Video Trial -- Grinder Startup And Shutdown

Here's my first attempt at putting a video into a post.

It appears to have worked.

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A Briggs & Stratton Solid State Ignition Conversion

This post is an accompaniment to my post about an ancient MTD reel-type lawnmower.

That machine's engine had no ignition coil when it was obtained. Here's a view of the engine with its coil missing.

The air-vane governor is there in disarray, but there's no ignition coil.

The 2.0 HP engine's model/type/code number is 60102 0294 01 690801. According to "Chilton's Guide To Small Engine Repair Up To 6 HP", the first five digits of that number signify the following:

6 = 6 cubic inches displacement.

0 = basic design series [whatever that means].

1 = horizontal Vacu-Jet carburetor.

0 = plain bearing.

2 = rewind starter.

The engine predates solid state ignition. Here's a view of its breaker points and condenser, resident under the flywheel.

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The Replacement Coil -- THURSDAY, DECEMBER 27, 2018

The Briggs & Stratton part number for a solid state ignition coil for this engine is 591420. That part renders the points and condenser immaterial to the engine's operation. (I'll be leaving the points and condenser in place, though. I'm unsure of how the pushrod is to be dealt with in the event that the breaker points are removed. So, rather than invite trouble, I'll just leave the breaker points alone.)

My son ordered a Chinese equivalent to P/N 591420 from Ebay, and it just arrived the other day. Here are two views of the coil.

Some notes on the coil:

• The spark plug lead is remarkably long -- almost twelve inches.
• The spark plug connector is a bit iffy. It's very easily dislodged from a spark plug's terminal.
• The curvature of the pole piece ends is odd; they appear to be meant for a much larger diameter flywheel than the one on my engine.
• There's no provision for the governor bracket's upper fastener. The governor will be attached only at its lower fastening point.
• The kill switch terminal takes a 3/16" spade terminal.

With that out of the way, we can proceed to install the coil.

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Kill Switch Wiring

The original kill switch wiring scheme has a wire from the kill switch to the condenser, then another wire from the condenser to the coil. That arrangement needs to be bypassed by a single wire from the kill switch to the coil. If you use the original kill switch wiring, you'll have the breaker points in the kill switch circuit interfering with the coil's operation.

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Mounting The Coil

I discovered that it matters which way around the coil is oriented.

The first time I installed the coil, I had it oriented so the kill switch terminal was outboard. I had spark, and the engine started and ran for a minute or so. Then, the engine quit and refused to restart. I'd get the occasional puff out of the carburetor, which suggested a timing problem. I unfastened the coil and put it back on the other way around (kill switch terminal inboard). The spark appeared to be stronger, and the engine started readily and now runs fine. Here's a view of the correctly installed coil.

Note the mismatch between the curvature of the coil's poles, and the curvature of the flywheel's perimeter. Note also that the governor bracket is fastened only by the single screw at the bracket's lower fastening hole. Neither of those conditions appears to present a problem.

Coil Air Gap Adjustment

See this post for a relatively easy way to make the air gap adjustment.

Governor Linkage

Here's a view of the correctly assembled governor linkage. (The governor spring is Briggs & Stratton P/N 691785. The spring that was originally on the engine was somebody's kludge.)

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And there we are. I've now got a working engine whose breaker points won't need periodic servicing.

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A CGE Model 4J70FB 3/4 HP Motor

I've had this old brute collecting dust in a drawer for years.

It weighs 40 lbs. Speed is 1,725 rpm. The shaft is 5/8" diameter with a 3/16" keyway; effective shaft length is 1 3/4". Input can be either 110 or 220 VAC, and it's reversible. Here's a view of the little wiring diagram inside the connections cover.

And here's a view of the actual wiring represented.

The motor would make a fine power plant for an 8" table saw, if anyone were interested in 8" table saws anymore.

Anyway, it's time it got a paint job, and maybe a new front bearing. (The bearing feels like it may be grease starved.)

