[Last updated: Thursday, April 25, 2019.]
I picked this up off Kijiji for $25.00 CDN.
For $25.00, you don't get a jewel, but you do get chains and maybe a working electric starter. The idea here is that even if this thing turns out to be scrap metal, the chains and electric starter can go on my son's machine. But before I write off the rest of it, I'll see if I can at least get the engine going. Maybe it'll be worth the effort and expense to restore this unit to serviceability. We'll see.
- - -
The 8/25 model designation indicates 8 horsepower/25 inch swath. It was made in Canada, so it must go back quite a ways. The Sears model number is C950 52477. The serial number is illegible -- it looks as though no serial number was ever embossed on the ID label. There's supposed to be a Sears engine model number on the engine's cowl somewhere, but I see no trace of one so far. I managed to find an owner's manual on-line, and I've downloaded and printed that. From what information I can piece together, the Sears engine model number is 143.756192, equivalent to Tecumseh model number HM80-155280K.
- - -
'Found The Sears Engine Model Number -- WEDNESDAY, APRIL 10, 2019
It was hiding in plain sight; it's stamped into the top of the cowl, hard by the electric starter switchbox. It's 143.746092, equivalent to Tecumseh model number HM80-155280J. Serial number appears as "SER 4321D".
- - -
One scarcely knows where to begin, there are so many problems with this machine. I'll just start tackling things as the fancy takes me.
- - -
Spark Plug
It's missing. It's supposed to be a Champion RJ17LM, a resistive spark plug. I have an Accel 198 on hand, a non-resistive spark plug. The Accel plug fits, and will serve for initial testing until I can get one of the Champion items. A 0.030" gap should work ok.
Spark Plug Wire And Connector/Boot
The spark plug wire emerges from the side of the cowl by the carburetor, instead of from the top of the cowl as it's supposed to. The connector/boot is loose from its wire. I'll see if I can reconnect it. Here's a view of what the connector looks like out from inside of its boot.
That doesn't look to me like an agreeable thing to connect to its wire, but I'll give it a go.
- - -
'Got it reconnected and did a spark test. There's no spark. Now the cowl has to come off so I can get a look at the ignition coil.
- - -
New Spark Plug Obtained -- THURSDAY, APRIL 4, 2019
I got the RJ17LM. It's a 14mm plug with a 13/16" hex. Resistance measures about 45 kohms.
- - -
Cowl Removal
Up top there's the starter switchbox to be dealt with, and the two uppermost cowl fastening screws. (One of the two screws is missing here.)
- Starter Motor Switchbox. Two 6-32 x 2" hex head screws, 1/4" A/F with No. 2 Phillips recess. Let the switchbox dangle by its line cord.
- Uppermost Cowl Screws. Normally two 5/16"-18 x 3/4" hex washerhead screws, 1/2" A/F.
(While I was manipulating the governed speed controller, its torsion spring popped off. One more flaw to be dealt with later.)
Just below the governed speed controller there's another cowl fastener, a 5/16"-18 x 3/4" hex washerhead screw, 1/2" A/F. (It's supposed to be 5/16"-24. The hole was probably tapped 5/16"-18 by some tinker who lost the 5/16"-24 screw.) That screw also secures a small bracket that holds the kill switch connection terminal. I may modify the kill switch connection to incorporate a quick-disconnect, so that the governed speed controller along with its kill switch can be readily taken away.
And at the lower right, there ought to be another 5/16"-24 screw. It's missing, and the holes don't line up at all correctly.
Normally, the primer tube would have to be disconnected from its nipple at the carburetor. The primer tube here is already off.
The locomotion speed selection linkage rod needs to be disconnected from its crank and let dangle. The rod will interfere with taking away the cowl if it's left in place. The rod on this machine is already disconnected from its lower crank, and its 5/16"-24 fastening nut and split lockwasher are missing.
And with all of that taken care of, the cowl can be coaxed off the engine and lowered away.
- - -
'Found The Hole Misalignment
Now I can see the reason for the hole misalignment at the lower right side cowl screw's location.
The flange where the screw resides is bent forward a ways. That shouldn't be too difficult to correct.
- - -
'Got That Corrected -- MONDAY, APRIL 1, 2019
I managed to bend the flange back to its proper position and get the holes to line up.
- - -
And More Trouble
One of two pawls is missing from the recoil starter.
Oh! Here's the missing pawl.
