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 →

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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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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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.

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NOTE 7/2020: I have discovered a limit on how fast the saddle can be moved without losing Z counts.  I assumed the limit would be above my maximum hand crank speed, but it turns out that you can lose counts even with moderately fast cranking – somewhere around 2″/sec saddle movement. For now, I manage by watching my handwheel speed, but it appears a faster uC than the MSP430 is needed. I will update when I have a solution.

12/7/22 – I just stumbled on this ESP32 Touch DRO setup on a site called Stockholmviews.com. This would most likely solve the above speed limitation since the ESP32 is much faster than the MSP430. I have not tried it yet: https://www.stockholmviews.com/wp/touchdro-diy-esp32-interface/?fbclid=IwAR0r8TOkRoQZHnrKf1z1ZNt1GjiT2w0daOuAEruxRSRDF2HHSnfO1FZsTZI

This is an 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 and don’t interfere with any travel distances or setups on this already smallish machine.

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This is bender specifically made to put a very tight radius bend in 5/32″ brass rod for banjo hooks. The original design was modified from this:  http://www.micromark.com/universal-bender,8229.html  but required a few revisions to get the desired result. Finally, when I was able to force the rod into a tight radius bend, some would crack. I learned that they needed to be heated with a torch before bending, but don’t have to be bent while hot.

The key difference between this and the little universal bender (besides less “slop” and tighter-tolerance fittings) is the movable round die is a “cam” that can be pivoted (with a 3/4″ wrench) and forced tightly against the stationary die while the bend is being made.

This was also my first exercise with hardening O1 tool steel. There are tons of guides on line covering this topic so I won’t go into detail here. Having the working surfaces hardened may not be necessary for bending brass but I wanted to play with O1 steel and this was pretty forgiving applications for a first try. It went quite well.

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This is a tube harmonica amp I built for my wife. It’s loosely modeled after an old Fender “Champ”. The circuit is a single-ended 6L6 design from Lone Wolf Blues: Lone Wolf Blues 6L6SE

The cabinetry and hardware became sort of an art project:

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I found two heavily trashed Ainsworth antique balance scales at the flea market. $40 later, they followed me home. Between the two carcasses, I was able to get parts to assemble one complete unit. Continue reading →

This is a home build of a two-channel tube-based studio preamplifer / direct box. The project web site is here:

Gyraf Audio G9

There are several recommendations/changes I have for future G9 builds, but it will take some time to get it all posted. Here’s an interior shot of my completed preamp.

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