning about high voltage in flipper coils

  • “The Flipper is a very violent assembly and if this actuator has to really push those blades a long ways to make contact if this one were straight out it would get pushed and bent severely each time the flipper kicked”

    Butch P@ 5:10 — Explains the mechanical engineering rationale for slight blade outward bend

  • “you do not want to overtighten this to the point where that Gap completely closes if it does you'll have a tight flipper for this one time if you ever take it Loose you will not be able to get it tight enough to hold that shaft in place anymore you'll have basically made this into a one use piece”

    Butch P@ 12:17 — Critical warning about permanent damage from overtightening

  • “it makes a sound when it closes and it makes a sound when it opens”

    Butch P@ 6:05 — Describes audible feedback in switch test mode for verification

  • “this becomes kind of difficult to pull out of the end of the coil because uh it catches on the coil sleeve because this lip here sticks out so far”

    Butch P@ 19:32 — Explains how wear creates mechanical resistance and weak flippers

Entities

Butch PpersonJersey Jack PinballcompanyThe Wizard of OzgameWilliamscompanyMarcocompany

Signals

  • ?

    content_signal: Jersey Jack Pinball launching a video series on pinball machine mechanics and adjustment, with flipper assemblies as the first installment.

    high · Butch P: 'I figured we needed a series of videos to look in detail at the way some of these things work' and 'this is the first in a series of videos'

  • ?

    design_philosophy: Jersey Jack Pinball emphasizes precision adjustment and understanding of wear mechanics in flipper design; prioritizes proper gap settings and stress reduction in component lifecycles.

    high · Detailed discussion of why leaf blades must be bent slightly outward, how play prevents binding, and the engineering trade-offs in tightness vs. reusability

  • ?

    restoration_signal: Video provides detailed guidance on flipper rebuild kits, wear part identification, and periodic maintenance intervals for collectors and operators.

    high · Comprehensive section on wear parts (coil stop, plunger/link, bushings, rubber rings) with before/after comparisons and rebuild kit references

  • ?

    operational_signal: Loose fasteners (nuts, cap screws) and wear on elbow joints are identified as common failure modes that degrade flipper performance over time.

    high · Butch P highlights eight mounting screws, EOS switch screws, coil stop cap screws, and three bushing nuts as maintenance checkpoints; demonstrates how loose nut causes elbow joint oblong wear

  • ?

    technology_signal: Williams flipper adjustment tool remains a standard for setting flipper bushing gap; new versions available from Marco and at shows.

Topics

Flipper assembly adjustment and maintenanceprimaryEnd-of-stroke (EOS) switch alignmentprimaryFlipper button cabinet switch configurationprimaryFlipper bushing and shaft binding preventionprimaryWear parts identification and replacementprimaryFlipper rebuild kits and componentsprimaryElectrical safety on energized machinessecondaryMechanical tools and adjustment techniquessecondary

Sentiment

neutral(0.5)— Educational and instructional tone throughout. Butch P is professional, methodical, and focused on technical accuracy and safety. No apparent bias or emotional content — purely technical documentation.

Transcript

youtube_auto_sub · $0.000

0:12
[Music] hey pinball fans Butch p with Jersey Jack pinball so many interesting things going on underneath a pinball machine Playfield I figured we needed a series of videos to look in detail at the way some of these things work things that we can do to adjust them to align them to make them work properly and things that we need to keep an eye on and uh watch out for wear on so that we can replace them and keep them working at their best this is the first in a series of videos to that effect and we're going to look at flipper assemblies today of which on The Wizard of Oz there are quite a few
0:44
The Wizard of Oz there are quite a few of them they pretty much everywhere under this Playfield so if you're ready let's get going here's a right flipper assembly demonstration device that I put together using plexiglass it's completely wired into my Wizard of Oz pinball machine with the coil end of stroke switch and flipper cabinet switch so it's fully functional as I said this is a right flipper assembly the difference between a left flipper and a right flipper
1:14
a left flipper and a right flipper basically there's two parts The Flipper base plate itself is configured just a little bit differently so there's a right base and there's a left base there's also a right crank and a left crank if you notice this piece piece here and here that is just reversed basically the arm comes off the other side and of course this screw and this uh bolt or put in backwards with the uh return spring holder there on the
1:45

medium · Butch P: 'there is a tool that used to come in a Williams goodie bag in the bottom of their cabinet uh you can find these at shows and on their junk tables or I think even Marco sells new ones on their website'

