I have a restored 8520 that I have used very little and suddenly and seemingly without reason the quill handle has a vibration that is tied to the spindle rotation speed. The handle vibrates only when raising and lowering the quill. I have pulled the gear housing off and do not see any gear damage, I expected none since the quill operates as it should. If anyone has any thoughts on what to look for, it would be appreciated.
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Clausing 8520 Vibration
- Thread starter gedkins
- Start date
- Joined
- Nov 25, 2015
- Messages
- 10,034
what kind of belts do you have?
is the screw that calms the quill down tightened up so it removes the chattering? If too tight and the spring is bottomed out, that is not good as well.
Does the vibration go away at higher speeds, is it only in one range of speeds?
can you shoot a video and post a link here.
is the screw that calms the quill down tightened up so it removes the chattering? If too tight and the spring is bottomed out, that is not good as well.
Does the vibration go away at higher speeds, is it only in one range of speeds?
can you shoot a video and post a link here.
Regular v belts. I believe I have the correct tension on the quill screws. Vibration is present at all speeds and frequency of vibration is tied to rotational speed. All speeds have the vibration. Will shoot video today and post.
Hi all,
Thanks Woodchucker for the support. A big shout out to Opsoff1 for nailing the issue as an alignment issue with the drive plate being 180 degrees out of position. I also have to inspect the tension screw and its state of wear therein. His long contemplation of the same problem I had on his machine saved me a lot wasted time, I was thinking bad bearings. The mill is back up and running pretty smoothly and hopefully the tension adjustment screw will banish the last of the very small vibrations during quill movement. Thanks again all. I look forward to scouring this site for great tips and knowledge,
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- Nov 25, 2015
- Messages
- 10,034
I don't remember the drive plate, nor do I remember there being a clocking issue. There is a black 1/2 to 3/4 plate on top of the pulleys that holds it all together and has the tension screw.. but I am lost on what you are talking about. I'm at a loss. I have had the head apart multiple times. I changed the quill lock from a bolt that squeezes the casting, to a bridgeport type of double cam lock. Best thing I ever did to that.
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- May 2, 2015
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- 154
Gedkins & I had a good back and forth on email and got this figured out.
I recently completed a complete resto on my 8525 - all new bearings, belts, everything. When I reinstalled the head and fired it up to run in the bearings, I was shocked at the vibration I was getting through the quill feed handle.
Initially I was so unnerved by the vibration that I took the whole head apart (again).
When I stripped it down to individual parts, I checked the spindle for runout. I did have some deflection at the very top. I was able to straighten that out to less than .001". I reinstalled the bearings and the whole head was put back together.
After I remounted it and turned on the machine - the vibration was still there. I think I sat on my stool for 2 hrs staring at the mill thinking about all the alignments, what was moving etc. I had put DTI's on the table reading off the bottom of the spindle. The nose OD & ID of the collet area was turning at less than a few 10ths TIR....so there wasn't any wobble of runout down low. It was all up top. If the quill feed lever was still - there was no vibration. Only when it was moved. the areas that interfaced during this movement were the drive plate and the splined section of the spindle with the "tension screw assy. After a long hard look - and putting another DTI on the OD of the drive plate - I surmised that it couldn't hurt to reorient the drive plate 180 deg. The splined section wasn't a press fit - there had to be smooth movement there. That's when it hit me that the drive plate was probably pinned in place after it was bolted on - so I did the reorientation and viola` vibration was 98% gone. The tension screw / spring nylon shoe were recleaned and a new spring installed. I was able to complete remove the vibration with fine tuning the tension on the spline.
My mill is older - 1959 so I only have one spindle tension screw on my drive plate. If you have 2 on yours, you should be able to easily tune the vibration out with equal pressure from each. I think there may be some misconstrued purpose for these tension screws in the drive plate - This aspect of the design was NOT intended to prevent the quill from falling down. If you want to prevent the quill from falling down - adjust the head clamping tension for the quill with the two bolts/screws that are above / below the quill lock lever on the left side. The drive plate tension screws are truly just to adjust / tune the spindle to keep it from moving around in the drive plate and keep that unintended vibration out.
