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Old November 18th, 2004 #1
Kind Lampshade Maker
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Default Don't give money to the Jews. Repair your own agricultural machines etc...

I'm presently repairing some aluminum casting and am using this epoxy for it:
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Old November 19th, 2004 #2
Abzug Hoffman
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Default Don't Give The Jews Anything

Just wanted to add my slogan.
 
Old November 21st, 2004 #3
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Default Dental wörk done with this epoxy

Here’s a photo of a project involving improvement of a lawn mower designed to cut tall grass. The Italian under licenced produced Tecumseh upright engine designed in the early 60s will be replaced by a virtually maintenance-free 2 cycle German designed and made 50 cc forced air-cooled moped engine. The cylinder head will be mounted 90 degrees from its original position to greatly simplify adapting to the machine. As you see in the photo, the untouched cooling fins (except for #5) denote the original direction of vehicle motion, because these fins came into play during vehicle motion so as to profit through wind cooling. Since little heat is generated at a stop light, the diagonal fins cooled by the fan, sufficed for temperature control at idle speed. The advantage of this was to reduce the size of the cooling fan to save on fuel and horsepower. Since wind cooling is now absent, because of serving as a lawnmower powerplant, the fins once used for wind cooling will now be cooled through forced air.
#1 shows how I sawed and chiseled away material and left stumps of which the epoxy will bind to form a new cooling fin
#3 shows the beginning of such reconstruction
#2 shows the holes drilled for anchoring the epoxy in case the coefficient of the epoxy’s expansion thru heat differs radically to that of the aluminum alloy
#5 shows the still standing original fins which have not yet been modified
#4 shows what remains of the 45 degree fins
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Old November 21st, 2004 #4
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Here’s a better view
#1- The re-construction
#2- The anchor holes
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Old November 22nd, 2004 #5
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Default In the mean time.....

Lets service the cutting blades. There is damage done, due to abuse and lack of maintenanace. Certain parts need replacement:
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Old November 23rd, 2004 #6
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1-The outer blades suffered the most severe damage
2- The indentation is better viewed and only a few hundreds of a millimeter deep. I don’t know the significance of these indentations. Perhaps they serve as a marker for how much material could be milled off before physical integrity gets undermined. But, the cost of milling this item might be higher than replacing damaged units, anyhow
3- 1 of the rivets holding these things together
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Old November 23rd, 2004 #7
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1-The outer blades suffered the most severe damage
2- The indentation is better viewed and only a few hundreds of a millimeter deep. I don’t know the significance of these indentations. Perhaps they serve as a marker for how much material could be milled off before physical integrity gets undermined. But, the cost of milling this item might be higher than replacing damaged units, anyhow
3- 1 of the rivets holding these things together
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Old November 23rd, 2004 #8
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A-1 of the bent outer blades. An attempt at restoring these would more than likely prove unfeasable
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Old November 23rd, 2004 #9
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B- The damaged surfaces seen from above. Theoretically,.these are wonderful mowers which operate as hair-clippers do. In reality, their missions assimilate those of M-16 rifles in mud.
I would recommend using a scyth instead of bothering with these type of mowers for the simple reason that the first mole hill that gets caught between the blades will wreak enough havok to considerably shorten the life of the blade assembly. In the case of this mower, the assemble eventually became stiff through corrosion and grass blades caught between the upper and lower blade assemblies due to non-maintenance and excessive clearance between both assemblies. A parent donated the machine to my daughter’s schmuel school, so we’re stuck with it. I need the Tecumseh stationary motor which came with the mower, thus have a chance of bagging it in trade with the moped motor which slips out of 1 of the gears due to abused synchronizer rings
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Old November 23rd, 2004 #10
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Default More than half way through

3- shows a curved fin at about 30 degrees from the another, not uncommon in the trade. Where these 2 fins touch the head, they seem too narrow. Yes, it’s possible to have the fins too close to one another, because the cooling process does not only take place through heat exchanging, but also through emittance of infra-red energy to the environment. Thus, when the metal gets too close to the other, the one heats the other up
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Old November 27th, 2004 #11
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This is the 3rd stage of epoxy application and filing. The final stage will be done on the engine, so as to fit the air shroud to as close a tolerance permitting. I’ve tried to file the fins as smooth and straight as possible, to avoid counter-productive air turbulances. Such care in detail is important, in this case, because the epoxy will withstand temperatures of up to 120 degrees Centigrade continual service and only up to 150 degrees momentary service. Since water boils at 100 degrees, I will have to insure the task by increasing the air speed through modifying the ductwork for the new configuration of the turned head, taking advantage of as much air as possible. The thermal co-efficiency of epoxy compared to aluminum is unknown to me. So, the best solution would have been to heli-arc beads on the head to build fins, but this takes a steady hand. Even though mine is much steadier than the Parkinpope’s, nevertheless it still isn’t steady enough for such a task. On top of that, I’ve never heli-arcked aluminum and don’t know anyone who would do this. Therefore, the bondo. I’m lucky that 2-cycle engines operate at lower temperatures than their 4 cycle counterparts of which to perform such an event on one of those would have been unthinkable.
#1 shows openings to employ bracket fins to draw heat

