Boley Leinen spindle lubrication

[henryr]

I have a very good condition Boley Leinen 8mm lathe and have been using Mobil Velocite Oil No.6 ISO VG10 for the spindle bearings. There are two oil cups on the headstock, one over the rear bearing and the other over the front bearing and it is rare that I have to top them up. If I run it at high speed for a few minutes the area surrounding the front bearing gets warm and rear bearing area gets quite a bit warmer, almost hot. My question is, is the Velocite to heavy a viscosity or could the bearings be too tight? And should they normally require more frequent topping up.

 

Thanks,

henryr

[nickelsilver]

That's the perfect oil for this machine. It's normal for plain bearing machines to get warm*, if it's not getting warm the bearings are too loose. If it's too hot to hold your hand on for 5 seconds after 30 minutes running the bearings are too tight. But ISO 10 is just right.

 

*When doing very high precision work it's good to let the machine run for a half hour first. A watchmaker friend who worked in the gear department at Mcdonell Douglass told me it was protocol to turn on all the machines 30 minutes at least before making parts. Another friend who was well known for handmade watches had thermometer strips on the heads of certain machines to know when they were warm enough.

[henryr]

Thanks for the great info. But I have never had the spindle, of any of my lathes, turning continuously for more than five or ten minutes and the Boley is powered by an EMESCO 90N 22000RPM motor. So what would be a reasonable speed to run, checking the temp often, for up to 30 minutes to see how warm/hot it gets?

[nickelsilver]

Oof, that's fast. Would have to know the pulley sizes to have a better idea what speed you're running, but around 2000 rpm would be great for most small work, I generally run 1500. So try around those speeds and see how it does.

[jdrichard]

2 hours ago, nickelsilver said:

Oof, that's fast. Would have to know the pulley sizes to have a better idea what speed you're running, but around 2000 rpm would be great for most small work, I generally run 1500. So try around those speeds and see how it does.

I use 0W20 full synth oil on all my lathes and have never had them get hot.  as well, you cut parts using a foot pedal to vary the speed for cutting and burnishing and other reasons.  1500 is more than good and not a lot of speed is required of blues steel or brass.

[nickelsilver]

Ah, didn't see the pics before. Those dental engines are really built for high speed use. You can make a simple countershaft that fits in the upper support where the dental handpiece works attach, something like a 5" pulley that goes to the motor pulley, and the pulley going to the lathe about the same as is on the motor shaft. That will give enough reduction that you can get the motor at a decent speed and still have torque.

 

I'm curious about the headstock on that machine, what does the spring do? I've owned a number of Boley Leinen machines as well as other makes and never seen that; it almost looks like the adjusting nut for the bearing play has been replaced with a brass sleeve, and that spring in giving a preload to the bearings. But you must have to fight against it when tightening the drawbar? A spring preload is common in some types of spindles with ball or roller bearings, but quite odd on a plain bearing machine.

[henryr]

I think I need a slower motor. If I understand RPM calculations it seems, with the motor @ 22,000 RPMs and a 5"dia. pulley between the motor  pulley and the lathe pulley, it will result in the lathe spinning at 9167 RPMs.

Example: .75 motor pulley @ 22,000 RPMs = 5"dia. pulley @ 3300 RPMs = @ 1.8 dia. lathe pullet @ 9167 RPMs . Is that correct?

And there is an adjusting nut and I'm guessing a previous owner made the brass sleeve to incorporate the spring to apply a slight load on the  draw bar to keep it from loosening during operation.  

 

 

[henryr]

Thinking about the home made sleeve with the spring, it seems a clever way to preclude a collet from working/vibrating loose.

 

 

 

Edited March 18, 2021 by henryr

[nickelsilver]

Ah yes was off on the secondary pulley, regardless would be good to drop to 1500- 2k; is also good to be able to halve the that too; the dental motors I've seen have been able to be regulated by a rheostat so that could help.

 

The spring keeping the drawbar from loosening is a no go. I often tighten, delicately, on sub 0.5mm parts, hollow, in brass or nickel alloy, never ever once had an issue with the drawbar loosening.

[henryr]

I believe the EMESCO foot pedal is a rheostat but having one that is controlled by a knob, with an RPM display would be a great addition. Is such a control available? I'd like to keep the EMESCO because it is a great looking motor, in like new condition, with good torque. I also have a no-name motor with foot control thats runs at a much lower RPM, and have no idea of its specs., but the torque is so low I can stop it by grabbing its spindle.

[jdrichard]

9 hours ago, henryr said:

I believe the EMESCO foot pedal is a rheostat but having one that is controlled by a knob, with an RPM display would be a great addition. Is such a control available? I'd like to keep the EMESCO because it is a great looking motor, in like new condition, with good torque. I also have a no-name motor with foot control thats runs at a much lower RPM, and have no idea of its specs., but the torque is so low I can stop it by grabbing its spindle.

You can buy a variable control foot pedal on aliexpress for 10 bucks.

[henryr]

I have variable foot pedals. I'm looking for a variable speed controller that uses a hand operated knod.

[nickelsilver]

Check out here

 

https://watchmaking.weebly.com/auxiliary-motor.html#

 

Also his whole site is fantastic.

[henryr]

27 minutes ago, nickelsilver said:

Check out here

 

https://watchmaking.weebly.com/auxiliary-motor.html#

 

Also his whole site is fantastic.

Thanks. it is a fantastic site