Thanks. What would be specs on a good deal for a used US-made vise?
Giants:
--I just paid $60 for an old Athol (Starrett) 4" jaw vise that opens to almost 6". It is a monster compared to the ones I have seen in most stores and at work.
--Most will print USA, or a town where they were made. Some will have a brand and model number. A lot of old Sears/Craftsman were made by companies like Columbian under license.
--Jaw width is not as important for most work and will be smaller than the newer offerings. 4-5" width jaws will be found on fairly large USA vises.
--The jaws and body exterior should also have more smooth, sloping curves. Jaws should have a wide V shape out to the edges of the jaw faces. Straight angles should only be on machined surfaces. Hard angles could not be reliably cast with older technology without causing a stress point in the material.
--Jaws should also meet parallel without binding the screw. Otherwise it may have been over-torqued creating a bend or bow somewhere.
--Ductile iron is the strongest material next to steel. Easiest way to check is to look for a lack of mold type lines on the jaws that are used when cast iron is poured.
--Ductile Iron will also make it heavy. My fixed base 4.5" Monarch ($100 + shipping) was considered homeowner duty and weighs ~42lbs. The Heavy Duty Prentiss version was ~57lbs. Both are built more to today's industrial standards.
--Check for any signs of cracks or repairs in the jaws and base. Recent repairs may be more questionable, but many vises have old repairs that have held for decades. Cracks in the slides are usually a non-issue and common on some brands.
--Square acme threads on the screw. These are stronger than the sharp edge bolt threads. More threads per inch will provide higher clamping force. Fewer threads per inch allow faster movement.
--Covered screw threads. Either a square or round slide that covers the entire length of the screw is needed to deter dirt. Fully enclosed bullet style are best, but command higher prices for it.
--The screw should also be using a washer or clip to hold it to the dynamic jaw. As you can see in the video, any one that has a hole/pin design in the screw will fail at that point.
--Fixed base is stronger than swivel base, but some need the added adjustment for holding work correctly.
--I can also move any vise screw with a single finger. If it binds alot, then it is either damaged or full of dirt.
--Minor cuts from hacksaws on the jaws are not a concern either. Sometimes people fill them with silver solder, but I just leave them as is.
There is a list of all the known USA brands at the beginning of the Vise repair 101 thread so you can keep an eye out for them while looking online or at used tool places.
https://www.garagejournal.com/forum/showthread.php?t=252830&highlight=vise+makers
I finally watched the video this afternoon. Honestly dudes, I'm thinking more along the lines of using a vise to sharpen mower blades. I understand the purpose of a torture test. But if I started swinging a hammer like that in my garage, I think my wife would call the police.
Brando:
All you need there is good clamping force, so it doesn't come loose while grinding. Any old 3-3.5" jaw width vise will do this well for around $30-60 off eBay. That 4.5" Forward on Amazon is the best designed new vise I can find for under $100. Put some quality grease on the screw and it should last far longer than needed and handle any other odd jobs you find for it. I've found that you don't realize how many times you can use a tool for something until you have it. I just used my little 1920s Columbian No 143 to hold a sharpie with fishing line spool to add line to my reel. It also has the clamping strength for most of my quick jobs.
Or fuel for the fire 
