Rollers in the bed, so long and heavy workpieces can be moved along and rotated under the ram without being lifted. The press addresses the handling problem rather than the pressing one, which on long stock is where most of the time and effort actually goes.

Because straightening is a cycle of measure, press, rotate and measure again, and most of that cycle is moving the work rather than pressing it. On a roller bed each movement is a push and a turn instead of a lift, which turns an awkward job into a routine one.

Shafts and axles, tube and bar, rails and beams, and machinery components in agricultural and construction repair. The common factor is length and weight - parts that a conventional press could deform but that nobody wants to lift and reposition repeatedly.

Roller spacing and load rating against the weight and length of the work, and total bed length so the piece stays supported at both ends throughout. An under-length bed lets an end drop as the work is moved, which is both a handling hazard and a source of error.

Yes - straightening without measurement is guesswork. Dial gauges and vee supports let the high point be found and the result verified after each press, and they are part of the setup rather than an optional accessory. Most poor straightening results trace to inadequate measurement.

Comparable at similar sizes, since the frame is generally a closed arrangement with the roller bed added. The difference is in handling rather than force, so choose on whether the work is long and heavy rather than on tonnage alone.

On many designs the roller bed sections can be removed or a flat plate laid over them, so the press doubles as a conventional press for shorter work. That flexibility is worth confirming if the press is expected to be the shop's only one.