Pete.
Member
- Messages
- 14,152
- Location
- Kent, UK
Got a j head for a Bridgeport here that was missing its motor as well as being apparently seized. The brake lever was stuck fast so I was hopeful that it was just corrosion sticking the brake shoes to the pulley.
I stripped the motor housing off and was very pleased to find that the quill, spindle and pulley bearings are buttery smooth and it was indeed the brake that was stuck in the pulley. An hour's cleaing up and everything works just fine, only the missing motor now to sort out.
The original 2-speed motor is 415v only and comes with a switch on the side, and it has a purpose-made mounting flange to allow for belt tension adjustment. They are also very expensive (this one had it's motor removed for £200 before the remainder was sold on). Since there is no 3 phase supply this machine will be VFD driven which makes the 2 speed motor impractible anyway, I decided to fit a 3hp WEG flange-mount motor I had hiding under the bench.
First I needed a pulley, but again using a non-standard motor which would require a sandwich plate meant that the pulley would also need an extended nose on the small end of the 4-vee set. I found a chunk of ally under the bench ans set about carving it out on the lathe. Took a couple of hours.
Then I had to broach a keyway in it. The motor has a 8mm key but I only had a 1/4" broach so I shoved that through the hole.
After that I had to modify the motor's key to give it a step so it would fit both motor and pulley. I stuck it in a vice on my surface grinder and side-ground the key narrower.
Offered it up with some steel spacers to get it all aligned.
All that is left o do now is drill and tap the pulley for a grub screw and make the sandwich plate that will allow the motor to swing on the pivot bolt in order to tension the belt. I picked out my rustiest piece of scrap 1omm plate and cut a 11 inch circle out of it using my lidl plasma cutter. It did a pretty good job for a tweaked-up 30a machine, used 2 drag tips cutting this out. Might have got round with 1 tip but the cut is ragged enough without me making it look even worse.
That was it for today my workshop was full of ozone smell from the plasma so bailed out. I will go back tomorrow, cut out the hole for the motor, drill and fix and it should be all done.
I stripped the motor housing off and was very pleased to find that the quill, spindle and pulley bearings are buttery smooth and it was indeed the brake that was stuck in the pulley. An hour's cleaing up and everything works just fine, only the missing motor now to sort out.
The original 2-speed motor is 415v only and comes with a switch on the side, and it has a purpose-made mounting flange to allow for belt tension adjustment. They are also very expensive (this one had it's motor removed for £200 before the remainder was sold on). Since there is no 3 phase supply this machine will be VFD driven which makes the 2 speed motor impractible anyway, I decided to fit a 3hp WEG flange-mount motor I had hiding under the bench.
First I needed a pulley, but again using a non-standard motor which would require a sandwich plate meant that the pulley would also need an extended nose on the small end of the 4-vee set. I found a chunk of ally under the bench ans set about carving it out on the lathe. Took a couple of hours.
Then I had to broach a keyway in it. The motor has a 8mm key but I only had a 1/4" broach so I shoved that through the hole.
After that I had to modify the motor's key to give it a step so it would fit both motor and pulley. I stuck it in a vice on my surface grinder and side-ground the key narrower.
Offered it up with some steel spacers to get it all aligned.
All that is left o do now is drill and tap the pulley for a grub screw and make the sandwich plate that will allow the motor to swing on the pivot bolt in order to tension the belt. I picked out my rustiest piece of scrap 1omm plate and cut a 11 inch circle out of it using my lidl plasma cutter. It did a pretty good job for a tweaked-up 30a machine, used 2 drag tips cutting this out. Might have got round with 1 tip but the cut is ragged enough without me making it look even worse.
That was it for today my workshop was full of ozone smell from the plasma so bailed out. I will go back tomorrow, cut out the hole for the motor, drill and fix and it should be all done.