Spindles are a critical component in a variety of machine tools used in a multitude of industries and serving many applications. A high quality spindle, designed using the latest technology, makes all the difference in the world. Yet many are unaware of exactly what a spindle is, how it works, why it may fail, and what should be done in the event of a failure. Here are some answers to these questions.

What is a Spindle?

A spindle is a highly precise instrument that utilizes rolling element bearings—typically ball bearings or roller bearings—that are produced with tolerances ground to within millionths of an inch. The bearings are then fitted into precision ground or bored housings with similar sizes and tolerances, making spindles similar to inspection grade equipment in terms of tolerance. Precision spindles also integrate bearing retaining caps, precision bearing locknuts, precision bearing spacers and sealing systems. The configurations are almost endless. Spindles must be designed to the specific parameters of their application.

Why Does a Spindle Fail?

Most spindles do not fail due to bearing fatigue, as many people think, since they are precisely designed with ample load carrying capacity. Rather, most spindles fail for reasons that include contamination of the bearing lubricant, abuse, improper lubrication procedures, and any combination of these reasons.

Importance of Spindle Failure Evaluation

Because failure modes are numerous and varied, it’s crucial to have spindles repaired by an expert. A proper evaluation will ensure a quality repair that will extend the bearing life and limit the need for future repairs, therefore saving money and reducing down time. Proper evaluation includes a test run (if necessary), cleaning and disassembly of parts, document construction and thorough parts inspection.

Who Should Repair Your Spindle?

A well-repaired spindle should function on the same level as a new spindle. While many OEM’s will repair their own spindles, they often overlook the full evaluation process and therefore the cause of failure, as well as the importance of cleanliness in the process. Small shops or repair services lack the resources, space, personnel, and equipment to perform a truly effective repair. By choosing EDAC Machinery, customers can be assured that repairs are performed by a company with the capability to conduct a thorough evaluation of the cause behind the failure. EDAC Machinery designs and manufactures new spindles, and this capability enables us to integrate the latest technology to ensure peak operating performance of any repaired spindle. A company offering full manufacturing capabilities, engineering support, parts cleaning equipment, and almost infinite knowledge and resources will ensure overall value and longer lasting results down the line.

See the attached links for a list of OEM spindles repaired by EDAC Machinery as well as technical information.

SPINDLES OEM’s REPAIRED

EDAC SHEET – GROS-ITE SPINDLE

Spindle Startup Procedure

Oil Air Lubricated Spindles

The following steps are required prior to operating your EDAC Machinery/Gros-Ite Spindle.

Handling:

A precision spindle must be handled carefully. The spindle should not be bumped or dropped. Each spindle is securely packaged in a custom fitted shipping/storage case at the factory. It is recommended that this case be retained for storage of the spindle when it is not in use. It is also recommended that the lubrication inlet ports and well as any drains or vents that were plugged or covered during shipment remain plugged or covered until the spindle is mounted to the machine or into a bracket. These features should remain covered or plugged until the Oil/Air lines are ready to be connected to the spindle.

Storage:

If the spindle is idle, or will not be used for more than 30 days, it should be stored in low humidity, and at normal room temperature (60-90 °F). To avoid contamination, all inlets must be plugged and all drains or vents must be covered to prevent the ingress of foreign particulate or liquids. Coat any unprotected metal surfaces with a metal protectant to prevent rust or corrosion. (See Start Up) The spindle shaft should be rotated during storage several revolutions by hand every 30 days. This will keep the bearings lubricated, as oil tends to settle in the bottom of the raceways during periods of long-term storage. This action also prevents false brinelling of the bearing races due to the inherent low-level vibrations present in most buildings.

Mounting Instructions:

As with any precision assembly, the mounting surfaces are critical to the spindle performance. All mounting surfaces (spindle and machine) should be stoned and wiped clean. This will eliminate any small nicks or burrs that may have occurred on the mounting surfaces during shipping and handling. Never deliver any shock loads or hammer a spindle. This will permanently damage the spindle bearings and result in reduced life. Use pullers and jack screws whenever possible. Mishandling the spindle will void the warranty. For cartridge style spindles it is only necessary to tighten the clamping screws sufficiently enough to prevent the rotation of the spindle housing in the bracket. Over tightening of the clamping screws may destroy the built-in clearances to provide ideal performance of the spindle bearings. This can cause overloading and overheating of the bearings and result in chatter and vibration as well as shortening the life of the spindle. If the spindle is belt driven: The proper tensioning of the drive belt is essential to the performance and life of the spindle. The belt should be tensioned enough to prevent slippage and vibration, but loose enough to prevent excessive radial load being transmitted to the rear bearings.

