You are having way too much fun!
You are having way too much fun!
Another thing that is not fun: replacing the somehow still functioning 1970's magnetic ballasts in a four tube fixture and having to spend quite a while and two whole Magic Erasers to scrub off the charring/scorch marks just to get it kinda clean. The marks were caused by some combination of overheating wires and the plastic casings of the huge magnetic ballasts. Still plenty of rusty spots where the old bulbs damaged the coating, but at least it is now fairly safe with a brand new - and properly grounded - electronic ballast, new clips/holders, and two T8 LED bulbs. Now I just need to get up into the attic to add some fiberglass insulation on top of the fixture to isolate it from the scorching summer attic air. The CR-V is parked under the only access point to the attic until the airbags get replaced, so may be a while. Kinda liking the Fiat 500X rental with its really tight turn radius, but way too many 'features' for my taste and way too cramped interior (not much smaller than the CR-V, but so much less room in both rear seats and cargo area). Also, really not a fan of electronically adjustable seats that only slide up-forward and down-back because they assume people's legs and torsos scale at the same rate.
Interference fit: Great for bearings, bad for doors!
Forgot to mention that what I thought was weld splatter on the rim was actually just the enamel to surface steel bond being stronger than the surface steel to sub-surface steel bond. So only four bolts and a little bent lip of steel holding these wheels together.
Also remembered that the former A/C vent (one of two; other removed and wall patched many years ago when termites hit the main beam of the house) to the garage that never had a garage door would be a very nice place to put new ducting to a dust/chip collection/exhaust system so I don't have to get a super expensive <30micron filter or cut new exhaust holes anywhere else. Would also help vent the radon gas since I've not yet installed a sub-slab venting system or completely resealed the many cracks in the slab or resealed all the walls where the old damtite crumbled off.
Also also finally got a cheap set of calipers and the wire gap in the stator is only 4.5mm wide, so have to reduce copper strip width to 4.2~4.3mm.
Last edited by tician; 07-15-2016 at 12:07 PM.
Home ownership: There's no ruin like home!
I have a 150 ft redwood tree on the lot line that is literally lifting my garage and bedroom into the air.
This tree is about 10 feet diameter. Quite impressive actually, and I like it a lot! But it has to go.
Except the city forbids taking down trees wider than 12 inches... (except with certain hoops I have to now learn)
Last edited by jwatte; 07-16-2016 at 08:37 PM.
Taking down a tree that big and old just seems obscene; would much rather move the house than the tree. Biggest tree on our lot and a half is an oak a few years younger than me at ~25 years and ~2[ft] in diameter. Was quickly replanted by the dumbass at the bottom of a very steep ~10[ft] hill next to the street so the branches always hit trucks and buses as they pass. About ten more oaks planted a few years later along the top of the hill within a few feet of the street for even more annoyance by branches hitting vehicles and SO MANY LEAVES every fall. Planting a magnolia under the power lines was not very wise and the privet along the property line is an ugly, horribly invasive abomination that has spread everywhere, but the most terrifying act of the dumbass was planting a beech tree directly in the path of the sewage line and/or on top of the septic tank the line feeds into. Nothing short of miraculous that it has not yet caused any problems in its 20-ish years of growth.
If I ever do manage to get a reliable source of income, one of the first items on the capital intensive hit list is the roof and siding with the enclosed porch and chimney going with them. The porch is floating on round steel tubes on small concrete pilings and somewhat attached to the exterior and roof of the house, but it has shifted away from rest of house on an actual foundation leaving a gap along some of the roof interface. Want to rip the majority of the structure off to leave just a deck then build a new flat-ish (green?) roof over the deck that is completely disconnected and sloping away from the rest of the house. There is very good reason to believe that there is no wood sheeting (or moisture barrier?) under the wood plank siding, so I want to rip it all off then replace the entire exterior that is not the brick/stucco clad cinder block basement/foundation walls with a high-albedo membrane. Better protection from the elements, easier maintenance, and no more exposed wood for carpenter bees to infest or easily access the attic (they just crawl between the gaps in the siding to get straight into the attic; depth of siding and walls does not change when transitioning between attic space and first/ground floor walls, so likely little to nothing isolating insulation from siding). Also less material to go to landfill if ever able to afford to gut the house and let the local fire department use it as a training site before knocking out the main support posts and dropping the entire house into its own footprint.