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Old November 28th, 2004 #12
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MENGELE still make agricultural machinery. Thats one European farm implement company whose products you are unlikely to encounter in Izrael.
 
Old November 29th, 2004 #13
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Quote:
Originally Posted by Dasyurus Maculatus
MENGELE still make agricultural machinery. Thats one European farm implement company whose products you are unlikely to encounter in Izrael.
You won't find that many Ford Motor Company products there either
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Old December 3rd, 2004 #14
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Default The merits of chain over belt

#25, #26, #34, #35 & #36 are components of a pully drive system using a belt tensioner as a clutch. These items will be replaced by an enclosed, maintenance-free chain 6 sprocket system driving an intermediary shaft. The clutch in the motor-gearbox assembly will take over, rendering the the drivebelt, which was suceptable to heavy wear as a clutch, obsolete.
A chain drive, is 98% efficient which is another advantage over the pully & belt system which lost considerably more energy through physical resistance
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Old December 3rd, 2004 #15
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Default Odds & ends dug up out of the toi box

#1, in the photo, represents an ordinary wheel bolt from my old junk Yamaha 500 SR which measures 22 millimeters diameter at the head and will be used as the drive shaft
#2 represents the hub which will be welded onto the shaft. It measures 22 millimeters inside diameter and is derived from a bicycle’s rear 3 speed hub of Fichtel & Sachs manufacture
#3 represents a gear which is to be fitted to #2 and held by a circlip. As shown, this is a 14 tooth gear. There are many of these gear patterns available. The largest to my knowledge consists of 21 teeth. This means that the final drive ratio can be altered at wish
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Old December 3rd, 2004 #16
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Since the head is rectangular instead of square, additional openings had to be made to allow airflow to the upper fins. I was uncomfortable with removing even more material, but that side where material was removed will receive cooler incoming air than the material on the opposite side. Furthermore, this engine will see service in northern Europe and not in Africa where this engine was also either exported there or built under license. So, I’m not going to lose sleep over it
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Old December 3rd, 2004 #17
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Default I srewed a spark plug today (into....)

I screwed a spark plug into the underside of the head as a holding fixture, proceeding the initial cutting. I neglected to file my vise, now and then to remove burrs. This resulted in scratches on the sealing surfaces . In this particular engine which doesn’t use a head gasket, a flat surface is critical. To correct this, I will simply use a fine grade valve-grind lapping compound to mate both sealing surfaces together again. I planned on using a 12mm x 17mm bushing and a 17mm x 40 mm ball bearing as an alignment fixture for this task, but the cylinder bore was still under 40mm.
In this case, I will use a dome crowned replacement piston from another engine to serve as a guide.
Since a hemispherically shaped combustion chamber was machined into the cylinder head, I will be provided with the necessary guidance for this lapping procedure, when I set the head onto the piston at the same time supporting the piston from underneath, moving the head back and forth onto the cylinder with the valve grind compound in between.
I am certain you could machine any brand of air cooled 2 cycle head together with the cylinder, in this way, to avoid using a head gasket.
I will experiment with this, during an upcoming project and report on it. You probably didn’t know that 50cc 2 cycle engines unintentionally have interchangable cylinder heads between certain manufacturers. I have a few of these in my shop and will inform you soon pertaining to this issue shortly
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Old December 4th, 2004 #18
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Quote:
Originally Posted by Kind Lampshade Maker
....You probably didn’t know that 50cc 2 cycle engines unintentionally have interchangable cylinder heads between certain manufacturers. I have a few of these in my shop and will inform you soon pertaining to this issue shortly
This is one of the heads which fits on the “Simson” motor I’m working on

#3 shows more than enough contact surface of this “Zündapp” cylinder head
#4 – the emblem of the Zündapp company
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Old December 4th, 2004 #19
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Here's what Zündapp built:

A shabby example, at that
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Old December 4th, 2004 #20
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And that:
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