View Full Version : Speed Changer Clausing Lathe Model 5914
01-23-2008, 10:10 AM
I am having problems with my speed changer (not moving full range; also speed changer handle being "loose" in one direction) on this lathe and I cannot find a description of the system and good information to determine the problem.
I do not have the Manual for this lathe but I can see someone offering at $35.00 + shipping.
Could anyone that have the manual tell me if this manual (or any other) contains the full info to repair this problem?
Other ideas are welcome too.
01-23-2008, 11:02 AM
I can help you with the hydraulic speed control, but I'd strongly suggest getting the manual from Clausing so I can walk you through the part numbers. For $25, Clausing will make a manual specific for your serial number, and there were several major changes to the 5914 hydraulic Vari-speed over the years:
Clausing Service Center: (800) 535-6553
The speed change being "loose" in one direction is probably air in the hydraulic system. If you have the round master hydraulic cylinder, there's a bleed screw on the upper cylinder by the speed control. Turn the lathe on, run it through its range a few times, run it up to high and then crack the screw until it leaks hydraulic oil. Make sure the reservoir has enough oil or you'll be making the problem worse (adding air).
If you have the square master cylinder, it has a self-purge mechanism: run the spindle down to the lowest speed where the motor sheave was at its widest position (and the pistons are completely collapsed into the pusher block), then hold the two control levers against the spring-stop for several seconds.
If the speed control is still mushy, the brute-force way to purge the hydraulic line is to unscrew the hydraulic hose at the slave cylinder while the machine is running, run the speed up to high, and then screw the hose back in. That's a somewhat dangerous way to bleed the system, but it seems like it should work if, for some reason, the bleeding instructions in the manual didn't work for you...
Not moving full range is probably because the Vari-speed sheaves are not pre-set the correct distance. That's also an easy fix:
The belt should be flush the the outside of the motor pulley at high speed, and flush with the outside of the clutch/brake pulley at low speed. If the spindle speed is too high, turn the spacer nut on the piston shaft counter-clockwise. If the speed is too low, turn the nut clockwise.
01-24-2008, 10:27 AM
Robert: Thanks a lot. I will be ordering the manual today and as soon as I get it will try your suggestion. But what I cannot understand is why it goes only partial travel, I probably need to spend some time to digest that.
The sight glass on the reservoir is broken and previous owner had patched with some rubber past. I will try to fix that first, maybe with a plastic plate sandwiched between rubber "O" rings.
01-24-2008, 10:50 AM
I cannot understand is why it goes only partial travel, I probably need to spend some time to digest that.
I need some more detail, but it sounds like you can't go all the way to top speed (2000 RPM) , or you can't go all the way to bottom speed (360 RPM in open-belt mode) ?
If that's the case, it's because the spacing on the Vari-Speed drive sheave needs to be adjusted: at high RPM (2000 RPM), the V-belt should ride up near the top of the sheave. At low speed, the clutch/brake V-belt should ride up near the top of the slave Vari-speed sheave. The Vari-speed sheave spacing is set by a screw that goes through the hydraulic pusher piston(s). Tighten that screw, and your RPM goes up (and the V-Belt will travel higher). Loosen it to lower the RPM.
The sight glass on the reservoir is broken and previous owner had patched with some rubber past.
The 5900 sight glasses are a proprietary size -- I was only able to find them from Clausing -- around $15. Part number 18-1073 "Oil Level Window."