This brace takes the kind of bits where the shank has four facets. I believe these are called Jennings Pattern bits. New bits of this design can be found but they are very expensive. Fortunately whole sets of ‘like new’ bits can be found on your favorite auction web site for the price of one or two new bits. I got an old boxed set of Irwin bits that appear to be unused. One sticking point on auger bits can be clearing of chips. But these have plenty of room between each revolution of the screw, and haven’t plugged up once so far.
This first photo shows boring a 1″ hole through a 4×6 white oak timber. I was surprised at how fast it went. I don’t think my hand-held power drills could drill that any faster with a brad-point bit, and certainly not with a spade bit. (Could a 1″ spade bit do that at all? If so I’d be worried about breaking my wrists. If you’ve seen my wrists you understand.)
But I think the best thing is how clean the other side of the hole ended up with this auger bit.
The tip of the auger bit is threaded. And in this oak I didn’t need to push down at all. I just turned the brace and the threaded tip pulled the bit all the way through – almost. Once the threads pierced the other side the bit smartly stopped going any deeper. I turned the timber over and finished the job by drilling into the hole made by the auger tip on the far side from where I started. It’s easy to splinter as the bit exits the hole. But with these old-school tools, the exit hole ended up as clean as the entry side.