Archive for June, 2013

Debugging a Troy-Bilt sicklebar mower

June 23, 2013

With the Jari on the disabled list (burned up motor, leftside wheel, and shroud), I set to rehabilitating the 42″ Troy-Bilt sickle mower I bought last weekend.  It started right up when I bought it, but it had a damaged belt, which I thought was the reason it jumped off the pulley when I engaged the sickle bar.  So I bought a new belt (1/2″x35″, for future reference), put it on, and it fired up the cutterbar, but it too jumped the pulley as soon as I put it under load.  There were two little bent steel ‘keepers’ on either side that seemed designed to keep the belt on, but they only extended halfway down the axial depth of the pulley, so I thought maybe they were insufficient, and I made better ones out of scrap aluminum.  However, as soon as I started to cut grass, the belt jumped the pulley again, and my new keepers very effectively ripped the belt in two.

mower broken belt

 

At that point I suspected something more fundamental, and in looking carefully I noticed that the motor pulley was axially mis-aligned with the cutterbar pulley by about 3/8″.  Joshua and I puzzled on it for a bit, and we noticed that the pulley was held on the end of the shaft with a suspiciously non-factory-looking bolt and stack of washers.  To my surprise, the pulley was not frozen to the shaft, but rather moved easily once the set screws were released.  I tapped it up into alignment:

mower shaft

 

Given the retrofit bolt arrangement, I didn’t judge that the set screws were capable of holding the pulley in place, so I whipped out a spacer on the Bridgeport – didn’t have round tubing the right size, but 1″ thin-wall aluminum square tube fit over with a bit of encouragement (must be a 7/8″ shaft):

mower shaft with spacer

 

I Secured the pulley with the bolt and washer stack, reassembled using the old belt (not about to blow another brand-new $14 belt on this mower), fired up, and it cut nicely for about 100 yards.  It was too hot in the middle of the day to really put it through its paces, but I think we’re provisionally back in the sickle-bar mowing business.

The Troy-Bilt seems a little slower than the Jari, but has 10″ of extra width, so they probably will work at about the same rate.  It’s a wider, heavier machine with janky plastic catches on the levers for the tank-style independent steering clutches, and at first go I don’t like it quite as much, but I suspect I’ll get accustomed to it.  Still, since I think I have a spare engine that will fit the Jari in place of the burned-up unit, I think I’ll order a replacement wheel and try to put it back in service eventually, as limited spare time permits…

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Pedal cider press does off-season duty as a broach

June 21, 2013

I’ve needed a hydraulic press on a couple of occasions recently, and haven’t felt like buying one of those clanky steel-frame jobs with a bottle jack – so on the last trip to Five Islands I brought back the cider press and bike-hydraulic setup, and we’ve been using it in the woodshed as a 20-ton press.  While it doesn’t have the adjustability of the steel presses, it does have a 24″ stroke, which goes a long way.  Here we have just finished broaching a Lovejoy coupling to accept a key:

press used as broach

 

I have a notion to upgrade the pedal-hydraulic power unit to make it less janky and more portable, making it better suited to other applications, such as operating a worm-drive winch to raise and lower wind turbine towers.  But in the meanwhile we might as well keep it well exercised…

Jari Mower RIP

June 16, 2013

jari on fire

I am sad to report that the Jari mower bit the dust this weekend.  I purchased it about two years ago from a guy upcountry, and put several hours into getting it running well.  I sorted out most of the issues, including the frozen-up cutter bar and rotted gas tank, but the replacement tank never quite fit right – there was a slight intermittent gas leak between the top of the tank and the carb, and I never could figure out why.  However, on Saturday it finally caught up with me.  The mower ran out of gas so I shut it off, filled the tank, and as soon as I cranked it up a small flame started on the surface of the carburetor. I tried to bat it out with a mat of fresh-cut green grass, and it almost worked, but the flames persisted.  I ran over to the neighbor’s and grabbed two fire extinguishers, and exhausted them on it, but by that time the metal was hot enough that it re-ignited after the powder stopped flowing.

I didn’t think it would explode, since the gas seemed to be escaping from the tank – at first through the leak, and subsequently through the zinc carburetor, which melted into a puddle on the ground.  Still, I ran down the hill for some hoses, to tap the neighbor’s water.  At peak the flames reached 6-8 feet high, but by the time we had the hoses up there the gas had burned itself out, and the fire was reduced to burning the rubber tire, belts, and the thermoformed plastic fairing on the front.  Ben Wilkins tossed a couple of pails of water on the smoldering heap and the excitement was over.

Once it cooled off, Bodhi and Kieran rolled the machine down the hill and I took stock of the damage.  The engine was pretty well baked (as I mentioned the carb had completely melted), the left tire and shroud were shot, and the belts were burned down to the fiber cores.  But the frame was intact, and even most of the paint was still in good shape – I tipped the machine over on its side when it caught fire so the tank was up, and there wasn’t much to burn up forward.  One of the idler pulleys looks pretty baked, so it would probably need to be replaced.  Joshua and I toyed with the idea of doing an electric retrofit, since sickle mowers don’t use a lot of power compared to rotary machines, and using two separate motors would significantly simplify the mechanicals.  Unfortunately, I haven’t got time to do a major rebuild (or an electric conversion), so today I bought another used sickle mower (Troy-Bilt make) from a nice retired couple in Cornish – I’ll tune it up next weekend and see how I like it.

Running the mighty Stroudwater

June 8, 2013

A couple of weekends ago, Emily, Andy, and Elsie came to visit, and Andy (who has done a lot more paddling than I) got the notion to run Stroudwater falls.

In dry times the river running through our front yard is little more than an overgrown brook, but when multiple inches of rain fall over a day  or more, it swells impressively.  Instead of sneaking around and through the abrupt ~1m rocky upper fall at low points in the bedrock, it rushes directly over the drop in a handful of weakly organized chutes into the millpond below.  We scoped it out and judged it (and the rapid below the ruined dam) doable.

running the stroudwater 1

Borrowing Joshua and Kelsey’s 16′ fiberglass canoe (not the beautiful cedar one his brother made for him), we carried upriver and put in.  The main channel in low water is a tight 180 degree bend at the far right, but we didn’t think we could maneuver that, so we went through the next largest chute, immediately to the left.  I half-expected we would end up swamping the canoe out of the knee-deep shallows below the fall, but although we shipped a few pails of water over the bow (which is not nearly as high as in some whitewater canoes), we passed without incident, and proceeded to run the rapid below the ruins of the dam and under the bridge, where Kelsey snapped some photos (see below).  Though these rapids were less imposing, we actually shipped more water over the bow, giving the boat a slow, plowing character in the flatwater below.  We pulled out on the  north side of the river shortly below the old bridge site and carried the canoe back over the bridge and home.

running the stroudwater 2

It made me wish the next half-mile or so of flatter water below the falls wasn’t so choked up with blowdown, so we could paddle to work – Pika Energy’s new home in Westbrook is similarly only a few hundred feet from the south bank of the Stroudwater, perhaps 3-4 river miles downstream.

running the stroudwter 3