Generator Rebuild

Hurricane Michael hit our area hard and took out power for almost 5 days. Luckily the small generator we already had was enough to keep the fridge running and some lights on, but not much else. The small generator is 120V only, so it also was not able to power the 240V well pump; 4 nights without running water was not fun. It’s not likely we’ll have another outage that’s this long for a while, but we have had a number of shorter outages that seem to indicate that this will be an ongoing problem – a bigger generator would be nice.

With that in mind we started looking at options; there are a number of ‘off the shelf’ options out there for whole-house standby power, but most of them are very pricey both to install and to run (propane particularly) and we couldn’t justify the cost for something that gets used so infrequently. What did seem to make some sense though was rolling the dice a surplus military generator; the prices are very low (when the condition is unknown), they’re way over-built, and are made to be repaired easily.

I bid on and won an online surplus auction for a diesel generator and picked it up outside our friendly neighborhood military base. It was a fairly easy move at ~1200lb; at pickup I just dragged it onto the trailer with a winch and to offload I tilted the trailer and winched it back down with iron pipes underneath as rollers.

To get it running I first put in new batteries (2x 12v car batteries) and troubleshot some miscellaneous electrical issues (broken connections, dirty switch contacts, etc.). From there it would crank but not run; bleeding the air out out the fuel lines fixed this and it started OK. Once running there was an erratic low frequency rattle that I traced to a bad rotor bearing on the generator head. With this bearing replaced it then ran smooth/quiet. The last issue was twitchy voltage regulation that I traced back to a dirty potentiometer; with this cleaned it held a stable 240V @ 60hz under a variety of loads. Along the way it also got an oil/filter change and a coolant flush/fill.

Altogether this was a very quick project, just a few hours to get everything sorted out. Up next will be setting aside some space for it (probably combined with a new area for trashcans and firewood) and getting it wired in with a manual transfer switch. It’s a “10KW” generator but that rating is on the very conservative side; in reality it’s closer to a 15KW or more consumer unit whose ratings are on the optimistic side. This should be enough to run the lights, TV, well, microwave, and at least one zone of HVAC.

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Custom E12 LED Bulbs

For the generator project (more on that soon) I needed some somewhat specialized replacement bulbs to fix the control panel lighting. These bulbs are 6W / 30V (the generator has as 24VDC electrical system) with a E12/candelabra base. They also have to be very short to fit inside the shades on the panel light holders. The 120V version of this bulb, model “6S6”, is very common and 3-packs were available for a few bucks locally. I knew these would probably be too dim but I picked some up anyways and tried them out. Not surprisingly the 120V filament at 30V barely glowed red.

Since the 6S6 bulbs didn’t work, the next option would have been to order the correct 6W/30V bulbs. The price for these bulbs seemed crazy though, so instead (and for less cost) I opted for a 4-pack of 24V LED lights of a similar size. Although the size if the LEDs was similar, the base type was meant for a wedge connection, so I had to get creative in grafting the LED lights to the E12/candelabra bases.

First I broke the original bulbs and chipped away the glass to leave only the base and wires. Next the wires were soldered to the LED bulbs, insulated with electrical tape, and the whole thing was pushed into the bulb base. The base was then filled with hot glue and the joint covered with heat shrink.

In the end I think they went together very nicely and since they’re LED they should last a lot longer while being brighter and draining the generator batteries less; best of all the whole setup cost less than the ‘proper’ replacement bulbs.

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Small Parts Organization

Background:

The new shop has given me the opportunity to rethink storage of the miscellaneous small parts I have laying around: nails, screws, nuts, bolts, brackets, cable ties, electrical connectors, fittings, etc. The previous system I had was to sort by type (i.e. nails) into individual plastic shelf bins (the common Blue/Red/Yellow type). This was better than nothing, but the downside was that every time I needed something I had to dump the whole bin into a sorting tray and search.

The new method uses a rack of portable parts storage cases.  These cases give the ability to sort by main type (i.e. nails all in one case) but also by individual size (i.e. 1″ finish nails). The cases also have removable bins inside of various sizes; by swapping these around I’ll be able to optimize storage – swap bins between the cases that have more big parts vs those that have more small parts.

I considered the individual drawer style of parts organizers also; when I’ve had these in the past it seemed like I was constantly opening and closing the tiny drawers to look at parts from above; the drawers also easily jammed closed when full. The parts storage cases should prevent both of these problems.

(There are lots of similar projects online that sparked the idea, so this definitely isn’t something I can take credit for coming up with.)

Construction:

Last weekend I built a cabinet to house the ‘machinist’ toolbox used for the mill and lathe tools; the cabinet also supports the lathe itself. For the countertop I’m again using the “Norm Abrams” design – plywood topped with a varnished hardboard layer that’s cheap/easy to replace when it gets too beat up; I had these at the last shop and they worked really well. I left room in the cabinet for this parts organizer idea, so today I just needed to outfit it with shelves to support the parts cases. The rack consists of the shelves themselves as well as spacer blocks that help support the shelves and make it easy to get the correct spacing. The process for making the shelves was as follows:

  • Rough cut each shelf from the plywood panel with a circular saw.
  • Square and cut the shelf to final dimensions on the table saw.
  • (For the first shelf) Drill holes at the corner of the handle area and finish cutting it out with the bandsaw.
  • (For all other shelves) Clamp the shelf to the first shelf and trim out the handle area area with the flush cut router bit.
  • Run the router over both front edges with a 1/4″ round-over bit.