The pawl's E-clip must have gone astray at some point, the pawl flew off its pivot and has been trapped inside the starter cup ever since. The pawl's torsion spring is still in place, and I have spare E-clips, so this should be an easy fix.
- - -
Loose Pawl Reinstalled -- MONDAY, APRIL 1, 2019
I found an E-clip that fits, so here we are with the loose pawl back in its place and operational.
- - -
And here we have the flywheel revealed.
Note that the fuel delivery tube is not properly in place -- the flywheel has been rubbing on it. Note also that the ignition coil is not an external one; it's hidden away under the flywheel. I wonder how one goes about setting ignition coil gap with that arrangement.
- - -
Loosening The Flywheel Nut
This presents a bit of a dilemma -- how to secure the flywheel while the nut is loosened. My Vise-Grip 20R chain clamp won't make it around the circumference of the flywheel. Jamming a bar into the plastic fan blades is not on, and that screen prevents applying the Vise-Grip chain clamp to the starter cup. So here's what I did.
I restrained the front end of the crankshaft with a blocked 9/16" open end wrench. A 3/4" deep socket applied to the flywheel nut got the thing loosened and off.
Here's the flywheel with the starter cup and screen taken away.
Note the broken fin. Some tinker must have tried jamming a bar into the plastic fan to restrain the flywheel -- not a smart move. I suppose now I should break off the fin directly opposite, so as not to have an imbalanced fan.
- - -
Flywheel Removal
Here's the puller in place.
This flywheel has no smooth flange for a puller's jaws to grip. The puller's jaws have to go under the starter ring gear.
- - -
The flywheel came off fairly easily. Here's a view of what's underneath it.
OMG! That looks to me like a points-and-condenser setup. Let's see what's under that cover.
Sure enough, it's points-and-condenser. This is a very old machine.
- - -
Following are the ignition system defects that I found and corrected:
- Spark plug connector not properly made to spark plug wire. I got it right on my second attempt at attaching the connector to the wire. The spark plug connector pictured above earlier is a nasty bit of business to deal with. There ought to be a better way.
- Condenser lead insulation rubbed clear through at one point. I taped the spot and made certain that the lead was safely routed.
- Points gap way too close. I don't have the figure for points gap for this ignition system. I set it for about 0.020".
- - -
Tire Chains Gone
The very first photograph in this blog post shows tire chains. They've been removed so my son can have them for his snowblower. Like everything on this machine, their installation was a wretched kluge, partially done with ty-wraps. I'm sure that my son will do a far better job of installing them on his machine.
- - -
Right Side Clutch Lever Pivot Pin Retention -- TUESDAY, APRIL 2, 2019
The right side clutch lever (auger drive) pivots on a 5/16" diameter steel pin that's supposed to be retained by a push-nut cap on either end of the pin. One of the caps is missing. I have a spare, but I'm not fond of push-nut caps; they're awkward to remove if you ever want to remove one. So, I drilled a 1/16" diameter hole through one end of the pin, and now I have a pivot pin retained by a cotter pin at one end, like so.
- - -
Throttle Lever Knob
The knob is missing.
I'll see if I can fabricate a replacement from these items.
There we have:
- 1/4"-20 coupling nut.
- 1/4"-20 x 3/16" thick hex nut.
- Knob with 1/4"-20 stud.
- Two 8-32 x 3/8" hex socket head screws, 9/64" hex socket.
Not too shabby. Next up is to add a quick-disconnect to the governed speed controller's kill switch, so that the governed speed controller can be easily removed for some repair work.
- - -
Kill Switch Rewired
Here's the kill switch fitted out with a 3/16" spade connector for a quick-disconnect.
I've also reinstalled the governor torsion spring that flipped off on me earlier. The spring seems more forceful to me than it ought to be. I'll deal with that further down the road when I get the missing governor linkage components.
- - -
Carburetor
And now it's time for some serious fun. I have to dismount and open up the carburetor. I've had the float bowl nut off, and what I saw in it didn't look good. Here goes.
- - -
Here's the carburetor off the engine.
Note the snapped-off screw that's lodged in a boss at the left of the photo. That's one of two screws for attaching the bracket that the carburetor cover (which is missing) fastens to. The odds of my ever extracting that screw remnant are slim to nil.
This photograph of the main jet's mixture adjustment screw and nut will give some idea of the internal condition of the carburetor.
It was a mess, with powdery stuff in the float bowl. I soaked and flushed it in my parts washer tank, and blew everything through with compressed air. I gave the main jet's adjustment nut a new O-ring and reassembled the carburetor. The float level looked high to me, so I tweaked that.
