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Regrind R8 to 30 taper?

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  • Regrind R8 to 30 taper?

    OK, heres an odd question. Can a R8 taper be reground to BT30 taper? Seems like it should be possible. The major OD for each taper is the same, 1.25" and the taper is nearly the same with R8 being 8.25 degrees and 30 taper being 8 degrees 17' 50". The taper would have to be gound and then the nose shortened a tad to bring the nose to the right diameter. I figure the drive collar could clamp around the nose of the spindle.

    Question is would I still have the benefits of a standard 30 taper spindle since there is less metal in the lower end of the spindle where the R8 collet pulls up into?

    I dont think I will ever find a 30 taper spindle for my supermax so this just kind of popped into my head.

    This super max is a clone of the BP series II. How close do they usually copy another machine when it comes to things like the spindle?

  • #2
    A quick look at a R8 and 30 taper holder verifies the major diameter are near the same. I never would have guessed that from memory. It might work.

    A problem would be the reduced contact area of the 30 taper. The lower taper of the R8 is about 1-1/8" long. The 30 is close to 1-7/8" contact area. Quite a difference.


    • #3
      ISO 30 is 16 degrees 15 minutes 6 seconds or 8 degrees 7 minutes 33 seconds half angle.

      R8 is 16 degrees 51 minutes or 8 degrees 25 minutes 30 seconds half angle.

      ER series is 16 degrees dead or 8 degrees half angle.

      Shove a 40mm x 1.5 thread on the end and fit ER's to it

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


      • #4
        Thread the nose. Now that would be fun...

        What I want is better quick change. I use the tormach system now but it can pull out in a heavy cut.


        • #5

          It might not be impossible to come up with a #30 spindle for your machine, I know that Supermax built some CNC knee mills that used a #30 taper with a standard drawbar (not the BT style most common on tool changer machines). Supermax became a trade name sometime in the ‘80s, the parent company goes by Y.C.I., Yeong Chin Industries, and they actually imported a lot of knee mills before they adopted the Supermax name, these were called Exacto I believe, that name might jog someone’s memory, I think they were all painted a lighter tan color, they sort of stuck out.

          I hope this helps



          • #6
            Originally posted by macona
            Thread the nose. Now that would be fun...

            What I want is better quick change. I use the tormach system now but it can pull out in a heavy cut.
            Tormach huh?I was wondering about that,are you using collets directly or endmill holders?

            Also what counts as a "heavy" cut by you?Curious as I liked the looks of the Tormach system.
            I just need one more tool,just one!


            • #7
              I have gotten parts from YCI for the mill in the past and except for saddle way wipers everything has been rather reasonable. I know my machine came with 30 taper as an option. I had though of calling them and asking but I can only imaging how much they will want for one! I will call next week for the heck of it.

              heavy feed say with a 1/2" end mill it will pull out. I have made some modifications to my draw bar and it works a bit better now. I have the collet holders and the weldon style holder. All in all they are rather well made and it sure beats dealing with r8 collets.

              Little machine shop is selling a quick change kit based on the tormach tool system. From my experimentation in the same type of quick release I can saw they have no where near enough drawbar tension to keep the holder from slipping.


              • #8
                Sorry I cant see that working perhaps I am wrong.look you can buy a int 30 arbour FOR $20 wouldn't that be safer in the long run and quicker.Alistair
                Please excuse my typing as I have a form of parkinsons disease