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  • broaching

    I am broaching 5mm keyways in steel gears. What is the best/correct lubricant? The shaft diameter is 22mm and I have reamed the holes, so everthing is straight and tight. My question is more about getting the greatest number of keyways before having the broach sharpened.

  • #2
    Oil-any kind motor,cutting,gear,etc,etc.

    a little lube on the teeth goes all long way,also we have a Dumont set at work that is over 20 years old and have yet to get dull,usually breakage is the culprit more than being dull.
    I just need one more tool,just one!


    • #3
      We broach .125 keyway in 303 cast impellar using off the shelf tools and get 500 or so before tool wears to much to use. I like tap magic or dark threading oil. The worse it smells the better.


      • #4
        A couple of points often missed when broaching are let the pressure off at regular intervals to allow the broach to spring back upright as often the ram face if not dead square will try to push it off vertical.
        Second is lube the broach ALL over , not just the teeth to stop it galling in the guide bush. It also stops the shimms from being pushed down thru the bush as well.

        A brilliant site for gettng broaching information is

        John S.

        [This message has been edited by John Stevenson (edited 11-04-2003).]

        Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.