September 28, 2022


Best Technology Perfection

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

When you are a machinist, your stock in trade is precision, with measurements in the thousandths of your desired device remaining prevalent. But when you’re a diemaker, your precision game requires to be even finer, and getting in a position to position applications and materials with seemingly impossibly granularity gets to be actually crucial.

For [Adam Demuth], aka “Adam the Machinist” on YouTube, the will need for ultra-good resolution machinist’s jacks that would not split the bank led to a design and style utilizing off-the-shelf components and some 3D printed areas. The layout facilities all-around an inch-metric thread adapter that you can select up from McMaster-Carr. The female thread on the adapter is an M8-1.25, although the male facet is a 5/8″-16 thread. The pitches of these threads are really shut to every single other — only .0063″, or 161 microns. To take edge of this, [Adam] printed a cage with compliant mechanism springs the cage holds the threaded pieces jointly and provide axial preload to take away backlash, and permits mounting of precision steel balls at each close to make positive the drive of the jack is transmitted through a solitary place at each individual conclude. Every entire turn of the jack moves the finishes by the pitch distinction, major to ultra-high-quality resolution positioning. Need to have even a lot more precision? Attempt an M5 to 10-32 adapter for about 6 microns for each revolution!

Although we have found diverse thread pitches employed for wonderful positioning prior to, [Adam]’s tactic demands to machining. And as handy as these jacks are on their own, [Adam] stepped factors up by using a few of them to make a kinematic foundation, which is finely adjustable in 3 axes. It is not pretty a nanopositioning Stewart platform, but you could see how introducing a few additional jacks and some actuators could make that occur.