Motorized Spindles:

If your spindle is motorized and requires liquid cooling use PH balanced water based coolant with a rust inhibitor. A good coolant is a 50-50 mix of water and antifreeze. Water with high salt or mineral content should be avoided, as it tends to leave deposits in the internal porting, which can become plugged. The coolant flow rate recommended is 6 gallons per horsepower per hour at a temperature of 70-80 °F. If oil is used as the cooling media, the flow must be increased to 15 gallons per horsepower per hour. The coolant pressure at the spindle should not exceed 35 psi.

Oil/Air Lubrication System

Designed to operate with Vogel Oil/Air Lubrication Systems

These spindles are manufactured with a lubrication inlet for each bearing position. It is absolutely essential that all of these inlets be connected to the lubricator.

This spindle can be operated with Air/Oil lubrication systems of other manufacturers. Please contact EDAC Machinery/Gros-Ite before operating this spindle on other than the above recommended system.

It is highly recommended that the fault signal from the lubricator monitoring devices be interlocked with the Start/Stop circuit for the spindle drive motor, preventing the starting of the spindle drive motor unless lubrication is present.

The Oil Mist Lubrication System may be installed in any plane, equal to, or above or below the spindle being run. Tubing should be 4mm OD x .85mm wall flexible plastic tubing. The minimum length must be 40″ with the maximum being 39 feet. In the event of long runs it is advisable to coil the tube in a helix of five turns as close to the spindle as possible. This coil should be either horizontal or 30 degrees up from the horizontal to allow the oil to collect in the bottom of the coils.

All fittings and connecting tubing are to be de-burred and flushed with clean, filtered solvent or oil and blown out with clean dry air prior to connecting to the lubricator and the spindle. This greatly reduces the chance of contamination entering the spindle.

DO NOT use Teflon tape on any of the connections between the lubricator and the spindle. Teflon tape may break or flake off and travel into the oil mist orifices in the spindle causing a blockage.
It is highly recommended that the Oil/Air Lubrication be started either manually or automatically approximately 10 minutes prior to the start of the spindle. This allows sufficient wetting of the balls and raceways. Spent oil should be present at all of the vents and around the end caps. Additionally, it is highly recommended that the Oil/Air Lubrication be allowed to operate for a period of 10-15 minutes after the spindle is shut down. This serves to act as a purging action to prevent the ingress of contaminants as the spindle cools down.
The air supply to the Oil/Air Lubricator should be clean and dry. The use of a combination filter/dryer prior to the Oil/Air Lubrication Unit is highly recommended. A coalescent type dryer is preferred to the desiccant type dryer. EDAC Machinery/Gros-Ite recommends the use of a P/N 79895116 filter/dryer with a .01-micron filtration rating available from MSC Industrial Supply.

The oil used in the Air/Oil Lubricator should be highly refined mineral-based oil with a viscosity of 135-165 SUS @ 100 °F. A listing of approved spindle oils is included in this manual.
There are certain situations in which a different type of oil may be substituted. However, in no case should the oil exceed a viscosity rating of 150-165 SUS @ 100 °F.

The use of oils with higher viscosities may cause an increase in stabilized operating temperature. The operating temperature of the spindle should be monitored and not allowed to exceed 120° F without approval from EDAC Machinery/Gros-Ite Spindle.

