Wednesday, June 2, 2010

Toothed, Bead ,Chain Belting …oh MY !

Since our quest is to lower the cost and improve operation of our RepRaps I felt the need for an alternative belt to what’s currently being used.

Long ago on one of my parts quests I picked up some “Diamond Braided Rope” as a possible drive belt or maybe used in an emergency to fix a RepRap. My belief now is that it’s a very good replacement candidate. The numbers speak for them self. I recently ordered Tooth Belting @ $1.81 a foot, plus shipping, taxes etc. The Braided Rope I purchased cost only $1.00 for 10 feet of the stuff.

Further, this might be a superior product for RepRap as seen in the general specs.
¼” x 10'feet
Braided for Strength
100% polyester strands
Resists rot, mildew, oil, and gas
300lbs working capacity

On the minus side that Red & White is ugly and changes to a V type pulley system would need to be made. It’s made in China, so maybe a pure color is sold someplace.

One feature I really like is that the material is very RepRap like. Looking at the pic you can see that the manufacturer hot slices the material for packaging. This is very advantageous for us. Using a hot means we can melt the polyester to any part we might wish. If we wish a continuous belt I would just butt the two ends together and melt them. If looks or an added protection is needed, then put the seal inside some shrink tube and presto you have a dirt cheap continuous belt.

Another feature: This is round material and therefore makes it superior in looping compared to toothed belts.

Where to buy? I purchased these at Harbor Freight Tools Item number 96186. Also sure these are available at other locations.


  1. doesn't braided rope have a significant amount of stretch? wouldn't that mess with accurate timing?

  2. Hi

    I tried fishing wire for my timing belt substitution.

    The main problems were. slippage, stretch which caused slippage and the endless Z belt coming loose causing slippage which destroyed my print.

    In the end I gave up and bought some timing belt. After all it's not a consumable and once it has been purchased that's it.

    However good luck with your project and I wish you well.


    Stephen George

    Disclaimer: I sell T2.5, T5 the timing belt in the reprap forums. (

  3. when dealing with tolerances of fractions of a mm, will this be accurate enough to *never* ever slip?

  4. Hi,

    It would be really nice to drop the expensive belts, although the belt splitter already helps a lot with that.

    However, wouldn't a non-toothed belt be a big problem with slipping/synchronisation?
    V-belts are usually better than toothed ones for power transmission, but introduce completely uncontrollable slippage. The slippage is small but for a 3d printer with sub-mm resolution I expect it will be a big problem.

    To go back to Darwin, I can get steel 3mm ball-chain (rated at 6kg) for 240JPY ($US 2.59) per meter at the local hardware store.
    It is indeed more expensive than rope, but still less than proper belts.
    Plastic bead chain (commonly used for blinds) might be a cheaper similar alternative.

    Another option for the non screw-driven axes would be to use Nylon monofilament (or thin flexible steel wire, etc.) on a drum, making sure the coils do not overlap (and maybe compensating for parallax in software)


  5. This looks like a 'kernmantle' type cord, with a parallel stranded core and a woven exterior. I'd be concerned about a few things:
    - It'll stretch under load.
    - It'll creep over time
    - The woven mantle can slide independently of the core, to a small degree

    All three of these are going to increase backlash and could potentially introduce some extra slop as the cord stretches under initial accelleration and springs back into shape as the acceleration is removed. Maybe this will be below the level of the 0.1mm precision that the reprap was designed for, however.

    I've been looking at a polyurethane round belt called 'bond-a-band' as a drive belt for small machine tools, and it satisfies many of your plus-sides of the cord you found, with fewer of the minus sides I listed. It isn't as cheap as the cord, but it is structurally quite simplistic so I imagine there are cheap imported equivalents to be had.

  6. How elastic is it? That is the main issue with using rope or thread instead of belts or chains - usually rope results in some backlash, which severely reduces the precision of a printer.

    Another issue is that it may slip on the driver pulley easier than a belt or chain.

  7. I’m of the opinion that with the proper pulley design this would be work. I like ball-chain over toothed belts. This material has one major advantage over some of the tests listed above. It’s a thick material, therefore has more surface area over say the Nylon fishing wire or toothed belts.

    All said it needs to be researched.