The DIY bow vise is easy....just get a bicycle repair vise from Amazon.
I would avoid the DIY bow press unless you have some fabrication and welding skills.
I followed the famous pipe clamp bow press build from archerytalk to a T.....and once under pressure the clamp got on a bind (due to pressure being too far from the pipe) and I could not unscrew and free bow....I barely got the bow out without damaging it
The "fixes" to this create a Rube Goldberg situation. The only presses I've seen that I'd trust are the ones that use a truck jack and basically replicate something like a LCA EZ Green press. If you can weld well enough to make one of those, then that'd be awesome. Otherwise, I'd save to buy a used press.
I have a portable Bowmaster press, and don't recommend it. This press gets much better reviews, but I haven't used it.
• A new concept in a portable bow press • Designed for quick and easy string/cable changes, peep installs, or cam adjustments • Lightweight (1.3 lbs.), compact and easy to carry • Easy adjustment and great versatility • Fingers are reinforcement to handle any poundage • Safety lock system holds...
lancasterarchery.com