Been browsing eBay for awhile for these things now and they are surprisingly expensive. I was mocking up a bar riser in front of one of my friends using a socket and was pleasantly surprised with how it looked. So I went ahead and made them permanent.
What you need:
(2) 1/2 Drive deep socket (must be 1/2 for the center bore of the socket to fit the bolts) (I used a 5/8 socket, 1/2 drive)
(2) 3/8 x 6inch Bolt from your local hardware store
(2) 3/8 Lock washers
(2) 3/8 Nuts
I first tried a 5/8 socket for a 3/8 drive but the hole wasnt big enough to feed the bolt through. It was even tougher to drill it since it is hardened steel. So I went back to the store and bought 2 half inch drive sockets and they worked out good
Total material cost me about $15. Your going to want to make sure your sockets dont have much lettering or designs on them, because we'll be cutting them off.
A mockup making sure everything fits like it is supposed to.
Built a homemade lathe. Make sure its secure.
I taped off the socket to protect from any damage if the blade slipped. I used a regular hacksaw blade with the socket spinning against the teeth. Use it near the edges of the blade where regular sawing doesnt wear it.
Also, note how Ive used the notch already cut into the socket as a starter. It will be very difficult to break through the chrome and hardened steal so just be careful and have patience.
The socket I used makes you cut through the thicket part of the whole unit...
Hopefully you will get a nice clean cut and not need to do much grinding.
Repeat with the other socket, assemble enjoy.