Toro Dingo Platform

Last spring I won an auction for a Toro Dingo TX427 mini skid steer. Uncharacteristic of my usual equipment purchases, it didn’t need anything other than cleaning and an oil change. It came with the standard bucket, and I also later got a pallet fork attachment and a tooth bar for the bucket. Over the last year it’s been extremely useful with various landscaping tasks, as well as moving around pallets of materials for various projects. Mostly though it’s the perfect tool for dealing with downed trees and getting logs to the sawmill or burn pile.

One limitation that became apparent is the machine’s limited counterweight – the back begins to lift well before the hydraulic pressure relief trips. An optional feature from Toro addressed this problem by adding an operator platform, but mine lacked this option. I’d kept an eye out for used Toro platforms, but they weren’t often available and were overpriced – especially after considering shipping. A simplified aftermarket version was available closer to when the machines were new, but these had stopped production.

With that considered I decided to build my own platform based on pictures of the aftermarket version. It consists mainly of an expanded metal stair tread cut in half and welded back together into a square. Two square tubes reinforce the stair tread, and then it all hinges on a length of black iron pipe that runs through brackets sandwiched between the frame and the existing counterweights. Stops were then welded on each side of the platform to hold it level when deployed. When folded up against the back of the machine, a bolt (with 3d printed knob handle) holds it all in place. It’s flat enough when folder to not be in the way for operating while standing on the ground.

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Kubota F2000 Wheel Rebuild

Recently one of the wheels on the mower broke. This hub of this particular wheel has always been a weak point and I’ve welded it back at least once. This time it was too far gone though and I intended to replace it… that is until I realized this wheel is a very odd size and offset that’s specific to this series of mowers. It wasn’t clear that replacements were obtainable. With that being the case I decided to machine a new flange that could be welded in place to reinforce the inner wheel. The flange consisted of a 1/4″ steel plate turned down to the right diameter, then center bored and hole pattern drilled on the rotary table. The flange was then welded in the wheel and the back side faced on the lathe to ensure the face of the wheel would be perpendicular to the axle hub.

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Audi S4 3.0T Secondary Air Cleaning

Part 1: Background

A while ago my check engine light began coming on sporadically, after scanning I found this was related to P0491 & P0492 errors. These errors indicate that insufficient airflow is available to the secondary air system that’s responsible for getting the exhaust catalysts up to temperature quickly at start-up. These errors would self-clear, but over time the light stayed on longer until eventually it stayed on.

I first checked all the ‘easy’ stuff related to this fault: the secondary air pump and solenoid both worked OK via VCDS and no leaks were found on any of the tubing. I also tested the “combi” control valves which successfully blocked air flow when blowing through the secondary air pipe and allowed air when manually actuated with a vacuum pump. At this point I ran a good amount of seafoam and intake cleaner through the secondary air pipe that goes under the supercharger, using a HVLP paint blower to push it through the system while the combi valves were held open with vacuum – lots of smoke, no change.

This unfortunately left blockages in the cylinder head’s internal secondary air ‘manifold’ as a most likely cause for the problem, there’s a TSB with lots of good info here: https://static.nhtsa.gov/odi/tsbs/2018/MC-10153120-9999.pdf (Required Reading for this topic!)

Options at this point, in order of consideration, were:
#1 – Take it to the dealer for the 120k mi extended secondary air warranty, I had ~110k mi at that point. I strongly considered this, but in the end it didn’t seem worth the hassle. With it being high mileage by their standards I fully expected to get push-back or some excuse for it not to be covered, while potentially being on the hook for their ‘diagnostics’ fees. Either way this was likely to be a less enjoyable experience than wrenching in the garage over a long weekend.
#2 – Buy the VAS6825 tool and do it myself. The TSB has plenty of info to do the job successfully, OK let’s just order the tool and …….. it costs how much?!?!
#3 – Make the tool myself and do it myself. The tool is simple enough, and I was reasonably confident a usable tool could be made at home. I went with the last option, let’s make the tool….

