We didn’t have any fires in the neighborhood where it might have been a problem, but I’ll try the water department this year …
Oddly, the water department repainted most of the fire hydrants along most of the roads last year. This one apparently didn’t qualify, for whatever reason, despite being only slightly off Rt 376 on Sheldon:
For scale, the cylindrical part of the blade is 1.0 mm OD.
The blade with the longer face (left above and bottom below) has seen the most use and is definitely rounded at the tip:
Three unused blades have sharp tips:
From the top, the (nominal) blade angles are 60°, 45°, and 30°, generally indicated by yellow, red, and blue plastic caps. However, various eBay sellers disagree on how to measure the angle (up from surface / outward from axis) and which cap colors correspond to which angles.
The unused 45° blade bracketed by the two used blades:
The two lower blades have angles somewhere between 30° and 45°, suggesting slack grinder and QC tolerances. If the actual angle matters to you, buy an assortment (from one seller!), measure what you get, and don’t be surprised when the results aren’t anything in particular.
Perhaps, with careful attention to alignment in a non-pivoting / collet holder, one might scribe exceedingly narrow lines.
For the usual inscrutable reasons, updating bCNC killed the USB camera on the MPCNC, although it still worked fine with VLC. Rather than argue with it, I popped a more recent camera from the heap and stuck it onto the MPCNC central assembly:
One of the bird box entrance reducers I installed nigh onto a decade ago is still on duty, although downy woodpeckers definitely want a larger hole:
Another reducer had gone missing over the years, so I made one from a length of PVC pipe:
It started as 1-½ PVC pipe, 1-⅞ inch actual OD and should fit into a 1-½ hole, so I measured 1.5 × 3.15 around the circumference, bandsawed out the excess, draped it over a 1-½ Forstner bit, toasted it with a heat gun, and squashed it so it’s just a little bit bigger than the (enlarged!) hole in the box.
Now the entrance is 1-¼ (-ish), just like it should be:
The bird box in the front yard has been attracting starlings, in addition to serving as a hawkperch:
The oblong hole required advanced manufacturing techniques:
The front face should be too slick for larger birds and the little ones will zip right into the hole:
The two starlings who’d been evaluating the box seem to have moved on; we doubt they’re now homeless.
The quadrature detector, the black block on the left, is oriented with its lens (and, thus, the actual detectors) pointed away from the IR emitter. I thought it might be an assembly screwup, but it’s actually worse: the PCB layout is wrong.
A note from Tristan in NZ explains the situation:
So I have a later model than yours. It has a 2nd PCB chunk between where the legs normally would be. Just a floating piece with two holes for the legs, holding the legs from the board […] to the main board.It is also pointing the correct way (with the lens towards the three leg emitter).
The new quad detector has only three pins and no convex lens, but the active area now faces the emitter across the gap.
Because the interposer PCB occupies the space previously devoted to the emitter & detector leads, Kensington apparently soldered the new parts directly to the top surface without any clearance:
It’s like they failed to put through-vias to the rear or didn’t route them to the bottom another way, hence the solder is under the component
Tristan managed to wreck the detector while attempting to re-solder the intermittent joints, a situation I’m painfully familiar with. He replaced it with a quad detector harvested from a mid-90s optical mouse and it’s back in operation.
So I think the correct “fix” for the old-style PCBs (without the new interposer) is to unsolder the detector, rotate it so the lens faces the emitter, then somehow rewire the pins to the original pads. This won’t be easy and definitely won’t be pretty, but as long as it’s pointed in the right general direction it should work:
mine works off axis quite a bit
Should either of my Expert Mouse trackballs fail, now I know what to do
Many thanks to Tristan for reporting his findings!