Machine Oiling Interval

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Robert LaLonde

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I am curious. What kind of oiling interval you think is suitable for a continuously running CNC milling machine?

One which may run for an extended period reciprocating rapidly over a short range of its travel.

I have 4 machines with automatic oilers, and I just purchased a 5th.

Of the 4 machines I already have one was setup by the manufacturer to apply oil to the ways and ball nuts every 15 minutes with an electro mechanical clock timer. It has what appear to be cast iron ways, and inspite of an original service date of 1984 the ways are in pretty good condition. If it was on all day it used about a pint a day of way oil. Maybe a hair more. It has other issues, but the ballscrews have almost no backlash and the way surfaces look very good. It does have oil metering emitters at every lubrication point. This limits the amount of oil delivered in a cycle, and assures lubrication points oil appropriately as long as there is no air in the lines. There hasn't been any air in the lines in years. I did recently change it over to a more modern programmable electric oiler, but the cycle rate is about the same, and I timed the duration to put out the same amount of net oil.

The other three are newer being 2-5 years old. One has plane cast iron ways, and the other two have square profile linear ways. They are all set to oil about every 20 minutes for about 15 seconds. They do not have emitters. Just open oil ports to the lubrication point. I get atleast some oil at every lubrication point every cycle.

Now to get to that fifth machine. Its a brand new machine. I purchased it with a bunch of options including an automatic tool changer, automated power draw bar, full enclosure, and an automatic oiler. This is a high end "pro/hobbyist" machine so I get to install all the options and setup the machine myself. In reading the manufacturer's notes it says it should have the electric oiler interval set at 240 minutes (4 hours) and it should pump oil for only 5 seconds. This set me back a bit so I asked the companies tech support about it and I got a general non-committal reply. "The oiling schedule that we set is only a starting point. It is adequate at this setting, but you can set it for whatever you would like."

The oiler itself is just another Chinese automatic electric oiler similar to the ones on my other machines.

In the specs for the machine it says, "The sliding dovetailed ways are hand-scraped and designed to withstand high loads and dampen vibrations. The ways have bonded PTFE filled acetyl sliding surfaces, hand scraped by skilled machine builders. Similar to brand name compounds such as Turcite® or Rulon®, PTFE compounds provide low friction and long life."

Is that way spec adequate to explain why they recommend such a short oil application period and such a long lubrication interval? Or have I been grossly over lubricating all my other machines for years?

The oil spec is just iso 68 way oil and includes a list of suitable oils including Mobile Vactra #2 which is what I use in all my other machines and with a dispenser even on my manual machines.

If their oiling recommendation is "generally" adequate do you think it takes into account localized scrubbing from the point I raised near the beginning of this post? Because I do complex 3D machining almost exclusively my machines may run for an extended period reciprocating rapidly over a short range of its travel on any given axis.

I would like to read your opinions, but do please read the whole post first.


Global Moderator
Staff member
H-M Platinum Supporter ($50)
Feb 8, 2014
I would rather oil more frequently with a shorter cycle time. Theoretically you should use the same amount of oil but in shorter bursts, should keep the oil film more consistent. Personally if I don't see oil dripping on the floor it's not enough for me. ;). I have my oiler set to run through a tank (quart?) in about 16 hours.


Hobby Machinist since 2010
H-M Platinum Supporter ($50)
Feb 27, 2014
I just replaced my oiler pump when the old one broke. Before it was manual, I had to push a button and I would run it for 10-20 seconds every few hours. Now withe new programmable one, I have it setup for 5 seconds every 20 min. Any longer and I start to see oil dripping out. I am having a problem with air in the lines to the vertical ways though. I just bought a higher quality check valve to put in both vertical way lines. Hopefully this will fix that issue. As to your question, I have no idea what is Optimum.

Norseman C.B.

Active Member
Dec 21, 2013
Machine tools, like women, work smoother, last longer, and complain less, when well lubed.......:cool:


Active User
Oct 14, 2014
My machine oils every 4 minutes but it’s a very small amount. I personally would oil more often then if you are getting excess oil and tramp oil in your coolant turn it down. Better to deal with a bit of tramp oil then to wear out your ways and ballscrews.
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