Can you put a regulator in the line to cut the pressure / flow to what is needed?

No. Oxy/prop will not burn properly at psi settings similar to O/A. That's why conversion tips work so poorly, the #1 complaint being excessive use of oxy.

The lowest an acet reg will set is 1lb. and that's not very accurate.

The AllStates rig piercing 5"+ with the oxy set in the 140-160psi range is only drawing around 5 ounces/ (ozpi?) (opi?) of propane.

To get a proper mix using a acet reg you'd have to be pushing 3x the psi or volume of oxy which is quite doable as an oxy/acet set up's oxy regulator is designed to keep up volume wise but not pressure wise.

By analogy it'd be like putting diesel injectors in a gas engine. It just won't work without retooling the whole device and you're right back to where you started.

I'm sure the guys who understand the chemistry are right about why it doesn't work. I can only speak for my own observations trying to do it. The flame appears to be blowing so hard that any steel that melts is immediately blown out of the puddle. If you turn it down low enough it doesn't do this it won't burn.

Anyway, the manufacturer says it can be done but they're in the business of selling the things. I've never met nor talked to anyone who could actually get a satisfactory weld with oxy/prop, even the AllState's torch.

Frosty

I have a Victor torch set up to burn propane. For the heck of it, I bought an adapter from ebay so I can connect the torch to a little disposable bottle of Mapp gas. I was able to weld with the Mapp flame. (That's saying a lot, because I was barely able to weld with an O/A flame the one time I've tried). Don't know if you could burn Mapp with the Allstates torch (or any really good reason to try), but it might be possible.

If you're a little wary at spending that amount of money, vintage progects has some reprints of projects to make bandsaws, power hacksaws etc.

This question may be a bit outside the parameters for a Blacksmith forum, but I'm looking for a bench grinder and don't have the money for a Baldor. Does anyone know of an affordable USA-made brand of bench grinder? If not, then what's the best brand for the money? I've read horrible reviews of the Dewalt grinders, and relatively good reviews of Sears-- but not knowing the writers "work orientation" I thought I would ask my fellow blacksmiths. Any help out there?