Stew’s Spot

The lathe is done! Wow it took long enough. Quick recap (please see part III for the full story)

There were a few parts missing after we finished the rebuild. Parts included a gib strip for the top slide and a spacer for the main spindle. Unfortunately you can’t run the machine without these parts, so another order from myford was needed. At the same time I ordered a dust cover and some other miscellaneous bits.

There was a motor include in the auction, it needed some work, like everything else. But there was no motor controller to be found so we needed to build one.

Motor controller

The controls consist of a Direction switch (forward, reverse) a Start button and a big mushroom Emergency stop. Also there are two 18A 240v contactors for the actual motor switching. Below on the right are the control switches, on the left are the two contactors.

Have a look below at how the motor and controller is wired up to allow you to change the motor direction, but basically you change the polarity on the start wiring to change direction.

Above you can see the finished wired up control box, all that’s still missing is the incoming power cord.

Testing

Once the final few parts and motor where installed it was time for some testing. We just found a large steel bolt then tried to round the head and cut a bit of a shaft out of the threaded bit.

We definitely need to get some sharper cutting tools, but the one we had did the job OK. You can see below the final result, not to bad for the first test!

What’s left?

There is lots and lots of tweaking and adjustments left to do. All the slides need to be tightened and aligned, there is also a bit of play in the cross slide lead screw. I’m not sure how much we can fix or if it’s going to need to be replaced. And we definitely need to get some new cutting tools.

So that’s it, all done. We now have a working metal lathe in the workshop. If you want to go back and see how things came together, here’s all the posts.

• Part I
• Part II
• Part III

Just to recap from Part 2. After cleaning off the dirt, grime and rust, things where looking good, thats until the paint started giving problems.

The troublesome paint has had 5 months to dry properly, so the respraying went quite smoothly.  We finally found the colour that closely matches the original Myford grey. Everything got a good degreasing and sanding before spraying a couple of new coats on.  The paint dried with out much hassle, the air was very humid (upwards of 90%) which causes some issues with water droplets but these where fixed with some more sanding and another coat. Read More…

Just to recap from Part 1. My Dad and I bought an old Myford Super 7 Lathe (Serial number SK68133) at an auction. At first glances it looked terrible but after cleaning off the dirt, grime and rust, there was hope.

Below is what we ended up with after completely dismantling everything to parts, cleaning, painting and finally reassembly. But thats not the whole story…

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A little bit of a departure from the usual electronics stuff. My Dad and I bought an old Myford Super 7 Lathe (Serial number SK68133) at an auction, we paid R1000 for it, quite a bargain actually.

We got the partially disasembled bed, a box full of the slides and parts, a nice sturdy stand/cabinet, a 3 Jaw self centering chuck and a 4 Jaw adjustable chuck. There was also an assortment of cutting bits and odds and ends. As you can see below the lathe was in bit of a bad shape, I believe it’s been sitting covered, but outside for over 10 years. Not sure about it’s history before that.
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Ah you’ve got to love long weekends.

I spent some time this weekend doing the initial design work on a new project that’s in the pipeline.  I’m building a DDS Function Generator for the workshop,  nothing too fancy (I can always borrow the work one).  It’s based around the AD9834 from Analog Devices and the goal is for it to have all digital controls, that includes the signal gain and DC offset, with Sine, Triangle and PWM outputs between 1Hz and 10MHz.

I’ve completed the basic design, but there are still some finer points to finish and simulate. The next step is find and source the parts that I’m going to use then complete the schematics and layout the PCB’s.  I’ll post on the progress.

At least the workshop is looking a bit more “used” than in the other photos.

Some photos of my Agilent DSO1002A Oscilloscope.

On Saturday I decided that my workshop need some more shelves over the workbench.

Work in progress…

And the final result looks pretty good, I also hung up some extra storage boxes and a bigger whiteboard.  There is enough depth on the new shelves to easily store equipment on it, the only problem now is that it casts a shadow on the bench from the florescent light on the top shelf.  I’m going to have to experiment with lighting under the new shelves to fill this shadow.

It’s time I had a proper supply on my work bench.  So I bough myself  a TTi EL302RT power supply to replace the PC power supply and small switch mode that I’ve been using up until now.   I’ve got a big TTi (QL355TP) in my work lab and it works extremely well so I doubt there will be any issues with it’s smaller cousin.

Specifications

• Linear regulated with low ripple and noise.
• Two isolated outputs of 0 – 30V, 0 – 2A.
• Constant voltage or constant current.
• Switchable local or remote sensing.
• Auxiliary output of 1.5V – 5V at 2A.

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