Greenlee punches (the type where you drill a hole, mount the punch, then draw the punch through the sheet metal with a bolt) can be a bit of a bear to use. The bigger ones usually require a lot of torque on the wrench to punch through the metal.
If you ever used this type of punch, I'm sure you've tried oil under the bolt. That doesn't work, the oil gets squeezed out and the bolt goes steel on steel.
I found that if you put a new zinc plated washer under the bolt, it's a lot easier to punch through the metal. I'd estimate it takes half the torque. I think the zinc plating behaves as a high pressure lubricant (lesson courtesy of bobistheoilguy.com). It only works once though. If you re-use the washer, the required torque is back up to high. The zinc plating seems to be galled off of the washer.
Try it.
[ September 10, 2003, 10:33 PM: Message edited by: Rick in PA ]
If you ever used this type of punch, I'm sure you've tried oil under the bolt. That doesn't work, the oil gets squeezed out and the bolt goes steel on steel.
I found that if you put a new zinc plated washer under the bolt, it's a lot easier to punch through the metal. I'd estimate it takes half the torque. I think the zinc plating behaves as a high pressure lubricant (lesson courtesy of bobistheoilguy.com). It only works once though. If you re-use the washer, the required torque is back up to high. The zinc plating seems to be galled off of the washer.
Try it.
[ September 10, 2003, 10:33 PM: Message edited by: Rick in PA ]
