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tiff_lee

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Ok brains trust, looking for any ideas/feedback as how to best restore the friction mechanism for the punch pads.

I intend to knock up a project thread documenting this cab when i'm all done (currently trying some stuff out with other motors/gearboxes) but apart from the audible noise from the 573 (thread plug >> https://www.arcade-projects.com/thr...noise-once-game-has-booted-initialised.21279/ ) this mechanism is the last problem I don't have a solution for yet.

Ok picture time:-

Here is one complete punch pad mechanism, motor, gearbox and pad. Not going too much into the motor/gearbox stuff as that will be covered later.

PWnhZM8.jpg


There is a potentiometer mounted on the top which is coupled to the pad via the two gear wheels. This provides pad position feedback via the security cart of all things.

nQ6tck2.jpg


There is a small DC motor and reduction gearbox which has a square drive on the output shaft that interfaces with a carbon/graphite/<something> slip ring in-between the two metal faces. Tension is applied via the springs pulling the bottom face up towards the other.

ZT2eG8i.jpg

h8N5wvE.jpg

Jj5JkeV.jpg


So in order to drive the pads out the (motor/gearbox) carbon ring rotates and the friction between this and the metal plates cause them to also rotate thus moving the pad out.
When the pad is struck this force overcomes the friction and the metal plates slip on the carbon ring allowing the pad to go back in even if the carbon ring is still trying to drive them out.

Given what IMO is the low height of the machine the top pads are perfectly placed as if you were actually throwing a jab at someone, while the bottom pads are somewhat awkward to punch as I find myself punching down at an angle. This is actually reflected in the state of the friction mechanisms as the top pads have next to no friction and are very slow to move out (the notion being these have been subject to the most abuse) , the bottom ones operate pretty much perfectly and the middle pads are well, in the middle both physically and functionally.

Friction plates of the top pad
FzNIjIw.jpg


Friction plates of the bottom pad
LAtIGoh.jpg


So while both worn you can clearly see there is more wear on the top mechanism than the bottom one and in operation it is certainly noticeable as the top pads are slow to respond (excessive slip due to the wear). When moving the pads by hand you can hear this in action, the bottom mechanism will actually all turn together (pad and gearbox) where as the top one just slips.

Quick vid here
View: https://www.youtube.com/watch?v=27QOUSAuFaA&ab_channel=lee3r24

I'm not sure what the finish on those plates actually is, some kind of electroplating?

The only real wear is the polished finished, there is no ridges or anything, however having them refaced isn't an issue (machining/blasting/sanding etc). For example, I was thinking of something along the lines of roughing the face up with say 600/800/<insert grade here> to remove that polished finish and then have the face re-plated (again no idea what with).

Curious to hear any other ideas, cheers.
 
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GeeDee

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I wish I had some advice to give, though this is still on my grail list myself lol. However, pinging @Cereth since maybe they would have some wisdom? I remember watching some semi-recent video of theirs talking about their punch mania cab(s?), and vaguely remember them talking about having to replace/work on the pads since they take such a literal beating at conventions.

Good luck!
 

tiff_lee

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though this is still on my grail list myself
haha I was the same, as soon as I saw this for sale I jumped on it even if it was $$$$$ you rarely see these out in the wild. Yeah the red focus pads almost feel hollow if you squeeze them as the core has been wrecked through 2 decades of abuse.
 

Cereth

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I haven't really messed with anything quite as delicate as this yet, as my next project for it is simply replacing the pads with ones that aren't chewed up. Quite a ways out on getting into anything that specific. I know someone else who has one who might know better, but don't remember what their screenname here is
 

tiff_lee

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I haven't really messed with anything quite as delicate as this yet, as my next project for it is simply replacing the pads with ones that aren't chewed up. Quite a ways out on getting into anything that specific. I know someone else who has one who might know better, but don't remember what their screenname here is
Have you got a spare set of pads lined up? I haven't even bothered looking for replacements I just assumed they are all going to be flogged out. I was considering going to an auto trimmers or some such and seeing if it was possible to have a leather skin/cover made like on a proper focus pad that I could slip over the top, which would also then open the door to putting new foam inside.

Looks like Plan A it is, i'll head over to see some electroplating people and see what they make of the parts.
 

tiff_lee

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Ok so dropped by an electroplating place today and the guy reckoned the coating was black zinc. After dipping it in some hydrochloric acid the coating came straight off

mpnLIMM.jpg


Upon closer inspection though there does appear to be some wear on the face itself. I'm not entirely sure if it's by design or just a by-product of where the cutting tool has been drawn across the face (like on a lathe) but there are grooves on the face which have pretty much been worn flat.

Edit: Ok just spoke to my mate who is a machinist and he said it's called a 'gramophone finish'

XNHDgMS.jpg


a closer look

EZX88yW.jpg
 
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