I was cutting a drive shaft down for my new project and found a card board tube inside of it. Is this placed inside of it for some reason? Really not sure
i've seen it before , i believe that they were used for sound deadening....i don't know if it actually worked
It is for sound/resonnance dampening. Leave it in there even if you have to cut it up....the driveline will be much quieter than an empty tube.
Well, I build driveshafts for a living. Yes they are for sound deadening, when they get loose inside almost impossible to balance.
I always removed it when shorting a shaft. I know what its for but never noticed any difference in sounds. Most of us use them in hotrods so the other noise drowns out any thing else if it was a little louder than stock. I installed one in my truck I made and its real quiet as to road or mechanical noise and there is no difference I can tell period.
I read awhile back in the internet that they hid the dead sea scrolls in a drive shaft. It's gotta be true, right?
Best explanation I heard was that it dampens the tube and changes the critical rpm where it will whip so they can run a smaller diameter/thinner wall tube for a given length. I always take them out too.
Yep, I don't know what it's for but they put it in big truck driveshafts too. I used to work at a place that would take brand new trucks and shorten the frames, for beer and pop trucks. I was curious the first time I saw it too.
You should see what they do when the car /truck burns to the ground. I'll try to take a shot of mine to show ya!
Packing inside a driveshaft is to change the natural frequency of the shaft. Typically done because gear noise from the differential is amplified by some driveshafts to the point where it's audible inside the vehicle (a no-no in new cars) Depends on O.D., wall thickness, length, etc. Not all shafts will need it. And when you shorten the shaft, you change the natural freuqency, so you may not need it. But it's not hurting anything by leaving it in....providing it's not loose and causing balance problems.
Every big truck shaft, pickup shaft, and passenger car shaft we build gets cardboard. One customer (Dodge dealer) brought us a shaft that had spray foam having been sprayed in it. Because the stuff couldn't get air to set, the liquid flowed around inside the tubing like bull snot and caused a hell of a vibration.
One might think the liquid 'spinning' would cause a 'balance', clinging to the 'lighter side'... Recall the 'hoops' with steel balls and/or oil on big rig wheels, to 'balance' them above given RPM... Experiments on the track abounded in the '60s, attempting to quell 'race imbalance'.
Must of been absent in a long empty dodge van I had in the early eighties. sounded like you were in an airplane .
I think concrete-filled lally columns would make decent driveshafts. Kinda heavy though, 8^) Jack E/NJ
I never put the cardboard back when shortening a shaft. I thought it would burn when I welded the end back on. and a driveshaft will exploded and flatten when its subjected to enuf heat.
Butch is 100% correct. I worked in a driveline shop in my younger days. We never put the card board back in either. Sent from my iPhone using The H.A.M.B. mobile app
I just having to tell a friend of mine that a lot of driveshafts came with them when he called me all wound up because he thought that someone had messed with it when the found the cardboard inside when he cut it in two to shorten it.
Quite a few years ago I remember a few people mentioning that they'd found what appeared to be rolled-up newspapers stuffed inside driveshaft tubes. The more I've thought about it over the years it started sounding like some used car dealers "field fix" for a driveline howl or harmonic noises. Maybe it helped to dampen the noise of a badly worn transmission or rear axle.
I work for a driveline company, its for sound deadening. We use a high density foam insert on stuff now a days though. Ive seen cardboard in them as well as paper wadding. And even seen a couple home made jobs with pool noodles stuff in there to cut the resonance down, if it works it works!