  • ?

    product_concern: Flipper assemblies experience predictable wear patterns (mushrooming coil stops, oblong elbow joints, heat shrink tubing wear, rubber ring deterioration) that require periodic replacement.

    high · Detailed visual comparison of new vs. worn parts; specific wear failure modes documented with examples

    • the uh return spring holder there on the opposite side also a quick word of caution when dealing with flipper assemblies if You' got the power on in the game and you're underneath the Playfield and you've got your coin door closed the coil is energized and that means these three lugs here all have 70 volts across them so when you touch those you will know it whether it be your knuckle or your finger or someone bystander just helping you something like that they're going to know it if they touch those lugs those
    2:15
    know it if they touch those lugs those are energized however our switches are low low voltage so the flipper switch there the end of stroke switch those aren't going to hurt you at all you just have to watch out for the lugs on the coil and there is a interlock switch on the corn door so that when it's open it disables high voltage underneath the Playfield so all three of those lugs will be disabled however it's just a better idea if you're not needing to use power to test what's under the Playfield
    2:47
    power to test what's under the Playfield you don't need to test it under power it's just better to work on the game under the Playfield with the power on the game turned off so just keep that in mind the first adjustment point on a flipper s mbly is the end of stroke switch that's this switch here that lies alongside the coil using a switch adjustment tool I like to bend both Blades of an endo stroke switch slightly outward away from the actuator you can see when I push the plunger in that the actuator is what
    3:19
    plunger in that the actuator is what actually closes the end of stroke switch I want it to not only touch right at the end but I want it to follow through and push that back blade that way just a little little bit I want to make sure that it makes a good connection so the way that I bend those blades outward with my adjustment tool the end of stroke switch is basically a leaf switch so Leaf switches we always bend the blades as close to the stack as possible as close to this point where
    3:50
    possible as close to this point where they attach these little uh screws as possible so I'm going to take my adjustment tool and I'm going to put it on the very end here and I'm I'm going to bend gently Bend each of these blades outward and I'm going to leave a small Gap in between there so that when my flipper kicks it closes the Gap and makes the switch the switch is normally open so the blades cannot touch one another until that end of stroke is reached I can check the adjustment with
    4:21
    reached I can check the adjustment with my hand by pushing on the end of this plunger here I don't want to push on the back here of this elbow because there's play in this joint and there's play in this joint that will mess up my adjustment so I just want to pull the plunger itself into the coil like so and push it until it hits the coil stop at the opposite end so the end of the plunger hits the opposite end of the coil stop over here and make sure that my switch makes and follows through just a little
    4:53
    makes and follows through just a little bit as that plunger hits the coil stop the reason I like to bend those Leaf blades just a little bit The Flipper is a very violent assembly and if this actuator has to really push those blades a long ways to make contact if this one were straight out it would get pushed and bent severely each time the flipper kicked whereas now I've got it bent back
    5:24
    kicked whereas now I've got it bent back a little bit it only travels a short distance and it's kind of already bent in that direction so that it's easier on that blade less chance of it snapping off over time so my final check with the Ender stroke switches is an electrical check to make sure that everything's making contact and that the computer inside the game recognizes that switch opening and closing so I've got the game set up in its dedicated switch test mode so when
    5:54
    its dedicated switch test mode so when these dedicated switches like the Ender stroke switch are made I'll hear the the game make a sound so it makes a sound when it closes and it makes a sound when it [Applause] opens and I can check it switch now makes sure that the Ender stroke switch is capable of doing what it's supposed to do in the game telling
    6:26
    it's supposed to do in the game telling the game that the flipper is indeed at the end of its stroke there's an adjustment to the cabinet flipper switches inside the cabinet you lift your play field up as I've done here in my wizard of O game and you see this is a double flipper switch it has two sets of contacts so the inner one activates the lower flipper and the outer one activates the upper flipper so I can do them independently I can flip each flipper independently or a quick push of the
    6:58
