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Clausing 8520 Quill Deflection & Noise Concern (Video Attached)

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GrizzlyBagWorks

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#1
Hi Guys,

I've just finished up my 8520 complete teardown, repaint, and rebuild. Every bearing in the machine has been replaced and all adjustments dialed in. The machine is very smooth and overall I'm happy. I'm a little concerned about some noise I'm getting from the machine at higher speeds when the quill is locked down. I'm getting ~.002 deflection in the quill when the quill is locked down. The noise is not coming from the spindle brake, it's a chatter at the spindle drive plate. Do I need to be concerned about this?

I do plan on adding in the Quill Drive Plate Spring Plungers. I'll likely do 3 plungers rather than 2 just to better center the spindle.

Thanks guys!

 

mikey

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#2
I don't know where the rattle is coming from but wanted to say that you did a beautiful job on the restoration!
 

Briney Eye

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#3
I've just reconditioned an 8520. It was a little tricky getting the top pulley sleeve centered around the spindle since it lacks a positive locating feature. I inserted several strips of shim stock around the spindle to keep the sleeve centered while I tightened the screws down. If yours is offset it might be allowing the splines to rub when you deflect the quill. Try a feeler gauge to see if the clearance is even all the way around. And lock the quill before you tighten the sleeve.

Mine came with nylon plungers that didn't work very well. I made new ones from brass, and they don't work very well, either. Getting strong enough springs seems to be part of it.
 
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GrizzlyBagWorks

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#4
Thanks guys! Briney, I'll have to double check but isn't there a shoulder on the piece that the pulley mounts to that inserts into the head? I don't recall there being any play between the two components. Between the 3 socket head cap screws and the shoulder it seemed to be a tight fit. I'll have to take a second look.

Just thinking here but perhaps I can turn that shoulder down on the lathe so it's a couple thou undersize, enlarge the counterbore and screw holes to give myself a little room to tune the fit.
 

woodchucker

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#5
Why not drill and thread the splined collar put a spring in use brass to put the pressure on, it should calm it down quite a bit. I experienced a ton of noise with a kevlar belt from Tractor supply. It went away when I put a link belt on, so I ordered a cogged set of belts.
 

Briney Eye

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Thanks guys! Briney, I'll have to double check but isn't there a shoulder on the piece that the pulley mounts to that inserts into the head? I don't recall there being any play between the two components. Between the 3 socket head cap screws and the shoulder it seemed to be a tight fit. I'll have to take a second look.

Just thinking here but perhaps I can turn that shoulder down on the lathe so it's a couple thou undersize, enlarge the counterbore and screw holes to give myself a little room to tune the fit.
I guess there are a few variations in the way that Clausing built these machines. The sleeve on mine (built in 68) has no shoulder. It has to be aligned before the screws are tightened. If I were to try turning one I think I would put an indicator on the spindle and check the concentricity against the inside bore first.
 

Silverbullet

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#7
Try loosening the belt tension just a tad. With the quill down it will make more deflection. I don't think you'll get rid of the noise , the spindle splines are wiggling in the column itself from what I hear and see.
 

GrizzlyBagWorks

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#8
I took an indicator to the spindle and the sleeve, tested the gap with shims, tried different positions, etc. When the spindle is not locked the spindle is centered. When I lock the quill the spindle deflects forward .002".

My thought is that I turn down the shoulder that locates the upper pulley by .002". Then enlarge the holes and counterbores for the SHCPs. That way I can slide the assembly forward, in the direction of the deflection. Hopefully I can get that shoulder spot on so I don't have to center it manually with shims. But even if I have to do that I'm fine with it if it eliminates the noise.

Unless anyone has any other ideas I'm going to give it a shot. I'll let you all know the results.
 

woodchucker

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#9
That's so wierd that it deflects forward since the lock is pulling the casting toward the back of the head, so you would think it would deflect the quill toward the motor, not forward.
 

GrizzlyBagWorks

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#10
Just wanted to give an update and let everyone know I was able to fix the noise issue. Here's what I did for those that may have a similar problem:

I chucked up and turned down the shoulder that locates the plate the pulley seats onto by ~.005. This gave me a loose fit in the casting so I could center it around the spindle. Then I drilled the 3 mounting holes oversized and enlarged the counterbore. This gave me rest of the adjustability I needed so the socket head cap screws wouldn't interfere with the fit.. Then it was just a matter of using feeler gauges around the spindle and centering everything while the quill was locked in the bottom position.

I'll do an update video so you guys can hear the difference. I'm quite happy. Now I just need to drill/tap the drive plate for the brass plungers to quiet it further.
 

Briney Eye

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#11
Just wanted to give an update and let everyone know I was able to fix the noise issue. Here's what I did for those that may have a similar problem:

I chucked up and turned down the shoulder that locates the plate the pulley seats onto by ~.005. This gave me a loose fit in the casting so I could center it around the spindle. Then I drilled the 3 mounting holes oversized and enlarged the counterbore. This gave me rest of the adjustability I needed so the socket head cap screws wouldn't interfere with the fit.. Then it was just a matter of using feeler gauges around the spindle and centering everything while the quill was locked in the bottom position.

I'll do an update video so you guys can hear the difference. I'm quite happy. Now I just need to drill/tap the drive plate for the brass plungers to quiet it further.
What's the vintage of your 8520? Mine was built in 1968 (serial #7720 IIRC) according to Clausing, and as I mentioned earlier has no shoulder on the plate, so I shimmed around the spindle before tightening it down, just like you did. I'm wondering whether Clausing added or removed the shoulder.
 

GrizzlyBagWorks

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#12
I own two machines. One serial number in the 270's and one in the 470s's. Both have a shoulder that is a tight slip fit into the head casting. The 270 machine is the one in the video (total rebuild). I rebuilt the head on the 470 machine (total tear down/new bearings, etc. - but not a cosmetic refurb) and it exhibits the same problem. I'll be doing the same modification to that machine as well. Video to come.
 
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