Re: [CAD_CAM_EDM_DRO] Re: Bridgeport Z axis knee how to

Hi Scott,

When I cnc'd the knee, I installed a ballscrew for the Z axis and two
170lb gas springs to offset some of the static weight of the knee. My
mill was new, but there was still a very small amount of play in the
gears. To further reduce this, I fitted a .001" or .002" (can't
remember) shim under the horizontal bevel gear. This caused the gears
to mesh more tightly and will likely cause premature wear - but did
virtually eliminate backlash. I check the gears after 2000 hours of use
and they still look fine, still now appreciable backlash. Don't overdo
the shimming though, or you'll really destroy the gears (or a bearing)
quickly. All up, my Z axis backlash was under a 'thou and was still
under a 'thou last time I checked it.

Regarding belts, I would recommend the Gates GT2 design profile for
belts and pulleys - I have noticed a small amount of backlash in my HTD
belts and pulleys - even though they are correctly tensioned. It's just
a function of the HTD tooth profile. But in my case it's not enough of
an issue to warrant replacing them...

Cheers, Peter

Polaraligned wrote:

>I have the table currently off of my 9x42 and used a test indicator
>to measure the knee side to side play. Came up with .0003" with my
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