    independently or a quick push of the button flips them both simultaneously you want to keep a gap kind of like I've shown here between them make them equidistant this innermost blade you want to keep a little outward bend on it so that it pushes The Flipper button back out when we look at the flipper cabinet switch from another perspective inside the cabinet you see that it's not near as simple a leaf switch as was the end of stroke switch with the flipper assembly this one's a a little bit more
    7:30
    assembly this one's a a little bit more complex so it has two contacts two blades on the inner part for actuating the lower flipper like I said and two blades on the opposite side for actuating the upper flipper and they're separated by a piece of what we call fish paper it's an insulating material so when I want to close the gap for the lower flipper I'm also going to have to bend the one contact blade for the upper flipper at the same time in other words
    8:00
    flipper at the same time in other words all three of those pieces will be bent at the same time to close that gap for the lower flipper and the outer blade has a stiffener on it which basically pushes the blade inward or allows it to come outward as I bend this see how it follows the stiffener I'm not bending the blade I'm just pulling on the stiffener here so I can use my switch adjuster tool there and I can bend the stiffener to close that Gap or open that Gap a little bit and I'm
    8:32
    or open that Gap a little bit and I'm able to do that because this blade here has good positive pressure against that stiffener it wants to follow it it's pushing against the stiffener so the stiffener then controls the exact gap for it and that's how you adjust for the upper flipper this is what a flipper bushing looks like it's a nylon piece that goes through the flipper base plate you can see it there in my assembly through the base plate all the way up through the Playfield and the shaft of The Flipper
    9:03
    Playfield and the shaft of The Flipper bat rides inside the hole and goes completely through the play field and into the assembly underneath and it's tightened with this nut on here to hold the shaft of The Flipper now it's really important that the flipper bat and the shaft of the bat in particular does not get Bound in any way no binding is going on so there's a little bit of a gap in here here you see when you turn the flipper kind of partially between halfway in between its
    9:35
    partially between halfway in between its end of stroke and where it lies in its normal State you should be able to move it up and down inside that flipper bushing with a little bit of play and that makes sure that the flipper bat does not bind if you don't have this little bit of play in there your flipper bat will set on top of this nylon here and the bottom part of the bat will actually start grabbing the nylon here as it tries to flip and it'll make for a very weak flipper and of course the amount of play
    10:07
    flipper and of course the amount of play you have between the bottom of your flipper bat and the top of that flipper bushing is defined by where you mount the crank portion of the flipper assembly underneath on the shaft of The Flipper bat so this goes up and down if you get it too close to there and you get this too tight The Flipper will bind the exact amount of play in this flipper bat is not really a critical thing it's just important that it have a gap in
    10:38
    just important that it have a gap in there and that you have freedom of movement for that flipper there is a tool that used to come in a Williams goodie bag in the bottom of their cabinet uh you can find these at shows and on their junk tables or I think even Marco sells new ones on their website but this is a flipper adjustment tool and it's used to kind of make make that Gap a little more predictable for you so to use this tool you just put the cut out here around the shaft of The Flipper
    11:09
    Flipper bat align it like so and make sure that it's all the way around and it provides your Gap now then you lift your play field up and now you tighten the crank down where there's basically no play at all it's right against the bottom of the flipper bushing there and when you're finished bring your play field back up you pull out the tool and now it created The Gap that you need to keep your flipper from
    11:40
    flipper from binding one last note when you're attaching the crank to the shaft of The Flipper B I'm going show you a brand new piece here you see the Gap in between here where these two pieces this nut pulls these together this Gap will close as you this tightens around the shaft of The Flipper now I'm going to zoom in on on the assembly here so you can get a better look at it that's a fully tightened one so the Gap close quite a bit you do not want to overtighten this
    12:10
    bit you do not want to overtighten this to the point where that Gap completely closes if it does you'll have a tight flipper for this one time if you ever take it Loose you will not be able to get it tight enough to hold that shaft in place anymore you'll have basically made this into a one use piece you don't want to do that so always when you're tightening crank onto the shaft tighten a little bit check it on the top make sure maybe even play a game and see if the flipper moves when you when you're playing the game and and adjust where its rest position is it it comes up in a
    12:41
