Emmental heatsink

Before I get too far along the way of integrating the scavenged (ex-VFD) heatsink into the reconfigured console box, I need to drill and tap all the holes for the servo drives and braking module. I only have one of the drives at the moment but that will change in the next few days. But no reason not to lay out their positions and get the heatsink ready for them. I can then fit the heatsink to the chassis and hopefully not need to remove it again.

As this is a complete one-off exercise, there's no need to do any fancy design work. Some of my past projects have required a fair bit of CAD work up front, to ensure they would actually work when I made them. They really weren't the sort of job where you just make a part, then figure out the next part and eventually end up with a finished item. I'm keen to get this up and running without prevaricating or agonising over it for weeks (= wasting time). So this is a case for marking positions with pen and masking tape, then centre punching / scribing positions and getting on with cutting metal. If I make a mistake I will have another go and hopefully nobody will die in the process.

I drilled out the tapping holes 2.5mm on the Blidgeport so they were nice and square, then set the machine to low range and power tapped the holes with a spiral point M3 tap. It's always a bit risky drilling holes into a finned heatsink. Even if you try to avoid the edges of the fins, there are usually a few you can't stay completely clear of. Anyway, job done, holes deburred with a countersink and the modules trial fitted with some cap head screws.

With the new holes and the original Hitachi holes, it resembles a piece of black Emmental cheese. It all seems to fit, with room for the various cables and connectors.

Finally, I removed the chassis plate and marked it out to take the terminal blocks I scavanaged from the original control cabinet. These are 18 ways each on a 9.5mm pitch, so ideal for terminating the incoming wirings from the servo motors, switches etc. I have some handy 3.7mm forked crimps that will fit nicely. Again, the holes were drilled and tapped on the Blidgeport (M4).

Before I consider the chassis plate finished I will need to drill and tap holes for several solid state relays (SSRs) to control the drawbar solenoid, coolant pump etc. The PSU caps, diode bridge etc will fit on a handy little side tray.