In a time before (digital) accelerometers and high-tech vibration sensors were available to make such a job easier, how were driveshafts actually balanced back then? Inquiring mind would like to know.
years ago we would balance racecar driveshafts by putting the car up on the rack with someone inside. put a rad hoseclamp on and turn it till the vibration went away. crude but effective..
Driveshafts would have been balanced on one of these. Stewart Warner Balancer ,this ones older than me and still gets the job done >>>>.
Nice machine. Can you explain how that balancer senses an imbalance on a shaft? It is through the bearings the shaft rolls on or through the motor that drives the shaft? I don't think it tells you where exactly the imbalance is on the shaft right? You'll probably have to figure out yourself by moving weights around the shaft I think.
i have seen how the stones on surface grinder are balanced, they use a cast stand with two parallel machined surfaces to rest the center shaft on, first the stand is leveled in both directions, then they move some adjustable weights around to make the mount balanced, when you can place the shaft on the stand and it stays without rolling then its balanced, the same could be done with a drive shaft by taping weights to the shaft that would be welded on later, may not be perfect but better then nothing.
It should tell you the exact degree the imbalance is at. I balance drive shafts for chinooks and blackhawks on 60+ year old machines. Theyre dead nuts.
My shop has an old Bear/Axiline balancer that's probably 30 years old. It uses dial indicators against a swinging cradle supporting the drive spindle, and a strobe behind a "clockwheel" for weight positioning. The operator runs in a knob to make the trigger switch contact and uses the dial indicator to figure approx how much weight to attach. These old balancers have a speed controller on the motor to eventually spin the shaft at the speed it operates at, 3000 rpm for automotive, 2000 for big truck. Late model balancers spin shafts slow, I can't figure out how they work properly, but not saying they don't. I'll do a tech deal one of these days on how we build.
<TABLE class=tborder id=post4121877 cellSpacing=0 cellPadding=6 width="100%" align=center border=0><TBODY><TR vAlign=top><TD class=alt2 style="BORDER-RIGHT: #e5e5e5 1px solid; BORDER-TOP: #e5e5e5 0px solid; BORDER-LEFT: #e5e5e5 1px solid; BORDER-BOTTOM: #e5e5e5 0px solid" width=175>racer67x<SCRIPT type=text/javascript> vbmenu_register("postmenu_4121877", true); </SCRIPT> </TD><TD class=alt1 id=td_post_4121877 style="BORDER-RIGHT: #e5e5e5 1px solid"><!-- icon and title --> Re: Driveshaft-balancing, how was it done back then? <HR style="COLOR: #e5e5e5; BACKGROUND-COLOR: #e5e5e5" SIZE=1><!-- / icon and title --><!-- message -->years ago we would balance racecar driveshafts by putting the car up on the rack with someone inside. put a rad hoseclamp on and turn it till the vibration went away. crude but effective.. <!-- / message --></TD></TR></TBODY></TABLE> In the early 70's I put a 429 merc in my brothers 68 ford p/u. he bought a driveshaft from Ford, and it came with those instructions exactly.
GM was dynamically balancing driveshafts (GM calls them propshafts) in the 1920s. GM had a group called Balance Engineering that engineered and built balancing equipment. Balance Engineering was spun off from GM several years ago and I think is still in business today.
#### The driveshaft fixture is a trunion 3rd bearing assembly that clamps the yoke in the machine as if it were spinning in the trans. The trunions ride in dashpot that convert hydralic motion to electric motion. The dashpots have 5 levels of sensitivity with 1 being the most sensitive. Any out of balance makes the strobe flash at the highest point of out of balance. Mark the shaft at the strobe flash point,rotate the shaft 180 degrees and the heavy spot is at the top. Sounds kinda complicated but it's really not. The neat thing about this machine is you can spin the shafts through the balance phase of rpm and actually tell if the shaft is running smooth like a gyro >>>>.
I have an old Bear Dy-Namic Balancer. I have it wired and running at this point. Just need to figure out how to properly balance a drive shaft. If any one can help Pm me.
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