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Shroud Removed

Four 10-32 x 5/16" hex head screws fasten the shroud in place. The shroud comes away easily once the screws are removed.

Note the two chips in the perimeter of the fan toward the top. Was that done on purpose for balancing, or was it accidental damage? I'll never know.

I'll remove the 3/16" key and burnish the rusty shaft before proceeding.

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A Keyway Flaw

Here's a shaft-end-on view of the keyway.

Note that the keyway is not cut perfectly radially -- it's slightly askew from the radius. That's making it impossible to fit a keyed pulley.

The only cure will be to file the key on one face so that the key has a slightly rectangular cross-section -- the key's 'height' will need to be slightly less than 3/16" to compensate for the tilted 'floor' of the shaft's keyway.

And here we have the key filed down so it fits a pulley.

Note the skewed fit of the key in the pulley's keyway. That skew is on account of the shaft's keyway, not the pulley's.

I have one other pulley that still doesn't want to fit, so I'll have to file down that key even further. The motor has to readily accept any 5/8" bore pulley that's handed to it.

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I got the key filed to where both pulleys fit, and noticed something that may have been faking me out a bit. It seems that a key can exhibit side-to-side binding in a pulley/shaft assembly, even though no sideways binding is evident with the key in the pulley or shaft on its own. (I hope you're still with me; this is difficult to describe.) It appears that slight sideways flaws in the two keyways that don't cause key binding in either keyway alone, may add in such a way that they cause binding when the keyways are mated. In any event, beware. Binding keys can present deceptive characteristics.

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Fan Removal

The fan's hub face resides 2 1/16" from the end of the shaft. The fan is held on the shaft by two 10-32 x 3/8" cup-point setscrews with 3/32" hex sockets.

And here we are with the fan off the shaft.

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Capacitor Cover And Capacitor -- FRIDAY, DECEMBER 21, 2018

The capacitor cover is fastened by two No. 8 x 1/4" round head, plain slot tapping screws.

The capacitor is a made in Canada Mallory P/N 842A466-4, 400 microfarads, 110 VAC. Measured capacitance is about 396 microfarads.

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Dismantling The Motor's Frame

Four 10-32 tie rods with 5/16" hex washerheads hold the motor together. (The head ends go at the wiring end of the motor.) The tie rods are 8 1/4" long. The tie rods have fibre flat washers under their heads. Curiously, one tie rod had no fibre washer, and another tie rod had two fibre washers. Four 3/8" A/F hex nuts complete the fastenings complement. There are no lock washers. Here's a view of the tie rod set.

With the tie rods out, it's time to knock off the wiring end end-bell. Doing that got me to here.

The rotor wants to remain with the rear bearing. I'll have to disconnect all the wiring to free the end-bell/rotor from the motor's frame.

Always take photos and/or make a sketch of wiring connections prior to disconnection.

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Wiring-End-Bell Dismantled

Here's the end-bell with rotor out of the frame.

A bit of judicious hammering got the end-bell separated from the rotor.

And out came the bearing with the aid of a puller.

The bearing is an NTN 6203Z -- 17mm bore x 40mm O.D. x 12mm wide, shielded one side. The front bearing is the same. The open sides of the bearings go outboard, facing a generous supply of grease.

Both bearings are in fine condition and well greased. My earlier sense that the front bearing may be grease starved was wrong.

Anyway, there we have the near complete teardown of the motor. I just have to knock off the front end-bell yet. Once that's done, I'll get on with cleaning and paint preparation, and give the motor a decent paint job. I'll clean, flush and regrease the bearings prior to reassembly.

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Front End-Bell Off -- THURSDAY, DECEMBER 27, 2018

Here's the front end of the motor dismantled. All has been cleaned of grease.

