C E Dunn
Plastic
- Joined
- May 6, 2002
- Location
- Cartersville, GA USA
Hi all. I have a Monarch lathe that was built in 1967. It came out of a school shop and so probably did not receive the best of care. The ways are in good shape and all of the feeds and speeds work. The lathe
has been more than accurate enough for the machines that we build for our plant. (I’m looking for a face plate by the way – LO). I have recently come across a problem, however. Maybe some of you could give
me some advice on the best way to correct it.
I was fixing to cut some 7/16-14 threads. After setting up the machine for this thread and getting ready to cut this thread I turned the machine on and engaged the half nut to take a slight cut to make sure that I hadn’t made a mistake and had it set correctly for 14 threads before I took a heavier cut. When I engaged the half nut the
leadscrew stopped. I cut the motor off and double checked the levers to make sure they were engaged properly. Sometimes you have to fiddle with the levers to get all the gears in mesh on this lathe. No luck. You turn the lathe on engage the half nut the screw stops – no torque. I figure there might be a clutch of some kind that needed adjusting or maybe a key or pin that was broken or partly so. I took the cover off to take a look inside the gearbox.
What I found was the following: The change gear for 14 threads has one tooth missing. The teeth on this gear are partly stripped on one side maybe a forth of the width of the face. The biggest problem is that the main gear which is always engaged on every change gear and transmits the torque to each change gear, the one which is moved laterally to engage each change gear, is also stripped on about a third of the face width. Evidently there has been a wreck in the past between these two gears. If these two gears are not lined up exactly
then when torque is applied the screw can be stopped. Eveidently I didn’t have these lined up exactly when I noticed the problem. The problem is that now I know how the main gear is weakened and could go under a heavy load which , of course, is sometimes applied. The gears, as near as I can tell without taking the gears out, are hardened.
What to do? ( 1) I’m told that to get a hardened gear made might be as much as $350-$450. (2) I could sell the lathe but I’m honest and I would point this problem out to a perspective buyer. This would also
cost me money, maybe more than replacing the gear. (3)Make a gear myself but it would have to be a soft gear and might not hold up with the hardened gears it would mesh with. (4) Find a used gear, but where? That might take forever. (5) Find a similar lathe that is worn out for parts. Might take forever. (6)Make a whole new set of soft
gears in the shop, maybe several spares. Can anyone give me some advice on this? I would appreciate it.
Thanks
Charles Dunn
has been more than accurate enough for the machines that we build for our plant. (I’m looking for a face plate by the way – LO). I have recently come across a problem, however. Maybe some of you could give
me some advice on the best way to correct it.
I was fixing to cut some 7/16-14 threads. After setting up the machine for this thread and getting ready to cut this thread I turned the machine on and engaged the half nut to take a slight cut to make sure that I hadn’t made a mistake and had it set correctly for 14 threads before I took a heavier cut. When I engaged the half nut the
leadscrew stopped. I cut the motor off and double checked the levers to make sure they were engaged properly. Sometimes you have to fiddle with the levers to get all the gears in mesh on this lathe. No luck. You turn the lathe on engage the half nut the screw stops – no torque. I figure there might be a clutch of some kind that needed adjusting or maybe a key or pin that was broken or partly so. I took the cover off to take a look inside the gearbox.
What I found was the following: The change gear for 14 threads has one tooth missing. The teeth on this gear are partly stripped on one side maybe a forth of the width of the face. The biggest problem is that the main gear which is always engaged on every change gear and transmits the torque to each change gear, the one which is moved laterally to engage each change gear, is also stripped on about a third of the face width. Evidently there has been a wreck in the past between these two gears. If these two gears are not lined up exactly
then when torque is applied the screw can be stopped. Eveidently I didn’t have these lined up exactly when I noticed the problem. The problem is that now I know how the main gear is weakened and could go under a heavy load which , of course, is sometimes applied. The gears, as near as I can tell without taking the gears out, are hardened.
What to do? ( 1) I’m told that to get a hardened gear made might be as much as $350-$450. (2) I could sell the lathe but I’m honest and I would point this problem out to a perspective buyer. This would also
cost me money, maybe more than replacing the gear. (3)Make a gear myself but it would have to be a soft gear and might not hold up with the hardened gears it would mesh with. (4) Find a used gear, but where? That might take forever. (5) Find a similar lathe that is worn out for parts. Might take forever. (6)Make a whole new set of soft
gears in the shop, maybe several spares. Can anyone give me some advice on this? I would appreciate it.
Thanks
Charles Dunn
