1. EDML#17 First Mill Head Service
By: John Sgouromitis
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2. Notes:
This document will demonstrate what I have done to repair the brake on the mill, it should not be used alone as a how to. However it may provide a useful reference to be used along side the actual maintenance manual for the machine.
This task was performed before the addition of the Power Draw Bars and will not cover how to safely remove that ancillary system.
Not all Mills are the same, there are key differences between the Bridgeport mill and the First Mills to be highlighted later.
The servicing of the mill head was completed with a lot of support and insight from the manufacturing instructor at Concordia University, Michael Rembacz and the Engineer in Residence at Concordia University Dominic Ng.
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3. List of Steps:
Removing electrical connection and junction box
Removing bottom bearing support
Remove rear continuously variable transmission (CVT) access panel
Rotate Mill Head 90° to the Left
Remove speed adjuster
Adjust and remove belt from motor Sheave
Top spindle bearing housing removal
Detach speed adjustment lever from CVT
Remove top of CVT housing
Remove lower CVT housing
Remove brake and spindle CVT sheave
Cleaning
Lubricating
Re-assembly
Tips:
Keep your work space clean and tidy, this will allow to easily find all appropriate hardware and tools.
Take pictures of the components before disassembling them to make reassembly easier.
Do not be afraid to ask for help! Especially when trying to move heavy objects such as the electric motor.
Try to keep all components and there hard ware together.
Remove the drawbar by lifting it out of the spindle and set aside.
Make sure the mill is in high gear with the speed at its lowest achievable RPM.
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4. Electrical connection removal
Steps
1-Before 0pening the junction box, lock out machines as per CON-EDML-027 LOCKOUT, make sure no power can be provided
2-Make sure to label the pink wires as they are connected to their respective black wires to facilitate reassembly.
3-Dissconnect the pink wires from the junction assembly
4-Remove the junction by unscrewing it from motor housing and carefully remove housing and rubber adapter while feeding the pink wires through the hole. Set aside in a safe and clean environment
Removing control panel:
1-Remove the two bolts and set the panel aside.
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5. 2) Bottom Bearing Support Removal
Steps:
1-Remove the three mounting screws from the support.
2-Use a pry bar to evenly distribute pressure while removing the housing from around the bearing. When nearing the end, support the housing as it may fall.
A-The Bridgeport mill will not have a bearing here.
Extra holes
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6. 3) Rear CVT Access Panel
Steps:
1- Remove four screws and panel, set aside.
(Notice the V belt and CVT sheave)
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7. 4) Rotate head 90° to the Left
Steps:
1-Loosen four head mounting bolts.
2-With the aid of an assistant, attempt to relieve pressure on the screw that actuates the motion. As the head leans to one side, the pressure will increase on the screw which may cause the screw to become stripped.
Head Mounting Bolts
Rotating Screw
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8. 5) Speed Adjuster Removal
Steps:
1-Remove four bolts and allow the adjuster to dangle from its chain.
2-Take note of the direction the chain had wrapped around the spindle.
3-Try to push the V-belt of the CVT to the center of the sheave, you may need to use a fiber mallet to strike the hammer to achieve this.
Speed Adjuster
CVT Sheave
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9. 6) Remove Belt from Drive Sheave
Steps:
1-Use the lift table to help support the weight of the motor, it can be fixed to the table using scrap wood and ratchet straps.
2-Remove two mounting bolts that attach the motor to the head.
3-Back the motor out slightly, and push the V-belt out around the sheave.
4-Remove motor and sheave together and set aside with sheave facing up.
5-For further reference, please see the Bridgeport Maintenance Manual page 4.8 (2J2-Head Motor Removal)
Mounting Bolts
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10. 7) Top Spindle Bearing Housing Removal
Steps:
1-Remove 3 bolts and reinsert into the blind holes located just beside the securing holes.
2-Apply torque slowly and evenly across all the bolts to slowly lift the bearing housing off the bearing itself.
3-Clean and set aside
Mounting bolts
Blind Removal Holes
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11. 8) Detaching Speed Adjustment Lever from CVT
Steps:
1- Remove the two bolts and corresponding bushings.
2-DO NOT LOOSE THE BUSHINGS, the mill will not operate with out them.
3-Once complete, the CVT cover can be completely removed.
For further reference please see page 4.9 of the Bridgeport Maintenance Manual
Screws with Bushings
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12. 9) CVT Housing Removal
Steps:
1- Remove four bolts visible from the top side of the casing, and the two bolts visible on the bottom of the machine at the rear.
2-Use a fiber mallet to lightly knock the casing loose.
3-Once free, make sure not to loose the locating dowel pins as there are critical for reassembly. (Be careful, mating edges are very sharp)
Bolts
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13. 10) Lower CVT Housing Removal
Steps:
1- Remove four bolts visible from the bottom side of the casing.
2-Use a fiber mallet to lightly knock the casing loose.
3-Once free, make sure not to loose the locating dowel pins as there are critical for reassembly. (Be careful, mating edges are very sharp)
4-To aid removal, you will need to release the timing belt from the large timing pulley.
Timing Pulleys
Brake System
Spindle
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14. 11) Removing Brake and Spindle Sheave
Steps:
1-Remove two cap screws as shown in the picture and separate the sheave and spindle from the casing. Once flipped over, this will expose the brake assembly.
Screws
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15. 12) Cleaning and Lubricating
Steps:
1-Use a brush to remove free dust and chips from the components.
2-Use a light degreaser to remove deposits of grease or rubber from the sheaves, shafts and bearing housings.
3-To clean the sheave on the motor assembly, please use the two bolts and nuts provided in the Bridgeport Maintenance binder to securely compress the spring allowing you to remove the snap ring and separate the sheave.
4-To lubricate the sheaves, put a very light coating of white grease on the shaft, key way and corresponding contact surface in the hole. Do not over grease as the sheave must be free of contamination and excess grease will make its way to the belt causing damage.
Snap ring groove
Key Way
Shaft
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16. 13) Re-Assembly
Reassembly is the reverse of disassembly. Make sure to catalog and replace the appropriate parts as necessary. If fastener heads have been damaged by removal or torqueing replace them.
For further reference and insight, please use the Bridgeport maintenance manual. It contains detailed assembly diagrams, parts lists and instructions. The instructions and drawing apply to the first milling machines as well with the exception of an extra bearing located under the CVT sheave on the motor side.
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