I've found that the x idler pulley tends to ride up against the top y carriage wood. This creates noise and other problems.

There are bearing and belt holders and all manner of x axis improvements but I've yet to see one to fix this. The idler rides up due to the belt being pulled up to mesh with the x carriage belt teeth.

My solution is to customise the teethes position to match the belts natural path.

This is based off of Joakim's x follower openSCAD file so it can match its customization for a perfect x axis sliding action, print his and mine as they replace 2 separate parts.

All comments and suggestions welcomed, heck just comment

I like many printed up belt tentioners from thingverse. Most worked fine but after a while they warped and got loose. I also had issues with them hitting the heads when they did get loose and wreck 12 hour print jobs.
These clips I designed use the existing belt tension design and add some height to the sides.

This thing reduces vibration of the Y-axis belt on my Prusa Mendel. Parametric SCAD file. Defaults are 8mm rod, 6mm ball bearing.

A standard motor pulley for T2.5 belts. 16 teeth, so works as a drop-in replacement for a 8-tooth T5 pulley.

Some say that this part is a vitamin, but I didn't believe them.

I printed this with 0.35 nozzle, 0.20 layers, 0.36 tracks and 10 secs per layer, with PLA.

A printable belt tensioner, with a fitting for a M3 bolt and nut

This is the T5 pully belt gear for 4mm shaft steppers. Please let me know how it fits your motors. I've only printed it on my prusa which may vary.

Juan Miguel García Haro
Pablo Marín Plaza

Universidad Carlos III de Madrid
Departamento de sistemas y automática
Máster de Robótica Industrial

In order to improve the tool OOML (http://iearobotics.com/oomlwiki/doku.php), we built this motorboat from libraries OOML whose they are written in C++. The MOTORBOAT is developed from zero and it is not based on any model previously developed by other programmers. We only use the code .SCAD of a propeller, to build our propeller (http://www.thingiverse.com/thing:8688 ).

Here is a video of the MOTORBOAT (in spanish):
Pulleys:
youtu.be/dUqTDfMHCe8
Gears:
youtu.be/C185LOEoUI0

Test in water:
youtu.be/0xFm2y-97Ts

All code is written by QtCreator program, this program can work in parallel with OpenScan program order to view the process of developing of the different parts.

The MOTORBOAT was divided into three parts. The first part is the physical structure of the MOTORBOAT and is intended to float on water. The second part is based on mechanical system pulleys and belt and is intended to transmit power to the propeller. The third part is based on other mechanical system gears and also aims to transmit power to the propeller.

The gear code has been parameterized to function as a new library OOML.

To supply power to the mechanical system we used a motor DC that is activated or deactivated through a switch.

Finally, the attached codes are. "STL" files. It also includes a ".RAR" file which includes all the generated files (."CPP", ."SCAD", ."STL").

Additional things.
To assemble the physical structure of the motorboat, we need:
Waterproof adhesive.
2 flange to hold the motor.
To assemble the mechanical system based on pulleys and belts, we need:
2 M3x10mm screws.
10 M3 washer.
2 M3 nuts.
1 square section belt 80Øx2.2mm.
To assemble the mechanical system based on gears, we need:
2 M3x10mm screws.
2 M3x20mm screws.
2 M3 nuts.
14 M3 washer.

This moon rover is pretty simple; the real point is the treads. The idea of turning my Stretchy Bracelet into tank tracks is thanks to BenRockhold. Turns out it works really well: if you push this around on a slightly grippy surface like carpet, the tracks roll easily.

In fact, the track keys into the wheels so well, this could probably be used as a timing belt or chain.

This is sort of an experimental idea to add to the fundamentals of the reprap project. It's a 3d printable replacement for existing recycling T5 timing belts used on repraps.
This belt should work with existing timing belt gears, it has a 2mm apex to trough height. It should also allow you to scale up repraps by printing additional sections of the belt and attaching them, and getting longer rods. It's also basically an internal-load modular rack and pinion system

the modular pieces now screw together with a regular metric reprap nut and bolt. the threads fit great with this pulley: thingiverse.com/thing:7218
I also didn't realize it but its a little bit like this thing: thingiverse.com/thing:8938
I just need to adapt a bracket to catch the belt system, and then it could probably work with existing hardware, and software.

Reprap discussion: forums.reprap.org/read.php?2,110697

If you replace your Y axis belt clamp with this it will provide a place for the limit switch to touch.

The shaft couplings crash into my X axis hardware on my Emaker Huxley; these are an attempt to allow full travel. They are smaller OD than the stock ones.
After installing them, I don't think they actually give you any more travel; Oh, well.

