I need to drill an 86mm dia hole through a 4 inch thick timber frame. Hole saws seem to max out at 50mm deep. How can I produce a clean hole? I could get to the other side (double brickwork) but I would need an SDS+ arbour about 8 inches long to get to the other side of the wood. Does anyone know where I could get a 86mm dia hole saw about 100mm deep?