Can these clamps be used as spreaders?

Yes. Each clamp converts to a spreader, so the pair can push a joint or frame apart as well as hold it together.

How much clamping force do they have?

They are medium-duty 12-inch clamps. The ratchet trigger gives quick, one-handed tightening, but they are built for light woodworking and repair rather than heavy shop pressure.

Will the pads mark my work?

The clamps have soft pads to protect surfaces. On delicate or freshly finished wood, check the pad contact before leaving a clamp on for long.

Two ratchet bar clamps, each 12 inches long.

Are they good for gluing up a cabinet or table?

For small cabinets, drawers and furniture repair, yes. For large panels or thick hardwood joints that need high force, a heavier bar clamp is a better fit.