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The HNBun C-clamp set is a set of cast malleable iron C-clamps with a 6 in jaw opening, an I-beam frame and a swivel pad. This HNBun C-clamp set review is based on the Amazon listing, not on hands-on testing.
It is worth considering if you need general-purpose clamps for fabrication, woodworking or automotive work and want a deep opening. Skip it if you want a clamp for use right at the arc with heavy spatter, or a clamp that doubles as a ground clamp.
Quick specs at a glance
| Item | Details |
|---|---|
| Type | C-clamp set (check the listing for the exact piece count) |
| Material (per listing) | Cast malleable iron, black coated finish |
| Jaw opening (per listing) | 6 in |
| Throat depth (per listing) | 2-5/8 in |
| Jaw pad (per listing) | 1 in wide swivel pad |
| Rated clamping force (per listing) | Up to 1,350 lb |
Always confirm the current numbers on the product page. A clamping-force figure is a manufacturer rating, not a guarantee of how a clamp behaves on a hot weldment.
What these clamps are and who they suit
A C-clamp is a rigid frame with a screw and a fixed anvil. An I-beam style frame puts more metal where bending forces are highest, so the frame resists flexing when you wind the screw down hard. The swivel pad on the screw end lets the pad sit flat on slightly uneven or angled work.
A 6 in opening makes these useful for stacking thick plate, holding angle iron to a bench, or tacking up frames. They suit hobby fabricators, home workshops and general repair.
The swivel pad is a point worth noting for welders: it grips with a small area, so for thin sheet it is wise to add a flat backing piece to avoid marking the metal.
How to check they fit your jobs
- Opening vs stack height: measure the thickest stack you will clamp. The 6 in figure is the maximum, so leave margin for the screw to tighten.
- Throat depth: the 2-5/8 in throat limits how far from an edge you can clamp. If you must clamp deep into a panel, you need a deeper-throat clamp or a different style.
- Set contents: confirm in the listing how many clamps come in the set and whether all are the same size.
- Where it sits relative to the weld: keep the clamp screw and swivel out of the spatter path where possible.
- Bench or table fit: if you plan to clamp to a slotted or perforated welding table, check the table thickness against the throat.
Pros and limitations
Pros
- Deep 6 in opening for thick stock.
- Cast malleable iron frame is a common, affordable choice for general clamping.
- Swivel pad helps on angled surfaces.
- Black coating helps against surface rust in a normal workshop.
Limitations
- The coating will burn off close to the arc, and spatter can damage threads.
- Cast clamps are not a fix for warping: weld heat will still move parts that are clamped rigidly.
- The small swivel pad can dent soft or thin material.
- Do not use a C-clamp as a current-carrying ground; it is not made for that and can arc at the contact point.
Using and caring for C-clamps in a weld shop
- Spread the load: put the clamp square to the work so the screw pushes straight, not at an angle.
- Tighten by hand until snug. Using a cheater bar or hammering the handle can overload the screw or frame.
- Keep threads clean and lightly oiled. Spatter on the thread is the most common cause of binding.
- Wipe the screw with a wire brush and a drop of oil after welding sessions.
- Inspect for cracks near the frame throat and for bent screws before each use. Retire a cracked cast clamp, since it can fail suddenly.
Wear welding gloves when moving clamps near finished welds, since the jaw and screw stay hot long after the arc stops.
Anti-spatter and storage tips
A light coat of anti-spatter on the screw and swivel helps spatter flake off instead of fusing. See our anti-spatter compound review for what to look for. Store clamps dry, with the screw backed off a little, to keep the threads free.
Alternatives and related guides
- Senjeok cast iron C-clamps review – another cast-iron option if you want to compare sizes and set contents
- Red C-clamp set review – a lighter-duty set that may suit smaller jobs
- Heavy-duty stainless steel C-clamp review – a stainless option for damp environments
- Welding table clamps review – built for slotted and perforated welding tables
Frequently Asked Questions
What does the 1,350 lb rating mean?
It is the manufacturer maximum clamping force quoted in the listing. Real holding power depends on how you place the clamp, the materials and the heat from welding. Treat it as an upper limit, not a working load.
Can I use these C-clamps while welding?
They are commonly used to hold work for tack welding, but keep them out of heavy spatter and avoid clamping across the weld path. The coating can burn and the threads can seize from spatter if unprotected.
Can a C-clamp work as a welding ground clamp?
No. A ground clamp is designed to carry welding current with good contact. A C-clamp is not rated for that and may arc or overheat at the contact point. Use a proper ground clamp.
How do I stop the screw from seizing?
Keep spatter off the thread, apply a thin coat of oil after cleaning, and use an anti-spatter product on the screw. Do not force a seized clamp with extra leverage.
Final verdict
The HNBun set offers a deep 6 in opening and a sturdy-looking frame for general shop clamping. Check the piece count, throat depth and jaw size against your projects, and keep it out of the heaviest spatter.
