I used a hack saw before i learned about fret widths.
I hardened the tooth picks with super glue..
i picked up a cheap saw at lowes the dude there even used a micrometer to check to see if it was thin enough. Also martin guitar was selling a "craft saw" for cheap have been using that for about a year now. My next adventure was to try a saw from Michaels craft store around 10.00 see pix below
I use a program i got for free called WFRET found it online for pc works real good prints out a template according to my fret amount and scale length.
i use a builders square and a "c" clamp to use as my saw guide.
slots work well with medium fret wire.
Sorry about the lengthy post just give it a try let me know if you have any more questions.
Uncle gus, about to build according to your 1 hr videos. Ok a question. You mention building several to have on hand to sell. About what do you charge for one of your 1 hr creations? I recently watched vids on the Pergatory Hill Harp and went Wow. Guess that is the normal reaction - huh. So modifying the build in your 1 hr vid to a 4-srtring to be tuned low E (bass) then EBE. Already have interest in it, so that is why I'm asking. If I sell it will be my first ever build sell. OH had my first build, sounded weak and thin. Changed the bridge and nut to match the 1 hr build and added a retainer to hold the strings down at the tail, amazing difference!