I have a small 110v MIG welder and it didn't come with any adapters to hold a 10 lb spool. When I got the adapter put together and mounted the 10 lb spool, I realized why no adapters came with it. It was only designed to hold one and two pound spools and at the end of this instructable you'll see where I modified the machine.
This is a quick and dirty hack because I needed an adapter right away.
Step 1: The Spools
I bought the 10 lb which I wanted to mount but the centre hole was too big. I also had an empty two pound spool that I thought would work.
Step 2: Cut the Two Pound Spool
The two pound spool was cut in half. These halves are going to fit inside the 10 lb spool shaft. You will also notice long screws in the background. They'll be used to join the spools together by going through the small holes already in these halves.
Step 3: Attach Spools Together
The holes in the two pound spool are in a very good spot for using the screws as a support. Both halves of the two pound spool were screwed onto either side of the the ten pound spool. The screws were placed behind the supports in the direction of travel and hopefully the screws will use the supports as a brace as the spool turns so the adapter doesn't rip apart.
Step 4: Modified MIG Welder
The space inside the machine was too tight for a 10 lb spool so the spool spindle was moved towards the back about four inches and I cut an opening in the back of the welder. A cover will be going over the spool so that I don't accidentally electrocute myself.
I am happy to say the adapter and welder work fine!