The carburetor is back on the engine, awaiting a start test.
- - -
Broken Screw Extracted
With the carburetor back on the engine, it seemed as good a time as any to make an attempt at extracting the broken screw remnant. I centre punched the screw, drilled it clear through 1/16" diameter, then 5/64" diameter, then applied a small screw extractor and out it came.
It's an 8-32 thread rolling screw. The thread it rolled in the carburetor seems to be slightly undersize; I'll want to chase the two bracket attachment threads with a bottoming tap.
- - -
Engine Test
'Fueled it up and it started first pull. I have the machine inside a basement workshop, and the governor is not operational, so I couldn't test the engine beyond seeing that it started and idled briefly. It certainly did that much, so it's on with overhauling this snowblower.
- - -
Leaky Fuel Shutoff Valve
I like the idea of having a fuel shutoff valve on a piece of equipment, but I don't like this one.
It leaks from around its stem even when shut off. I'll have to see about a replacement; I doubt that the valve is at all serviceable.
- - -
New Fuel Shutoff Valve Obtained -- THURSDAY, APRIL 4, 2019
The small engines place in Pickering had just the thing.
It's all plastic. 'Looks like it should last for a season or two.
- - -
Left Side Clutch Lever Slop
The left side clutch lever (locomotion drive) pivots on a 5/16" diameter steel pin, the same as on the right side (auger drive). This clutch lever pivot isn't missing anything, but there's a lot of slop in the pivoting. I bored out the handlebar holes to 11/32" diameter (they were almost there already from wear), and installed an 11/32" bushing cut from hard brass tubing from the hobby shop. I've added CA adhesive to fix the bushing solidly in place.
I'll leave that to cure overnight, and reassemble the lever tomorrow. That bushing installation ought to get the lever's pivot slop down to within reason.
- - -
Starter Motor Mounting Trouble -- WEDNESDAY, APRIL 3, 2019
There appears to be nothing on this machine that isn't FUBAR. One of the starter motor's upper mounting tabs is broken off, and the remaining upper tab is badly worn and distorted.
Additionally, one of the starter motor's lower 1/4"-20 mounting holes has a broken-off screw seized in it.
I managed to remove that screw remnant. I didn't so much 'extract' it as I bored it out. The job cost me a 5/32" cobalt twist drill. Some thread chasing got me back a useable 1/4"-20 threaded hole.
I'll remount the starter motor and thoroughly test its operation before I give it to my son. I have tried the motor, and it seems to work ok, but I should give the starter drive a good workout to be certain that it engages and disengages properly and consistently.
- - -
Starter Motor And Drive 'Ok' -- MONDAY, APRIL 8, 2019
The mesh of the starter drive's spur gear with the flywheel's ring gear looks marginal to me; I'd like to see the gears mesh more deeply. I can see no way to improve it. Perhaps it's normal.
In any event, the starter does work. The drive engages, cranks the engine, and gets kicked out of engagement when the engine starts. I'll dismount the starter and give it to my son for him to install on his snowblower.
- - -
Discharge Direction Crank Removal
- Cotter pin and washer at front end of crank.
- 3/8"-16 hex nut, 9/16" A/F, with washer(s) at eye-bolt.
- - -
V-Belt Drives Disengagement & Engine Removal
The drives reside under a cover fastened by two 1/4"-20 screws.
The 1/2" wide belt at the left in the above photo is auger drive. The 3/8" wide belt to the right is locomotion drive.
The auger drive belt's tension idler is operated by the right side lever on the handlebar. The locomotion drive belt's tension idler is always operational; a spring keeps it in the belt-tensioned position.
To free the belts from the engine's pulleys, proceed as follows:
- Loosen off the two auger drive belt retaining rods. (1/2" wrench.)
- Remove the auger drive belt's tension idler pulley. (9/16" wrenches.) The nut is a prevailing torque type. Note that the pulley's hub is asymmetrical; its longer end goes to the tension arm.
- Unbolt the engine from the frame. Four 5/16"-18 x 1 1/4" hex head screws, 1/2" A/F, with split lockwashers.
- Tip up the rear of the engine to permit the auger drive belt to come off its engine pulley.
- Shift the engine and tug on the locomotion idler as required to permit the locomotion drive belt to come off its engine pulley.
- The engine is free to be removed from the frame, provided that the governed speed controller has been detached and the kill switch wire disconnected.
