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Hardinge Superslant 3 axis X axis seized. Taking apart and hopeful repair

Vitran

Aluminum
Joined
Mar 31, 2016
I have a Hardinge Superslant that I changed over from the Fanuc to a LinuxCNC board. With that, I had always told myself to check the lube as the old lube level switch didn't work. Well, I forgot it and then during the middle of an operation everything went bad. The X axis servo overloaded, stopped and the axis seized.

This is my progress of what I am doing to resolve it. I will do what I can to solve it, if I can. When I started I didn't know if the ball screw or the ways were sized.

This morning, start
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Turret and tail stock. I placed wood in case the turret fell, but even without the belt drive connected, nothing was moving.
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The status of the X axis servo motor. The belt/pulley did not want to move at all.
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First I removed the main cover. Screws on side, bottom, and top.
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I acquired this lathe either third or fourth hand. It seems there was 'something' bolted to the back of the camber shown here by the clean circle, but I have no idea what it was. A lamp of some sort?
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Cover off, I removed the lower front panel to remove the door.
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Lower panel removed. It had two plates and foam between. The foam was quite oil soaked.
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I looked at the ball screw at the bottom. It seems a metal cover plate that was to be there was missing.
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Remove a plastic cover which has a lip around the side to remove debris. This was quite brittle. Aged plastic.
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Beneath was a set of screws and the central screw. I removed the center plug and black oil poured out. The two smaller screws at 10 and 5 on the round disk came out (metric size?) but the plate did not come out. I took a bolt and tapped it 9/16-NF and threaded it in to the center plug to pull the cap out.
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Ungodly oil poured out. About two tablespoons of this black stuff.
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From the manual, I can make a tool with two pins to remove the outer nut. I would then remove the inner hex nut on the ball screw to remove the bearings. Afterwards I removed the three nuts holding what I assume are way clamps or something like it. Shims of metal that maintain pressure between the turret and the ways.
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Next I looked towards the top. I removed the upper covers. The black plastic had already been broken by someone else's hand it seems. Notice a small bar of metal slot near the bottom. That is what I believe is the top of the way sliding shim. Maybe.
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More removal exposing the gear and ball screw ends.
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Exposing the sides of the turret.
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It was at this point I started experimenting. Granted, I am not the best experimenter.

Experiment 1. Can it move?
Using a 7/8" socket set, I could (with some force) turn the ball screw nut. So ball screw works.

Experiment 2. How much can it move?
Taking a hydraulic power pack, I put the cylinder on blocks and pushed the turret up. No movement. Using the socket set, it moved 0.5mm, then 1mm upwards. I can only tighten the nut on the end of the ball screw one direction, so I don't want to go further as I cannot go the opposite way. But it does indicate I can move along the ways with great force.

Experiment 3. Likely what I should have done first. Put penetrating oil onto the ways.


The outcome:
It barely moves. It seems seized. I have removed the nuts holding the shims, so maybe I can get them out somehow.
The ways are held together with bolts coming up from below. That doesn't seem good, as I can't get to them. From the manual it says there are 10 bolts and I can only see the two two pair.

Next steps:

Option 1. Remove turret, look at it from below.
Not the best option. There are bolts on the side to remove the X from the Z axis ways. This would involve a bunch of removal of wires and seeing if I can pull apart the axis to get to the nuts and get to the ways. I don't know if the ball screw is accessible from below.

Option 2. Remove the ball screw?
Not sure if this would do anything. I don't think the bearings are bad, but they are coated in black oil. It could also have the chance if spilling bearings all across the floor. However, this does make it seem that the ball screw cartridge would be accessible from one side during install, possibly the bottom as noted in Option 1. There is no noticeable access port to the ball screw from the top.

Option 3. Tap out the way blocks
I don't know if tapping the spacers holding the ways in place will slide them out the bottom. I don't know if anyone has done this or if this could work.

Option 4. Send it.
A bad idea. A phrase said multiple times by my colleague right before he snaps a bolt with his impact gun. I don't know if I can slide the turret off of the frame somehow to clean this up. It is promising that I could move it a mm or so, however that was with a bottle jack and a lot of torque.

Any suggestions? I will not be back at this for about 3 weeks as I have to fly out to do a service call half way across the continent.
 
You are JUST getting started on this ever expanding scope of work adventure!!!

The top turret is held on with these parts that screw into it.s-l1600.jpg

If you look at the end of the turret from the end of the Z axis, you will see 2 Allen set screws that will clamp these parts.
There are 2 more on the other side.

You will have several hours of work getting the hoses & cables unhooked from the turret so you can remove it. Including at least one spot where you will probably take the other end apart because of how it was put together.