There’s now an empty space in the cabinet behind the cases that I may eventually tap into and repeat the same idea using the smaller version of the cases; this would be accessed from the side of the cabinet, but for now it’s not needed.

I intentionally got a couple extra cases. This allows more options for swapping around internal bins, but primarily it’s so I have backups in case a case ever gets broken and exact replacements are no longer available.

All that’s left is to add an inset door (the cases are offset to the left to allow room for a door and hinges on the right), a slide-out platform at the top, and then finish trimming/sanding/painting everything.

(I also finished and painted the walls/trim then ground and epoxied the floor over the last several weekends, but I forgot to get in-progress pictures.)

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Sliding Doors

The shop floor plan allows for a large opening between the ‘far’ end of the shop and the auto repair/bus area. This will allow tools to be easily shared between both spaces; during a big auto project the repair bay can become an extension of the workshop. The opening is also big enough to bring in the front or rear of a vehicle if ever needed. When auto projects aren’t underway though I’d like to have doors cover this opening to prevent dust/mess from wood/metal project leaving the shop area and to save on shop heating/cooling costs.

The size of the opening presents a problem – swinging doors would have to swing ‘out’ of the shop to avoid hitting cabinets, and the large sweep would require moving anything parked on the garage side out of the way temporarily, kind of a hassle. To avoid this problem, sliding doors made the most sense.

The shop build project is being run with the materials cost set to minimum and the end-product quality set as high as is practical. This sounds unrealistic but is actually possible with the trade-off being time; it’s not a problem though since I count this as hobby time and there’s no particular deadline. The sliding doors are a great example of this – sliding doors and hardware are outrageously expensive compared to the raw materials cost. Building my own also gives me full control, in this case I wanted to avoid the farmhouse/barndoor/rustic look in favor of cleaner traditional/modern look. Over the last few weekends I’ve built the doors and tracks below, key points:

  • Door frames from 2×6’s, planed down to standard 1 3/8″ door thickness
  • Mortise and tenon joints connect frame pieces (tenons via table saw dado stack, mortises via router and chisel)
  • Slide rail is two 3/16″ x 3″ x 10′ flat bar sections welded in the middle.
  • Door bracket pins turned and threaded on lathe then welded to brackets.
  • Aluminum rollers turned on the lathe, held to the brackets using standard 608 skate bearings.
  • Brackets recessed into door frame and secured to the doors with studs welded to back side for a completely smooth front.
  • 1/4″ Tempered glass sourced from local glass shop.
  • Groove along bottom of door and small bottom bracket keep door located against the wall and limit inward overtravel.
  • Roller to door top spacing and roller flange width prevent door from lifting/falling off rail.

There’s a good bit of finishing work still left, but I’m happy with the results so far.

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Shop Insulation

The shop is coming along well and this weekend the bulk of the insulation was installed. Friday night we picked up R15 Roxul batts for the walls and installed in just few hours. The attic was another story though and all of Saturday and Sunday AM were spent crab walking over attic joists installing baffles. The baffles are needed to keep the blow-in insulation from falling out of the attic area and into the soffits. The roof over the garage has a shallower pitch towards the edges (if you visualize a pizza hut roof you’re not far off) which made it especially tricky to get access.

Once the baffles were up we picked up the blow-in insulation Sunday mid-day and had it all blown in in couple hours. The high pallet of insulation looked really odd on the trailer, but was secured well. Even compressed it’s not very dense, this was ~900lbs maybe ~1100lbs with the machine.

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The Bridgeport has landed

I’ve had my eye out for the last few years for a milling machine to expand on machine shop capabilities. Finally this weekend I was in the right place at the right time to see the right listing come up and jump on it. As Bridgeport-style milling machines go it’s on the smaller side, but for my purposes this will be ideal. It was built in 1942 and is one of the early the “round ram” style machines with an “M” head. The previous owner has a makeshift rotary phase converter installed; consisting of a larger 3phase motor and a rope to pull-start it. This works fine for now but I may eventually replace it with a variable frequency drive.

How to move a mill had always been a concern when considering getting one. It weights in at ~1800lbs (the bus is ~2300lbs for comparison), which is exactly at my trailer and tow vehicle’s listed rating after adding the weight of the trailer itself. I think the rating has more to due with structural limits though and it did fine with plenty of power/brakes on the ~30mi trip. Loading was a breeze since the seller had an overhead crane.

The mill’s weight is concentrated in a small footprint with a lot of the weight being relatively high-up; 2×6’s were used to distribute the load across the trailer structure rather than the weak mesh floor. I had not considered the height and got lucky that the top of the mill while on the trailer cleared the garage door by about 1/2″. It wouldn’t have been a problem really, but this made the difference between unloading inside vs outside. During unloading the trailer and ramp were supported with wood cribbing and the mill was inched along using ratchet straps and a long metal bar. As long as you don’t get in a hurry with moving heavy stuff the worst that can happen is that it takes forever.

