Shapeoko Belt Drive

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crash831
Posts: 16
Joined: Wed Jan 21, 2015 5:46 pm

Shapeoko Belt Drive

Post by crash831 » Wed Jan 21, 2015 6:04 pm

Hello,

I've preordered the Shapeoko 3 however there is one thing causing some hesitation. The belt system seems a bit flimsy and inaccurate to me. Could one of you shapeoko owners tell me if you've had any problems with it? All else looks strong and beefy. It just seems like the belt would stretch and give or something and I dont want to take chances on another flimsy machine. After owning a Zen Toolworks PVC frame CNC, I've become quite paranoid about any flex in a machine. On my current one the bit chatters and cuts stuff its not supposed to with mere 1.5 mm cuts at 800 mm per minute.

Thanks in advance!

WillAdams
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Re: Shapeoko Belt Drive

Post by WillAdams » Wed Jan 21, 2015 6:09 pm

The SO1 used MXL timing belts quite successfully. The SO2 and 3 both use GT2 belts which are intended for power transmission and a significant improvement.

On the Parts page, we have tried to collect brief notes about the components of the machine: http://www.shapeoko.com/wiki/index.php/Parts

with sub-pages for further details. Belts and Pulleys has such a page: http://www.shapeoko.com/wiki/index.php/ ... nd_Pulleys which has a section on References which will allow you to check the characteristics of the belts.
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
Nomad 883 Pro #596 (bamboo)

Hans
Posts: 290
Joined: Tue Dec 25, 2012 5:19 am
Location: Connecticut, USA

Re: Shapeoko Belt Drive

Post by Hans » Wed Jan 21, 2015 7:11 pm

The belt system is a lot stiffer than I originally thought. Part of what I turned out to be wrong about was how big the cutting forces actually are. Using a machining calculator, you can get a pretty good estimate of how much force a cut requires. A 1.5 mm wide, .75 mm deep slot in Delrin at 800 mm/min takes about .4 pounds, for example. Based on Gates's numbers for belt stretch at the center of the work area, that's less than .02 mm of give and IME results in good surface finish. As a rule of thumb I use up to 1 pound for finishing and up to 5 pounds for roughing, though it's possible to power through cutting boards at 10+ pounds without the machine complaining.
Shapeoko #1,123

cvoinescu
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Re: Shapeoko Belt Drive

Post by cvoinescu » Wed Jan 21, 2015 8:54 pm

First time I got my hands on a belt, I was very surprised. It looks like rubber, bends like rubber, so you expect it to stretch like rubber -- but when you try, it feels like reinforced concrete. Very strange sensation.

Anyway, I'm very happy with belt-driven mechanisms. It's by far the easiest and least expensive way of doing it, and the performance is very good.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

crash831
Posts: 16
Joined: Wed Jan 21, 2015 5:46 pm

Re: Shapeoko Belt Drive

Post by crash831 » Sat Jan 24, 2015 2:46 pm

Thank you all for your time and input In answering the question. It has really removed any doubt in my mind and I'm quite excited to get my hands on "The Big 3"

Thanks again,
Crash

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