How to use a big diameter shaft clamp (20mm+)

Clamping Large Diameters (Damper Bodies, Stanchions, etc.)

When working with large parts like damper bodies or stanchions, proper clamping technique matters. These aren't just small shafts, and bad habits here can lead to slipping, ovalisation, or hidden damage.

1. Clean Everything, Thoroughly

Always clean the clamp and the part you’re clamping with isopropyl alcohol one, two, even three times. If it’s been sitting on your bench or you’ve touched it since cleaning, clean it again.

2. Wrap with Paper or Shop Towel

Wrap the part with a clean towel before clamping. This improves grip, reduces the risk of slippage, and helps spread clamping force without damaging the surface.

3. Center in the Vise - Unless You Have a very good vise

Try to clamp the part as centered as possible in your vise, and make sure the jaws grab near the middle of the clamp.

If your vise isn’t very precise (and most aren’t), clamping off-center can cause the jaws to tilt under pressure, making your part crooked.

✔ If you have a high-end vise that doesn’t flex or tilt when torqued, it’s less critical, you can clamp slightly off-center.

✘ For most people: keep it centered for best results.

4. Never Clamp Horizontally 

Do not clamp large-diameter parts flat (horizontal) in the vise even if your jaws are wide, the clamp will flex on the sides and the force will only be applied in the middle.

5. Protect the Shaft

If a damper shaft is sticking out from the body, make sure it doesn’t rest on the vise base or anything metal. One scratch is all it takes to ruin it.

6. Don’t Overdo It

With Clean surfaces and a paper layer, you don’t need to tight the clamp that hard. Tighten gradually and test. If it slips, clamp a bit harder, if it still slips, clean again. Torque isn’t the solution, isopropyl alcohol and paper are!

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