Hardinge HLV Serial Number 106 ( ca 1950 ) Restoration

[JPH]

Yesterday evening, Dan, a friend of Bob assisted in cleaning and reassembling the spindle into the head.

The goal of the assembly at this time is to check if there is anything wrong with the bearings; to check if the axial looseness can be taken out; to check if proper pre-load will solve the "rings on face cut" problem.

The head had been moved to the right, away from the gear box, as shown in the previous photos.

When the left bearing was removed from the left of the head, it was noticed that the "paper" seal between the bearing keeper ring and the bearing was torn at about 6 o'clock. On reassembly, that tear was moved to about 11 o'clock. It ought to be replaced.

Bob mentioned that a similar seal for the front (right) bearing was missing when he disassemble the spindle from the head. That ought to be replaced.

We found that the pre-load ring, which threads onto the spindle left of the left bearing had been cross threaded at one time. It had chips in the threads as well as other stuff. I carried a sliver from the thread home in my finger. The internal as well as the mating external threads were cleaned with solvents, oiled, and carefully mated. This was repeated several times until the threads cleaned themselves up.

When mating large diameter, fine threads, sometimes it helps to turn the parts in the opposite direction with very light pressure until the internal and external threads align. You can feel or even hear a slight click.

We did not pre-load the spindle bearings last night.

Before the spindle installation into the head, the bearings were cleaned in solvents and the special lubricant mentioned above was put into the bearings by fingers. We avoided too much lubricant.

Bob does not like the color of the machine and has already experimented with chemical removable of the paint on small parts that had been taken off the machine. Bob knows what chemicals were used.

Hence, I think the machine is destined for disassembly. At that time more photos will be taken.

Power has not been applied to the spindle. It has been suggested that just the spindle be turned under powef to see if the bearings are ok by measuring the temperature rise.

 

[JPH]

The bearing lubricant that was used is Kuber Isoflex NBU 15. Its working temperature is up to 150 deg C, 266 deg F. It's shelf life is 3 years.

When the container for the lubricant was opened, Bob noticed a clear fluid and mostly white goop. The clear fluid is the oil; the goop is an emulsion of oil and soap. Kuber adds other stuff to make their NBU 15.

Notes from Machinery's Handbook, 26th edition, near page 2317:

1. Grease is an emulsion of oil and soap, or other stuff.

2. It works by the oil seeping out of the emulsion.

3. Mechanical churning, heat, shear of the grease can deplete the oil, causing less than expected oil when the bearing is working.

4. When packing the bearing, only 50 to 75% of the space ought to be filled. Overfilling of the bearing with grease causes overheating of the bearing and failure of the grease and the bearing.

5. The life of the grease is halved by approximately 18 deg F. rise in temperature.

6. Well lubricated bearings will show 10 to 50 degrees temperature rise of the race.

7. "More is better" not for grease !

8. Addition of grease at regular intervals, or when temperature rise indicates lack of lubrication.

So, Bob, lets figure out how to measure the temperature rise when we spin up 106.

 

[JPH]

Yesterday, pm, Bob had a dial indicator on the face of the spindle; the preload ring was hand tightened; axial play was 0.000_2, that is, 2/10 mil (0.005 mm); the spindle turned smoothly by hand.

We don't know the grade of the bearings, so all I can say is that that is within expectation.

The machine and the head were cold to the touch.

We did not apply power to the spindle.

We are considering several ways to measure the temperature of the head and will have something in place before we apply power to the spindle.

 

[JPH]

Bob had removed the gear box. He has taken photos during the disassembly. But we intent to take more detailed photos during the reassembly, then post those.

Tonight, the goal was to power the spindle with no load and to see if the bearings are quiet, and to see what the temperature rise is.

We started at about 300 RPM, and incrementally took it to 2000 RPM over an hour. Periodically we checked the temperature. We also listened for any peculiar noise. The spindle was quiet. There was quite a bit of noise from the variable speed contraption and the belt. The temperature rose from 51 deg F at the beginning to about 76 deg F when we stopped.

Intermittently, we measured the axial play, with the spindle stopped. The axial play was still about the same as reported above. I think that will be reduced as we increase the preload.

We have to fabricate the flat pin wrench for the preload ring. Then we will increase the preload and see how the temperature rises.

We used an optical tachometer. We also used an infrared thermometer.