Drill America 13/16" X 30" Long Auger Bit - DMS Series - Heavy Duty Wood Boring Drill Bit for Professional Carpentry, Woodworking & DIY Projects

Bit punches through 3 railroad ties at a time with no issue. Chuck size is 7/16 on it so just be aware of that. Helpful hint for those without a 7/16 chuck driver, use an impact to run it down using a 7/16 socket, put your drill with a chuck on the bit and use that to extract. As long as your drill can handle the chuck size it will pull the bit out. Just be ready for the bit the whip of the drill. Drilled 8 holes through triple stacked ties and the bit still looks new.