Why they are expensive
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metalb00b00
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you just said it yourself, it's the thermal pad that's expensive, not the mounting hardware.
s2udio
Well-known member
Maybe buy from somwhere cheaper.?
Digikey are a rip of merchant for basic electronic parts.
I think in the past I got 100 T22O insulators and bushes for less than three quid from evil bay.
Buy the screws etc seperately far cheaper
Digikey are a rip of merchant for basic electronic parts.
I think in the past I got 100 T22O insulators and bushes for less than three quid from evil bay.
Buy the screws etc seperately
far cheaper
There may be some crazy labor content from collecting the sundry parts to make a kit of parts. On the same page they show the actual thermal pad for like $0.10 so probably labor and overhead...
JR
JR
Andy Peters
Well-known member
s2udio said:Maybe buy from somwhere cheaper.? Digikey are a rip of merchant for basic electronic parts.
For what it's worth, this part from the other mainline catalog distributors is highly similar to the DigiKey price. See https://www.findchips.com/search/4880SG what I mean?
So my guess is that the wholesale price from Aavid Thermalloy is the reason why the kit costs what it does.
I think in the past I got 100 T22O insulators and bushes for less than three quid from evil bay.
Buy the screws etc seperately
Screws and hardware and crap like this, sure, eBay might be an option.
dmp
Well-known member
Just market pricing I expect. They obviously aren't pricing for small quantity, attentive buyers.
You can buy the pad and shoulder washer for $.28 and use any screw and nut to put it together.
No serious manufacturer would pay that much for that little... that price screams they do not want to sell them kitted that way, or nobody with a clue is managing prices, which amounts to the same thing.
JR
JR
Gene Pink
Well-known member
JohnRoberts said:
The high price is based on having to make up kits. Someone in a warehouse has to go out and pick 100 of each part per order, bring them to a shipping bench, and then accurately put one of each part in 100 little bags, and staple them. Not efficient on their end, and they will charge for that convenience.
Just order 100 of each in bulk, you put together as needed, much cheaper and easier for the warehouse guys.
I worked in an Ingersoll Rand warehouse for a bit, those sort of assembled kits were really annoying and time consuming to put together. Likely these kits would be appealing to some company sending out a replacement part which included mounting hardware, and they didn't want to mess with stocking the parts and making up their own kits. Big business efficiency.
But I gotta say, those 30" dia. air compressor pistons at that warehouse, way up on the top racks, were really cool, not to mention the totebox full of piston rings next to them. Some cylinders were there too. Makes one consider blacksmithing up the ultimate Harley V-twin. It would have to be a two-stoke, as all the had there were 12" reed valves. There were also some roots style blowers there. ;D
Gene
That would be the ultimate "stump puller" (nickname for big one hole motorcycles), but I don't recall any being two stroke.Gene Pink said:
JR
> I don't recall any being two stroke.
Big 2-jug 2-stroke: https://en.wikipedia.org/wiki/Scott_Flying_Squirrel
Many large locomotives used 8-inch bore 2-strokes (but not reed valves).
The highest-power piston engines running are 2-stroke. This one has 960mm jugs, about 38 inches on my ruler. (Stroke is more than twice bore.) Most of these come from work by Sulzer.
Big 2-jug 2-stroke: https://en.wikipedia.org/wiki/Scott_Flying_Squirrel
Many large locomotives used 8-inch bore 2-strokes (but not reed valves).
The highest-power piston engines running are 2-stroke. This one has 960mm jugs, about 38 inches on my ruler. (Stroke is more than twice bore.) Most of these come from work by Sulzer.
The flying squirrel sounds nice but my recollection of stump pullers was motors with tons of torque at low RPM ... Maybe those locomotive two strokes made some serious torque, but I recall more like old hogs and other big displacement 4 stroke singles.PRR said:
I owned a nice 2 stroke road bike (RD400) but it sounded more like an egg beater... that said it would lift the front wheel a little too easily if I wasn't paying attention while passing cars. Making it difficult to steer with the front wheel off the ground.
Quick little rice rocket. JR
> tons of torque at low RPM ...
The cargo-ship engine is 5 MILLION pound-feet torque at 102rpm.
Remember that if Gene scored just 14 of those I-R pistons, he'd be part way there.
102 is not a "low" RPM for a 8-foot stroke. About like your 302 V-8 turning 3,400. Well under redline, but as fast as you'd want to spin for 0.2-million-hour life. I'm guessing a prop-ship has no need for low-low-RPM torque. I bet stump-pulling boats (tugs) put more power into churn and prop-loss than in the stump or stuck-ship they work against.