    its rest position is it it comes up in a different spot each time if it does that you pull it back to where you need it to be align it again and then you tighten it a little bit more and try it again tighten a little bit more but do not overtighten this don't ever close that Gap all the way the last flipper adjustment or alignment to be more specific and this is done in conjunction with tightening the cranks onto the shafts of The Flipper bats underneath the Playfield is to align your flipper bats with the return guides here on either side so
    13:12
    return guides here on either side so that the ball rolls smoothly off of the guide onto the flipper and you can also use these little holes that are pre-drilled in the Playfield as reference points so if I line one of these up and set it to where the hole is just on the inside of the flipper B I want to do the exact same thing on the opposite side so that when I'm finished with my alignment and tightening my flippers down my flippers appear symmetrical to one another in the rest position and in the fully extended or kick position they still look
    13:43
    kick position they still look symmetrical so the way I accomplish this is I get my Gap set up so that my flipper bat does not bind I set that up with the small Gap that I showed you earlier and I tighten things down pretty snug not completely tight cuz I still want to be able to rotate the flipper bat on the shaft underneath so I can align it properly with you know how I want it to look on the play field so once I get it aligned properly I tighten it down really good and tight and then I
    14:14
    it down really good and tight and then I play games and check and make sure that when it flips up it flips to that normal position and it returns where I want it if it's not tight enough that flipper battle work its way down each time I flip it and that means I just need to readjust it and tighten it again things you want to check periodically to make sure they're tight are all the screws that hold the mechanism to the underside of the play field there's eight of them on this flipper assembly want to make sure that your Endo stroke
    14:44
    want to make sure that your Endo stroke switch stays tight so these two screws are tight you want to make sure this screw there's a nut underneath here and this cap screw right here can work its way loose sometimes it's really hard on that elbow joint when it gets Lo loose so you should not be able to turn that with your hand it should be tight all the time there are also two screws cap screws holding in the coil stop those should be tight really tight all the time and the two screws holding the coil
    15:14
    time and the two screws holding the coil in place these Phillips should be tight in addition to the three screws that hold the flipper bushing this big white plastic Circle here in place from above the plexiglass allows you to see the three nuts that are used on the opposite ends of those three screws that hold this flipper bushing in place so the flipper bushing goes through in this direction from underneath the Playfield connects to the opposite side of that flipper base plate
    15:45
    opposite side of that flipper base plate with three Philips head screws that go clear through the BL base plate and then have these three nuts attached to them those three nuts there sometimes will make their way loose also and you'll find them in the the bottom of your cabinet what you'll have to do is pull the flipper Mech completely off the bottom of the play field put the screws uh back into the nuts tighten everything securely and then put it all back together again last thing I want to talk about is wear Parts on a flipper parts that are
    16:16
    wear Parts on a flipper parts that are going to wear out need to be replaced you'll need to check periodically to make sure your flipper is working the best it can I'm going zoom in a little bit here first of all is the flipper
    17:31
    it has a lot of play in it and you can tell that this has been broken needs to be replaced a lot of times people replace these when they're rebuilding flippers and and changing out parches because they get kind of gunked Up Down in the Hole there a lot of lot of black suot things like that get down into this uh hole and kind of uh inhibit the shaft of The Flipper from turning inside there so a good clean set of these every time you rebuild your flippers will keep that from from happening also when I say flipper rebuild the typical
    18:02
    when I say flipper rebuild the typical Parts in a flipper rebuild are the crank and Paul assembly here and the plunger and Link this whole piece the uh coil stop will get worn and end of stroke switch and and spring those are the kind of things that normally come in a in a flipper rebuild kit and you can buy Williams flipper rebuild kits online at many places those those will work just fine for Jersey ja pinballs so the main physical wear type Parts on The Flipper mechanism are the
    18:33
    Parts on The Flipper mechanism are the coil stop here that's fits back in the back there holds the back of the coil in place and the Paul and crank flipper plunger and Link assembly this entire piece right here and that's the part that that sits inside the flipper coil and what happens when the flipper flips is this plunger smashes into the the coil stop like so over and over again when The Flipper reaches its end of
    19:09