Setting the Lubricator

The Vogel Oil/Air Lubricator has several adjustments that need to be made prior to operating the spindle. They are:

  • Air pressure at the regulator.
  • Air pressure at the spindle.
  • Lube Interval (Pause Time)
  • Time & Pressure
  • Monitoring Time

Included in this manual is a listing of the proper settings for your new EDAC Machinery/Gros-Ite Spindle. A temporary pressure gage should be installed in a tee at the spindle oil mist inlet to ensure proper setting of the pressure at the spindle. With the temporary gage in place and the oil mist line connected to both the lubricator and the spindle, adjust the pressure regulator to the setting supplied. This pressure is read on the gage mounted to the regulator body. Adjust the air bypass screw on the lubricator to the setting supplied. This pressure is read on the temporary gage installed at the spindle Oil-Mist inlet.

Once the pressures are set, adjust the drops per minute to the specified value.
Remove the temporary gage from the Oil-Mist line and connect this line directly to the spindle.
When the above adjustments and gage removal have been complete, allow the lubricator to run for 10-15 minutes and observe the vents and end caps on the spindle. There should be air and oil present at these points. Once the presence of air and oil have been verified, begin running the spindle. The temperature of the spindle should be monitored closely for the first hour of operation as a safety precaution.

Oil Mist Data

Type of Lubricator: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE
Type of Oil: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE
Air Pressure at Regulator: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE
Air Pressure at spindle: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE
Oil Drops per Minute: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE

Spindle Test Data including test speed and stabilized operating temperatures are included in this manual on the EDAC Machinery/Gros-Ite Final Inspection Form included in the installation manual supplied with the specific spindle.

START UP:

Although your EDAC Machinery/Gros-Ite Spindle has been thoroughly tested to the full operating speed at the factory, we suggest that when you receive it, or after it has been sitting idle or in storage for thirty (30) days or more, the spindle should be run up gradually prior to full time operation. We also suggest the following:

  1. First rotate the spindle by hand to insure that it spins unobstructed or without any noticeable noise.
  2. Then begin running the spindle at 10% of the max operating speed for a period of 15 minutes
  3. If the temperature does not exceed 100 °F or if you have no temperature sensor, hot to the touch. Increase the spindle speed an additional 25% and run for 15 minutes.
  4. Continue this process increasing the speed each time by 20% until the full operating speed is reached. If at any time during the run up the spindle exceeds 120 °F the spindle should shut down and be allowed to cool to ambient temperature before restarting at the previous speed. If after a run of 15-30 minutes the spindle does not stabilize or show signs of stabilization contact EDAC Machinery/Gros-Ite Spindle for further information.
  5. Once stabilized at the full operating speed the spindle should run no hotter than 120 °F. After this initial startup is completed the spindle may be now run at the full operating speed immediately upon start-up. However, please note that if the spindle has been in storage for thirty (30) days or more, this process should be repeated.

If the machine the spindle is mounted to an automatic speed ramp up, it is recommended to give the spindle a 15-30 second ramp up to full operating speed after the initial star up procedure has been completed.

Tool Installation

Avoid installing a cold tool in a warm spindle. This is of particular importance with the shallow tapers in an internal grinding spindle. By installing a cold quill in a warm spindle, the quill will be positioned too deep in the spindle shaft taper due to thermal expansion from the heat. When the spindle assembly is subsequently cooled down you will create a shrink fit of the quill in the taper, and most probably, the quill cannot be removed without machining and doing potential damage to the bearings.

Grease Lubricated Spindle Start Up Procedures

The following are some simple steps you need to follow prior to operating your EDAC Machinery/Gros-Ite spindle.

Handling:

A precision spindle must be handled carefully. The spindle should not be bumped or dropped. Each spindle is securely packaged in a custom fitted shipping/storage case at the factory. It is recommended that this case be retained for storage of the spindle when it is not in use.

Storage:

If the spindle is idle or will not be used for more than 30 days it should be stored in low humidity, and at normal room temperature (60-90 °F) to avoid contamination, rust, corrosion, etc. Coat any unprotected metal to avoid rust or corrosion with a metal protectant. (See Start Up) The spindle shaft should be rotated during storage several revolutions by hand every 30 days. This will help prevent the weeping of oil from the binding material in the grease. This action also prevents false brinelling of the bearing races due to the inherent low-level vibrations present in most buildings.

