WD 40 as drilling lubrication?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Jonas Liebel, Apr 16, 2018.

  1. Jonas Liebel

    Jonas Liebel

    Jan 20, 2018
    Hey there,

    I just wanted to ask if using WD40 for my drilling is a good idea and if not what I could use instead.

  2. Rhinoknives1

    Rhinoknives1 Gold Member Gold Member

    Jul 1, 2013
    Cool Tool for one is made for this. WD-40 has to low if a viscosity to help much..
  3. Drew Riley

    Drew Riley Riley Knife and Tool Knifemaker / Craftsman / Service Provider

    Oct 17, 2007
    WD-40 is pretty good for aluminum. Is it the best solution for steel? Not really. Better than nothing? I suppose.

    Personally, I like Molydee, though if you want a more budget friendly option, grab a gallon of sulfur based thread cutting fluid in the plumbing section of your local big box store. Should run you around $20 and last the rest of your hole drilling career.

    Warning: it stinks.

    Then again, so does burning up and breaking drill bits. ;)
    Rhinoknives1 and kuraki like this.
  4. Rhinoknives1

    Rhinoknives1 Gold Member Gold Member

    Jul 1, 2013
    Yeah, I didn’t like the Sulfur smell or the smoke! It is cheap thought.
  5. John Cahoon

    John Cahoon JWC Custom Knives Knifemaker / Craftsman / Service Provider

    Apr 13, 2017
    I've been using simple 3 in 1 oil for a long time on 01,5160 and 440c on a band saw and a drill press. Not sure if it's the best but cheap enough, always available and never any issues?

    + it don't smell, I do add more as I get into the hole.
  6. 12345678910


    Jul 13, 2009
    WD 40 is mostly kerosene, it works on Aluminum

    Dark sulphur cutting oil in the plumbing section of Home Depot

    Anchor Lube works.

    I checked your profile - If you're really from Germany you may have mentioned that - no US sources will apply
  7. tiguy7

    tiguy7 Gold Member Gold Member

    Jun 25, 2008
    WD-40 is not a lubricant. It is a Water Displacement (WD) coating to prevent rust. Look for a dedicated drilling and tapping fluid like Tap Magic. I like the Sulphurated oil, especially for Titanium, but it is messy. If you break a tap in Titanium, you can dissolve it with battery acid.
  8. Pinoy Knife

    Pinoy Knife

    Aug 9, 2002
    try 30W motor oil. not 10-30
    the old machinist guys used 30 W oil in the "squirt guns" most of the time. not the best but can be found everywhere and cheap.
  9. gunfixrjoe


    Aug 11, 2011
    Brownells has a product called Do-Drill. It works exceptionally well......
  10. Geoff Flato

    Geoff Flato

    May 23, 2017
    Lubricating and cutting oils are not the same thing and are not interchangeable. I don't feel like a long drawn out rant, so I'll just say either use proper cutting fluid, or nothing. Dry is better than using motor oil or the like.
    Feeds and speeds, and quality tooling will make more of a difference than dry vs cutting fluid.
    gunfixrjoe likes this.
  11. rtz

    rtz Basic Member Basic Member

    Mar 19, 2010
  12. Bill DeShivs

    Bill DeShivs

    Jun 6, 2000
    And WD 40 is a light lubricant. It contains mineral oil.
  13. Geoff Flato

    Geoff Flato

    May 23, 2017
    You'd be better off using water than wd-40 on steel.
  14. JTknives

    JTknives Blade Heat Treating www.jarodtodd.com Knifemaker / Craftsman / Service Provider

    Jun 11, 2006
    I absolutely love STP oil treatment for drilling and tapping. Learned this from an old time machinest.
  15. Natlek


    Jun 9, 2015
    One old time machinist here produce some agricultural tools /make around 1500 screw thread M18 or larger daily / His words are that with pork fat thread cutting dies last much longer then with any commercial product that he tried ...............I used that too .
  16. skillgannon


    Apr 27, 2009
    I like cutting wax. I think it's actually for cutting and it's not messy
  17. kuraki

    kuraki Fimbulvetr Knifeworks

    Jun 17, 2016
    There is no one size fits all cutting fluid, though many fluids can be used for many different operations it doesn't make them optimal for those operations. The purpose of the cutting fluid is to reduce heat. Some do it by reducing friction (oils), others do it by convection and reducing friction to various degrees (soluable oils, semi and full synthetic coolants).

    Drilling in particular is a challenging operation to lubricate or cool properly that people take for granted. The (typical HSS twist) drill is doing two things, at the center web where the surface speed is near zero, it's extruding the material. At the cutting edge where the flute meets the face, it's cutting material. The heat is generated by the friction of the extrusion, as well as by the friction of the cutting action, and to a lesser degree by the lands of the drill rubbing on the drilled hole wall, and the chips traveling up the flute or becoming compacted in the flute and then rubbing on the drilled hole wall.

    In order to cut, you want an oil that lubricates the surfaces of the work and tool that are rubbing but not the actual cutting edge. The entire operation is dependent on the cutting edge biting into the work, which requires some amount of friction. This is why oils that are meant for reducing wear on parts meant to slide across each other such as ATF or motor oil are poor cutting fluids. Their long polymer chains have tight bonds that are designed not to break under extreme pressure (like the cutting edge of a tool or the piston ring in your car). It's also why animal fat does in some cases work well, the bonds are not as strong and break under that high pressure while remaining intact under lesser pressures (such as chip/flute contact.) Sulphurized, chlorinated, or molybdenum types of cutting fluids also work on this principle of providing the right amount of lubrication for the right amount of pressure and breaking down where the cutting occurs.

    Then there's the workpiece component. WD40 or kerosene or any light mineral oil works well with Aluminum because the extrusion of the material is relatively easy, the cutting is relatively easy, and you're not trying to avoid the kind of heat that breaks down the cutting edge, rather the kind of heat that allows the material to solder to the cutting tool. Lubrication is less important than convection, which light oils do better than heavy oils, while retaining some small amount of lubricity in comparison to say water. Higher demands require higher lubricity.

    Tapping titanium is maybe one of the more demanding operations a knifemaker will do. Taps have a lot of surface area contact. They are small diameter in relation to the amount of cutting force required. They have very little or no relief behind the cutting edges. Titanium deflects and has a lot of spring back, resulting in what amounts to something like a chinese finger cuff around your tap. This is why high lubricity high pressure cutting fluids like Moly Dee are preferred for operations like this.

    If I was going to have one cutting fluid in my shop to handle everything, it would be regular sulfurized pipe threading oil. For drilling, tapping, reaming, and milling with HSS endmills or slitting saws. It will work relatively well in just about any HSS tool/steel work situation.

    I prefer to have Moly Dee or Boe Lube or at least Tap Magic for tapping titanium and stainless or high alloy steels. Kerosene for Aluminum unless tapping deep holes, then an aluminum tapping fluid is handy. And a synthetic coolant for misting HSS endmills or flooding surface grinders.
  18. Drew Riley

    Drew Riley Riley Knife and Tool Knifemaker / Craftsman / Service Provider

    Oct 17, 2007
    Excellent post.

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