Counterweights from barbell weights

This might be a sort of remix but I do not know where I got the original bolt. I expanded it and made extensive changes. The idea is to use a barbell weight (they are all a standard size) and reduce it so it fits on the counterweight shaft of a telescope. The nut screws down to hold the weight firmly while the bolts hold it to the counterweight shaft. The two given here are for a 13mm and 20mm shaft. (~1/2 and 3/4") It was originally made to fit on my Star Adventurer equatorial mount (13mm). There are 2 sizes, one is for 1 counterweight, an extended one with hold 2 counterweights. Pictures show them with 2.5 lb weights. The screw holes fit a 1/4x20 bolt.