If you have a big drill press and have a table vise just clamp the lock side in and put in a thin kerf cut off wheel from McMaster & Carr and be on your way just letting the wheel do the cutting while you guide it in. Many will caution you that you'll make the shaft wobble doing this and you just might. Still, I know makers that did this for many folders for years using a heavy duty floor standing press and it never gave them any issues doing it.
The short cut can be done first using a band saw and even a wood cutting band saw can make a quick cut that is short and fairly accurate if you plan and use a 14 to 18 tpi blade for metal cutting. You'll eventually burn up the blade but quite honestly I can get two years or more easily out of good blades cutting titanium like its butter the entire time. All I've ever had is a 14" Delta/Rockwell floor standing band saw.
If all you have is a hand held rotary tool you can mark your line and use a thin cut off wheel and actually cut the thinner stuff fairly well. Get into the slab stuff you are in for a long haul though. I know makers that did the drill press technique to double duty their machine making it a mill when needed just as pictured. You use what you have and roll your own in this biz!

If you want to see just how fast a wood cutting band saw can zip through sheet titanium for short cuts and do so repeatedly using the same blade for years just watch here. This band saw has cut more metal and titanium in it's life than wood although I have used it for wood too. I read an article years ago about Stan Fujisaka and in that article he expressed how he preferred cutting sheet titanium with the higher speed saw. After doing it both ways I fully agree. I am currently approaching year three for use on the blade being used in this video and it has cut a lot of titanium! I sold about 600 of those pry bars last year alone that doesn't include all the sheet cutting for cutting custom lock sides and liners and pocket clips. Even using a waterjet service for a lot of the work this saw still sees a lot of action and it goes through ti like a hot knife through butter all the way up to .160. If you can start the line where you want to enter with your thin kerf disc, even if it is just one used in a handpiece you can zip the saw through in a controlled cut pretty good by drilling your spot hole at the corner where the long cut and short cut meet. Just follow the line in nice and quick. The trick to cutting ti or even thin up to maybe 1/8" aluminum before it heats so much it starts bonding to the blade, is to keep the piece moving. Letting the blade sit in one spot too long is going to heat up and anodize that spot so much that it will wipe the teeth right off the blade if you are not careful.
[video=youtube;b0vFkyDuAUY]https://www.youtube.com/watch?v=b0vFkyDuAUY[/video]