 

Part 2: Tool Creation

From photos online, the official tool (fig. 1) appeared to just be two smallish diameter flexible pressure washer tubes: one that’s basically a tiny sewer jetter, spraying forward, and the other that sprays out sideways. The main passage can be cleaned manually (coat hanger, vacuum), so only the sideways spraying tool is needed. The sideways spraying tool also comes with two plates, a bushing, and an attached scale to correctly position jet in front of the perpendicular passages while still allowing some movement for wiggling the jet around for better cleaning. For my purposes the whole bushing, plate, and scale arrangement would also be omitted – I’d be using a camera to locate the distance to the passages and then positioning the tool manually. There’d be no damage risk from a misaligned jet, as water doesn’t cut aluminum at 4000psi, so the water would just come squirting back out around the tool. I assume the official tool only has the extra complexity to justify its exorbitant price and to make it more suitable for use in a professional environment.


Figure 1: Official VAS6825 tool

With that settled, I only needed a long tube with a right angle nozzle. The small diameter pressure washer hose they use for this isn’t commonly available and even if it were its not clear that any fittings would fit inside the passage. (They use a crimp connection to get around this, but that’d require expensive crimp tooling in the strange tubing size – big money for something that I’d likely never use again). The good news is that the main secondary air passage is perfectly straight, so there’s no reason for flexibility at all. With this in mind the plan quickly coalesced around using some steel tubing. The tubing I selected was a 3ft length of 3/8″OD with 0.083″ wall thickness (McMaster 89955K459). This thickness is massively overkill vs the 4000PSI of my pressure washer, but a big ID isn’t needed for flow and I was more concerned with having enough metal thickness to get good welds.

From there I took a spare chunk of 1/2″ round bar, bored a 3/8″ hole to accept the tubing, and tapped the other side to 1/4″NPT for the pressure washer coupler. (fig. 2) I did this on a lathe, but it could be done with a drill press or drill/vice if centered carefully. This was then welded* to the tube on one side along with a simple plug on the other.(fig. 3) At that point I had a fully sealed tube to which I drilled an ~0.043″ hole on the side of the end, giving me the right angle jet. (fig. 4) The hole size depends on the specs of the pressure washer, check tables online, 0.043″ was right for 4000PSI / 3.5GPM. The official tool appears to have 3 holes – I suppose you could calculate the right hole sizes for this and do it that way, but the single hole is already tiny and any performance loss from this is easily overcome by wiggling the single jet around more/longer. Lastly, add a line along the tool so it’s clear which way the nozzle is pointing. Total cost less than $30.


Figure 2: Making the end adapter


Figure 3: End adapter welded to tube, coupler fitting attached


Figure 4:Nozzle Orifice Drilled


Figure 5 : Testing

*Warning: This is effectively a DIY hydraulic line under a few thousand pounds of pressure. It can
fail forcefully with risk of injury.

 

Part 3: Cleaning

As always, remove the entire front of the car using whatever method/sequence you prefer. You’ll need unobstructed access to the front of the engine. I was able to suspend the bumper/radiator support from the ceiling and hinge it open like a gate to avoid disconnecting the AC lines. Note though that this puts strain on the upper radiator hose and that will crack the coolant crossover pipe, so disconnect it first. I only left the hose connected because I couldn’t get it off the pipe without destroying it, so it was probably doomed either way.
Get access to the secondary air ‘manifold’ freeze plugs (fig. 6); there are a number of things in the way (belts, coolant flange, hoses, etc) but if you’ve gotten this far you’ll figure it out. Pop one side of the freeze plug with a drift punch and it’ll rotate so you can yank it out with needle nose pliers. Remove coils and plugs at this point also.


