1. #1
    I bought this several years ago to increase the speed on my benchtop mill high enough to use single flute V-bit carbide engraving cutters for marking vernier wheel graduations on a job, when I'd finished the job I put it on a shelf and forgot about it.
    Last year I came across it again and for no really good reason decided to pull the chuck off - it came off but so did the taper it mounted to, scrapping the output shaft! Back on the shelf it went.
    Last week I noticed it again and stripped it to find that the centre shaft was mainly 10mm with a 6mm section for the floating top bearing and a ground "race" in the middle for the speed increaser ball drive to engage.
    Yesterday my latest order of 4 ER11 Collet chucks on 10mm shafts arrived and a plan sort of came together, this morning I spent an hour turning, grinding, polishing and reassembling with the result in the photos.


    I need to check runout with an indicator but it was imperceptible when running in at 200 to 2500 rpm input mounted in a 30mm ER40 collet in the lathe,

    - Nick
    Last edited by magicniner; 27-04-2014 at 06:32 PM.

  2. How did it get on ?

  3. #3
    It works really well, thanks Lee.
    It's nice to be able to push 1mm endmills through steel and aluminium at a manageable manual feedrate instead of having the mill in top gear with the motor screaming and still worry about breaking tools.
    Next time I strip it down I'll measure it all up and create a solid model, it ought to be an easier build and more durable than the geared speed increasers for which plans are available,

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