Mounting Instructions:

As with any precision assembly, the mounting surfaces are critical to the spindle performance. All mounting surfaces (spindle and machine) should be stoned and wiped clean. This will eliminate any small nicks or burrs that may have occurred on the mounting surfaces during shipping and handling. Never deliver any shock loads or hammer a spindle. This will permanently damage the spindle bearings and result in reduced life. Use pullers and jack screws whenever possible. Mishandling the spindle will void the warranty. For cartridge style spindles it is only necessary to tighten the clamping screws sufficiently enough to prevent the rotation of the spindle housing in the bracket. Over tightening of the clamping screws may destroy the built-in clearances to provide ideal performance of the spindle bearings. This can cause overloading and overheating of the bearings and result in chatter and vibration as well as shortening the life of the spindle. If the spindle is belt driven: The proper tensioning of the drive belt is essential to the performance and life of the spindle. The belt should be tensioned enough to prevent slippage and vibration, but loose enough to prevent excessive radial load being transmitted to the rear bearings.

Start Up:

Although your EDAC Machinery/Gros-Ite spindle has been thoroughly tested to the full operating speed at the factory, we suggest that when you receive it, or after it has been sitting idle or in storage for thirty (30) days or more, the spindle should be run up gradually prior to full time operation. We also suggest the following:

  • First rotate the spindle by hand to insure that it spins unobstructed or without any noticeable noise.
  • Then begin running the spindle at 10% of the max operating speed for a period of 15 minutes.
  • If the temperature does not exceed 100°F or if you have no temperature sensor, hot to the touch. Increase the spindle speed an additional 25% and run for 15 minutes.
  • Continue this process increasing the speed each time by 20% until the full operating speed is reached. If at any time during the run up the spindle exceeds 120°F the spindle should shut down and be allowed to cool to ambient temperature before restarting at the previous speed. If after a run of 15-30 minutes the spindle does not stabilize or show signs of stabilization contact EDAC Machinery/Gros-Ite for further information.
  • Once stabilized at the full operating speed the spindle should run no hotter than 120 °F. After this initial startup is completed the spindle may be now run at the full operating speed immediately upon start-up. However, please note that if the spindle has been in storage for thirty (30) days or more, this process should be repeated.

If the machine the spindle is mounted to an automatic speed ramp up, it is recommended to give the spindle a 15-30 second ramp up to full operating speed after the initial startup procedure has been completed.

Motorized Spindles:

If your spindle is motorized and requires liquid cooling use PH balanced water based coolant with a rust inhibitor. A good coolant is a 50-50 mix of water and antifreeze. Water with high salt or mineral content should be avoided, as it tends to leave deposits in the internal porting which can become plugged. The coolant flow rate recommended is 6 gallons per horsepower per hour at a temperature of 70-80°F. If oil is used as the cooling media, the flow must be increased to 15 gallons per horsepower per hour. The coolant pressure at the spindle should not exceed 35 psi.

Tool Installation:

Avoid installing a cold tool in a warm spindle. This is of particular importance with the shallow tapers in an internal grinding spindle. By installing a cold quill in a warm spindle, the quill will be positioned too deep in the spindle shaft taper due to thermal expansion from the heat. When the spindle assembly is subsequently cooled down you will create a shrink fit of the quill in the taper, and most probably, the quill cannot be removed without machining and doing potential damage to the bearings.

Oil Mist Lubricated Spindle Start Up Procedures

The following steps should be followed prior to operating your EDAC Machinery/Gros-Ite spindle.

Handling:

A precision spindle must be handled carefully. The spindle should not be bumped or dropped. Each spindle is securely packaged in a custom fitted shipping/storage case at the factory. It is recommended that this case be retained for storage of the spindle when it is not in use. It is also recommended that the lubrication inlet ports and well as any drains or vents that were plugged or covered during shipment remain plugged or covered until the spindle is mounted to the machine or into a bracket. These features should remain covered or plugged until the Oil Mist line(s) are ready to be connected to the spindle.

Storage:

If the spindle is idle, or will not be used for more than 30 days, it should be stored in low humidity, and at normal room temperature (60-90 °F). To avoid contamination, all inlets must be plugged and all drains or vents must be covered to prevent the ingress of foreign particulate or liquids. Coat any unprotected metal surfaces with a metal protectant to prevent rust or corrosion. (See Start Up) The spindle shaft should be rotated during storage several revolutions by hand every 30 days. This will keep the bearings lubricated, as oil tends to settle in the bottom of the raceways during periods of long-term storage. This action also prevents false brinelling of the bearing races due to the inherent low-level vibrations present in most buildings.

