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  • Question About Oil In Collets

    I started a new project last week, the RG-G Gatling gun. I figured that I would make the carriage first because I prefer the metal working to woodworking so the carriage would then be out of the way and finished. I used the milling machine to cut a 2 inch by 2 inch pocket in the oak with a 1 inch mill that has a 1/2 inch shank. After 1 pass I returned back the same pass to cut a parallel pass and noticed that it was cutting deeper on the pass that I had just cut. After checking a few things I found that the mill had been pulled out of the Collet somewhat just by the cutting action. I was taking very aggressive cuts due to it being wood which may have contributed to the problem. The Collet was tight but I tightened it and it did it on the next pass also. I then removed the mill and cleaned the shank and the inside of the collet. After that I had no more problems. I use Triflow as a lubricant and rust preventative because it protects for a long long time. I know I had recently sprayed the collets with Triflow and am assuming that it caused the problem. My question is should the inside of the collet not be oiled or does it need to be cleaned every time it is used. In the past I had sprayed them with WD40 once and in awhile and never had a problem. Maybe the Triflow is just to slick. What is the proper way to store collets and should they be cleaned inside before each use? Thanks.

    Dwight

  • #2
    R8 Collets suck for retention.

    I think triflo has teflon in it which might cause problems. I have never needed a rust preventative on tooling in my shop. Unless you are in an extremely humid environment with temp swings you may not either.

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    • #3
      I always run some clean dry paper towel in the bore of the collet before use to ensure that it is dry and clean.
      The shank of any tooling inserted into the collet gets the same treatment. No issues with slipping collets.
      Home, down in the valley behind the Red Angus
      Bad Decisions Make Good Stories

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      • #4
        From Tormach - Best Practices for Preventing Collet Slip or read the entire report Tormach - Preventing Collet Slip pdf.

        Oil on the tool shank/gripping surface of the collet is not recommended.
        Last edited by TriHonu; 03-29-2015, 10:26 PM.

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        • #5
          I must admit I've even had dill bits spin on me due to oil, I wipe them these days.
          Never had any trouble with an auto lock chuck, even if dripping with oil as the cutter is bottomed in it, ain't gonna spin!
          Mark

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          • #6
            I've only had that happen a couple times. The collet and cutter were not oiled. Too heavy of a cut compounded by a not so sharp cutter and a little chatter or vibration can cause the cutter to slip in the collet and be pulled down. Cheap collets that run oversize or are poorly ground internally can also lead to the problem as they don't grip evenly.

            JL...............

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            • #7
              IIRC, it was found that you'll get more holding torque if the collet taper is oiled, even if the tool shank is oiled, compared to both being dry.

              Of course, you'll get slightly higher holding torque if the tool shank is dry and the collet taper is oiled.
              Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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              • #8
                Thanks for the good information. I guess I'll keep the Triflo away from the collets and clean the bore of them.

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                • #9
                  I always blast out the taper of any collet chucks, the exterior of the collet, bore of the collet, and shank of the tool, with carby or brake cleaner specifically to avoid tool pull out. Any thin film of lubrication will reduce the pull-out force of the tool substantially.

                  It is true, however, that a lubricated collet taper will give greater pull-out force - there will be more elastic strain on the collet as the draw-torque will effectively be higher. This is only useful, however, if the collet itself is keyed to the spindle - otherwise you could end up spinning the collet in the spindle taper. Which is why I don't do it with collet chucks - I'd rather accept slightly reduced pull-out force (which isn't really an issue with the nut torqued to 100in-lbs as it should be), than risk spinning the collet in the holder.

                  If you're using ER collets/ holders, consider getting a ball-bearing collet nut. You'll be able to achieve far higher clamping force on the collet for the same amount of torque.

                  Either way as an immediate remedy I would suggest much lighter passes in the wood - I imagine it would cut not unlike brass, and due to its elasticity want to suck the cutter out of the holder due to the cutting forces on the flutes.

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                  • #10
                    It was an R8 collet. I have a set of ER 40 collets that I use mostly in the lathe for small stuff. I did get an R8 ER 40 holder and was planning to try them in the mill but never got around to using it. Force of habit I guess. I did take big cuts in the wood thinking that it's only wood so I can hog it out. The wood was chestnut oak and it is tough and as you say it definitely wanted to suck the cutter out. Lesson learned I will keep the inside of the collets dry from now on. I normally only use the Triflo on the lathe ways / compound and the mill table / vice when I am going to be gone on a job for a couple weeks. But I remember a few weeks ago when I was doing the mill I saw the collets in the holder with the faces exposed and sprayed them lightly. I still really like Triflow and use it for a lot of stuff but I now know where not to use it. Have a good day.

                    Dwight

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                    • #11
                      Originally posted by Sun God View Post
                      It is true, however, that a lubricated collet taper will give greater pull-out force - there will be more elastic strain on the collet as the draw-torque will effectively be higher. This is only useful, however, if the collet itself is keyed to the spindle - otherwise you could end up spinning the collet in the spindle taper. Which is why I don't do it with collet chucks - I'd rather accept slightly reduced pull-out force (which isn't really an issue with the nut torqued to 100in-lbs as it should be), than risk spinning the collet in the holder.

                      If you're using ER collets/ holders, consider getting a ball-bearing collet nut. You'll be able to achieve far higher clamping force on the collet for the same amount of torque.

                      Either way as an immediate remedy I would suggest much lighter passes in the wood - I imagine it would cut not unlike brass, and due to its elasticity want to suck the cutter out of the holder due to the cutting forces on the flutes.
                      Oil in the spindle has not been linked to collet spinning afaik. In fact I don't know anyone who has spun a collet in the spindle without using some very large tool that got jammed (say a slitting saw), or didn't tighten the drawbar worth a damn.

                      Spindle tapers can transfer insane amounts of torque, and the key in R8 is not worth the metal its made out of as it will definitely shear if the spindle taper slips.
                      Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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