And add lots of fun getting the encoder off from a seized screw with out damaging it! Those couplings driving the encoder don't break when you need them to without damaging the encoder.

Just be glad it is black goo coming out of the bearings not brown slime (rust) and water, with a bearing seized solid.
I dealt with 2 on the Z2 axis lead screw on 2 machines in the same shop. These machines had come from a very diverse past history.
The first one we tried to salvage we took the turret off first then the X axis drive, and finally the entire saddle after the Z axis screw was out. The lube lines were all in drilled passages with 2 or 3 types/sizes of Bijur metering units.
The drilled passages were plugged solid with varnish and crud, with NO lube getting through to either X or Z.
The X axis drive was similar to what you have lots of black oily goo for bearing lube.
After the saddle was off, the X screw removed then the balance was taken apart with wood blocks and a small sledge hammer.

I had tried to force some lube into the various passages with 2000 PSI nitrogen, even left with pressure on overnight, to get the X slide freed up, to no avail.

It was a dry thirsty machine that had only coolant for lube for quite awhile.

The second machine was quite intermittent for a year or so and finally died . As I was parting it out, I found Z2 was seized so bad I couldn't budge it with a 4Lb sledge and punch on the screw drive pulley. The slave processor wouldn't come ready because the servo was not able to wiggle the screw 1 encoder pulse. This was very similar to your original problem.

Bill
 
Thanks for the post. The turret came off. I found the electrical disconnect for the turret. Someone put a new plug on the end of the cable and wrapped it in electrical tape, so some history is on this turret. I also noticed a cover plate on the x axis I see in the manual was missing.

I removed the set screw nuts and lifted the turret off the saddle about a quarter inch before realizing I don't have a means of holding the turret so I paused. I used a small pump jack to separate the two and it came off with next to no force. Chain hoist setup coming next.

I removed a lot of encased grease off of the z axis ball screw chamber while I was working. I expect a lot more on the x axis.

Next step is to remove the turret then separate the x axis from the z axis. Then I remove the x ballscrew and force the x axis off the end and clean the ways. At least that is my plan.


One aspect of this machine I would like to solve is a nearly 0.75 thou backlash in both the x and z axis. I am using the encoders on the ballscrew. As I am opening up everything I may as well fix it. I solved it before with backlash removing code.

As far as I know there are two ways a ball screw could have backlash. Either the balls have worn out the grooves on the shaft and there are a pair of ball screw nuts that can be sepertated, or the shaft of the ball screw has loose bearings on the end that are allowing the shaft to move side to side. I am unsure which is more common.
 
Updates.
I was in the states doing repair work, then in isolation. Just got a chance to get back on this.

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Getting chain hoist to lift out turret

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5/8-11 bolts for lifting out saddle. Home Depot did not have 5/8 bolts or washers, but they did have 5/8 concrete anchors with nuts and washers.

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Four large bolts and two taper pins were holding the saddle in place. A 1/4-20 bolt was used to extract the taper pins.

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The fluid distribution lines. I should have removed these blocks and lines entirely at the start. I broke three lines, maybe more. The lines were old and I don't believe they had high pressure as it was pressurized by the air tank. When I removed the saddle, it tapped one of the lines by accident snapping them. The saddle is really heavy, maybe >800lbs? Also disconnect the hydraulic oil for the turret balance and the way oil line before removing the saddle.

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I don't know what this blue material is. I damaged it slightly on one of the pads. I would like to replace it.

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Have to disconnect the X max and min travel to extract the turret as well. This is my hall sensor box with the pull up resistors in the barrier strip things.

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Saddle out of the machine on a cart

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This was not in the manuals. There are two screws here. One locks the bars in place, the other pulls the bars out. These bars are the ways.

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One of three way wedges extracted. I am unsure the exact name of these bars.

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Disconnecting the ballscrew block, the cross slide slid off the end with a few taps of the hammer.

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Cousin wearing fashionable clothes and not touching the oil, but the saddle is now free. The ballscrew is stuck, bearings stuck.

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Bearings. These will need to be replaced. From a post on another thread I found (see below) the bearings are metric and imperial having metric on one side and imperial on the other. Not sure what they are at this time. I will extract them in a few days. I need a dual pin thing to take these nuts off.

It does seem that the lack of oil in the machine was not the issue, but a stuck bearing. Unsure what will happen as I extract these. I have been planning on replacing them as the X and Z axis had a 0.75 thou backlash issue. RobH (from the post below) found they were bad and replaced them which could be the cause.

Hardinge Superslant retrofit - Page 3 - LinuxCNC
 








 
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