Figure 6: Secondary Air Passages from the front of engine

Next use the right angle camera mirror to find the air passages with the angle of the exhaust manifold flange for reference. The passages are drilled straight from the flange (where they dead-end) up to the back of the exhaust valves. Point the mirror up in that direction, it’s the part of the passage that goes up into the valve that we want to clear, the other part that dead ends onto the back of the exhaust flange is only there because it’s much easier for them to manufacture the head that way. Once the passage is centered in the field of view mark the camera cord where it enters the cylinder head, I used colored electrical tape with different colors for each bank; repeat for all 6 passages. (fig. 7) Reference measurements in table 1.

Driver (US) Passenger
Front 75mm 45mm
Middle 165mm 135mm
Rear 255mm 225mm

Table 1: Distance from Port Edge to Passage Center


Figure 7: Marking the individual passage locations

Warning: Make sure the camera body is securely attached to the cord! Even though my camera (depstech) appeared to be one piece it decided to separate – the cord pulled out and left the camera guts and front body in the passage. This could be disastrous as you’d then need to drop the transmission to pull off the combi valve to push the camera body out from the other side. I was extremely lucky this happened close enough to the end that I was able to access it with small needle nose pliers and pull it out. It re-assembled no problem, the cord had a connector inside the camera body. After that I epoxied the cord to the camera body and wrapped them together with electrical tape for extra insurance.

Next put the camera and cleaning tool next to each other with the mirror and nozzle orifice aligned and transfer all the markings onto the cleaning tool.(fig. 8) All that’s left at this point is to drop the exhaust before the catalysts, setup a big storage container to catch the water, insert the tool, and start blasting. (fig. 9) You’ll also want a catch container up front under the tool, drape a wet rag (if it’s dry it’ll blow away) over the tool so that the water coming out will hit it and drop into the catch container. Insert the tool to the depth of the first marking and rotate so the line on the tool is facing the right way (the same angle you found the passage with the mirror). Set a timer for 3min and pull the trigger. You’ll get an initial blast of dirty water from the main passage as the jet eats through the blockage, this should pass almost instantly. If it doesn’t, you’re off-target – try rotating and moving the tool in/out until water stops blasting out of the front. It’s very apparent when you’re on-target, no water comes out of the front and there’s a satisfying gurgling noise. For the remainder of the time I just moved the tool in/out and rotated back/forth, changing direction when water began coming from the front. Repeat for all passages.


Figure 8: Transferring passage depths to cleaning tool


Figure 9: Blasting! (not shown aligned)

Once complete, use a vacuum extractor to try to pull water from all the plug holes. It was clear during blasting that one exhaust valve was open on each bank, and these two cylinders did have a little bit of water. Next crank it a few times with the plugs out as a precaution before fully reassembling and clearing all the codes.

The camera had a hard time focusing on the clogged ports, I had to really work to get usable pictures but you can see a very small dark area in the middle of the before shots – I believe these were the only open area and you can definitely see the edge of the port, so everything in-between was crud. (fig. 10) After cleaning I got great pictures with no effort at all that immediately showed fully clear. (fig. 11) The process was a success and the code has not returned as of many months later.


Figure 10: Typical Passage Before Cleaning


Figure 11: Typical Passage After Cleaning

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S4 Clutch Replacement

The clutch on my car finally started slipping when under full power. This wasn’t completely unexpected since it originally came from a high-traffic area of NJ. I was able to get it replaced over the past two weekends plus a couple of weeknights. There wasn’t anything particularly difficult about this and it’s well documented online, just lots of small challenges in a row with figuring out how to access various fasteners.

While I was at it I took the opportunity to replace belts, plugs, change the supercharger oil, etc.

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Custom Desk – Monitor Lift Mechanism

I got the idea for the monitor lift from an example online using all-thread as lead screws to drive a platform. Essentially I’m just replicating this idea but with a few tweaks that take advantage of having the lathe to make it better/stronger, easier to build, and to take advantage of spare parts I already had.