(Also shop is in-progress in the background, walls starting to go up)

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New Shop

It’s been over a year since the last update but with good reason: we’ve moved. As a result of the move I’ve been busy with a long list of projects to get the new place up to standard. It isn’t exactly a complete fixer-upper, but it definitely is/was behind on a lot of maintenance and upkeep.

With this change comes more garage space; the plan is to have more dedicated areas in the garage to better serve the three (sometimes conflicting) purposes of: #1 Machine Shop / Wood Shop, #2 Auto repair bay (Doubles as Bus storage), and #3 parking for commuter cars.  Key to this idea is building a partition wall between garage and shop areas –  cars will no longer get covered in sawdust during projects, and the extra wall will create more wall space for workbenches, machines, and storage.

The design has part of the partition wall at 45deg to make the commuter parking area larger for easier loading/unloading. This also leaves some space for a utilities closet to house the air compressor, dust collection, and the house’s existing central vac unit. Putting the utilities in a small ‘lean-to’ shed on the exterior like I had at the old place would have been a better use of floor space, but there really was no good place for it on the exterior and that would have added more complexity.

I’ll be building 100% of this as I have free time, so it may take a while. Realistically completion will probably be about this time next year.

Garage Plan

 

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Jet Engine Oil System – Test Run

Tonight I tested the oil pump – it worked so well that the pressure blew off one of the plastic tubes I was using for testing and sneezed oil over everything. After I cleaned up the mess I connected it into the system and did another test run. The extra resistance of the oil passing through the turbo bearings caused the pump to stall out on the first attempt. The pump was originally designed to move air, so it’s not surprising that oil was too much of a load. To remedy this I made a new crankshaft for the pump on the lathe with as short of a ‘throw’ for the piston as possible. With the shorter throw, the pump is moving less oil per rev which reduces the load and prevented the motor stall. After this change it successfully ran continuously and held an average pressure in the system of about 75PSI, right about where it needs to be. To keep things simple I don’t have a bypass or pressure regulator in the system; because of this the pressure gauge flutters with each pump stroke but this doesn’t hurt functionality.

The motor draws about 5A, at 12V this is ‘only’ 60Watts and is about the same or even a bit less than when it was an inflator pump. Since it will now be running for longer time periods though I need to keep an eye on the motor temperature. I also need to protect the plastic gear from the (eventual) heat of the combustor above. To address both of these problems I’ll likely make a heat shield for this area as well as add a cooling fan.

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Jet Engine Oil System

This weekend I resumed work on the jet engine project. When I last left off I had just completed the frame and mounted the turbocharger/combustor. I had also fabricated an oil tank out of an old propane tank and mounted it under the turbo, but had hit a bit of a wall with what to do for an oil pump. There are electric oil pumps available, but basically all of them would be overkill for this application. Also, since this is a hobby I’d much rather put in the time to make something custom vs paying for parts. Turbocharger jet engines have been done by many others, my approach with this is to see how compact and well packaged I can make one – that doesn’t happen by bolting together a bunch of off-the-shelf parts.

I had considered using the bus’s old oil pump, but this created more problems than it solved (connection of inlet/output pipes would be a challenge as would driving it and selecting a motor). Today after a taking a fresh look at it I realized that an old 12V tire inflator pump that I had could be adapted to work. The plastic casing had broken, but the ‘guts’ were all metal and should hold up to oil pump duty. The only problem was that the cylinder head of the pump had no way of connecting an inlet pipe – being designed for air, it just drew in air from a small hole. To fix this, I made a new cylinder head on the lathe with one large hole in the center. A tee fitting screws into the head and I’ll put a check valve on each side. This larger single-hole head should also help compensate for the increased load of pumping oil, much thicker than air. Once I start running oil through it I may have to make some tweaks to avoid overload (lower voltage, thin oil, etc) but this at least gives a path forward for experimentation.

I also shortened the oil tank to make more room underneath for other support systems and made a threaded port on the lathe to weld into the tank to connect the oil pump. The welds aren’t the greatest looking, but are leak-free and that’s what matters – they should clean up OK after some grinding. For now the whole project is in fabrication mode, but once everything is in place and working I’ll go back and do body/paint work on all the parts to make it look nice too.

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Converti-bug Top Replacement

Last night and today we replaced the top on the Beetle. It was in ‘OK’ shape but was showing its age and the back window had begun separating/leaking, requiring roof replacement. Complexity level for this ranks right up there with an engine rebuild or debugging bad assembly code. The biggest challenge is that all the miscellaneous springs, ropes, and bungees involved don’t have the usual ‘this clearly bolts there’ pattern – instead it’s a spider web of cords that have to be routed just right, and their appearance changes greatly depending on how far up/down the roof is. With the help of lots of reference images though it all went back together correctly. Fortunately for modern tops like this there’s enough repeatably between cars that the tops come pre-cut with all the right seams/edges pre-made; there’s no trimming or other ‘upholstery’ type work that would be required on an older car.

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