Hi
I was ordering some spares and saw you can go to 9mm belts by changing the pulley.
What benefit would this give a s3?
Also can this be done on the newer z plate with an open ended belt?
Best
Luke
9mm belt benefits — half again the tensile strength and grip — belts stretch less, less likely to break, and it’s more difficult for the machine to skip a tooth — there may be an improvement in cut quality — that was reported for the SO2 when this upgrade was first tried. Also, aesthetics — they look better and are more in proportion with the balance of the machine.
It doesn’t seem to be possible to do this for the Z-axis — it’s awful tight in there, and endless loop belts don’t seem to be available in 9mm width — also, the forces are sufficiently smaller that it ought not to be necessary. A better upgrade would be to switch over to an Acme Z-axis, but the belts work surprisingly well, so that no one seems to’ve found that necessary.
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Sounds like its worth an upgrade and I will keep the old belts as spare.
Never heard of the acme upgrade.
Thanks for cleaning that up.
As I noted, no one has done it for the SO3.
Some links from the wiki if you’re curious:
- http://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#9mm_wide_belts_for_SO3_X-_and_Y-axes
- http://www.shapeoko.com/wiki/index.php/ACME_Z-axis — this is for the SO2, and the comparison is against the M8 threaded rod which was used on it — the advantage of the belt drive is it’s even faster. The disadvantage is belt stretch if seen at these loads. A notable advantage is that belt drive all around makes the machine resistant to damage from crashing — the belts will skip teeth rather than allowing the machine to bend or break parts as a threaded rod or Acme screw will do (until it hits the torque limit of the motors and they begin to skip).
I didn’t realise it was a standard upgrade in the Jan upgrade - amount of things I’ve added… live and learn 
I have ordered three and will do that upgrade at some point…
You’ll need 3 belts (I’d suggest getting enough to have a full spare set) and 4 pulleys (EDIT: assuming you go ahead and buy one more, just in case as a spare) — belt anchors and idlers are already sized appropriately.
Were does the additional pulley go?
Sorry, miscounted. was remembering four motors, and somehow conflated the Z into the count as well — 3 pulleys, plus one spare. Edited.
I got my new 9mm belts today and fitted them - they look pretty decent - time will tell if they are a big improvement - the good thing is I now have 1 spare 9mm belt and 3 6mm belts.