- - -
Binding Discharge Chute Rotation
The discharge chute binds when rotated leftward from centre. Let's see what that's all about.
Discharge Chute Removal
Three 5/16" x 3/4" carriage bolts with hex nuts, split lockwashers and 5/16" SAE flat washers. The nuts are 1/2" A/F.
Discharge Rotation Flange Removal
Six 8-32 x 1/2" hex washerhead screws with nyloc nuts. Screw heads are 1/4" A/F. Nuts are 11/32" A/F. The six screws fasten three retaining lips underneath.
And here's the problem.
The stationary rotation flange is distorted. If I can't straighten that satisfactorily, I'll have to add spacer washers to the assembly of the retaining lips, to give the lips more clearance underneath.
- - -
'Got it.
Some judicious hammering with a big punch got the flange reasonably straight. Reassembled, the discharge rotation flange now turns freely all the way around.
- - -
Separating The Auger Housing From The Frame
Note: You'll want to have assistance with this, or a means of propping up the handlebar while you do the separation. Doing without one or the other would be awkward, and possibly a bit dangerous.
The auger housing is fastened to the frame by four 5/16"-18 x 1/2" hex washerhead screws, 1/2" A/F. Loosen off the two lower screws. Remove the two upper screws with the handlebar either held by an assistant, or propped up on something. The two lower screws act as hinge pins, permitting you to gently lower the handlebar to the ground. That gets you to here.
Mouse nest and all. The belts are free to come out now. The 1/2" wide auger drive belt measures 31 1/8" outer circumference (O.C.). The 3/8" wide locomotion drive belt measures 36 3/16" O.C. Legible on the locomotion belt is "MURRAY 000025".
- - -
Locomotion Belt Tension Idler
This idler is identical to the auger drive belt's tension idler. Two 9/16" wrenches are needed to remove it. The nut is a prevailing torque type. Note that the longer end of the idler's hub goes away from the tension arm. Note also that there's a flat washer between the idler's hub and the tension arm.
I'm giving both idlers' bearings an application of roller chain lube.
- - -
Impeller Bearing
P/N is 85087. There's considerable slop in it. The auger drive pulley has to come off.
Auger Drive Pulley
The pulley is 6 1/2" diameter on a 7/8" diameter shaft. The pulley's rear face sits about flush with the rear end of the shaft. There's a 3/16" keyway and a 1 1/8" long key, and two square-headed 5/16"-18 setscrews in the pulley's hub, 5/16" A/F. I don't have a four-point or an eight-point socket wrench for the square-headed setscrews, but a twelve-point 3/8" socket seems to fit the square heads well enough. Here goes.
Whoops!
Both setscrews broke off. Now I've got serious trouble.
'Got The Pulley Off
'Drilled out the setscrews with cobalt drills. Much heating and hammering and pulling later, I got the pulley to come off.
That pulley may be salvageable. I may have to drill and tap the setscrew holes for 3/8" setscrews.We'll see.
With the pulley out of the way, let's get a look at the impeller bearing.
- - -
Pulley Reinstalled -- FRIDAY, APRIL 12, 2019
There was enough of 5/16"-18 female threads left in the pulley's hub that I thought I might get away without re-threading the hub's setscrew holes to 3/8"-16. I used hex head screws for setscrews, and installed them with blue threadlocker.
We'll see how that holds up. If it fails on me, more drastic measures will be in order.
- - -
The Impeller Bearing
Two 5/16"-18 hex nuts (1/2" A/F) with split lockwashers hold the impeller bearing's flange in place.
And here's just what I was afraid of.
Not only is the ball bearing worn out, but the 7/8" diameter impeller shaft's bearing land is worn down to under 27/32" diameter. The entire auger/impeller assembly will have to be disassembled so that the worn impeller shaft land can be dealt with.
- - -
Oh, No, It's Not!
I've made a shim band for the worn land from 0.0105" thick sheet steel.
The bearing fits over that nicely. It'll work. If need be, I'll apply runny CA adhesive or Loctite RC/609 so it can wick in with the shim band and ensure a snug fit between the impeller shaft and the inner race of the bearing. I'll get a new bearing and I'll be away, without having to tear down the entire auger assembly and its gearbox.
- - -
Obtaining A New Bearing
I went to the small engines place in Pickering, and they had the flanged bearings in stock for about $70.00 CDN. That's not on, so I've got BDI Canada looking into getting me only the bearing itself -- I can reuse the existing flange. Here's a view of the bearing and flange pressed apart.
