Drawer parts

The part I need looks like a tack glide, but the one I need screws in. It's made of hard plastic shaped like a disc with hole for a screw or thick plastic washer which allows the edges of the drawer to sit on top of for easy open and close gliding.
I need a replacement due to the ones intact are worn out and cracked. The drawer does not use a roller runner in its rails; it just slides on the rail that is attached to the table inside the middle and under the middle of the drawer, not the sides.
I'm not too sure the tack glides would work since the holes already there made by the screws are huge. Could there be another part that your company carries that are comparable to the tack glide but with a screw?