Bronze Lead Screw Spindle Nuts. These metric acme spindle nuts move the backgauge sledge on many of the larger size Polar guillotine paper cutters, such as on some of the Polar 115, Polar 137, and Polar 155 paper cutters. (fixed side nut Polar part number 233573 and spring side nut Polar part number 234824) Original Polar part number 055510 for the set, or ZA3.055510.
They are sold as a pair. The price is for one pair, including the Buna-N O-ring.
For reference, these fit on the leadscrew with an outside diameter of 40 mm. Both nuts fit in the 60 mm diameter bore, in the front and back side, of the backgauge sledge. The moving sliding one on the front side (spring side) is 81 mm long. The stationary or fixed one on the back side (fixed nut) is 65 mm long.