Drill bit sizes in 64ths chart
Enough of that and you will have a pretty good handle on what it takes to drill a hole! Maybe you can apply for a government grant to pay for it all.It’s very convenient to have a drill chart around with bit sizes, so we thought we’d put one here for you. For more complete data collection repeat at various temperatures, monitoring and recording the bit temperature for each hole. Repeat all the tests with various speeds. Test the hypothesis with other drill bits, drilling methods, and materials. Formulate a hypothesis concerning the size of the hole obtained with that bit and that particular drilling machine/method and that material. On many bits you can measure across the steel just beyond the flutes, keeping away from any numbers if they are stamped into the steel.Īlthough this is more of an engineering problem, I think the scientific method could still be used by devising an experiment: measure enough samples of the object (the threaded rod) to determine the dimensional variation, pick and measure a candidate drill bit all along the working length, measure the runout in the drilling machine with a precision rod in the chuck at the test length from the front of the chuck, drill several holes, measure and test each for fit, if the hole is too large or too small repeat the test with another size. Also, measuring across the cutting edges of a drill bit is tricky because of the spiral and the way the edge is machined. This helps the standard bit get started correctly in wood for a more precise hole.
Also, when drilling in wood I like to start the hole with a machinist's center drill bit which is very short and can't flex. For more accurate holes I use screw machine bits which are relatively short and stubby and much stiffer because of that. Jobber length drill bits (a standard length) are more likely to wobble when drilling because of their length. Drilling into wood can be worse since wood is non-homogeneous and the bit can try to follow the grain. If you are drilling by hand or if there is any runout on a drill press/chuck or the bit flexes or chatters the hole will be larger than the bit. Perhaps your scientific method wasn't quite scientific enough. The good companies like Norseman and Triumph have charts on their websites that explain which drill types work well on which materials.Īs Tom mentioned, your experience makes sense. They are a bit more wear resistant but are brittle and have thicker cross section that make them work poorer in some materials. If there was, the hundred thousands of machine shops and manufacturers would have found them. Even sellers like Snap-On just sell the set for triple its value and then will actually warranty items.įor high quality, stick to Norseman, Viking, CTD, Cle-line, Triumph, Chicago Latrobe, Champion, etc for legitimate sellers. Any sellers on ebay will always be suspect.ĭrill Hog, Drill America, etc. This even includes Snap-On and other premium sellers.
Any suggestions? I have a lot to do so I would be willing to purchase an odd size bit.Īny drill bit with a lifetime warranty is either massively overpriced for the quality or they plan to be unavailable for warranty or make it so difficult that they won't have to warranty any. I have borrowed a set of metric bits and will try them next. I've experimented and found that I can thread them through a 13/64 hole but it is very tight. I am drilling holes in several pieces of mahogany to insert a 10-24 threaded rod. With the understanding that there are no dumb questions - here's one If the threaded rod needs to slide freely without slop for some mechanical reason, I might consider drilling a larger hole and gluing in a bushing, perhaps a piece of tubing if I could find one that fit or make a bushing by drilling brass, aluminum, or HDPE or Delrin or something. Mostly the insides of the wooden holes were burnished to a slightly larger size. I slightly flattened and widened a section near the end of a rod a bit with a hammer, filed a few grooves to help cut then spun the rod along the hole. To slightly enlarge a hole in wood I've made "reamers" from a steel rod. If fibers are suspected you might try dousing the inside of the hole with sanding sealer then redrilling after it's dry. Do you just need to insert the threaded rod or do you need for it to be able to slide freely but without slop? If the 13/64 is too tight in side grain, could it be that fibers on the inside are making the fit too tight? Maybe the drill bit is not sharp enough. In side grain such as through a board or in end grain? Maybe describe in more detail what you need to do.
This chart has "close" and "free" fit drill sizes for common machine screw sizes.