Polish Underfolder Flat

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The Polish Underfolder is the most popular underfolder parts kit and this was the first specialty flat that I had perfected by modifying existing flats in 2004.  Now they are stamped out specifically for the Polish Underfolder from raw steel.

  • Receiver flat thickness= 1mm (.040") 
  • Material 4130 Annealed
  • Comes with bolt guide rails
  • Rails and flat need to be heat treated after bending

Reccomended rivets and center support (not included with flat)

  • AKS Underfolder Rivet Set
  • 1mm Center Support

To use these flats you will need to have a 5mm and 7mm reamer.  The physics of bending sheet metal make it next to impossible to have a bend close to a hole without distorting.  To solve this the holes on the flat are undersized and need to be reamed to size after bending.  Look at the receiver flat instruction page to see more info.

The rails that will come with the flats are pictured below. They have mag stabilizers on both rails to keep the mag from tilting and causing feed problems.  Before installing the rails you will need to trim the mag stabilizers to match the caliber of flat you are using.




This item is made in the United States and counts as a 922r compliant part.

AK flats are not legal to ship to California, Colorado, Connecticut, Delaware, District of Columbia, Hawaii, Illinois, Maryland, Massachusetts, Nevada, New Jersey, New York, Oregon, Rhode Island, Vermont, or Washington.

Customers who live in the above referenced states, who order restricted items online that are ineligible to be shipped to them, will have their order refunded, less a 20% credit card refund processing fee.

Premium Flat Options:
With Y & I Embossing
Receiver Thickness:

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