May 18, 2024


The Techno Universe

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

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

When you’re a machinist, your stock in trade is precision, with measurements in the thousandths of your most popular unit staying popular. But when you are a diemaker, your precision sport wants to be even finer, and being ready to position instruments and material with seemingly impossibly granularity becomes truly crucial.

For [Adam Demuth], aka “Adam the Machinist” on YouTube, the will need for extremely-great resolution machinist’s jacks that would not split the bank led to a layout utilizing off-the-shelf components and some 3D printed areas. The style facilities all over an inch-metric thread adapter that you can pick up from McMaster-Carr. The woman thread on the adapter is an M8-1.25, though the male side is a 5/8″-16 thread. The pitches of these threads are extremely close to every other — only .0063″, or 161 microns. To just take advantage of this, [Adam] printed a cage with compliant system springs the cage holds the threaded elements jointly and present axial preload to clear away backlash, and permits mounting of precision metal balls at each individual conclusion to make positive the power of the jack is transmitted by a single issue at each individual end. Each complete convert of the jack moves the ends by the pitch variation, main to ultra-fantastic resolution positioning. Need to have even more precision? Try an M5 to 10-32 adapter for about 6 microns for each revolution!

Though we have observed distinct thread pitches employed for good positioning before, [Adam]’s strategy desires to machining. And as handy as these jacks are on their own, [Adam] stepped matters up by making use of three of them to make a kinematic base, which is finely adjustable in 3 axes. It’s not really a nanopositioning Stewart platform, but you could see how incorporating 3 more jacks and some actuators could make that transpire.