Adding a VFD to an Odd-Duck Milling Machine (Enco 100-1525) Motor

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Fig 1.VFD box wiring

A while back, I got a nice deal on an early 90’s Enco 100-1525 milling machine. It’s a Chinese 2/3 size Bridgeport copy with an 8″x32″ table. This machine has a 3-phase motor, which I consider a plus because it means I can have knob-controlled speed by adding a VFD (Variable Frequency Drive).

Adding a VFD is usually not too complicated with typical two-speed three-phase motors, but this machine turned out to have a 4.3-to-1 speed ratio between the two ranges (unlike the typical 2-to-1 ratio). With a 2-to-1 ratio, it’s usually fine to run the motor only on the high speed range and then use the VFD for speed reduction. There is a small torque reduction at low speeds when doing this, but for home shop use, it’s fine.

But with the Enco mill motor’s 4.3-to-1 ratio, if I only drive the high speed motor coils and then try to dial down the speed to cover the slow range, the torque loss is too much. This meant I had to keep BOTH motor speed ranges and devise as way to switch between them.
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Quick and Dirty Combo PC board & Box

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PCB/box combo ready to go after a bit of deburring.

Maybe when you get a new hammer, everything is *not* a nail, but when you have CNC, everything turns into a CNC project ;-). I used to hand-cut a lot lot of copper-clad circuit board material for a variety of projects. It was a quick and dirty way to get stuff built, but cutting PC traces and peeling copper with a hobby knife is slow and hard on your hands.

After needing more than one of this little test box, I turned the board AND box into a quick CNC-cut “kit”, much like model airplane parts.  Continue reading

Smartphone Microscope Mount

I needed to get decent images off a microscope in fairly short order. Though I was in a “rush”, it still took a full day to get to a working solution. It is still incredible to me how much time it takes to make something that doesn’t obviously suck.

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Phone mount clamped to eyepiece. Unfortunately I couldn’t show a phone in place because I need my phone to take the shot. The phone mounts between to two cork pads.

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Emco Maximat V10P lathe QC gearbox bearing replacement

Years back I managed to find one of those “dream” home shop machinery deals. An Emco Maximat V10P lathe was sitting in a dusty pile at the back of a bike shop in Alameda, CA. This is a very much sought-after home shop machine. The shop owner said the machine was taking up space, so we made a deal and it followed me home for a more-than-fair price. It’s been a great lathe, but was in far from tip-top shape and has needed some TLC and upgrades. One thing that I’d been meaning to address for long time, is that oil constantly dribbled out of the quick-change gearbox onto my bench. What follows details that fix.

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Emco Maximat V10P after most of the fixes/upgrades

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Bose L1 Tower PA Repair

This is a repair of Bose L1 tower PA system. These skinny tower speakers are somewhat of a marvel because they are designed to stand behind the musician (aimed RIGHT AT the microphone) and don’t generate feedback (in most situations). Ah, the miracles of DSP.

It turns out these PA’s have a frequent failure in their power supply. Read on for details.

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1st generation Bose L1 tower PA system

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Tormach PCNC 770 DIY Enclosure

I recently got a Tormach PCNC 770 CNC milling machine. So far, I’m very happy with it (but have not cut much yet). I figured that since I wouldn’t be using flood cooling, that I could get away without a full enclosure. But even with mist rather than flood, chips were shot everywhere, so I decided to roll my own enclosure using 80/20 parts https://www.8020.net/

There are lot of similar designs on-line, but the one I used most for guidance was by sauni68 on YouTube: https://www.youtube.com/watch?v=FddiAAuI2Rg

His was a design for a PCNC 1100, but his video still has several good tips that are appropriate for the 770.

Photo Feb 19, 4 47 45 PM

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TouchDRO Machine Position Digital Readout for Emco Maximat V10P Lathe

This is a outstanding machine DRO for hobbyists, not just an outstanding DIY project, but a super DRO even compared to high-end pro machines. The beauty of TouchDRO is that it uses a (cheap) Android tablet for the display and control (I used a 1st-generation Nexus tablet – $50 on eBay) while the scales connect to a small (user-built) box that wirelessly sends data to the tablet via Bluetooth. The extra cute thing about this particular DRO installation is that all that parts are very small don’t interfere with any travel distances or setups on this already smallish machine.

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