Long winded -- but hopefully thorough.
I think those that have reinstalled there drive plates with out having to clock it are the owners of mills where the drive plate was manufactured dead nuts concentric to the spindle axis. Mine mill is also older (1959) and has only one tension / spring / shoe assy in the drive plate. I think this experience is a great motivator to upgrade to a second tension screw system like the later mills have.
Scott
I recently completed a complete resto on my 8525 - all new bearings, belts, everything. When I reinstalled the head and fired it up to run in the bearings, I was shocked at the vibration I was getting through the quill feed handle.
Initially I was so unnerved by the vibration that I took the whole head apart (again).
When I stripped it down to individual parts, I checked the spindle for runout. I did have some deflection at the very top. I was able to straighten that out to less than .001". I reinstalled the bearings and the whole head was put back together.
After I remounted it and turned on the machine - the vibration was still there. I think I sat on my stool for 2 hrs staring at the mill thinking about all the alignments, what was moving etc. I had put DTI's on the table reading off the bottom of the spindle. The nose OD & ID of the collet area was turning at less than a few 10ths TIR....so there wasn't any wobble of runout down low. It was all up top. If the quill feed lever was still - there was no vibration. Only when it was moved. the areas that interfaced during this movement were the drive plate and the splined section of the spindle with the "tension screw assy. After a long hard look - and putting another DTI on the OD of the drive plate - I surmised that it couldn't hurt to reorient the drive plate 180 deg. The splined section wasn't a press fit - there had to be smooth movement there. That's when it hit me that the drive plate was probably pinned in place after it was bolted on - so I did the reorientation and viola` vibration was 98% gone. The tension screw / spring nylon shoe were recleaned and a new spring installed. I was able to complete remove the vibration with fine tuning the tension on the spline.
My mill is older - 1959 so I only have one spindle tension screw on my drive plate. If you have 2 on yours, you should be able to easily tune the vibration out with equal pressure from each. I think there may be some misconstrued purpose for these tension screws in the drive plate - This aspect of the design was NOT intended to prevent the quill from falling down. If you want to prevent the quill from falling down - adjust the head clamping tension for the quill with the two bolts/screws that are above / below the quill lock lever on the left side. The drive plate tension screws are truly just to adjust / tune the spindle to keep it from moving around in the drive plate and keep that unintended vibration out.
Long winded -- but hopefully thorough.
I think those that have reinstalled there drive plates with out having to clock it are the owners of mills where the drive plate was manufactured dead nuts concentric to the spindle axis. Mine mill is also older (1959) and has only one tension / spring / shoe assy in the drive plate. I think this experience is a great motivator to upgrade to a second tension screw system like the later mills have.
Scott
- Joined
- Nov 25, 2015
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- 10,034
I only have one tension screw, but no issues with clocking. Very surprised to hear that.
It is not vibration, but a slapping of the splines in the drive plate that it reduces.
I had tried using Kevlar belts, they had a slight set, and the noise was horrendous. I then tried some fenner belts, also very loud.
I now have segmented (toothed/ cogged) belts that are noisy like a tire road noise, but don't slap the splines.
And I disagree, the tension screw does lower the slapping, but it also does a good job in adjusting the rate of drop on the quill. The screws for the casting DO NOT, do a good job in that respect. I wish that Clausing had a return spring.
It is not vibration, but a slapping of the splines in the drive plate that it reduces.
I had tried using Kevlar belts, they had a slight set, and the noise was horrendous. I then tried some fenner belts, also very loud.
I now have segmented (toothed/ cogged) belts that are noisy like a tire road noise, but don't slap the splines.
And I disagree, the tension screw does lower the slapping, but it also does a good job in adjusting the rate of drop on the quill. The screws for the casting DO NOT, do a good job in that respect. I wish that Clausing had a return spring.
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- May 2, 2015
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Jeff,
I agree 1000% that I wish the Clausings had a return spring.