Mounting Instructions:

As with any precision assembly, the mounting surfaces are critical to the spindle performance. All mounting surfaces (spindle and machine) should be stoned and wiped clean. This will eliminate any small nicks or burrs that may have occurred on the mounting surfaces during shipping and handling. Never deliver any shock loads or hammer a spindle. This will permanently damage the spindle bearings and result in reduced life.

Use pullers and jack screws whenever possible. Mishandling the spindle will void the warranty. For cartridge style spindles it is only necessary to tighten the clamping screws sufficiently enough to prevent the rotation of the spindle housing in the bracket. Over tightening of the clamping screws may destroy the built-in clearances to provide ideal performance of the spindle bearings. This can cause overloading and overheating of the bearings and result in chatter and vibration as well as shortening the life of the spindle.

If the spindle is belt driven: The proper tensioning of the drive belt is essential to the performance and life of the spindle. The belt should be tensioned enough to prevent slippage and vibration, but loose enough to prevent excessive radial load being transmitted to the rear bearings.

Motorized Spindles:

If your spindle is motorized and requires liquid cooling use PH balanced water based coolant with a rust inhibitor. A good coolant is a 50-50 mix of water and antifreeze. Water with high salt or mineral content should be avoided, as it tends to leave deposits in the internal porting, which can become plugged. The coolant flow rate recommended is 6 gallons per horsepower per hour at a temperature of 70-80 °F. If oil is used as the cooling media, the flow must be increased to 15 gallons per horsepower per hour. The coolant pressure at the spindle should not exceed 35 psi.

Oil Mist Lubrication System

The majority of EDAC Machinery/Gros-Ite designed (and most other competitor’s) spindles using Oil-Mist Lubrication were designed to use a Norgren Oil Mist Lubrication System consisting of the following:

  • #B12-221-A2LA Filter/Regulator
  • #10-015-004 Lubricator
  • #18-001-015 Mounting Bracket
  • #18-014-001-013 Solenoid Valve

Please contact EDAC Machinery/Gros-Ite if this spindle will be operated with a lubrication system other than a Norgren Oil-Mist System.

It is highly recommended that an air pressure switch be installed on the output side of the lubricator to ensure that there is oil mist pressure to the spindle. The signal from the pressure switch should be interlocked with the Start/Stop circuit for the spindle drive motor, preventing the starting of the drive motor unless oil-mist pressure is present. It is also highly recommended that an oil level switch be installed in the oil mist reservoir. This switch can be interlocked in the same manner as the pressure switch. The Oil-Mist Lubrication System should be installed at a point higher than the spindle being lubricated and not more than 15 feet from the spindle. The connecting oil mist line(s) should be arranged to eliminate any loops or sharp bends that could create oil puddles or restrict oil flow.

Use plastic tubing with a minimum inside diameter of 3/8″ from the lubricator to the spindle. All fittings and connecting tubing are to be deburred and flushed with clean, filtered solvent or oil and blown out with clean dry air prior to connecting to the lubricator and the spindle. This greatly reduces the chance of contamination entering the spindle. DO NOT use Teflon tape on any of the connections between the lubricator and the spindle. Teflon tape may break or flake off and travel into the oil mist orifices in the spindle causing a blockage. It is recommended that Loctite Hydraulic Sealant #569 be used. Use only brass, stainless steel, or un-plated steel fittings on the connections between the spindle and the lubricator.

Plated fittings should not be used as the plating can shear off and either block a mist orifice or damage the bearings. It is highly recommended that the oil mist be started, either manually or automatically, approximately 10 minutes prior to the start of the spindle. This allows sufficient wetting of the balls and raceways. Spent oil should be present at all of the vents and around the end caps. Additionally, it is highly recommended that the oil mist be allowed to operate for a period of 10-15 minutes after the spindle is shut down. This serves to act as a purging action to prevent the ingress of contaminants as the spindle cools down.