The goal of this creation is to place the ToM APB (Automated Build Platform) belt under high tension, so it acts much like a solid plate surface (emulating the HBP (Heated Build Platform) surface) while retaining the ejection capabilities of the APB.

This is a lever arm that stretches out your APB belt. Under high tension, the belt resists flexing up at sides due to warping stresses during cooling and sits flat on the heating board before printing. The arm attaches to the sides of the roller bar, and friction is kept to a minimum by bearings at the point of contact.

The lever arm tension is set by manipulating a screw.
This bolts onto the stock APB, requiring only two bearings and two short m3 screws to be purchased. Misc M3 screws will allow this to be bolted onto the ABP. However, proper-length countersunk head 10mm to 15mm M3 screws should be used for the tension-setting screws in order to avoid their sticking out and running into the z-stage bars during homing and printing.

I recommend using a sturdy belt to handle high tension (such as Tunell's Steel Conveyor Belt for ABP. thingiverse.com/thing:9127).

Using this tensioner and a kapton-covered steel APB belt, I have been able to achieve quality near that of the Kapton-covered Aluminum HBP while preserving the ability to queue up multiple parts and remotely print. It's not perfect, but I'd say it's pretty darn good.

This thing has been updated, use the version 1.1 files; the 1.0 files have just been left for reference.
I designed this so that I could more easily use a Prusa-style belt setup while using the original 624 bearings on my Sells Mendel x-carriage.
PLA bushings just seem to have too much friction to me, and linear bearings can't be put on or taken off the X-axis without removing the smooth bars from the end brackets. (Not to mention the extra expense just to try that out).
By making the space for a tool head or hot end to fit through rounder, instead of the old long-narrow shape (on left for comparison), this allows you to mount a tool at either 90 degree angle, like the Prusa x-carriage.

I also put holes on the side to mount a 40mm or 32mm PC north-bridge fan to cool any plastic extruder filament drive.
The bottom part has now been updated so there should be enough room to fit a standard mendel hot-end in there at the 30 degrees angle that greg's hinged extruder mounts it. In my case I simply took the original lower section of my mendel x-carriage, snapped off the part that used to support belt clamp bolts, and cut away some material from the bottom.

My models were quickly based on Idaholion's solidworks models of Mendel parts (picture of original for comparison), so I had to rotate the STL files in blender after exporting them (you will find the STEP files are at a silly 90deg orientation.
I also noticed when I went to upload the updated files that I had previously posted the wrong .blend file from a different thing, derp. I can't believe the 16 people who downloaded it by then didn't tell me though :P

Don't get caught playing pocket pool while trying to find your breath tabs in your pocket. Just put them on your belt for really easy access.

I'm not sure how well everyone's clamps for holding the X belt to the X carriage have held up, but mine slowly but surely degraded to the point it wouldn't hold the belt anymore without loosening up significantly about 45 mins into a print. Yeah, I could have printed spares, but it was even warping the x carriage itself :(

So, for those of you who are still rocking the old school x carriage, here is an alternate x belt holder that should work fine or at least hold you over until you can print some newer parts.

I've been printing with it for about 10-15 hours and it's still going strong so you shouldn't have any issues with it.

I bought this radio on Ebay...............no belt clip :=(
I've been waiting to make this one for about 6 months now.

Tighten your Ultimaker belts
Parametric Design
Slim, fits in small space of Y belts
Adjustable tightening (via cable tie)
I have printed and fitted 4 on my machine today

After having backlash problems on my RepRap Mendel X-axis and getting sick of the awkward round-4-corners belt path, I decided to give it a re-design, in the hope of shortening the belt to take up some slack while simplifying the construction.

These brackets make the belt-path compatible with carriages intended for Prusa Mendel. I have included an adapter bracket that allows it to still be used with the original Mendel X-Carriage when necessary, however the idler bearing and pulley need to be spaced quite far out from the plastic parts in order to keep the belt parallel to the X-axis, with a full nut and a washer or two in the case of the bearing.
I hope someone will design something like the OpenX Carriage (http://www.thingiverse.com/thing:6278) but compatible with this, so that a 624-bearing-based carriage can be used with the Prusa-style belt-path, that is if I don't design one first.

