Parm
Respect The Sound System
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years ago I saw this dude balancing rocks on Brighton beach. Not to that scale though
- Thread starter 8ob
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years ago I saw this dude balancing rocks on Brighton beach. Not to that scale though
Parm
Respect The Sound System
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dunno about this one, but no, not normally
I toyed with buying a used, knackered crank balancer earlier this year, it was a simple affair, very much like a lathe bed.
The electronics are readily available, if not cheap. I decided against it - enough projects, not enough life left to do them all...
The electronics are readily available, if not cheap. I decided against it - enough projects, not enough life left to do them all...
slim_boy_fat
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slim_boy_fat
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Most folk just call me; Orange Joe
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My dad showed me pictures of the foundations being poured for a linear accelerator at the hospital a few years ago, hundreds if not thousands of cubic meters of special boron concrete if I recall, don't remember exactly what the machine did but cancer treatment rings a bell.
Bullet2012
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ronan
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There is a balancing jig in the college, i often looked at it and could see no reason why it could not be used for crankshafts, if it was a bit longer. Its actually a simple thing, A welded up box section frame, a steel roller on pillow blocks, with Accelerometers in the horizontal and vertical. The software tells you where to apply weight, or remove it in the case of a crank.
The thing is started and run with the steel roller deliberately unbalanced and the students have to work out what to do to get the thing to run smoothly.
The thing is started and run with the steel roller deliberately unbalanced and the students have to work out what to do to get the thing to run smoothly.
Pete.
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Almost certainly. I cut out part of a foundation for one of those at a famous hospital the year before last. They were modifying the building to replace the machine with a newer model. The foundations were big but not nearly that big and the only reason they were doing it is because the manufacturer required it to guarantee the machine. The surrounding concrete walls were also a couple of feet thick - for shielding!
'100 feet deep' could only be friction piles which are pretty standard.
sako243
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I'm not sure that the mass beyond a certain point is going to help, what that point is I don't know at the moment (too early in the morning). The point about vehicles influencing the measurement is going to be relatively moot in this particular instance unless it happens to be perfectly in sync with the RPM of assembly under test / calibration.
I haven't looked into the logistics of a suspended unit but when we talked about building one for you (sorry, been assuming we're on Bob timescales here so had a few years to spare) the crank would have been on a solid base. Ultimately the accelerometers only want to be looking in one axis and it's looking for the biggest oscillation that is in sync with the chosen RPM, anything not in sync is filtered out.
My gut feel is that as long as the mass you're clamping the crank to its sufficiently bigger than the crank for you're purposes will suffice. Ultimately the compression and characteristics off each cylinder is going to affect the balance so you're not going to be able to fully balance it without it being in the engine. Even then variations in temperature of each cylinder / piston etc are going to affect things.
In summary, any extra mass in the base is going to help but there'll be a point of minimal gains after that.
I haven't looked into the logistics of a suspended unit but when we talked about building one for you (sorry, been assuming we're on Bob timescales here so had a few years to spare) the crank would have been on a solid base. Ultimately the accelerometers only want to be looking in one axis and it's looking for the biggest oscillation that is in sync with the chosen RPM, anything not in sync is filtered out.
My gut feel is that as long as the mass you're clamping the crank to its sufficiently bigger than the crank for you're purposes will suffice. Ultimately the compression and characteristics off each cylinder is going to affect the balance so you're not going to be able to fully balance it without it being in the engine. Even then variations in temperature of each cylinder / piston etc are going to affect things.
In summary, any extra mass in the base is going to help but there'll be a point of minimal gains after that.
8ob
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All will be revealed
Seems idiot proof on the set up side of things,probably just as well 
Anyway I have an @sako243 I can call if I pickle my brain.
Is this for a high performance engine, Bob? If so, are you going the whole hog & blueprinting it? [and since my nose is bothering me, what's it going into....]
Yes John plenty of that going on, I have been very disappointed with some of the work that I have sent out so going to have a go at in house.
Ed I am soooooooooooooooooo glad you have moved from a two up two down to that new gaff, you are probably coming to grips by now just how expensive and time consuming some of these building projects can be, chuck seven kids, some renters, a farm and a business to run in the mix and you may appreciate why things take a tad longer here
. Rome wasn't built in a day, then again I wasn't on that job. 
Its not just for cranks, these chipper rotors can quite often need rebalancing after getting damage repair, heaviest thing I envisage balancing would be about 100KG
Biggest would be about 1mtr in diameter so the stands would need to be quite tall.
sako243
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@8ob have actually been giving this some thought recently.
There's another thing that came up yesterday which would be good if I can get the accelerometers up and running for (might also be useful for your guys). Was planning on spending some time on it today but that's all gone to the crapper...
Perhaps easiest if we chat this evening? The electronics side of things isn't that difficult but I've been putting it off because the workshop's been in a constant state of flux so haven't had a chance to make up a test rig (basically something spinning like a crank but that is balanced with some threaded holes to just knock the balance off for the purposes of testing).
There's another thing that came up yesterday which would be good if I can get the accelerometers up and running for (might also be useful for your guys). Was planning on spending some time on it today but that's all gone to the crapper...
Perhaps easiest if we chat this evening? The electronics side of things isn't that difficult but I've been putting it off because the workshop's been in a constant state of flux so haven't had a chance to make up a test rig (basically something spinning like a crank but that is balanced with some threaded holes to just knock the balance off for the purposes of testing).
