I thought I would just show this, I use this for my draw bar on my RF30 mill. Used it now for about 12 years.
The brass adds weight and also stops too much damage to the draw bar hex end.
Used to give it sharp tap.

This gives an idea of the size, and how I made it. The plain handle shaft is 12 mm dia, the knurled part is 20mm dia. The handle was made in two pieces just screwed and ‘loctited’ together. The plain part is screwed into the head.
The brass bit is 29mm dia x 30mm long
The draw bar is also about 12 years old, and has been “whacked” quite a few times.
   

The brass bit is drilled and tapped to accept a standard long grub screw which was loctited to the head.
   

The standard ½” drive socket (19mm in my case) required a ½” square drive milled on to the head part.
The socket is held in place by a shaped washer and screw. This just stops the socket falling off.
   
   

This shows the damage to the brass bit, after twelve years there is going to be some.
   

I also made one for the Sherline mill, quite a bit smaller.
   
   

Made in a similar way except the square end is 3/8” and purchased. The reason to purchase it was for the “holding ball” so that I could use different size sockets. On the Sherline I use English and metric size draw bars.
   


DaveH