Any photos??
I ask as I have a seized compressor pump. Not very old but just locked up and seems to be big end as they don't have shells.
I think I might need to mount the crank to get it round and shiny again.
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I ask as I have a seized compressor pump. Not very old but just locked up and seems to be big end as they don't have shells.
I think I might need to mount the crank to get it round and shiny again.
Agroshield
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The cutting force will tighten a RH thread at the headstock end when in normal rotation direction (downwards to the front). If that RH thread is put in the tailstock with the same rotation direction, the cutting force will try to unscrew it.
I imagine it will be something like this:
You need a couple of sub-fixtures because the jaws of a chuck will not go past the centre. Depending on the throw of the crank a chuck-within-a-chuck could work.
In all the crank grinding videos, they stress the need for a steady on the journal being machined. And the cutting forces from grinding are much less than turning.
With a straight Armstrong holder, you might need to assess the side clearance of the holder body to the webs of the crank or use a LH/RH pair (PITA as then you have a blend line). Either way, it is not easy to hit the full width of the journal with one tool.
northwest
Searching for the Holy Grail.........
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Thing is, if it is trying to unscrew it, it is also trying to elongate it so it is just getting tighter between the two ends. Little chance of it unscrewing, mine doesn't.
Seadog
Save the planet. It's the only one with rum!
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Most folk just call me; Orange Joe
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Having now seen the crankshaft in person, I think I'm going to try to clean up the ends that run against bushings in the housing but I'll leave the conrod journals as they are, looks like it's going to be more trouble than it's worth to make a good job of it.
I do need to make new conrods though, this one's knackered and the other is missing. What do we think to making these?
(Excuse the white line for now)
The originals are cast brass (Maybe bronze? It is acting as a bushing after all) so my first thought was to buy a big chunk of brass and machine them from solid. That'll need to be two 150mm pieces of 25x60mm flat stock, or perhaps a 65mm round. This was the only price I could find online and even if a proper supplier is half that, it's not happening! Unless someone has some they're willing to let go a little closer to scrap value, I need an alternative.
My first thought was do it in steel and press in a couple of oilite bushings but I'm also wondering if I could make it in two pieces, split at the white line and joined with a fine thread, maybe solder it too, that way I'd probably only need much more realistically priced 25mm bar.
That or cast it, I've got loads of scrap brass but no experience or tools for casting so I'm thinking it's probably not worth bothering with.
Nothing's gonna happen at least until Christmas btw so plenty of time to think about it.
I do need to make new conrods though, this one's knackered and the other is missing. What do we think to making these?
(Excuse the white line for now)
The originals are cast brass (Maybe bronze? It is acting as a bushing after all) so my first thought was to buy a big chunk of brass and machine them from solid. That'll need to be two 150mm pieces of 25x60mm flat stock, or perhaps a 65mm round. This was the only price I could find online and even if a proper supplier is half that, it's not happening! Unless someone has some they're willing to let go a little closer to scrap value, I need an alternative.
My first thought was do it in steel and press in a couple of oilite bushings but I'm also wondering if I could make it in two pieces, split at the white line and joined with a fine thread, maybe solder it too, that way I'd probably only need much more realistically priced 25mm bar.
That or cast it, I've got loads of scrap brass but no experience or tools for casting so I'm thinking it's probably not worth bothering with.
Nothing's gonna happen at least until Christmas btw so plenty of time to think about it.
Woody.v8
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If you give me some dimensions I will measure some reliant rods to see if they are anything like closeHaving now seen the crankshaft in person, I think I'm going to try to clean up the ends that run against bushings in the housing but I'll leave the conrod journals as they are, looks like it's going to be more trouble than it's worth to make a good job of it.
I do need to make new conrods though, this one's knackered and the other is missing. What do we think to making these?
(Excuse the white line for now)
The originals are cast brass (Maybe bronze? It is acting as a bushing after all) so my first thought was to buy a big chunk of brass and machine them from solid. That'll need to be two 150mm pieces of 25x60mm flat stock, or perhaps a 65mm round. This was the only price I could find online and even if a proper supplier is half that, it's not happening! Unless someone has some they're willing to let go a little closer to scrap value, I need an alternative.
My first thought was do it in steel and press in a couple of oilite bushings but I'm also wondering if I could make it in two pieces, split at the white line and joined with a fine thread, maybe solder it too, that way I'd probably only need much more realistically priced 25mm bar.
That or cast it, I've got loads of scrap brass but no experience or tools for casting so I'm thinking it's probably not worth bothering with.
Nothing's gonna happen at least until Christmas btw so plenty of time to think about it.
Pete.
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The conrods might have been nitrided. Would make the surface harder than the steel pin.
ronan
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Didn't know you could nitride aluminium.
Maker
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I think it's something like 4.25" between centres, 1" bore, 1" thick at the crank end, I don't know about the gudgeon end, half inch bore maybe. It would be quite fun machining them so don't look too hard.
Even untreated, I wouldn't be too shocked to find the hard side wearing faster. If some abrasive material finds its way in there, it can bed into the soft side and wear the hard side much faster, I think it's more common with plastic against metal.
Weeell, yamaha conrods don't have anything between the rod and chrome steel gudgeon pin, and they do zillions of revs and thousands of miles. They do have soft metal be bearings though...
I think it's something like 4.25" between centres, 1" bore, 1" thick at the crank end, I don't know about the gudgeon end, half inch bore maybe. It would be quite fun machining them so don't look too hard.
Even untreated, I wouldn't be too shocked to find the hard side wearing faster. If some abrasive material finds its way in there, it can bed into the soft side and wear the hard side much faster, I think it's more common with plastic against metal.
Inch bore be? Mower rods....
ronan
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Triumph engines used to run the gudgeon pins directly in the conrods, after a certain year, and they didn't wear. I was looking at the ones in my engine when i rebuilt it and i could not see any wear. I believe the Japanese did it as well, running camshafts directly in the cylinderhead castings, and if the oil is kept clean, they don't wear much either.