First I cut the all-thread rod to length and then I turned down one end of each to fit the inside diameter of some spare bearings. I left an extra bit on the end and turned it down to fit the inside diameter of a timing belt drive sprocket – this was later replaced with a chain sprocket due to slipping.  I repeated the same on the top side of each rod (without the extra bit for the drive sprocket) and then I cut some metal brackets to hold the outer bearings. I then cut a small platform and attached two nuts to it that would connect it to the threaded rods.

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These parts were all assembled into the desk; a few small shims were needed to get the rods exactly parallel. I then connected the threaded rods together with a small #25 chain drive. To power the lift I tried a few different test motors and eventually settled on the guts from a small/cheap electric screwdriver – this provided enough torque while not requiring a huge power supply. It could be a bit faster and I need to add some sound damping, but it’s working very well for an initial attempt.

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I also made some mounting plates to adapt the monitors to a fixed mounting since the regular bases were too wide. The monitors were then mounted to a 2×4 that acts as a spacer and also adds strength to the platform. Once the tabletop is in place the 2×4 and the rest of the mechanism will not be visible since the monitors will rise so that their bases are just flush with the top – I’ll likely add a trim piece to block this off. The monitors also drop low enough that the table top will clear with no problems.

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The last step was adding limit switches and rewiring – moving the toggle switch up runs the lift up until the positive switch is tripped, and moving the switch down runs the lift down until the lower limit switch is tripped.

Desk

Next up will be making the tabletop…

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Prop Straightening

Continuing with the home office/study/library build, I found some decoration via a damaged airplane propeller. I was able to straighten it out using the press and some 2×4 blocking. The aluminum is springy so the key to getting it flat is to bend a bit past flat, just enough so that when it springs back it’s straight.

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There was a possibility that the amount of bending needed would create cracks. Based on prior experience with aluminum, I would expect for the paint to flake and for the surface underneath to turn white just before cracks occurred and I was looking out for this. If cracking had started, the plan was to heat the area with a torch until it was annealed, then continue bending – this would also have required repainting, so I’m glad it wasn’t needed.

For mounting it to the wall I cut a circle of 3/4″ plywood on the bandsaw. The circle is just small enough to fit into the prop hub, but too big to go through the smaller hole of the inner hub. Long cabinet screws then secure the plywood to a stud, sandwiching the prop in place. I plan to make another circle, paint black, and fit it into the hub to cover the structural piece.

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Balalaika Repair

We recently received a Balalaika from family that once lived in Alaska.  The balalaika is a common folk instrument in Russia and there is a long Russian history/connection in the part of Alaska where this originated. It had been in storage and a few parts were missing that needed to be replaced:

– End Pins – 1 of the 3 end pins remained and I used it as a reference for turning 2 more matching pins on the lathe from a plastic rod.

– Bridge – The bridge was missing but I found dimensions that seemed to match the shadow that had been left by the original bridge; I used these dimensions and some reference photos online to make a replacement out of a scrap of maple. This was very quick work with the belt sander.

– Strings – This was the easiest part, available online.

With the parts replaced we were able to tune it and it seems to play OK…

With an endoscope camera I was able to find two labels inside:

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Left Translation: Balalaika. Article #205. Airbrush method finish. Nationwide Standard of Russian Soviet Federative Socialist Republic 83-72. Price 6 rubles 70 kopeks. Leningrad, 15 Chapaev St.

Right Translation: Ministry of Local Industry of Russian Soviet Federative Socialist Republic
Main Directorate of Production of Musical Instruments
Lunacharsky Factory of Folk (plucked string) musical instruments
Leningrad

The left label is also stamped with a 1973 date

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Piano Automation Begins

This weekend I designed and began fabrication of the parts needed for adapting the solenoid valves to the piano’s tracker bar. This adapter will consist of two 3/8″ aluminum plates. The top plate will have holes to accept the solenoid valves, and the bottom plate will have holes to interface with the piano’s tracker bar. Grooves will be machined into the bottom plate to create airs channel between the tracker bar holes and the solenoid valves above. The two plate will then be sealed together, covering the grooves; a similar construction technique as some carburetors. As long as the grooves are carefully routed, each valve should connect to exactly 1 tracker bar hole.

