I wanted to put an inexpensive drill chuck on a Harbor Freight angle grinder. The grinder has a standard 5/8"-11 male thread and most drill chucks are 1/2"-20 female thread, so one would think there would be numerous inexpensive adapters? I could find none on Amazon. I certainly did not want to spend $50 for an adapter to put a $10 drill chuck on a $10 angle grinder. I found these adapters, two for $10 and figured I could alter them as far as threads because half of the adapter threads was already there. Actually it was quite easy I chucked up the adapter in my lathe turned down the male 14 mm to a 1/2" , then ran the turned down portion into a 1/2"-20 die. Already had the fir 5r thatbut they can be purchased on Amazon for about 10 bucks delivered. The adapter fit the angle grinder perfectly and also the 1/2"-20 was ideal for the drill chuck. So just a little effort I ended up with an adapter for $5. No I have another adapter I could use for 14 mm or alter that for another half inch or something else like 10mm.