Need a Jam Nut?
By Don Wiederhold
I needed a 1/2-13 jam nut, so I came up with the following method to quickly make one.
First, find a 1/2-13 bolt long enough so that when put in the lathe chuck the head of the bolt goes past the backside of chuck jaws. Set the protrusion of the bolt past the front of the jaws to the thickness you want the jam nut to be (Photo 1). In this case, I set it to 7/32".
Position your facing tool against the end of bolt. I preloaded and set my dial indicator to zero at this point. Place a 1/2-13 nut onto the bolt and start facing, until you reach the position you previously set on the indicator to mark the end of the bolt (Photo 2).
You can then take the nut and bolt out of the chuck as a unit and clamp in a vise for filing off the sharp edges. When finished, remove the nut from the bolt; put a countersink in your drill press; place a block of wood on the table; and, using a wrench to hold the nut, chamfer the faced off end of the threaded hole of the jam nut.
Finally, run a tap through the nut to remove any burrs.
I’ll leave it up to you to figure out how to make a left-handed jam nut!