To remove the motor, make sure the electrical cable is disconnected. Then loosen the motor by loosening one of the motor mount bolts. Slide the motor forward a little allowing for the v-belt to be removed from the motor pulley.
Once the belt is removed, the motor bolts can be removed and the motor is free. It only took one of us to lift the motor. Other milling machine owners have switched over to DC. Here is a reference we found: Building a DC Drive for the Bridgeport Spindle. Our goal is to run everything in the machine shop from the available solar energy system we have. The AC motor is rated at 1 hp(horsepower) which is about 746 Watts. Currently, our system's maximum capacity is 400W. We will be adding two more solar panels to give us an 800W system.
Something about this machine makes me think the mill head is a robot head and we just removed it's brain.
Our second try at removing the knee was successful. We realized the knee wasn't as heavy as we thought; it was still heavy though. The reason it was so hard to lift on the first try was due to the dovetail jamming. If you are not lifting the knee vertically, that dovetail will jam. It helps to have an extra person pushing the knee against the column to keep the ways in contact.
It's important to protect the parts of the mill from further damage. We used a piece of cardboard as buffer between any parts and the shop floor. It's good to put down card board for anything you want to protect from getting scratched up. Some surfaces on the mill are precision surfaces; we want to make sure their condition is preserved.
With the knee out of the way we went on to remove the knee pedestal. This part only has two fasteners; which secure it to the column base. Now we're almost there; just the head, ram, and turret are remaining.
The head is only secured with four fasteners. The nuts are loosened and taken off. In the above picture you can see a wrench on the upper left nut. The best thing to do would be to support the head while removing the nuts. I was worried the head would slide off, but if you keep a little pressure on it and don't walk from it, nothing bad will happen. I was able to take down the head myself. Next time I would do it with two people or a crane just to make it easier on myself.
Now the robot has no head. Oh nooooooo!!!
I was pretty surprised, in a good way, when I learned how the head attaches to the ram. We're pretty much taking apart the mill in a random fashion, without looking at manuals or exploded views. I never really thought about how the head can stay firmly attached while being rotated. This system really makes sense. The t-bolts are removed by sliding them down and pulling them out through the t-slot.
Pictured above is the ram adapter featuring the quill housing adjusting gear. This is what the quill worm gear(pictured below) pushes against as you rotate the head.
Taking apart this machine has been a lot of fun so far. With all of us having strong backgrounds in mechanical engineering, it's definitely a sight to see the constructions of theses amazing machines. This machine appears to be over-engineered by today's standards, but in my opinion, they did an excellent job. This machine has already been around for 50 years and with the work we're putting into it, we're expecting another 50.
Head: It's been so long pedestal; I see you haven't buckled under the pressure.
Time to pull out the ram. Below you will see the ram pinion with handle. The vertical bolts(2 on each side) fasten the turret to the column. The horizontal bolts fasten to the ram clamps, which lock the ram in place. The ram clamps are inside the ram. Above the ram pinion is the ram pinion set screw, which keep the pinion in place.
With the ram clamps and set screw loose, we attempted to turn the ram pinion. The handle here isn't greatest; it's really easy to bruise your hand. I wrapped some shop rags around it and after putting my weight on it, the ram slowly started to move. We're not sure how long it's been since the ram was moved but it felt pretty locked up.
The ram is almost off. For some reason the ram gets to a point where it wouldn't move any more. The pinion or ram was locking up. We decide to move the ram in the other direction, to see if it would come off that way. No luck there either.
For now the ram is stuck. Later on we discover why. It's pretty obvious in the picture below.
Since we couldn't get the ram separated from the turret, we took it off in one piece. The turret is removed by removing the four vertical bolts that secure it's base.
We were planning to put this part on the floor but we didn't make it; the ram and turret are super heavy. With three of us lifting it, and somewhat struggling, we opted for the table.
Here is a view of the inside of the column, from where the turret used to sit. Pretty amazing foundry work here.
Back to cleaning more and more shavings. There is no shortage of shavings hidden in this machine.
Picture above, within the column, is the spider. This part has four threaded holes which fasten to the turret bolts, securing the turret to the column. This part allows the turret to remain fastened while also having the freedom to rotate, similar to the head and ram.
The day of backbreaking work is over and we look forward to getting some rest. After being curious about the weight of the individual mill parts, I find this reference: Bridgeport Repair and Troubleshooting Page. Here is the breakdown it gives:
- Head(w/ motor) - 200lbs.
- Ram Adapter - 90lbs.
- Ram - 218lbs.
- Turret - 214lbs.
- Column - 715lbs.
- Knee - 257lbs.
- Saddle - 142lbs.
- 48" Table - 365lbs.
For the most part these weights feel correct. I guess we don't know our own strength.
...to be continued.
Good write up that explains how to take one apart, like for a move, very helpful for a newbie. Thanks.
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