I have also included an optional second idler bearing bracket to go directly next to the motor bracket, so that the belt turns slightly less of a sharp angle as it goes round the pulley, hopefully reducing belt wear, though I really don't think it's necessary.
The big circular holes in the motor & idler2 brackets are there to allow ventilation around the X-motor, so that PLA parts don't heat up too much. (I wanted test parts to be biodegradeable in case I messed up)

N.B. I have updated the files for the main brackets at either end as I found a couple of weaknesses in my first prototypes where I cut away excess corner material too liberally and found that the slots for m3 captive nuts shrank more than I thought they would, making it difficult to fit them. They should also be easier to print now.

a belt tensioner which mounts the pully with two 624 bearings.

One of the things I've been trying to do is print a pulley with a captive nyloc nut. However, the pulleys in PrusaJr's and Greg Frost's github pages, and the ones on thingiverse, all have some problems. Mostly it's that they are not parametric, or not openscad, or just stl, or rely on other files (Prusa's and Greg's) for some reason. So, as a way to get into learning OpenSCAD, I took Giles Bathgate's openscad copy thingiverse.com/thing:3104 of nophead's original thingiverse.com/thing:2079, and the latest one from Prusa's github github.com/prusajr/PrusaMendel mashed them up and tweaked extensively with the following:

• fully parametric, allows any size of pulley base, length of pulley teeth, number of teeth (see note below), number of captive nuts, size of captive nuts and a few other things besides (constants are at the beginning, currently, rather than using configuration.scad)
• new parameters for:
- nut trap shape - allows hex or square nuts to be accommodated
- nut depth - can be edited for different nut types ie nyloc
- pulley base height - can be set to 0 for no pulley base
- pulley base diameter
- pulley teeth height
- number of captive nuts
- angle between captive nuts
• changing motor shaft size doesn't change the shaft cylinder outer dimension (weird mistake?)
• nut trap now parametised with nut size, and is consistent with opening (sides are smooth)
• can have a belt retainer on the open end of the pulley, made with a 45º ramp, to keep wandering belts on the pulley (not tested, can be turned off)
• grub screw hole altered for better printing
• no other file/library dependencies (I thought this was useful as this part often get reprinted on its own)

Update
• parameters for different tooth shape (T5 and XL specified)
• option for T5 or XL pulleys; amend tooth profile parameters and uncomment relevant part for correct tooth spacing
• space between shaft and captive nut is adjustable (triffid_hunter)
• belt retainer height is adjustable (triffid_hunter)

The scad files can be used to create a wide variety of pulleys and toothed idler sprockets, I've made a few different STLs to show, but in the end it's far better to download the scad file and make your own.

Description of included three scad files:
"pulley-T5-8_old_tooth.scad": does NOT have parametric number of teeth, it is fixed at 8 teeth. Everything else is still parametric. The teeth are the same size and spacing as the Prusa/Giles Bathgate/nophead version, which has generally proven reliable.

"pulley-T5-N_old_tooth.scad": you can specify how many teeth you want, however choosing 8 teeth creates a pulley that is slightly smaller (about 0.7mm) in diameter than the Prusa version. The tooth profile is still the same as the original tooth profile from the nophead version.

"pulley-T5-XL-N_tooth.scad": is fully parametric, and uses a tooth profile that is defined by parameters, which allows for T5 or XL shaped-teeth. The tooth shape is subtracted from the pulley, unlike the original version, which is additive. I have included a couple of files for comparison, called "T5-tooth-comparison" scad and stl. The basic difference is that the original version has longer tooth spurs, but the angle of the tooth ramp is incorrect. You can adjust .scad file for deeper teeth, but if there is too much clearance you will get lash from the pulley. The attached STL files are generally sized with a small amount of tolerance, rather than being exact fit. "rtnr" means the pulley has a belt retainer on the end. All pulleys have a 3mm hole for an M3 grub screw, and a slot for a M3 nyloc captive nut. The wall outside of the nyloc nut might be a bit thin for a lot of pressure on the grub screw on the 8-tooth versions.

Regarding tooth spacing: the relationship between the outside diameter of the pulley teeth and the number of teeth is not linear. I took the data for pulley teeth outside diameter from cmtco.com/catalog/tp_mt.html#T5 and sdp-si.com/D265/HTML/D265T016.html put it in Excel and graphed the difference of pulley OD over number of teeth. After a few attempts at manually extrapolating the formula from the curve, I used the trial version of CurveExpert Basic from curveexpert.net/download/ which quickly deduced a formula. This is all shown in the attached excel file. I slightly simplified the formula, added it to the scad file, adjusted the tooth placement and it seems to generate accurately sized pulleys. But the size of the 8-tooth pulley is extrapolated from the end of the curve, and I have nothing to check its diameter is accurate, as 8-tooth pulleys aren't commercially available as it bends T5 belting beyond it's specification. I did the same for XL belt. I can add more variations if there is any interest, eg T2.5, T10, MXL, 40DP, L.
HTD and GT2 belts have rounded teeth, so will require a different method of creating the tooth profile.

