Although I'm not 100% convinced the "JD Squared" tube bender is going to cut it for me with this particular exhaust task. However, it's pretty awkward to use, even with a long "helper" tube fitted to the actuator handle. Here are some observations about its use - and thoughts about how to add a power assist.
The default assumption in the US is that any man worth his salt will have compressed air in his (work)shop, so one of those "pneumatic to hydraulic" adaptors would be a fairly simple matter to connect up. This would allow a hydraulic cylinder to be fitted to the bender - and be operated from a compressed air supply. We don't do that over here so much and even if we did, there are every few of those "pneumatic to hydraulic" products available.
Here's a JD Squared (clone) bender fitted with a hydraulic cylinder. Note that although it says "$200", that price doesn't include any actual dies...
So, how about simply fitting a large Chinesium ballscrew and driving it with an impact driver? Just pulling specs out of my ass, I'm thinking a 32mm ballscrew with a 5mm pitch would suffice. Generally, these seem to rated at around 4 Chinese tonnes of dynamic load.
Looking at a HLTNC (a semi reputable Chinese supplier of SFU3205?), I'm seeing a static load bearing capacity of ~50kN and a dynamic load of ~17kN. That's between 1.7 and 5 tonnes of force in street talk. With the kind of leverage we see on that bender of about 20:1 when fitted with a 1m helper bar (~5cm active length at the ratchet bar), I'd be needing to apply about 85kgf or 250kgf on the helper bar to exert a similar force manually. I'm pretty certain I've never come close to that, so as far as calculations go, I think we can leave it there - "an SFU3205 ballscrew will be man enough", even allowing for Chinese units of measure.
So what would it look like, this ballscrew power feeder thing?
Check the bearing loads - that looks adequate.
That will do. Let's focus on making it happen.
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