I have to respectfully disagree about the tension screw in the drive plate. Unfortunately, Clausings manual does not address the screw at all other than the part #'s. There is however, an oblique reference to the screws in the head casting: "HEAD CASTING - is split and has two screws that have been set to provide an accurate fit between head and quill. This setting should not be disturbed unless play develops between quill and head. To eliminate play, adjust the two screws on each side of lock bolt until all play has been removed. Move quill up and down in head to make sure it slides freely with no play - do not have adjustment too tight."
Clearly the quill/spindle assembly should never fall under it's own weight. There is no reference to the tension screw in the drive plate to account for preventing freefall. The two screws in the head casting do prevent just that. They are an adjustment for fit of the quill in the casting/ adjustment to reduce play (and by extension - prevent free fall)
For a machine that is small but built so sturdily, I can not believe that designers would use a 3/16' nylon shoe & spring to prevent the quill/spindle/bearings/collet/drawbar/collet ejector assy & all the hardware that weighs - what 20-25lbs? from falling.
The drive plate interface with the spindle requires a non interference sliding fit. That in turn is going to result is some level of clearance between the two. (hence noise) Those singe or double tension screw/spring/set screw assy's are truly for reducing what we have all termed "slap".
I have examined quite a few 85XX series Clausings and almost all of them had the tension screws turned in so hard (in an attempt to prevent quill free fall) that the spring(s) were crushed and the nylon shoe was mashed.
It is actually very easy to adjust the two head casting screws to prevent free fall, yet still have a silky smooth travel. My tension screw assy in the drive plate has just enough pressure on the spindle to eliminate the slap & vibration. I can grab my collet ejector knob at the top of the spindle and pull my quill up by hand - no mechanical advantage via the gear box and it will stay where ever I leave it.
With respect - this is my experience.
Still jealous of your Bridgeport style quill lock...
Scott
I agree 1000% that I wish the Clausings had a return spring.
I have to respectfully disagree about the tension screw in the drive plate. Unfortunately, Clausings manual does not address the screw at all other than the part #'s. There is however, an oblique reference to the screws in the head casting: "HEAD CASTING - is split and has two screws that have been set to provide an accurate fit between head and quill. This setting should not be disturbed unless play develops between quill and head. To eliminate play, adjust the two screws on each side of lock bolt until all play has been removed. Move quill up and down in head to make sure it slides freely with no play - do not have adjustment too tight."
Clearly the quill/spindle assembly should never fall under it's own weight. There is no reference to the tension screw in the drive plate to account for preventing freefall. The two screws in the head casting do prevent just that. They are an adjustment for fit of the quill in the casting/ adjustment to reduce play (and by extension - prevent free fall)
For a machine that is small but built so sturdily, I can not believe that designers would use a 3/16' nylon shoe & spring to prevent the quill/spindle/bearings/collet/drawbar/collet ejector assy & all the hardware that weighs - what 20-25lbs? from falling.
The drive plate interface with the spindle requires a non interference sliding fit. That in turn is going to result is some level of clearance between the two. (hence noise) Those singe or double tension screw/spring/set screw assy's are truly for reducing what we have all termed "slap".
I have examined quite a few 85XX series Clausings and almost all of them had the tension screws turned in so hard (in an attempt to prevent quill free fall) that the spring(s) were crushed and the nylon shoe was mashed.
It is actually very easy to adjust the two head casting screws to prevent free fall, yet still have a silky smooth travel. My tension screw assy in the drive plate has just enough pressure on the spindle to eliminate the slap & vibration. I can grab my collet ejector knob at the top of the spindle and pull my quill up by hand - no mechanical advantage via the gear box and it will stay where ever I leave it.
With respect - this is my experience.
Still jealous of your Bridgeport style quill lock...
Scott
- Joined
- Nov 15, 2020
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- 151
Scott, what tension thread are you referring to?
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- May 2, 2015
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Brandon
The tension screw is the one that goes in through the drive plate perpendicular to the spindle. 1/4-20 set screw with a spring and a nylon shoe that contacts the spindle spline.
Older machines only have one and newer machines (mid 60’s +) have two - 180 degrees apart.
Scott
ETA - the name "tension screw" is one of convenience - it is tagged in the parts diagram as nothing more than a set screw.
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