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Hardinge HLVH Worm Wheel for speed adjust

jperrin

Plastic
Joined
Jul 29, 2023
I have a hardinge HLVH and I recently changed out the belts and while following the procedure for setting the stops for the speed change mechanism I adjusted them too far which caused the acme nut to reach the end of the shaft at the motor housing end where it jammed while the motor was still spinning causing the worm wheel to strip out. Hardinge has a 90 day leadtime and want $250 for the part, I'm hoping someone might have one and/or would be able to help me figure out what to put into a site like rushgears.com to see what their price is. I'm not familiar with worm wheels and how to get the correct measurements.

I had also read in the maintenance manual that the worm wheel was sometimes a straight tooth gear? I'm assuming something like that might be easier to find but was the worm gear different or only the worm wheel changed?

Thanks!hlvh-wormwheel.jpg
 
I should have mentioned, I did order the part with hardinge, and they said someone else who ordered one in March got it by April, I just don't want to be stuck with one 90 day max leadtime option if I break another one :D
 
I should have mentioned, I did order the part with hardinge,
Good thing ... just measure the center distance off the machine itself, then you can get everything else you need off the worm, that's easier to measure than the wormgear. I THINK the Jones & Ryffel book with all the gear formulas is online, that's the easiest one I think for turning measurements into theoretical numbers.

But you'll want to be sitting down when you get the rush price. Maybe have some smelling salts handy, too. At $250 you're not going to do better than the real thing, noplace nowhere unless you let some guy with a south bend and a homemade milling attachment hack one out.
 
The most common reason for the motor to keep driving that speed change is the machine is not correctly phased. If moved to a new location and the plug is not "phased" like the previous location the speed change motor will go in the wrong direction with the wrong limit switch at the end of the travel.
The correct way to fix that is to switch the lines 1 and 2 in the cabinet. Sometimes line 3 is a strange voltage with no center tap. Someone that does not know better will just switch the spindle reversing switch and try to carry on. The first time you do a speed change it will lock up on the gear box. You have to turn off the power and turn the screw by hand to un-jam it then reverse the wires. Not necessarily in that order.
 
The most common reason for the motor to keep driving that speed change is the machine is not correctly phased. If moved to a new location and the plug is not "phased" like the previous location the speed change motor will go in the wrong direction with the wrong limit switch at the end of the travel.
The correct way to fix that is to switch the lines 1 and 2 in the cabinet. Sometimes line 3 is a strange voltage with no center tap. Someone that does not know better will just switch the spindle reversing switch and try to carry on. The first time you do a speed change it will lock up on the gear box. You have to turn off the power and turn the screw by hand to un-jam it then reverse the wires. Not necessarily in that order.
In other words: **do not monkey with the speed control until the correct spindle rotation direction is confirmed**.
 
The spindle rotation and wiring is all correct, I have been successfully using the lathe+speed changer for several years. It was not until I replaced the belts and attempted to follow the procedures to adjust the stop limits that I made a mistake and didn't notice I had moved the limit too far allowing the housing that contains the acme nuts to come into contact with the limit switch housing which immediately stripped out the worm wheel.

I did receive the new worm wheel from Hardinge in 3 weeks, much less than the quoted 90 day leadtime. My lathe is back up and running and much quieter with the new belts.
 








 
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