Metric And Inch Threads Fight It Out For Ultra-Precise Positioning

When you are a machinist, your inventory in trade is precision, with measurements in the thousandths of your chosen device being common. But when you are a diemaker, your precision video game wants to be even finer, and currently being equipped to posture tools and material with seemingly impossibly granularity gets to be seriously essential.

For [Adam Demuth], aka “Adam the Machinist” on YouTube, the will need for ultra-fantastic resolution machinist’s jacks that wouldn’t split the financial institution led to a design utilizing off-the-shelf components and some 3D printed areas. The structure facilities all-around an inch-metric thread adapter that you can pick up from McMaster-Carr. The woman thread on the adapter is an M8-1.25, although the male aspect is a 5/8″-16 thread. The pitches of these threads are incredibly shut to each and every other — only .0063″, or 161 microns. To choose advantage of this, [Adam] printed a cage with compliant system springs the cage holds the threaded pieces together and give axial preload to take away backlash, and lets mounting of precision metal balls at each finish to make absolutely sure the drive of the jack is transmitted via a single position at every single stop. Every complete flip of the jack moves the finishes by the pitch difference, main to extremely-great resolution positioning. Need to have even far more precision? Consider an M5 to 10-32 adapter for about 6 microns per revolution!

Though we’ve seen different thread pitches employed for high-quality positioning before, [Adam]’s technique requirements to machining. And as practical as these jacks are on their have, [Adam] stepped factors up by applying a few of them to make a kinematic base, which is finely adjustable in three axes. It is not quite a nanopositioning Stewart platform, but you could see how incorporating three extra jacks and some actuators could make that transpire.

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