The bearing is 7/8" bore x 2" O.D. x 5/8" wide. The closest that BDI was able to come up with is 9/16" wide; that may have to do. If it turns out that what BDI comes up with is a light-duty bearing, then I'll have to bite the bullet and get the OEM part. The impeller bearing leads a hard life; the loading on it is variable, and often brutal.
- - -
Impeller Bearing Obtained -- MONDAY, APRIL 8, 2019
'Got a proper one, and the price turned out to be within reason -- $34.95 CDN. BDI turned out to be a washout; they didn't get back to me, and when I got back to them they didn't seem to know what they were talking about. 'Went back to the small engines place in Pickering, and they came up with this item.
Etched on the inner race of the bearing is "FK 1640-ZZ KWP".
- - -
The Bearing Flange Fasteners
Two 5/16"-18 screws with inaccessible heads hold the impeller bearing's flange in place. I'll need a way to keep the screws from turning while I install and tighten the nuts on them, so I cut slots in the screws' ends with a Dremel cutoff wheel, like so.
- - -
Auger Bearings -- MONDAY, APRIL 8, 2019
Before installing the new impeller bearing, I thought it wise to pull the entire auger assembly and attend to its bearings.
The auger's two sleeve bearings are fastened by four 5/16"-18 hex washerhead thread rolling screws, 1/2" A/F. Here's a view of one side's bearing.
There's a circlip and a washer to come off at each end of the auger shaft, then the bearings are free to come off, along with another washer. Auger shaft diameter is 1". Bearing rotation is sluggish from dried out, fouled lubricant, so a dismantling and cleaning is in order here.
- - -
New Impeller Bearing Installed -- MONDAY, APRIL 8, 2019
Here's the new bearing fastened in place, with CA adhesive applied to its interface with the shim band and the shaft.
Should that bearing ever need replacement again, it'll take heating the shaft to soften the CA adhesive. CA adhesive is not terribly heat resistant; it starts to soften at about 100 degrees Celsius (212 degrees Fahrenheit). So I shouldn't have created a situation here that can't be dealt with, should the need arise in future.
- - -
Left side Wheel Off
Here's a view of the left side wheel's Klik pin retainer.
The pin was a bit balky from rust. I got it out with a little punching and wriggling.
Fortunately, the wheel's hub isn't seized to the axle; the wheel came off fairly easily. The axle has a push-nut on it to keep it in position.
- - -
Right Side Wheel Off
The right side wheel fastens to the axle at the inboard end of the wheel's hub by a 1/4"-20 hex head screw and nut. That arrangement struck me a bit odd, but there's a reason for it.
The right side axle is quite stubby. It doesn't go the full length of the wheel's hub; it only projects about 1 5/8" from the side pf the frame.
- - -
Tires
Tire sidewall data is:
CARLISLE Turf-Saver
13 x 5.00-6 2 PLY RATING 20 PSI
'Turf-Saver'[!?] I don't imagine that they're the original tires. 'Turf-Saver' doesn't exactly conjure up visions of good traction in snow. At least they appear to be holding air.
The CARLISLE brand is still with us.
- - -
Auger Housing Skids
It looks like augur housing height is set for a gravel driveway on this machine; the skids are positioned fairly low.
I'll raise those skids as far as they'll go, and that should give me a satisfactory auger housing height for pavement.
The skid fasteners are 5/16" carriage bolts, 3/4" long with 5/16" SAE flat washers, split lockwashers and hex nuts, 1/2" A/F. I'll reassemble with anti-seize compound.
- - -
Scraper Bar
It's held onto the auger housing by five 5/16" carriage bolts, 3/4" long with 5/16" SAE flat washers, split lockwashers and hex nuts, 1/2" A/F.
There's something odd about this scraper bar. When I raised the skids to lower the auger housing, the scraper bar was much too low. I had to flip the scraper bar around in order to get the bar to go higher, and then I still had to lower the skids to get scraper bar clearance.
Anyway, I reassembled the scraper bar's fasteners with anti-seize compound, as I did with the skids' fasteners. If further adjustment should be called for, at least I'll have fasteners that can be readily loosened.
- - -
Bottom Cover Off -- FRIDAY, APRIL 5, 2019
Yikes!
Lots of mouse debris to clear out.
- - -
Transmission Concerns -- SATURDAY, APRIL 6, 2019
Here's a closer view of the transmission's innards.
