Wobble in Clausing variable speed drive


http://www.youtube.com/watch?v=mPOSb_VhQq8

My variable speed drive, both pullies actually, wobble when they operate. I shot a video of it at 5 Hz. It appears to be crooked or off
center. Might be some bushing missing or something. It could be that the wobble in the primary pulley causes wobble in the driven pulley.
Anyone would have any idea?
i
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Not sure, but I'd pull the belt off and see if the bearing/bushing inside the pulley has a lot of play due to wear.
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wrote:

Ayup. A very very common issue with Clausings and pretty cheap to replace.
Gunner
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You guys mean the bushing inside the outer variable pulley on the motor, right?
I will take the lower VS assembly apart today and will look, as I need to get a few parts from Clausing anyway.
i
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In which case, as per Gummer's sig, grab yer wallet and yer ass.....
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EA


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I disagree and find Clausing price on this line of lathes very reasonable.
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It depends on what you need. If it's a common replacement part, then they are likely to have them in stock and the prices are reasonable. It's it's a bit more unusual and they have to make one from scratch at today's hourly wage, the prices can be astronomical. The good news is that they will often sell you dimensioned drawings if you want to make your own. They do the best they can to to help folks keep the older machines in service, and I have to applaud them for that.
Doug White
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On Sun, 07 Feb 2010 11:15:43 -0600, Ignoramus3837

Unlike other models. Crom..the motor belt on my Clausing 1500 is $108 plus shipping!
Gunner
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Isn't the service group for Clausing an umbrella-type group that does Kalamazoo saws, Clausing, and, iirc, BP?? mebbe a cupla others?
These muthafuckas wanted $900 for an effing cutoff switch for the Kal (that you coulda made from a piece of 1/8x1/2 alum and a HD toggle light switch), and $1300 for just part of the mechanical variable speed control.....
Even the rep on the phone said, Goddammmmmm........
Mebbe Ig is independently wealthy.....
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Yup.
http://wess.freeshell.org/bushing2.jpg
Wes
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Iggy, You can be certain that this wobble is an effect of wear. Only disassembly will reveal the cause. Everything else is speculation. Steve

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Wear in the delrin bushing. IIRC, the fit between the bushing and the shaft of the other pulley flange should be 0.001".
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
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OK, I have taken the whole thing apart, which was very easy.
Something does not yet make sense to me.
Here are some things I found out. I made a large number of photos and will post them after some thinking.
1. The fit between the delrin bushing and the epoxied shaft on the inner pulley, is good. The epoxy on the inner half of the pulley is black and not green.
2. The epoxy on said shaft is in good shape.
3. The keyway between the inner and outer pulley is all beaten up. this keyway is on the epoxied part of the inner half.
4. The 3/8" shaft, on which the hydraulics is mounted, is held in a special bushing that is held inside the outer pulley by a retaining ring. The ring was broken (but still there) and a small part of the rim (part of the pulley) holding said ring, is broken off as well.
That shaft, due to not being held properly, was wobbling inside the pulley and that partly explains why the hydraulics was wobbing as well.
More disconcerting is that the inner hald of the pulley wobbled as well. Yet, it was held tightly on the motor shaft. It also is cast iron and coule not be bent and it does not look bent. Furthermore, the motor's shaft does not look bent either. It makes no sense to me. I am missing something.
The damage to both halves (worn keyway on the epoxied part, damaged rim to hold the base for 3/8" shaft for hydraulics), seems to be repairable with a little bit of nickel welding and another lathe (I can probably use my friend's lathe, hopefully). Of course, welding on the pulley with epoxy means that epoxy would need to be redone.
I will not start any repairs, until I get a complete understanding of what is going on, what is not working and what is causing what.
i
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Ignoramus3837 wrote:

Suspect motor mounted on resilient vibration damping mounts allowing the wobble of the items hung way out on the shaft to cause wobble of the motor itself.
Just an educated guess, I haven't been in one of those lathes before.
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wrote:

Particularly if the belt has a "stiff" spot on it.

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That would be very helpful, I read though this and was responding earler when my computer crashed for the second time today, second time in about 3 years.

That epoxy is teflon impregnated. It is green. At least that is what I've been told. Take that with a grain of salt though.
http://wess.freeshell.org/driven_green.jpg
The above link shows the green coating damaged showing the black coming though.
Of course the instructions that come with the delrin af bushing calls it epoxy.
http://wess.freeshell.org/bushing1.jpg
Searching around I found this link. http://www.epoxyproducts.com/2_fillers.html
Go down a bit, teflon powder to put in epoxy. I used moglice to repair mine. I'd be interested in trying that if I did it again.
I also might have just ran a new bushing a bit longer on the original coating.

Is the cut keyway battered or is part of the delrin bushing missing the keyway section?
http://wess.freeshell.org/bushing2.jpg

Do you have telescoping gages to measure the ID of motor side pulley and compare it to the motor shaft?

I did some of my machining on my lathe.
http://wess.freeshell.org/spindle_driver.jpg
Threaded rod and a soft plug, stuck inside the spindle tube.
http://wess.freeshell.org/When_the_drive_is_down_you_improvise.jpg
Big drill powering spindle, held by my uncle.

Best to study this thing carefully before doing anything permanent.
Wes
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Yes. My 5914 had a very bad wobble, which turned out to be due to the bottom VS pulley assembly coming loose on the motor shaft and battering itself. The root cause was a setscrew that had become loose, but neglect by the prior owner or owners had allowed the problem to worsen.
The whole story is in "Clausing 5914 VariDrive Wobble" and children posted to RCM in January 2008.
Joe Gwinn
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My issue is similar in some ways.
First of all, the thin 3/8" shaft that held the hydraulic system, became loose and vibrated. I think that this accounted for most of the racket.
Second, the inside lower half pulley is not a perfect fit for the motor shaft. So, the motor shaft is not bent, the pulley half is perfect, and yet they are not aligned.
My feeling on this matter is that vibration of the lower pulley is not nearly as big of an issue as vibration of the hydraulic shaft.
I am tempted to paint the motor shaft, which may eliminate this clearance, and then replace the 3/8" shaft that holds hydraulics, and call it a success. I am reading your thread now.
i
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I would take it apart and look before coming to a conclusion. Ultimately, the repair was not difficult.
Nor is paint strong enough. If you must, use very thin steel shimstock.
Joe Gwinn
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    These pulleys (assuming that they are like the ones on my Bridgeport) have a Delrin sleeve separating the sliding pulley from the shaft of the motor. These wear out. There is also Delrin around the key, and if this wears out too, you start machining away the side of the keyway in the motor shaft. (Hmm ... does yours have one of the Vari-speed sheaves on the motor, or is it between an idler and another?) I had to get a replacement rotor for my Bridgeport's motor. The rebuild kits are relatively inexpensive, when compared with the price of new motors or shafts -- but some shops believe in "run them until they die" and never sink the time into replacing the sleeves and bonding the new ones into place properly.
    Good Luck,         DoN.
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