The cargo-ship engine is 5 MILLION pound-feet torque at 102rpm.
Remember that if Gene scored just 14 of those I-R pistons, he'd be part way there.
102 is not a "low" RPM for a 8-foot stroke. About like your 302 V-8 turning 3,400. Well under redline, but as fast as you'd want to spin for 0.2-million-hour life. I'm guessing a prop-ship has no need for low-low-RPM torque. I bet stump-pulling boats (tugs) put more power into churn and prop-loss than in the stump or stuck-ship they work against.
Actually my 4.6L is more like 280 cubic inches. 8)PRR said:
Speaking of torque, back in the 70s I put an electronic ignition on my RD400,. it used hall effect devices and an extra magnet on the rotor so it couldn't start and run backwards (2-strokes are funny that way). I gave some late night thought into smart variable spark timing to milk a little more oomph and mileage out of the blue smoke belching dragon, but this was before $2 micros (and knowing what to do with one if i had it), so it didn't happen.
JR
I remember a story of a 2 stroke in a very iconic boat of my town, it had some iron balls you should heat with a torch before starting it up, then when you start it it would start backwards and you need to cut the gas till it almost stops, when it bounces shout to the cap on board so he would max the gas and get the timing just right so it runs the way it should.
JS
JS
> so it couldn't start and run backwards (2-strokes are funny that way).
> when you start it it would start backwards
The flaw you wanted to fix is a feature on the big boat engines. MUCH cheaper to run the engine the other way than to put reverse gears in a 5 mega-lbft drive shaft. However they start by blowing compressed air in, through a which-way valve, so none of that bouncing off TDC to get it going the other way.
And the locomotive engines had poppet valves, they knew which way to go. (Reversing was switching wires on the generator-motor set.)
The torched "ball" was probably a "hot tube ignition". Predates spark plugs. Still a thing in model engines (except heated with a battery to start).
I had an electric clock. Basic AC motor will turn either way. This had a gizmo, turned backward, finger hit a peg, "bounced", now it was going right. That broke, so we had to finger-bounce it after some power failures. I now have a clock that turns the wrong way, but is numbered the wrong way, so it is all right.
> when you start it it would start backwards
The flaw you wanted to fix is a feature on the big boat engines. MUCH cheaper to run the engine the other way than to put reverse gears in a 5 mega-lbft drive shaft. However they start by blowing compressed air in, through a which-way valve, so none of that bouncing off TDC to get it going the other way.
And the locomotive engines had poppet valves, they knew which way to go. (Reversing was switching wires on the generator-motor set.)
The torched "ball" was probably a "hot tube ignition". Predates spark plugs. Still a thing in model engines (except heated with a battery to start).
I had an electric clock. Basic AC motor will turn either way. This had a gizmo, turned backward, finger hit a peg, "bounced", now it was going right. That broke, so we had to finger-bounce it after some power failures. I now have a clock that turns the wrong way, but is numbered the wrong way, so it is all right.
My car has an electric heater for when it's cold in the mornings... And the van i used to move past sunday had one too but you need to short the wires to the battery for them to work.PRR said:
You also need to be careful, they take a special type of fuel from a different pump ;DI don't know which is the right way on your hemisphere, I like my clock turning the same way the water in the toilet!
JS
mike-wsm
Member
PRR said:
Back when I was am apprentice we had to make a sweep frequency oscillator. Being a lazy beggar I took an existing unit and added a synchronous clock motor with a couple of sprung stops so it self-reversed. Worked perfectly!
Unlike those Ford windscreen wipers which slowed to zero when you put your foot on the gas......
Laziness is the father of invention.... 8)mike-wsm said:
Yup the old windshield wiper motors ran off manifold vacuum and when you floored it the manifold vacuum dropped to nil... but why were you flooring the gas pedal in the rain? ;D IIRC some premium cars used a vacuum reservoir tank, to smooth out short term vacuum changes...
That same changing manifold vacuum was used to advance ignition timing under heavy throttle since the denser fuel mixture will burn faster.
JR
That ECU sucks! (sorry, I had to...)JohnRoberts said:
Now some use fuel sensors and knocking detectors to adjust the timing even with different fuel qualities to be right before knocking. I was surprised no one did electromechanical valves (solenoids) and take the timing belt out but that started last year.
JS
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