Where could I get toothed belts and drive gears for a home built printer? My bed is 21 inches long so I’d need perhaps 3 42 inch belts. Are they ever sold not as loops, but by the foot? What do people mostly use?
I used MXL simply because it was easier to find at the time than GT2 here in the states. Not the case anymore, but I’ve ordered 15ft continuous sections of the stuff from McMaster-Carr without problem. I had to get pulleys that were almost 5mm ID, and drill them out to fit my motor shafts. I’ve since moved to GT2, but I don’t know of any place that sells GT2 in continuous length like that…
Gt2 is the most common theses days, in addition to mcmaster car, http://sdp-si.com or robotdigg http://www.aliexpress.com/store/228043
Robotdigg sell 10m gt2 6mm for 23 bucks
I’m using a 1500-3M-15 HTD belt (which is the profile that the GT belts are based on) for my 430mm long x-axis. It came as a continuous loop, but industry-oriented sellers also offer open-ended belt by the millimeter (or foot/inch if you’re buying imperialistic belt).
The pulleys are much more important that the exact belt type, though. You’ll find many “GT2” pulleys offered on eBay that have a tooth profile that looks nothing like a GT profile, which will consequently not grip the teeth properly and likely damage it.
@Thomas_Sanladerer
@Tim_Rastall What is the best belt profile out there now for use on 3d printers ? What factors in to the choice of belt GT2 vs GT3 vs … ?
@William_Frick good question, if you look at what the likes of Ultimaker use, it’s gt2.
Any of the GT or HTD profiles are fine as long as you try to get one with a 3mm or finer pitch. While I don’t think T5 belt was really as bad as its reputation, I’d recommend against using it on a new bot when you can get a more modern profile instead.
@Whosa_whatsis prefers Syncromesh, while @Tim_Rastall seems to be a fan of Spectra line. Both of which are valid options in my option.
@Thomas_Sanladerer Aside from cost why line over belt ? As I put more thought into a corexy build it would be worth knowing
@William_Frick because toothed belts always have distinct teeth (duh), they will always introduce a marginal amount of non-continous movement into the linear drive - for example when the teeth ride over an unprofiled idler. This is sometimes visible as distinct ripples on otherwise perfectly straight walls. Spectra line is almost perfectly even, but requires a one-time calibration.
But price really is the biggest factor: i paid over 70€ for my X and Y belts, pulleys and idlers, all of which would have cost less than 10€ when done with Spectra.
@Thomas_Sanladerer Thank you ! These dumb questiions of mine yield some surprising answers and the odd 'why didn’t I think of that ’ moment.
And Robodig sells 50 meters of 70lb test braided line for $3.80 -
I do like the spectra but it’s a bugger to adjust on my machine and I might convert to belts some day. I suspect 9mm htd would be my choice then. Just to add another thing to the mix, @Shauki is using packaging strap successfully as a toothless belt.
Oh, and just even though spectra leaves no atrifacts like a toothed belt, is does allow you to see the effects of overpowering steppers etc, I noticed this today after printing with some particularly shiny pla.
I prefer T2,5 over GT2. Its not about tooth profile but about belt construction. GT2 and similar constructed belts are like bungie. I’m still waiting on some scientific proof that some profiles are better than others, until then the belt construction is all what’s its all about.
@Matej_Rozman that depends - belts always have some sort of reinforcement integrated, with the main options being steel wire or braided glass fiber. T belts usually use steel wire, while HTD and GT are more popular with glass fibers. Both tooth families are available with both types of reinforcement, though, with glass fiber being more flexible and steel wire being less elastic and stronger.
Yes @Thomas_Sanladerer I understand all this, but I do not belive both tooth families are available with both types of reinforcements. Although GT2 can be found (really rarely) with steel reinforcements, I was told by manufacturer when I wanted to order this exact combination, that there is no souch technical information for this exact combo (GT2/polyester w/steel wire). So until they start to make it I will stick to T2,5. Dont get me wrong, GT2 is probably better, but its just not strong(stiff) enough to carry all this weight we put on our machines and run it under high acceleration&speeds. Its probably good (overkill) enough for scanners, photocopiers, ect.
@Matej_Rozman agreed. Even though I have two 15mm wide belts driving my Y-carriage with two heated beds, I still had to reduce acceleration down to a shameful amount because I was getting horrible resonance issues with fast subsequent moves.
With newer printer designs, the flaws introduced by softer belts are somewhat mitigated - stationary beds and bowden (or even direct-drive 1.75mm) extruders are reducing the moving mass and allow the softer, but lash-reduced belts to get comparable results to T belts and heavier axis.
Just out of interest, what is it that makes GT belts more prone to stretching? I might hazard a guess that they are shallower, meaning they bend more readily and hence can accommodate for fewer strength members…
Duh, don’t worry, didn’t see the comments about steel/poly etc.