The air supply to the Oil-Mist Lubricator should be clean and dry. The use of a combination filter/dryer prior to the Oil-Mist Lubrication unit is highly recommended. A coalescent type dryer is preferred to the desiccant type dryer. EDAC Machinery/Gros-Ite recommends the use of a P/N 79895115 filter/dryer with a .01-micron filtration rating available from MSC Industrial Supply.

The oil used in the oil mist lubricator should be highly refined mineral based oil. Depending on the type and style of the spindle, the oil will have a viscosity of 54-66 SUS @ 100 °F or 150-165 SUS @ 100 °F. The specific type of oil used to lubricate the spindle is specified in the instruction manual included with the spindle.

A listing of approved oils is included in this on line manual.

Setting the Lubricator

The Norgren Lubricator has several adjustments that need to be made prior to operating the spindle. They are:

  1. Air Pressure at the regulator.
  2. Air Pressure at the spindle.
  3. Oil Drops per minute.

Included in this manual is a listing of the proper settings for your new EDAC Machinery/Gros-Ite spindle.

A temporary pressure gage should be installed in a tee at the spindle oil mist inlet to ensure proper setting of the pressure at the spindle. With the temporary gage in place and the oil mist line connected to both the lubricator and the spindle, adjust the pressure regulator to the setting supplied. This pressure is read on the gage mounted to the regulator body. Adjust the air bypass screw on the lubricator to the setting supplied. This pressure is read on the temporary gage installed at the spindle Oil-Mist inlet.
Once the pressures are set, adjust the drops per minute to the specified value.
Remove the temporary gage from the Oil-Mist line and connect this line directly to the spindle.

When the above adjustments and gage removal have been complete, allow the lubricator to run for 10-15 minutes and observe the vents and end caps on the spindle. There should be air and oil present at these points. Once the presence of air and oil have been verified, begin running the spindle. The temperature of the spindle should be monitored closely for the first hour of operation as a safety precaution.

Oil Mist Data

Type of Lubricator: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE
Type of Oil: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE
Air Pressure at Regulator: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE
Air Pressure at spindle: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE
Oil Drops per Minute: SEE DATA IN MANUAL SUPPLIED WITH SPINDLE

Spindle Test Data including test speed and stabilized operating temperatures are included in this manual on the EDAC Machinery/Gros-Ite Final Inspection Form included in the installation manual supplied with the specific spindle.

Start Up:

Although your EDAC Machinery/Gros-Ite spindle has been thoroughly tested to the full operating speed at the factory, we suggest that when you receive it, or after it has been sitting idle or in storage for thirty (30) days or more, the spindle should be run up gradually prior to full time operation.

We also suggest the following:

  1. First rotate the spindle by hand to insure that it spins unobstructed or without any noticeable noise.
  2. Then begin running the spindle at 10% of the max operating speed for a period of 15 minutes.
  3. If the temperature does not exceed 100 °F or if you have no temperature sensor, hot to the touch. Increase the spindle speed an additional 25% and run for 15 minutes.
  4. Continue this process increasing the speed each time by 20% until the full operating speed is reached. If at any time during the run up the spindle exceeds 120 °F the spindle should shut down and be allowed to cool to ambient temperature before restarting at the previous speed. If after a run of 15-30 minutes the spindle does not stabilize or show signs of stabilization contact EDAC Machinery/Gros-Ite for further information.
  5. Once stabilized at the full operating speed the spindle should run no hotter than 120 °F. After this initial startup is completed the spindle may be now run at the full operating speed immediately upon start-up. However, please note that if the spindle has been in storage for thirty (30) days or more, this process should be repeated.

If the machine the spindle is mounted to has an automatic speed ramp up, it is recommended to give the spindle a 15-30 second ramp up to full operating speed after the initial startup procedure has been completed.

Tool Installation:

Avoid installing a cold tool in a warm spindle. This is of particular importance with the shallow tapers in an internal grinding spindle. By installing a cold quill in a warm spindle, the quill will be positioned too deep in the spindle shaft taper due to thermal expansion from the heat. When the spindle assembly is subsequently cooled down you will create a shrink fit of the quill in the taper, and most probably, the quill cannot be removed without machining and doing potential damage to the bearings.