    stroke so if we look in detail at these main wear Parts on The Flipper you see here's brand new parts in the foreground and in the background are worn parts so the coil stop starts off nice and smooth and round and flat as it wears it gets a dimple in it like that it gets mushro shroomed out and this becomes kind of difficult to pull out of the end of the coil because uh it catches on the coil sleeve because this lip here sticks out so
    19:45
    far the plunger and Link when they're smacking into that they have the same problem nice and beveled on a brand new piece very flat mushroomed out on a worn one so this lip again starts to catch on the coil sleeve that sits inside the coil and any resistance to that plunger moving in and out translates into weak coil and weak flipper so remember when I made the note about keeping this cap screw and nut
    20:18
    about keeping this cap screw and nut pretty tight here making sure that that stays nice and tight that becomes really important because when that nut gets loose it causes wear in this elbow joint right here so if I look at a new piece right here and I can check out its play in it it's pretty tight it doesn't have much play in it a worn piece however at this joint right here has all kinds of play look at all that movement all that movement then keeps
    20:49
    movement all that movement then keeps this elbow from doing its job which is just to make that turn there if it has play in it it takes away from my flipper strength so I've loosened this up a bit to kind of show you what's actually causing this loose joint here and what the wear looks like so we have a cap screw that goes all the way through inside here now is a little metal
    21:25
    bushing and just fell out there so this little metal bushing rides inside this hole right right here and the screw actually goes through the center of that to hold it all together but you see all the play in there that's from the wear this hole here should be round not oblong like that and the same thing can occur with this hole it can develop a little bit of wear in there and become oblong also the two of them combin to make for a very very weak flipper combined of course with this rubbing on
    21:56
    combined of course with this rubbing on the inside of your coil sleeve resisting the plunger wanting to go inside the weakness in the elbows can make for a very weak flipper so you need to replace these parts periodically they are wear Parts other parts that can wear on that crank if you look at where the heat shrink tubing here makes contact this arm makes contact with the end of stroke switch that constant rubbing on that blade tends to make the heat shrink tubing wear and makes a place here where
    22:29
    tubing wear and makes a place here where now if this can start peeling up just a little bit it can catch on the end of stroke and stick your flipper in the up position all the time to where it doesn't want to go to its rest position it's hung up on that Ender stroke switch blade so you just basically pull this off you can replace that with a/ qu in piece of heat shrink tubing just cut to length and heat shrink it back onto there that's good to go again if you look at the other side of this where the spring that pulls the flipper back to its rest position hooks in the return spring it can actually
    23:02
    in the return spring it can actually wear into the metal there and cause that metal to fail and the loop will then pull out the other end that is that happens time to time you can replace just this single part here or as I said earlier we just kind of replaced the whole uh flipper paw plunger and Link assembly crank all that stuff spring as part of a rebuild kit periodically when we notice our flippers are getting weak last but certainly not least when it comes to wear Parts on the top side of the Playfield are the flipper bat
    23:33
    of the Playfield are the flipper bat itself and the rubber ring that go on it the flipper bats can crack from time to time a flipper is a very violent assembly as I mentioned before the metal ball steel ball is smashing into this flipper bat all the time so the bat is plastic metal versus plastic you know it's going to win that battle so you can replace the entire bat and shaft assembly and go through all the steps we went through earlier in the video to replace that can also change the color
    24:03
    replace that can also change the color of your flipper bats they come in a variety of colors so you can change it and make your game look the way you want it to look same thing with the flipper rubber rings there's a variety of styles and colors and and uh different types of rubber rings that can go on a a flipper bat and uh make it look the way you want it in your game they will wear the rubber rings from over a period of time as uh the ball hits the tip especially here when you're trying to make saves and the ball going down the middle the rubber ring will wear here at the edge
    24:34
    rubber ring will wear here at the edge and you'll need to replace that from time to time keeping them clean though and the black stuff off of them will will make them last a lot longer in your games well I won't say that's all I know about flippers but it's getting pretty close so until we meet again in the next video keep on Flipping go challenge one of your friends to a great game of pinball take care guys [Music]