When machining or metalworking typically, 90% of the work is planning. A considerable portion of that’s workholding and fixturing: how you retain the workpiece safe, whereas nonetheless enabling entry to the elements of the fabric it’s essential to attain. The commonest instance is the nice ol’ screw vise, however these are sometimes unsuitable for the job as they don’t present superb entry. Magnetic chucks could be very helpful alternate options, which is why Chris Borge 3D-printed this magnetic chuck for his DIY tapping arm.
Magnetic chucks are available in three main varieties: electromagnet, electro-permanent magnet (EPM), and everlasting magnet. The primary sort is the simplest to grasp: they’re simply highly effective electromagnets that you just activate when it’s essential to maintain one thing. EPM chucks are very fascinating, as they use energized coils to completely magnetize the magnets when vital. The benefit is that they solely want vitality when magnetizing or demagnetizing — the remainder of the time they don’t eat energy and can stay within the set state.
Borge’s is the third sort: a everlasting magnet chuck. This sort has regular everlasting magnets, similar to the type you’d use to stay one thing in your fridge—although normally way more highly effective. The neat characteristic of a everlasting magnet chuck is that it may flip “off,” so you may take away the workpiece. That “switching” characteristic works by bodily shifting materials with low magnetic reluctance into or out of the magnetic discipline, successfully “shorting” the magnetic circuit and eliminating outward magnetic flux. Robert Murray-Smith has a improbable video on this topic for those who’d wish to know extra.
On this venture video, Borge improves upon an outdated everlasting magnetic chuck design. In truth, it’s fairly much like the design Rober Murray-Smith supplied as an illustration in his video. It consists of six metal nuts organized in a hexagonal sample, with everlasting magnets between the nuts. A second, virtually similar, meeting sits on prime of the primary. When rotated into the “on” place, there may be robust magnetic flux. When rotated into the “off” place, the magnetic discipline turns into very weak—non-existent, if good.
Borge 3D-printed the elements to carry these assemblies in place. That features a cam mechanism that interprets linear movement into rotary movement for switching the chuck. A layer of poured epoxy on prime helps to maintain the work floor comparatively flat and clean.
This isn’t very highly effective, as magnetic chucks go. However it’s adequate for holding a tiny screw vise in place when Borge must faucet one thing. Due to the magnetic chuck, he can simply transfer that vise into place after which maintain it securely in place.
