I'm going to chime in with my experience attempting to build a wire soap cutter. I have very minimal wood working skills, like middle school woodshop status, and I gave up on trying to build my own cutter. I looked at
http://goldfinchsoaps.weebly.com/blog/diy-wire-cutter-soap-mold
I drew out plans, and was going to go with the Bud's cutter style arm with the bolt instead of using hings on a framed base. I ordered some guitar wire and pegs off Amazon and it all seemed like it wasn't going to be too hard to do.
Somethings I learned along the way were, there was a reason the blog put their soap cutter on a wood board base instead of a frame. Making a frame perfectly even and straight is harder than you think the first time around. I tried twice and it still wasn't sitting flat. Using a wood base board is way easier and saves a lot of time.
I got as far as making the base with the slot for the soap to sit on which wasn't bad. But after trying to make the second frame, I decided it wasn't worth my time or materials anymore. I spent probably $40 in wood from Home Depot not including the bolt, wire lug, and other things necessary tools to finish the project and I would have probably wasted more money on wood than it would have cost me to just purchase one from Etsy. Creating the arm part was going to be pretty similar to creating the frame base and at that point, I was over making a wonky wood frame.
I think a log splitter would have been easier to attempt as my first wood working project, but this cutter def. isn't as easy as I thought it would be. Using the hinges instead of bolt will save you a lot of time. I had to cut down the arm piece where it pivots so it would have clearance underneath but using the hinge would eliminate that need.