DiAcro...
Probably just about every aircraft made since WWII has at least one part on it formed in a DiAcro press brake. Good value, simple, effective equipment. Rotational inertia is scary as hell to use, but that's the way it was done for more than 4 decades, until hydraulics took over, and they are still in use today. It's not unusual to see 60 year old DiAcro's in even hi production shops today.
As you found out, tooling selection can be an issue, as is capacity. There is another step up in this line that looks like it will do 1.75 diameters, but DiAcro was never really in the tubing market, and this line of equipment targets shapes forming. It appears that the vertical forming axis of the tooling is quite low, which restricts the overall tooling fitment capacity... i.e. Impossible to get reasonable diameter tube tooling.
In all great old fashioned equipment, well made stuff. It isn't done like this anymore, but, I don't think you'll get what you need out of it due to the reasons above.
The other one you're looking at looks interesting from a price standpoint. Here's the criteria I would use for eval:
1: ROI. If you want it just for your hobby shop, this may not be all that important, but at least make sure it'll last long enough to get a reasonable production cycle out of it before you out grow it, or it unrepairably breaks. Also factor in the stuff below. As the price goes up, the other criteria become more important. If it's going to have a production value, carefully consider wether or not the price is a true value proposition over "X" piece variance, verses time, which never works.
2. Capacity. Narrow capacity ranges get tricky, and more often than not come back to bite you. For a tube bender, more is better in almost every case.
3. Source Support. Tooling availability, Maint. support, trainning, etc. I always call and place a "pretend" order for some of the outside ranges of tooling to see if they actually have it in stock, real price, etc. Consider where the source is physically located, and if that will be an issue.
4. Fixed Configuration. Is it going to be limited to a stand alone piece? Provisions for mandrels? Positioners?
5. Classification. Is it a budget approach to an accepted configuration? I.e: pneumatic verses servo electric? Budget, Production, Hobby. Find a classification to fit it into. Evaluate considering this.
So, from what I could tell, I'd be looking at the tooling availability, the capacity seems limited to 1.75, but at what CL radius? Might want to check wall thickness too. It also makes mention of pneumatic control, I don't know exactly what that means in this case. Is the foot pedal pneumatic to a trigger valve? Servo Electric? It makes big mention of 180 degree capacity, so what. Even the budget production servo benders will do that, at a minimum. If you'll be thinking production value, I'd want to see mandrel upgrade and at a minimum, a positioner.
Pay attention to the follower. I can't quite get a read on the vertical rotation, but think in terms of how close you can get 2 bends next to each other, and in what directions. Bronze followers rock, anything else is going to have issues, if you try anything but steel.
Let me know what else you see as you get into it.
--ron