There's a spring washer to bias the rotor rearward, and a shim washer that reside in the front bearing's cavity. The bearing is press-fitted onto the shaft. The bearing's outer race is an easy slip fit in its cavity. There's what I take to be a felt grease seal of sorts at the outboard end of the bearing cavity in the end-bell.

And here's a close-up view of the start winding switch actuator.

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All Done -- MONDAY, DECEMBER 31, 2018

Here's the motor all painted and reassembled.

I repacked the bearings with Canadian Tire's Motomaster Wheel Bearing & Chassis Lubricant No. 28-0422-2. That's great stuff that I'd trust with my life.

The motor went back together easily; I had no trouble with bearing fits. The motor runs beautifully.

Here's a brief video of the motor starting up and shutting down

And there we are -- a nicely refurbished motor. Now I just have to find a use for it.

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A Performax Mini Wood Lathe Restoration

I picked this up off Kijiji recently.

It's an elderly Performax mini wood lathe model No. 90233. Swing over bed is 8". Swing over toolrest is 5". Distance between centres is about 14 1/4". Headstock and tailstock tapers are both MT1. Spindle thread is 3/4"-16.

I saw when I was examining the lathe at the seller's premises that the machine was flawed -- the motor wouldn't start consistently. But I'd driven quite a distance to see the lathe, and I have a soft spot for decrepit old machinery, so I bought the thing hoping that the motor problem might be something easily corrected

As it turns out, I got hosed. The lathe has a bad motor.

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A Look At The Motor Failure -- THURSDAY, DECEMBER 20, 2018

Here's a view of the failed motor's commutator.

Note the discoloured segments. I don't know enough about how DC motors' rotors are wound to analyze that any further.

Symptoms are erratic starting and 'lumpy' running. Sometimes the motor will start on its own; mostly its shaft needs to be given a nudge to get it going.

I suspect that the failure may have been brought on by a motor stall episode. A stalled motor would, I imagine, draw excessive current through the commutator segments in contact with the brushes. The motor was probably ruined in a matter of seconds.

Replacement Motor

Performax appears to be no longer with us, but Busy Bee carries a mini lathe that's essentially the same as the Perfomax unit -- Craftex model CT172. I ordered a replacement motor from Busy Bee, P/N CT172MOT, and the motor appears to be identical in all respects to the Performax motor. I wired the motor to the Performax control box, and the motor works with that. So, it looks like I'm on my way to having a working mini lathe here. Here's a view of the new motor.

The label on the motor says, "250W -2.3A PH1 CLASS B".

The motor's electronic controller gives the motor a soft-start characteristic. I could live without that on a wood lathe, really, but there we are.

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Restoration Begun

I've torn down the machine for repainting. An addition I thought would be beneficial is a mounting base for the lathe's bed. The lathe bed's 'feet' have M8 threaded holes in them for bolting the lathe down. The holes are not easy to lay out for, so I thought I'd do the layout chore once on a 2"x8" plank, and thereby give the lathe an easy to bolt/clamp base. Here's a view of the lathe bed on its new base.

That plank is 32" long. It gives the lathe bed a nice, solid base that can be readily bolted or clamped to a work surface. There are three M8 x 50mm hex head screws holding the assembly together. The screws' heads are in 1/2" deep counterbores, like so.

Lathe Bed And Headstock Painting

I had to construct a crude stand for painting the lathe bed, like so.

That worked out well. That photo above shows the lathe bed with a coat of grey primer on it. Two coats of Tremclad grey are still to come.

Here's the headstock fully primed and painted with Tremclad grey.

The spindle bearings are in fine condition; it would have been folly to dismantle the spindle for the sake of easy painting. So, I masked both spindle ends and the label. That was quite a chore, but well worthwhile.

Still to be painted are the mounting base plank, tailstock and tool rest.

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Progress -- TUESDAY, DECEMBER 25, 2018

The lathe bed, headstock, motor and motor controller are back together.

