There are a lot of ways that metals can be formed into various shapes. Forging, casting, and cutting are some methods of getting the metal in the correct shape. An oft-overlooked aspect of smithing (at least by non-smiths) is the effect of temperature on the final characteristics of the metal, such as strength, brittleness, and even color. A smith may dunk a freshly forged sword into a bucket of oil or water to make the metal harder, or a craftsman with a drill bit might treat it with an extremely cold temperature to keep it from wearing out as quickly.
Welcome to the world of cryogenic treatment. Unlike quenching, where a hot metal is quickly cooled to create a hard crystal structure in the metal, cryogenic treatment is done by cooling the metal off slowly, and then raising it back up to room temperature slowly as well. The two processes are related in that they both achieve a certain amount of crystal structure formation, but the extreme cold helps create even more of the structure than simply tempering and quenching it does. The crystal structure wears out much less quickly than untreated steel, therefore the bits last much longer.
[Applied Science] goes deep into the theory behind these temperature treatments on the steel, and the results speak for themselves. With the liquid nitrogen treatments the bits were easily able to drill double the number of holes on average. The experiment was single-blind too, so the subjectivity of the experimenter was limited. There’s plenty to learn about heat-treated metals as well, even if you don’t have a liquid nitrogen generator at home.
Thanks to [baldpower] for the tip!
Continue reading “Reducing Drill Bit Wear The Cryogenic Way”
Oh, sure – when you buy a new set of drill bits from the store, they come in a handy holder that demarcates all the different sizes neatly. But after a few years when they’ve ended up scattered in the bottom of your toolbox for a while, it becomes useful to have some sort of gauge to measure them. [Caspar] has the solution, and all you need is an old steel rule.
The trick is to get a ruler with gradations for inches and tenths of inches. After cutting the ruler off just after the 6″ point, the two halves are glued together with some steel offcuts and epoxy. By assembling the two halves in a V shape with a 1 mm drill bit at the 1″ position, and a 5 mm drill bit at the 5″ marker, a linear slope is created that can be used to measure any drill bits and rod of the appropriate size inserted between the two.
It’s a handy tool to have around the shop when you’ve amassed a collection of bits over the years, and need to drill your holes accurately. Additionally, it’s more versatile than the usual method of inserting bits in appropriately sized holes, and can be more accurate.
Now that you’ve organised your drill bits, perhaps you’d like to sharpen them?
Drill bits are so cheap that when one is too chowdered up to keep working, we generally just toss it out. So you might expect a video on sharpening drill bits to be somewhat irrelevant, but [This Old Tony] makes it work.
The reason this video is worth watching is not just that you get to learn how to sharpen your bits, although that’s an essential metalworker’s skill. Where [This Old Tony]’s video shines is by explaining why a drill bit is shaped the way it is, which he does by fabricating a rudimentary twist drill bit from scratch. Seeing how the flutes and the web are formed and how all the different angles interact to cut material and transport the swarf away is fascinating. And as a bonus, knowing what the angles do allows you to customize a grind for a special job.
[This Old Tony] may be just a guy messing around in his shop, but he’s got a wealth of machine shop knowledge and we always look forward to seeing what he’s working on, whether it’s a homemade fly cutter or a full-blown CNC machine.
Continue reading “Sharpening Drills Bits The Hard Way”
When you’ve got a scanning electron microscope sitting around, you’re going to find ways to push the awesome envelope. [Ben Krasnow] is upping his SEM game with a new rig to improve image capture (video link) and more easily create animated GIFs and videos.
The color scheme of the SEM housing gives away its 80s vintage, and the height of image capture technology back then was a Polaroid camera mounted over the instrument’s CRT. No other video output was provided, so [Ben] dug into the blueprints and probed around till he found the high-resolution slow scan signal.
To make his Teensy-LC happy, he used a few op-amps to condition the analog signal for the greatest resolution and split out the digital sync signals, which he fed into the analog and digital ports respectively. [Ben] then goes into a great deal of useful detail on how he got the video data encoded and sent over USB for frame capture and GIF generation. Reading the ADC quickly without jitter and balancing data collection with transmission were tricky, but he has established a rock-solid system for it.
Continue reading “Scanning Electron Microscope Images And Animations Pulled By Impressive Teensy LC Setup”