The friction drive wheel is at its 'high gear' (No. 6) position. The wheel travels leftward toward the friction disc's centre for the lower 'gears', then leftward across centre for the two reverse speeds.
The axle bearings are bronze sleeve bearings, badly worn. I suspect that they never got a drop of oil. There's still service life in them with adequate lubrication, but I'll see about getting replacements.
The hexagonal spindle that carries the friction drive wheel is rusty, making speed selection balky.
In sum, the drive components ought to be taken out for a good cleanup, then reinstalled with proper lubrication throughout.
- - -
Final Drive Spur Gear
It's a 48 tooth gear made of plastic. It's in remarkably good condition.
- - -
Axle Bearings
The right side bearing is worn clear through in places.
The left side bearing is not as bad, but it's badly worn too. If I can't get replacements, I'll just have to install the bearings 180 degrees around from how they were, so that the relatively unworn 'bottoms' become the load-bearing 'tops'.
- - -
New Axle Bearings Obtained -- THURSDAY, APRIL 11, 2019
P/N is 44 075 (each). The new bearings are steel, not porous bronze. They'll want to be kept well oiled, since they'll have no inherent lubricity as porous bronze bearings do.
- - -
New Recoil Starter Handle -- WEDNESDAY, APRIL 10, 2019
Snowblowers are supposed to have big, D-shaped mitten grip recoil starter handles on them. This machine came with a regular handle like you'd find on a lawnmower. I got a proper handle from the small engines place, P/N 590574. Here it is installed.
- - -
Transmission Clean And Lubricated And Ready To Go -- THURSDAY, APRIL 11, 2019
- - -
Governor Lever And Link -- TUESDAY, APRIL 16, 2019
The small engines place in Pickering had a used link that they sold me for a dollar. I fabricated a lever from steel sheet material a little over 1/32" thick. I patterned the lever after the lever on an 11 hp engine that I have -- supposedly the 8 hp engine takes the same governor lever as does the 11 hp engine. Here's a view of my governor lever in place.
It looks like that's going to work.
- - -
Reassembly Almost Completed -- MONDAY, APRIL 15, 2019
The discharge chute is back on.
I relocated the dicharge chute's angle-locking wingnut from the right side to the left side.
I used a longer carriage bolt there, and added a Nyloc nut to prevent the wingnut from unscrewing from engine vibration and getting lost.
I haven't fastened the V-belt drives cover yet. I still have some fiddling to do with governed speed and fuel mixture settings, so I still need access to the engine's pulleys for my photo-tachometer to read.
- - -
Oil Change -- THURSDAY, APRIL 25, 2019
In my area, winter temperatures seldom go below zero Fahrenheit (about -18 Celsius), so 5W30 oil is fine. For temperatures consistently below zero Fahrenheit, the Owner's Manual recommends synthetic 0W30.
The hexagonal oil drain cap takes a 5/8" wrench. You may need to grip the oil drain tube with Vise-Grips to prevent the tube from unscrewing instead of the cap.
Draining the oil is awkward on this machine, because of the placement of the drain tube so near over the right side wheel.
A suitable length of tubing quickly slipped onto the drain tube's end once the cap is off is helpful.
Nowhere could a find the figure for engine sump capacity. The engine took 600ml (about 20 fl. oz.) to fill.
- - -
Shear Pins -- THURSDAY, APRIL 25, 2019
As is so often the case on old snowblowers, the shear pins on this machine were a kluge. Here's a view of one of the 'shear pins'.
That's an SAE Grade 5, 1/4"-20 screw employed as a shear pin. SAE Grade 5 is pretty tough -- not something you'd want to rely on to shear when it's supposed to. I got the proper items from the small engines place in Pickering.
1/4"-20 x 1 3/4" hex head screws with collars and Nyloc hex nuts. The collars go under the screws' heads, and fit into oversize holes in the augers' axle sleeves.
The finished installation looks like this.
The screws' heads are marked "307A". 307A indicates a screw hardness nearly equivalent to SAE Grade 2 -- a relatively soft, low carbon steel. There's a technical note on 307A here.
- - -
Why The Collars And The Oversize Holes? -- THURSDAY, APRIL 25, 2019
The only reason I can think of is so that no amount of tightening will squeeze the auger axle sleeves down onto the auger axle shafts; i.e. 'clamp' the augers to their axles.
- - -
To be continued.
# # #
# # #