A half successful attempt to run my G36 at 38,1cm/s using a 3D printed sleeve, which slides onto the capstan to thicken it to twice its original size.
The result is surprisingly good for something 3D printed, but nowhere near acceptable. Also, the capstan shaft would have to be moved back by the thickness of this adapter, so the contact point of the capstan and the pinch roller would be at the same place as with the thinner shaft.

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