Announcement

Collapse
No announcement yet.

Involute Gear Cutter

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Involute Gear Cutter

    HELLOW GUYS I WAS LOOKING FOR A INVOLUTE GEAR CUTTER 8 PITCH FOR 10 TOOTH PINION. MSC AND MCMASTER CARR SHOW ONLY CUTTERS GOING DOWN TO 12 TEETH.WHERE DO I LOOK NOW ?? ALSO WAS THINKING IS IT POSABLY TO GRIND A ENDMILL TO CUT GEAR TEETH THANK YOU AND HAVE A HAPPY THANGIVING TTG

    ------------------

  • #2
    Tom

    One of the other post John Stevenson mentions where his article on making specific form cutters is posted to do exactly this. Take a look at the other posts about gear cutting.

    Comment


    • #3
      I'd recommend doing a web search for "involute gear cutter". If you can find somebody who makes them, MSC claims they will order anything if you can supply a part number.

      As far as using a milling cutter, that depends on the speed and load. The harder you work the gear, the closer you want it to perfect.

      Comment


      • #4
        Tom, The reason you can't find a cutter below 12 teeth is that the involute profile that gears follow becomes undercut at about 16 teeth on a 20 degree pressure angle. It's more on 14.5 degree.
        As you get lower the undercutting gets more pronouced and weakens the teeth.
        Commercially they alter the tooth profiles on small pinons to reduce this. One way is to increase the diameter of the small pinion and reduce it's mating gear.
        Not technically correct, but a 10 tooth wheel isn't perfect anyway, you could use a 12 tooth cutter and relieve the side a bit by taking two more cuts , one each side.

        John S.
        .

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



        Comment


        • #5
          Try Ash Gear in the Detroit area. If you can't find it from them it probably isn't available.
          Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.

          Comment


          • #6
            ash gear and supply. http://www.ashgear.com
            Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.

            Comment


            • #7
              if u can vary engagement , a 12 t. cutter will work ok , if not it still may , or u can blue & file out the interference ......if used in slo speed applications , fudge factor opens up the possibilities.....ground lathe bit w/ flycutter works...u could rough it w/ horiz. mill slit/slot cutter of correct contour

              best wishes
              docn8as
              docn8as

              Comment


              • #8
                Tom,

                You didn't tell us if this is a gear to fit into an existing gear train or a new gear train entirely.

                If it is an existing train, you are stuck with the pressure angle of the mating gears. In that case, you can grind your own single-point flycutter bit using the fact that the radius of the involute curve at the pitch circle equals the sine of the pressure angle times the number of teeth divided by twice the diametral pitch. In this case it would be Sin(20*)x(10/(2*8)) = 0.214" if the pressure angle is 20* or 0.156 if it is 14.5* There are other dimensions to consider as well. See Ivan Law's "Gears and Gear Cutting"

                If the whole gear train is being cut from scratch, you might consider increasing the pressure angle to 30* to reduce the undercutting problem . . . or add additional gears to the train to get the ratio you need without using a 10-tooth wheel.

                Good luck.

                ------------------
                Rich Kuzmack

                Pi = 355/113 . . . to
                <85 parts per billion

                [This message has been edited by Indexer (edited 11-29-2002).]
                Rich Kuzmack

                Pi = 355/113 . . . to less
                than 85 parts per billion!

                Comment


                • #9
                  Thanks for all the good imfo.here is a little more about this pinion. it is a swing pinion in a portable 6000LB crane. it turns slow .ring gear is auto fly wheel type.pinion is 1.450dia. teeth are 1.800 long on the end of a shaft1.250dia.*9inch

                  Comment


                  • #10
                    <font face="Verdana, Arial" size="2">Originally posted by Tom GUINN:
                    Thanks for all the good imfo.here is a little more about this pinion. it is a swing pinion in a portable 6000LB crane. it turns slow .ring gear is auto fly wheel type.pinion is 1.450dia. teeth are 1.800 long on the end of a shaft1.250dia.*9inch</font>
                    In which case how about modifying the starter dog off the starter motor that drives this ring gear?

                    Ironically enought my large 18" band saw stripped a pinion tonight. I didn't even realise it was gear driven. I thought the drive shaft drove the wheel direct but inside the pulley there is a fibre wheel driving a gear on the inside of the drive wheel.
                    This is a 4Mod pinion with 12 teeth, about 6DP.
                    HPC at Chesterfield here in the UK have a Delrin one on stock for 7.50 UKP, about $10.00 and have promised me one for 10 am Monday.
                    Out of interest I looked up an 8 pitch 10 tooth pinon and they list one for 14.50 UKP, about $23 so it maight pay to have a look stateside for a gear as they could be cheaper than a cutter.

                    John S.




                    [This message has been edited by John Stevenson (edited 11-29-2002).]
                    .

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



                    Comment

                    Working...
                    X