Drill America 12 in. L High Speed Steel Aircraft Extension Drill Bit Set (5-Piece)

These worked perfectly for drilling through 6-10″ diameter tree logs on our rustic porch project. They handled both wood and steel easily and stayed sharp throughout the job and are great value for money.We’re building a rustic porch from real cedar and pine logs and wanted to hide the steel mounting brackets inside the logs. We used the ¼” bit to drill pilot holes through the tree logs so we could locate the metal brackets inside. Since we were bolting through the logs with ¾” bolts, I needed a longer drill to ensure that I could get through the entire log in one go so that the holes would line up properly from front to back.Since the drills are 12″ long, I found that a rafter square was very helpful in making sure that the holes are drilled square to the wood. I just rested the rafter square on the log and then lined up the drill bit to make sure that the hole was a close to 90 degrees as possible and it worked pretty well.The flutes are quite short (2.5″ on the ¼” drill increasing to 4.5″ on the ½” drill) so I found that I had to back out the bit a few times to let the swarf and sawdust clear from the end of the drill. The holes were clean and tight however.In some cases, there were steel mounting brackets embedded in the end of the logs and the High Speed Steel drill tip had no problem drilling through the 3/16″ thick steel so that we could make one pass through the entire width of the log. Just make sure to drill the metal on low speed on your drill to preserve the drill tip from overheating.We also used the larger ½” bit for drilling the holes for 5/8″ lag bolts in pine log “˜K’ braces with similar success. We pre-drilled the pine “˜K’ brace and then held it in position and drilled into the posts and beams. As with the ¼” bit, we had to back the bit out a couple of times to clear the flutes. We then enlarged the top 2″ of the hole with an 11/16″ auger to accommodate the lag bolt shoulder and the bolts went in perfectly.The ¼” drill was still in good shape after drilling through 11 cedar posts which also required drilling through 22 pieces of 3/16″ metal plate.When not in use, the drills come with a plastic pouch which rolls up for compact storage in the tool box and also helps keep all the drills to hand when you’re using them on-site.

One of the bits broke as soon as it hit a hard spot in the wood.

A must have set of extension drill bits for the shop and the tool box. Over the many many years of being an electrician/ home builder / mechanic/ and just an overall jack of all trades I have probably purchased more drill bits than I can count. It used to be that a good set of drill bits was pretty expensive, but not so any more, so you can now own a good set of regular size drill bits and a set or more of these longer drill bits. This 5 piece set has the ones that I use most of the time, but it never hurts to spend a little more and get a set with 7 or more.

Well heat treated HSS. HSS is High Speed Steel that is used in machine shop for cutting tools used on steel and other materials. This set of drills is well heat treated, meaning they are hardened and properly tempered for drilling steel. Exactly like the drills I have used in machine shop for decades. I have purchased tools stamped HSS that were not heat treated and about worthless for cutting steel. Be alert to proper speeds for these drills. You CANNOT use these in a drill press designed for wood because you cannot run the RPM’s slow enough and you WILL burn up the drill. AND the larger the drill diameter the slower it needs to run. There are speed charts available on the Internet for drilling steel and aluminum. The SPLIT POINTS are very well done. A split point can often be used to drill from solid instead of needing to step drill, meaning you do not need to drill smaller holes before the full size. And the lips are perfectly on center producing 2 chips that are equal thereby drilling an on size hole, not oversize.They come in a roll up plastic carry pouch with separate pouch for each drill.