Rotor magnets should arrive in the next couple days, so will finally be able order the rotor plates after verifying the magnets are not magnetized along their 30mm length. Intend to wind every tooth/pole of the stator identically with both ends of the winding exposed on the perimeter of the motor so the electrical termination can be easily modified by a few wires on the exterior of the motor. Finally sat down to work out winding/termination patterns to make the 10 pole rotor spin in the 8 pole stator with consistent step size and probably going with either X-terminated 4-phase or 2-independent-phases like the bipolar stepper it once was. They are functionally equivalent and can use the same switching sequence, so really only question is "do I want all current through a single common point/connection for potentially finer step control, or split it in two for slightly lower chance of burning out a winding?" Or just go with lower torque 8-phase unipolar stepper for cheapest controller (8 low-side N-FETs)? One unipolar arrangement permits control as three or four adjacent/consecutive poles always powered and turning on/off in simple sequence spinning in same direction as rotor, which is super easy to control but results in highly unbalanced forces on rotor/bearings.
Last edited by tician; 07-21-2016 at 03:45 PM.
This is the worst part of the SF Bay area for that, unfortunately.would much rather move the house than the tree
I'd love to have a lot big enough where that would be possible
The tree probably isn't super old -- there's no "cathedral" around it, and Sequoias grow very quickly.
I bet it was fresh when the house was built, in '46.
Wasn't really thinking "move the house elsewhere in the lot"...
If I ever had the funds (I can dream), after removing this house I would use the existing sub-grade foundation/basement walls as a simple retaining wall and build a new steel framed house within the old footprint suspended from two reinforced concrete piles down to bedrock spaced along the long axis of the house. No more worrying about flooding or significant infiltration of radon gas into the living space, and can easily adjust the height of the house on the piles to keep it level. Current house is quite large, but nearly half of the house's area is the basement that is unlivable storage space with really high radon levels and occasional flooding because the exterior was never properly sealed, the weeping tile is largely ineffective, and the basement slab is barely a foot above the sediment filled former creek bed. Old slab and foundation from the garage, mudroom, and laundry room section of the current house would get a new disconnected garage, workshop, and utility control center. Prefer to have everything contained under a large, slightly arched, heavy steel green roof on several more piles just outside the existing foundation to keep things cooler (and pretty well protected from the occasional tornado, falling tree, and heavy snow) and have wire ropes or chains hanging along much of the perimeter to be colonized by native wisteria to form a living wall from ground level to green roof.
Magnets arrived today and are indeed magnetized through the 3mm thickness, so do not have to start over searching for magnets to use in the rotor. Actual dimensions of the 30mm x 5mm x 3mm magnets are 29.12mm x 2.66mm x 4.66mm, so more room for adhesive in the cutouts of the rotor plates than I was anticipating which is not a horrible thing. Probably two weeks before I get the plates since I did not bother to add any rush to the order and not paying for prime.
Got the rotor plates today since it took way less than 8 days to cut out a single P1 sheet of 3mm clear acrylic. Some very cool patterns in the scraps that I'll probably put to use with edge lighting somewhere. Wishing I had made the shaft cutout closer to 8mm. I was going for ~7mm to then tap for M8 since I have M8 threaded rod and thought I had an M8 tap (kit only actually has M3 to M7; doh!), but arrived with 7.08mm ID so could have gotten very close to 8mm for the proper shafts that should arrive tomorrow without any additional work... Oh, well. Going to grind some of the 8mm shaft to make a reamer since there is quite a bit more than needed for the motors (two 8mm x 300mm shafts intended for use with recirculating ball linear bearings in 3D printers).
Also going to try cold/warm forging some scrap copper wire into the strips I need to wind the motor instead of buying and cutting copper sheet. Have a spool of cheap PVC insulated solid wire in the 22~24AWG range that I will likely never use for anything, and some salvaged wire in the 16~18AWG range (from fluorescent fixture and ballasts) that could be used for experimenting instead of taking straight to the recycle center. Also have some decent 14/2 cable that could be used if necessary, but rather save that for actual household needs.
Hoping to pop by harbor freight sometime this week to pick up a 20 ton bottle jack to use to try to fix the basement door frame then eventually turn into a big press with the addition of quite a bit of steel. Might also pick up a bigger heat gun since the heaterizer is insufficient to get 3mm PMMA to its glass transition temperature in a timely manner. Probably first try the alternative: draw out the specific areas I want the PMMA to bend on a piece of MDF and put down some ceramic tape insulation and cheap nichrome wire sealed between kapton to make heater strips. Wanted to have these transparent planters built and hanging in the nearly-floor-to-ceiling windows so long ago (a literal hanging garden, not just terraces), but keep getting distracted and/or procrastinating. Still not sure what these plants are called, but really need to reclaim the shelf of the unit they currently occupy.
Acrylic doesn't wear very well, and if you try anything tighter than a slip fit, you'll quickly get cracking.Got the rotor plates today since it took way less than 8 days to cut out a single P1 sheet of 3mm clear acrylic
You may already know this, but it sounds like you're trying to use the acrylic for rotating wear parts? Or is this just for encoders?
Hmm. I think I have 300 feet of 12/3 laying somewhere since 2007... I wonder if that's worth anything today?Also have some decent 14/2 cable
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