Overkill
Final modifications to the hovercraft engine mounting plate… drilling four 3/8″ holes in 1/2″ of aluminum… a cordless hand drill would have worked fine. But that’s not The Way. Ultimately I had to correct for a bad OEM drawing of the plate on the bridgeport, but the new hovercraft engine is is ready to assemble.
Inverting SSR
This is part of a cooling system for the cabinet. This relatively inexpensive (on ebay) Watlow series 900 temperature controller has a single output and two alarm relays. The output and one of the alarm relays have snubbers inside and can trip fans on their own. The second output was NC and needed a relay to invert it. I used a solid state relay (SSR) to do it and it is currently controlling the halogen light. It turns on if the temperature goes over 81. Woo! Three more simple wiring harnesses to fabricate and then the whole mess to install in the cabinet. The concept is that a set of filtered fans will run full-time to drive fresh air into the cabinet (not quite working yet) to achieve ambient temp, say below 85 or 90 degrees. If the temperature goes above that, a single extraction fan will turn on. If it goes up another 5 degrees a second extraction fan will turn on, and 5 degrees above that a third, honking big fan will turn on. The extraction fans will probably suck in some dust, but better that than melting down.
Welding headers
Today I got to weld again, for the first time in about 8 years. I like TIG welding, it’s very satisfying, though I think I gave myself a bit of a tan – my skin has that “just welded” smell. The tubing is an exhaust header for the hovercraft motor. I also fabricated a nice metric broach to cut a keyway in the shaft adapter I designed (and Mark cut out on the Mori Seiki I fixed last week). Fun work… tired now…
Blooming Yard
The yard is flowering very nicely at the moment….
depearlized
Pearl parts
If you have a blackberry pearl and you work near metal dust or filings it will not last long.
I took mine to SRL yesterday and needed to use it with dirty hands. I wiped them off on my shirt, really, then used it a few times and noticed that the trackball had stopped running smoothly. The problem is not just the dirt (see the black streaks around the knurls on the little potato masher shafts), but metal flakes that stick to the magnets.
Turns out the blackberry’s trackball works with four little hall effect sensors on the mother board (you can see one of the black sensors in the top right of the cavity where the trackball was). The black ends of the four little (TINY) potato mashers are magnets and attracts dirt… and tools.. and make them endo and stick to things in very annoying ways as you try to reassemble the trackball. If you get a metal flake wedged between the sensor and the magnet cylinder as you roll the cylinder past it you draw nice metal residue rings around the black magnet, which do not come off easily (but fortunately do not affect operation).
Cleaning each bit carefully with rubbing alcohol, blowing out the cavity and the magnets, and particularly working on a strip of tacky paper (like painter’s masking tape) makes it possible to clean the parts and get the little metal bits off. The pearl itself is very likely to make a break for it across any gradient. It’s only 3.5mm in diameter; do not lose it.
These instructions helped. Basically pry the silver ring off gently from the front (under the 2/t/y key) and pop the trackball assembly out. Mine did not have the second metal retaining ring in it and seems to work fine without it.
All back together now, but it will not be accompanying me into environments with metal dust and chips as the sensor is perfectly designed to draw them into the workings and specifically right to where they will jam the rollers. It does seem fairly immune to finger grease and pocket lint though.