I cut the 3/8″x6″ plate on the band saw and then milled to final length. I used an edge finder to locate the plate edges, and then used the mill’s digital readout to position above each row/hole. For each row I took 2 passes, first spot drilling with a center drill and then drilling to size with a twist drill. 88 * 2 plates * 2 passes = 352 cycles of positioning the X axis and drilling a hole. Once all the holes were drilled I sanded sides to remove burrs from the holes and scratches from the rough plate.

Next I installed and wired the solenoid valves in the top plate. The solenoid valves are an exact fit to the hole, but I added a bit of CA glue to ensure they stay in place. Wiring consists of scrap Ethernet cord that’s been stripped back; Every ~7 solenoids each share a common wire to reduce wiring, but it’s still ~100wires.

I’m happy with the results so far; this is by far the most precise thing I’ve made on the mill and everything is lining up perfectly. The next step will be to 3D model the grooves and convert these to paths to run on the CNC router. I’ve done some aluminum milling with it previously so it should work out OK, especially since it’s just cutting the shallow grooves – I wouldn’t have trusted the router to drill the holes as well as the mill did.

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Window Crank Adapter

It’s not particularly hard to use a window crank, but multiplied by several windows it does take a little bit more time than it could.  With this in mind I created an adapter for a cordless drill to more quickly open/close windows, particularly as it’s starting to cool down some and we’re using the windows more.

Construction was relatively straight forward, it’s just a bit of aluminum turned to size and with a hole drilled with the same size as the OD of the splines on the window crank mechanism. The only tricky part was creating the splines since this is the first time I’ve attempted it. The lathe has a built-in index plate that allowed the adapter to be positioned in the 12 evenly divided positions required; once it was in each position I used a small lathe tool to broach a slot, moving the carriage back and forth with the lathe off while slowly raising the tool. I then turned a bit of steel rod to size and pressed it into the back of the adapter.

Overall it turned out OK – the splines aren’t the greatest due to the tool not being very rigid, but it’s plenty good enough for it to engage with the window and hold solidly.

 

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Kubota F2000 Snow Plow

We don’t get much snow here, but when we do it takes a lot of shoveling to get out to the road. If conditions are just right we can be stuck for several days waiting for it all to melt. As a result I’ve had a mower/atv sized plow on my watch list since last winter. Recently a new open-box plow popped up that, after factoring in their free shipping, I got for basically scrap value or less. I think the reason for the low price was that it had originally been part of a kit, but all the mounting parts were missing.  For my purposes that’s OK though – no one makes a kit specific to the F2000 anyways, so I was always going to need to fabricate the mounting parts myself.

Making the mounting bar just consisted of cutting some 1″x2″ tube to length, squaring off the cuts on the mill, drilling holes for the pins, and then welding everything together. From there the plow’s base just clamped between the mounting bar and another section of tube.I made the clamping bolts fit just inside the plow base’s big hole so the plow can be rotated by loosening the bolts. Since the push bar connects to the standard implement mounting points, the plow can be raised/lowered the same way as the mower deck. I also needed to make some stepped bushings on the lathe to fit the plow base to the plow.

Kubota doesn’t list a tow/plow rating for the F2000, but it’s 4WD with a 3 cylinder diesel and built exactly the same as a ‘normal’ compact tractor, the only difference is that its seating position is spun around 180deg. For occasional plow usage I don’t foresee any issues. I may need to tie into the plow base’s rear holes for stability and to prevent unwanted rotation, but I’ll try it out first to see if this is necessary.

As part of the plow installation project I also went through the mower’s electrics and replaced a lot of corroded connectors with solder/heatshrink splices. It turns out the glow plugs hadn’t been working all along. With the glow plugs now working it starts a lot faster and in winter this will likely be a necessity to start at all.

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