It's looking good and running fine. Following are some notes on the lathe's drivetrain:

V-Belt

The V-belt is a miniature, metric-dimensioned thing that I can find no information on. All there is on the belt by way of ID is "KK-516", like so.

The belt is 6mm wide at the top. I imagine that a replacement belt could be had from Busy Bee, as was the motor.

Speed Adjustments

The motor controller's printed circuit board has two potentiometers on it.

You can scarcely see them in the above photo. They're at the upper left of the circuit board, between the circuit breaker and the line cord.

One potentiometer is marked "L" for low speed; the other is marked "H" for high speed. Low speed is supposed to be 750 rpm; high speed is supposed to be 3,200 rpm. It's not a critical or precise adjustment. Ideally, the adjustment can be done with the aid of a digital photo-tachometer, which is how I did it. Use only an insulated tool to make the adjustments; you'd run the risk of zapping yourself and/or the electronics were you to poke around in there with an ordinary screwdriver.

Next up will be to paint the tailstock casting and the toolrest.

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All Done -- SATURDAY, DECEMBER 29, 2018

Here's the lathe running with a blank mounted between centres.

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Further Notes

Spur Centre

The spur centre that came with the lathe was blunt.

I'm not sure how a spur centre's point can get blunted, but someone managed it. I very nearly botched the job, but I managed to give the spur centre a reasonable point on the metal lathe.

For good measure, I bought a new MT1 spur centre from Busy Bee. (Busy Bee P/N B1673.) The Busy Bee item is quite nice.

Tail Centre

A blunt live point centre came with the lathe.

I sharpened up the point on the metal lathe.

I get along fine with only a point tail centre; I seldom, if ever, feel the need of a cup centre. But, to make the lathe complete, I got an MT1 live cup centre from Busy Bee. (Busy Bee P/N B1677.)

Faceplate

No faceplate came with the lathe, and I couldn't see having a lathe without one, so I went looking on Amazon and found just the thing.

It's a nominal 3" diameter faceplate for a 3/4"-16 spindle. It's a Maxwood No. 5106. Actual diameter is 80mm. There are four 5mm diameter screw holes on a 60mm diameter circle. The wrench flats on the hub are 32mm A/F.

Spindle Wrench-Rod

A six inch length of salvaged 6mm diameter steel rod serves as a wrench-rod for the spindle.

Knockout Bar

No knockout bar came with the lathe. The headstock and tailstock both take a 3/8" diameter rod through.

I had a length of 3/8" rod with a 1/4"-20 tapped hole in one end of it, so I cut a six inch length off of that. I made up a 10-32 to 1/4"-20 coupler from a piece of 1/4"-20 threaded rod, and added a salvaged knob. That gave me a nice knockout bar that I'm quite pleased with, like so.

And there we are -- a reasonably well-fitted-out mini wood lathe. To exercise the thing, I made a magic wand on it from a salvaged length of broomstick.

The lathe performs nicely; motor power is quite adequate. One gets accustomed to the soft start feature's time delay on startup. All in all, a pleasant little machine

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Masking T-Nut Flange Ends For Painting

I had a plywood motor mount base to prime and paint that had some 1/4"-20 T-nuts in it, and I didn't want paint getting into the nuts' threads. In the past, I've just gone ahead and painted over the open-ended flanges of T-nuts, and then chased any paint-fouled threads with a tap. That's always struck me as a slovenly way to about it, so I thought I'd try masking my T-nuts this time.

With a 10mm diameter gasket punch, I punched out some masking tape discs and applied them to the T-nuts' flanges, like so.

(The nut at the lower right is still to be masked.)

To punch out the discs, I laid some tape gently on a clean hardwood surface for a backing, then applied the punch. When peeled off, the masking tape discs still had sufficient adhesiveness to them that they could be stuck down onto the T-nuts' flanges.

Here's a view of all four nuts masked and gone over with primer.

And here we are with the painting fully done and the masking discs removed.

And there we are -- no more paint-fouled T-nut threads.

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