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Carlton radial arm drill wont elevate

Angry750

Plastic
Joined
May 8, 2024
Location
Michigan
Hello,

We have a Carlton 8" arm 19' column radial drill that has stopped elevating. The operator was using the press but is now unable to lower or raise it. I can see the elevating screw spinning when the up or down button is engaged, but there is absolutely no movement in the arm. I couldn't find much information or mechanical drawings about the elevating mechanism. I read that some drills have a safety feature that disengages the mechanism if the arm is driven down into the workpiece. Does anyone have any ideas? There haven't been any issues with the drill before this. Neither of the limit switches is tripped, the arm unclamps, and the elevating screw rotates in both directions, but it doesn't lower or lift the arm. It's almost as if a clutch is not engaging, but I don't see any visible clutch. Any help would be appreciated. It looks like the screw may be raised up about 2 inches from being fully seated in the bottom screw support which may be a safety engagement . Does anyone know how to reset this if it is the case?
Thanks for your help
Jason
 
Check the emergency stop and the rotation of the vertical screw motor.

Sometime you don’t know the rotation is wrong because you never go that high or that low, If you go past the stop you break the casting and scrap the machine.
When you push down on the up / down lever the head should go down. lift up on the lever the head goes up.
With the rotation wrong the opposite-way travel won’t work
 
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So I let it run and hit the limit switch and it reversed directions, and the arm just started moving again. I'm not sure if they somehow disengaged the elevating mechanism by running it into a die because the screw does not rotate during normal operation. Is there a safety that can disengage the elevating mechanism? What I was reading on some drills is that holding the up button will cause the screw to raise up slightly to remove the nut from the top of the elevating screw. I'm not sure if this is the case, but it looks as if the screw is slightly raised out of the seat on the bottom of the screw. This is a new machine to us and I'm not sure if it was already this way or not? Could they have over traveled and somehow engaged a safety that keeps it from powering into workpiece? I don't have any odd noises and everything travels smoothly. Not sure what would allow that screw to spin i would think there would be some pin or Dowell installed to prevent it from spinning. Now the machine is working fine again but i would like to know the cause so it does not happen again.
 

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One of the fitters in work did a good fix on the nut, he made the nut then split it with a slitting saw and fitted it without pulling the machine to bits, smart not hard as they say , not like the hard slow and expensive I’ve walked into so often when the mrs tells me, why didn’t you just……and the buggers are usually right, and they know it when you make the excuse why you did it the hard way,.. you know best dear, rolls eyes.
Brian block did a great bridge crane cable test with a Carlton, should be standard viewing for rigging and lifting courses.
Mark
 
So I let it run and hit the limit switch and it reversed directions, and the arm just started moving again. I'm not sure if they somehow disengaged the elevating mechanism by running it into a die because the screw does not rotate during normal operation. Is there a safety that can disengage the elevating mechanism? What I was reading on some drills is that holding the up button will cause the screw to raise up slightly to remove the nut from the top of the elevating screw. I'm not sure if this is the case, but it looks as if the screw is slightly raised out of the seat on the bottom of the screw. This is a new machine to us and I'm not sure if it was already this way or not? Could they have over traveled and somehow engaged a safety that keeps it from powering into workpiece? I don't have any odd noises and everything travels smoothly. Not sure what would allow that screw to spin i would think there would be some pin or Dowell installed to prevent it from spinning. Now the machine is working fine again but i would like to know the cause so it does not happen again.
Is the shaft in your picture not the clamping mechanism?
 
So I let it run and hit the limit switch and it reversed directions, and the arm just started moving again. I'm not sure if they somehow disengaged the elevating mechanism by running it into a die because the screw does not rotate during normal operation. Is there a safety that can disengage the elevating mechanism? What I was reading on some drills is that holding the up button will cause the screw to raise up slightly to remove the nut from the top of the elevating screw. I'm not sure if this is the case, but it looks as if the screw is slightly raised out of the seat on the bottom of the screw. This is a new machine to us and I'm not sure if it was already this way or not? Could they have over traveled and somehow engaged a safety that keeps it from powering into workpiece? I don't have any odd noises and everything travels smoothly. Not sure what would allow that screw to spin i would think there would be some pin or Dowell installed to prevent it from spinning. Now the machine is working fine again but i would like to know the cause so it does not happen again.
I managed to obtain the service manual. According to it, there's a safety feature in place that prevents the machine from powering down during operation. This safety mechanism allows the clutch nut on top of the elevating screw to slip, thus stopping the arm from moving and allowing elevating screw to rotate. It seems that the problem stemmed from the arm clamping mechanism failing to unclamp fast enough and triggering this safety feature. To address this, I made some adjustments to the arm clamp, and it appears to have solved the issue.

To test it, I replicated the problem by keeping the clamp engaged and manually activating the 'down' contactor. If the shaft starts spinning, it means the clamping force of the arm is adequate. However, if the arm lowers, the clamp will need to be tightened. On the other hand, by engaging the 'up' contactor manually while the clamp is still engaged, it will Re-align the elevating screw with the clutch nut and restore the drive mechanism.

I'm happy to report that this problem has been resolved. I want to extend my gratitude to everyone who contributed.

Best regards,
Jason
 
Unclear, they were using it as a press? Using it like an arbor press with no rotation? Did they push too hard and a safety kicked out?
It would not surprise me if it has a safety if a drill is too dull and you try to push it too hard the machine stops feeding
BilLD
 
Unclear, they were using it as a press? Using it like an arbor press with no rotation? Did they push too hard and a safety kicked out?
It would not surprise me if it has a safety if a drill is too dull and you try to push it too hard the machine stops feeding
BilLD
No, the arm clamping mechanism was too tight. When they went to travel the head down the safety kicked out the elevating screw because of the resistance of the clamp not being fully released. Worked as it should. Adjusted the clamping mechanism a 1/4 turn- per service manual -no issues since
 
I ran one of those quite a few times as an apprentice. Never even knew it had a clutch in the elevating mechanism. Learn something new every day.
 
If you look at top of screw near nut there is a what looks like a locking washer with large teeth that interlock. Overloading the screw causes that to slip. The manual is calling it a clutch nut. You would intentionally make it slip in order to remove nut easier according to the service manual.
 








 
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