Clamping Force Calculations for Drilling & Face Milling

Calculate? No. Just tighten the clamp.

How would you measure tightness anyway?

Don't complicate things.

Also depends on the clamp style, a smooth face clamp will need a higher clamping force than, say, a diamond cut clamp face.

How tight is tight enough?

I'm not aware that this would ever be a consideration to a good machinist.

If it is an automated process, one might need to calculate some air cylinder diameters, for instance.

OK.

There are companies out there like Enerpac® for example that specialize in work holding and fixturing devices.

Place a phone call to them or use the online catalog to gather this type of information.

They have different sizes how to choose the right one without at least estimating the clamping force ?

You have only given us half the question. The other half is what sort of material and what clamping equipment is available.

For one off pieces, the usual trick is if it moves tighten things up or add more. You just have to get a feel for it. It is called experience. If you underestimate the chances are you will not get the experience. If another clamp will fit, use it.

BAB