KFL+ & Positive Post Problems

[stimpy]

Posted this in another forum but I believe that forum to be pretty much dead and not visited, so posting here.

Bought a new KFL+ for my girlfriend today and took it completely apart to clean before building it. When starting to put everything back together, I screwed the center pin in through the bottom into the positive post but the positive post has free reign to spin to the left and right. Even worse, regardless of how much I screw the center pin in, the positive post can move up and down which creates a gap & play which halts the 510 connection.

I've even used a wrench to hold the positive post down just to make sure it's not 'moving up' as the center pin is being screwed into it and it makes zero difference. The positive post can still spin to the left and right and up and down (which moves the 510 connection up).

Not to complicate the issue, but I bought a Russian 91% months back and the same problem is happening with that one. I figured it was a defect and just tossed it in a drawer until I found the time to deal with it.

I'd expect the center pin to pull the positive post down as it screws into it and secure itself tightly but the opposite is being done.

What am I missing here? It's a brand new unit (both are) and the center pin has only been removed once on the KFL+ and has never been removed on the Russian 91%.

 

[crxess]

Seems obvious you are missing something, Just not sure what.
I have 7 units and have never run into this, much less twice.

Simple check:
Unscrew Center pin from pos. plate.
Set Pos. plate aside
Press firmly against Center pin and check that threading reaches BELOW the Deck.

Does it?
If yes, remove center pin and hand thread Pos. plate to it.
Does it thread fully down to thread stop?
If yes, get someone else to tighten it.

 

[vapdivrr]

maybe missing the plastic little insulator, this seats the end of the 510 center pin (the end near the threads) if this piece is missing the center pin doesn't have anything to pin against and will move upwards

 

[Clark F]

I ran into this problem, the positive pin threads were stripped even though it was purchased brand new. I ended up buying a fat daddy's rebuild kit to fix the issue. Hopefully that is not the problem with yours.

 

[RuinerXL]

Not sure if this is the issue, but when I first got my Russian 91% I had this same problem. It was because I didn't realize that there are several parts that make up the center pin assembly.

Per the above diagram, to get the positive post (13) to stop swinging, you need to remove the contact plate (19) and use a small flat-head screwdriver to tighten the center pin (18). Once you've removed the contact plate, you'll see the center pin has been machined to accept a flat-head.

If this is totally not your issue, I apologize in advance for the explanation, but I know this is exactly what I was missing when I first tried to assemble the R91.