Thursday, July 25, 2019

Tormach 770M+

A Tormach 770M+ arrived last Friday and I've been getting it ready to use ever since while actually trying to get actual work done.

Just a piece of trivia, the Tormach machines have been known to use stepper motors rather than the more costly and arguably better servo motors. The 770M for example uses stepper motors. The 77M+ is an upgrade to the very recently released stepper motors. The advantage is servo motors are quieter and have built in encoders. A server motor for instance will run into something and not provide any feedback that it didn't actually move. But a servo motor has a feedback loop with the software to register problems when the motor didn't actually moved the distance it was asked to move.

Interesting trivia fact. The Apple II floppy drives had stepper motors instead of the more expensive servo motors and had no end stop switches. If you've ever been around an Apple II when it booted up you'd hear some loud bangs from he floppy drive. Sometimes it would go on for a long time sometimes for a short time. The reason is Woz knew the number of revolutions from the end stop if the head was in it's furthest position. So they ran it that number of revolutions to get it to the end stop and you'd hear the loud bang the number of times that the head was positioned from the length of travel minus it's current position. It simplified the disk drive and despite being loud had no ill effects.

Anyway, back to reality. The Tormach takes up a large amount of space in the garage, and not all the tooling showed up at the same time so there isn't much that I can do. The vice is in and reads zero deflection. That means it's nearly perfect, or fast least as perfect as my gauge. The vice itself has a 1/4 of 1,000 deflection in the middle however. NOTE that I'm not a machinist and still getting used to the jargon so that may be totally wrong.

The DIN connector for the electronic gauge isn't long enough, so I have an extension cable on order. I will 3D print a mount for it to go somewhere above the door. In fact I am currently 3D printing a lot of little parts to clean things up.

There are a couple parts I need to make for the Raspberry Pi Super Computer, but I don't think the tooling will get here in time so I'll have to take my part to a local machine shop.



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