Peter Parfitt said:
Any router operation should be considered as dangerous and nobody should attempt to do any operation unless they are sure of what they are doing.
This router operation is very dangerous and nobody should even attempt it, no matter how sure of what they are doing they may think they are.
When things go south here, they will go bad in a hurry. You are holding the opposite side of a dainty frame that’s only connected by two bits of short grain material. If you are lucky, the frame breaks and the ensuing missile flies harmlessly off the wall behind you. The frame could dig into your hand, break fingers and send bits of wood flying. The stress on a 1/4” shank bit can snap the cutter off sending it flying across the room.
Peter Parfitt said:
The main thing I tried to get across is that one must always work in such a way that the wood has to be pushed against the force of the cutter which is trying to push it back towards you.
There are better ways to demonstrate the rotation of the bit and the proper direction to move material across the cutter head.
Peter Parfitt said:
Nobody should attempt any operation with any tool that they have not been taught to do in a face to face class situation.
People teach others bad or dangerous methods face to face often enough. If anyone paid to learn to trap the workpiece between the cutter and fence in a classroom situation, they should probably get a refund.
I’m sorry if I come off harshly here. I went to school for woodworking. A school has insurance premiums and liabilities to worry about. Safety is more focused there than the average woodworker’s basement/garage shop. This operation would never fly there.
Just move the fence 120mm minus the diameter of the bit and work on the opposite side. If the material moves off the fence, then the bit is in the free space of the aperture. A pattern could be made 3 inches larger on all sides. You could then use a pattern bit or flush trim bit to size the hole and a rabbit bit to make the rebate. This would keep hands and push blocks farther from the cutter.
Hope this helps
Ed