The drive dogs look easy to make AkL , easier than modifying the ones you have.
You would just need some round steel , short lengths with the centre holes drilled on a lathe.
Then you could weld 4 short lengths of 1/4 Inch Square Key Stock to each round hub that was drilled or machined out.
Then you just cut the back of the dogs for the drive pin to lock into with a hacksaw or file or grinder.
I think a drill press could be used instead of a lathe to drill the centre holes but it would take longer as you would drill half way, after you centre punch the centre ,then drill the other side half way through to get the complete hole through.
Drill the centre hubs out with a smaller drill than needed first ,then if the holes in the centre don't line up perfectly use a round file to make a straight hole then drill all the way through with the correct size drill bit from one side.
I guess you could drill the centre holes without a drill press ,I've done it before but it takes a while to get a good centered hole.
