Steel core belts

I bought Gates-branded GT2 belts from SDP/SI along w/ pulleys back when I upgraded my SO3 to 9mm belting, and bought extra for the XL upgrade — still holding up well (when Carbide 3D sent me steel core belts I put them on my SO3).

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GT3 belts are compatible with GT2 sprockets, but not GT2 pulleys?!

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SDP/SI doesn’t have many GT3 belts in stock. What length GT2 Z axis belt did you get?

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From that, I was probably mistaken. Sounds like GT3 generation belts work with GT2 generation sprockets/pulleys, and gen 3 pulleys don’t exist :upside_down_face:

It however didn’t seem like Gates offers other reinforcement outside of fiberglass, so don’t see much gain outside of quality and lifespan. Still would have the same/similar elongation characteristics; For me it be more worth it with steel or kevlar options.

I hadn’t realized that. Good to know as I def tighten mine to the max. May have been the problem.

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Gates GT3 belts are apparently specified for 6.6 times the working tension of their GT2 belts. Who knows what the specs are for the tested (generic Chinese?) Shapeoko GT2 belts?!

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Just wanted to let @Griff know that the cost has tripled for gt2 kevlar belts from the supplier in the Netherlands, at least regarding the price @DanStory paid for his in January compared to just last week when I ordered some…

I’ve noticed the same…
To avoid the $10 upcharge on orders under $30 with SDP/SI you need to buy 5 belts and the closest they offer are 516mm and 524mm. This puts the grand total, after shipping, at $43 for 5 belts and most of them aren’t even in stock. If I knew which (516mm or 524mm) to get I could order 2 or 3 along with several meters of 9mm to avoid the $10 upcharge…
Very frustrating trying to source a quality Z belt from a domestic supplier.

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The machine originally used 524 (or maybe it was 528?) belts, so the 524 should be okay. 516 will work as well, just won’t afford as much adjustment — they were out of both when I ordered, so still on the second set of belts I was sent.

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IMO buying them from Texas Belting rather than SDP/SI would be wise. Unlike SDP/SI, they don’t obfuscate Gates’ part numbers and apparently have more stock.

Assuming you’re talking about Gates’ belts, rather than Kevlar.

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As soon as I decipher the part numbers I’ll be ordering some GT3 from Texas Belting. Thanks @gmack.

The first group of three numbers is the total length of material in millimeters and the last group of two is the width. The 528-2MGT-06 belt shown in the posted cart should be right for the Z-Azis - right @WillAdams? The length of the 9mm belts (which will need to be cut) will be dependent on the Shapeoko size. I don’t know what’s right for them.

528 should be okay — the worst case scenario is you’d need to add some sort of filler to the static pulley area to take up the slack.

For the X and Y, just get more length than you need and cut it to length as needed:

  • SO3/XL Y-axis: ~800mm
  • XL X-axis/XXL: ~1200mm

That may be easier said than done. The longest I could find was 1164mm.

You should be able to find belts in arbitrary lengths — just specify the total length you want.

Are the gates belts currently available at sdp/si higher quality belts than the fiberglass reinforced belts that were being shipped with shapeokos back in Dec 2018/Jan 2019? I switched to steel cores and have had problems with them like @Griff.

That’s a good question. I don’t know. I suspect that belt sourcing is one of the things which has developed over time, and which is vulnerable to pricing concerns.

I’d like to think that the company which developed the profile and does on-going research would produce a better quality product, but nothing to specifically support that beyond my on-going good luck with the Gates-branded belts I bought just before upgrading my SO3 to an XL years ago.

Well, i just ordered a set.I have a generic/knock-off roll of gt2 and some random steel core ordered from Amazon left. Ill post some close up comparison pictures when the Gates belts arrive.

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Maybe @The_real_janderson and/or @AlexN (others) would be interested in repeating their excellent tests with Gates branded GT-2, GT-3, and Kevlar belts? The specs for the GT-3 belts seem quite promising!

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@gmack The info you posted on the gt3 belts and @WillAdams experience with gates branded belts is what prompted me to purchase some. As always, thanks for your valuable input!