Lubricating ER-11 collet taper?

Hi all,

Looking for a bit of input here – I noticed that there was a fair amount of very fine rust on the inner surface of my Nomad’s ER-11 spindle. It actually managed to corrode a couple of my collets before I realized what was happening.

Which leads me to my question: should the collet taper be greased or otherwise lubricated to discourage rust formation? It seems counterintuitive to me that you’d want to lubricate a toolholder that works entirely using static friction, but as the taper is also a sliding/mating surface I could get my head around it being recommended.

It should be kept clean — your concern about oil is valid, since even a tiny bit of lubrication will cause things to slip, so use a degreaser after.

There’s a bit at:

Note that the collets are a consumable item, so any which are damaged should be replaced.

You should be able to clean the Nomad spindle surfaces with just a paper towel and suitable cleaning materials — if it won’t come clean, contact us at and we’ll work out how to handle this.

Might I ask what environment you have the machine in? stable temp or wide variations? Humid or dry? My Nomad is a wet basement, and I spend about $30 to $40/month during the worst of the year to run the dehumidifier as primary protection for several machines and way too many other tools (as well as several other protective measures).

I ask because, if your environment is less controlled, there are a number of ways to prevent rust formation. Two easy ones are: a) a small heater, like those sold for firearms storage, in the machine to keep the temperature a few degrees above ambient, and therefore at a lower humidity; 2) remove the collet and nut when not in use (they should be loosened when not in use, anyway) and roll a small piece of VCI paper (vapour phase corrosion inhibitor) into a tube and slip it into the spindle bore, then put a plastic cap, like a pipe thread protector cap, over it. VCI materials leave no residue. ALL of my tool storage gets regular replacements of VCI capsules or paper, but my Nomad has not needed it, to this point.

Also, if you machine wood, clean the machine of chips and dust thoroughly after use. The wood chips and dust may hold moisture in the enclosure. I have seen this with woodworking machinery a few times.


Thanks everyone for your excellent replies!

The machine lives in my garage, which isn’t humidity-controlled. I live in a fairly dry area (rains maybe a couple weeks per year, total), though. No other part of the machine has developed rust, and I keep the rods and leadscrews clean and lubricated with the Superlube PTFE lubricant that C3D recommends. I do machine wood occasionally, but I diligently clean the entire machine of dust and chips after each use. The machine may live in the garage but I don’t put it away wet.

I cleaned the spindle bore by rotating a dry shop towel in it until no more rust came off; knowing whether it’s actually clean is tough for me, as I don’t have a borescope to check it visually. It doesn’t look like the rust has progressed any further, and I’ve taken to removing the collet and nut when the machine’s not in use. I was unaware that (at least) loosening the collet is recommended procedure, so thank you very much for pointing that out!

Sometimes I need to split machining jobs up over several days, and in those cases I was leaving the tool and collet installed and tight for 3-5 days at a time (in order to avoid losing my work zero/tool length). I think in the future I’ll just go through the extra step of re-probing for tool length between segments of a multi-session job.

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Boeshield T-9.

Boeshield T-9 will leave a lubricant behind. So if you use it to remove rust then do as Will Adams suggested and de-grease. You can use brake cleaner but be careful not to get it on plastic. You could spray the brake cleaner in a bottle cap and use a q-tip to clean the inside of the spindle shaft. Just get it lubricant free. If you are a gun owner you could use a brass barrel cleaning brush or if you are not a gun owner simply buy one at Walmart or other retailer. The brass is soft and will not harm the steel shaft.

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T-9 is more for “Rust & Corrosion Protection” than “Waterproof Lubrication”. In my experience, it does that remarkedly well (on both cast iron and steel). As stated in the literature, it doesn’t remove rust, their “Rust Free - Rust and Stain Remover” (as well as any other much less expensive phosphoric acid based) product should be used for that prior to it’s application.

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I have used Boeshield T9 and it leaves a residue behind. Maybe it dries later but it has an oil like feel when first applied. I would de grease the collet to be sure if you use any cleaner or rust remover.

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Page 37 of the Technomotor Handbook recommends a mix of thinner and oil. Precisebits sells "Son of ColletCare® and ColletCare +P+®, a revolutionary solvent/lubricant that is designed specifically to clean, lubricate and protect the precision ground surfaces of electric and air spindles." They also provide collet care guidance.

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How does this square with the advice above to avoid lubrication/residue on the spindle bore? I trust that Precisebits knows their onions here, and wouldn’t sell a product whose use results in worse spindle wear/performance than without.

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from the sounds of it I’d try a minimal approach to tackle this issue. if more effort/time is deemed necessary you can take it a step further.

clean all rusted items as best of your abilities

spray a rust inhibitor of your choice into a clean rag and wipe onto collet and spindle bore when not in use. this should prevent excessive application and allow for quick removal later.

prior to each job take a clean rag with a degreaser of your choice and wipe the collet and spindle bore clean. you may get away without the degreaser as you are just removing the thin film.

in my experience / environment I do not have to address rust, and only occasionally wipe the collet and bore clean from any dust/debris.

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