Any observations, comments and/or suggestion for additions or further improvement gratefully received.

Ancestry of this object goes back to the first parametric file set for the Mendel, and in particular the Z pulley.

OK if we lived in a perfect world, this thing shoudn't be needed at all. Its intended purpose is to deal with the consequences of the flexing of the motor mounts related to belt tension, above all on the Simplified Prusa Mendel's X axis.

Because of the flexion of the mounts, we get a lack of parallelism of the axes, and the belt wanders on the pulley and gets grossly out of alignment with the carriage.

But why are the motors mounts flexing?

Because plastic-saving design has got the pieces quite thin. Actually excessively thin for their intended function.

So all of this could be easily solved by putting back plastic where it is structurally needed! (and we'll save quite some time and zip ties). Designers, wake up! You have gone too far with some reductions in plastic! We need significantly stiffer mounts for the Y and X motors! (I'll try to help with design, but this will take some time).

Checking old files: Selis Mendel's massive Y bracket was 17.5 mm thick!

So on the interim, to help the belt keep straight, we have this cap (and crummy zip ties and...)

Same design as chrille but modifies to use 6-32 nuts and bolts.

Update: Added belt attachment with teeth for the other end of the y-belt.

the OpenX carriage is incompatible with the Prusa design because the belt runs differently. I created these adapters to hopefully work with the prusa belt.

!!! I don't have a prusa, yet, to test with, so this is just an idea for now. If you want to print and try, go right ahead and please give feedback!

I found it a bit challenging to get the Y-axis belt tension just right by using the belt clamps, so I made this Y-belt tensioner in SketchUp. It allows for more accurate tensioning of the belt using a M3 bolt and captive nut. The design is based on the belt tensioning system used in GregFrost's LM8UU X-Carriage (http://www.thingiverse.com/thing:9869).

The holes have the same spacing as the original belt clamps, so you should be able to simply replace the existing clamps without drilling new holes.

The tensioning bolt can be reached with an allen key even with the build plate mounted on top.

Sorry for the SketchUp design. I haven't taken the plunge into parametric modelling yet...

I want to build pulley system to drive Prusa Mendel Z-axis using only one dual shaft motor .
I was looking for XL pulley for my Prusa Mendel Z drive.
The only one I found is 10T XL at thingiverse.com/thing:7454
So I build larger XL pulley about the size of NEMA 17 motor

I use SPD/SI's Part Number:A 6Z 3-27SF03708 as my size reference.
sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=41873&GroupID=218

I also change the bore size from 1/4" to 5mm and using two M3 nut in the hub

Belt Width 0.375"
Bore Size 5mm
Flange Configuration 1 Flange / With Hub
Pitch Diameter 1.719"
Outside Diameter1.700"
Overall Length 0.813"

After seeing the Ultimaker Belt Tensioner by psync (http://www.thingiverse.com/thing:10034), I decided to model my own that didn't need a screw. But of course there's also Roboteer's Paperclip belt tensioner (http://www.thingiverse.com/thing:4535)

Note: It's been mentioned in the comments that there isn't enough space between the new style Ultimaker slider blocks and the belts. Which causes the tensioner to hit the blocks.

This is an upgrade/mod for Ultimaker or really any belt-driven device.

I had some slack belts on my Ultimaker, and I was inspired by this parametric buckle thingiverse.com/thing:9633 to come up with a printable solution.

My first version was closed and similar to the belt buckle, but then I realized the difficulty in mounting it to the belt since it would have involved attaching the screw under tension. A quick Dremelling added a gap that I used to then slide the affixed device over the belt (see photos).

If you are missing steps in the X or Y on your Prusa, it could be because the belt is getting caught between the fender washer and the bearing. The best solution is a belt guide such as GregFrost's (http://www.thingiverse.com/thing:8574), but those require you to disassemble your printer before you can install them.

These belt bushings aren't quite as good, but the simply slip over the rod, so you can install them just by loosening a couple nuts. They fill the gap between the bearing and the washer, and are a bit slipperier, so they should help reduce binding.

Inspired by a design by Wilson (http://www.thingiverse.com/wilson).

A parametric buckle for connecting and tensioning two flat lines. The knot shown in the picture slips in one direction only - if you apply tension to the inner of the two line ends. If the tension is equal or larger on the outer line, it is self-locking.

Not safe for any purpose, but I tensioned mine (10mm bars, solid print) up to some 5kN.

Parameters:
- Line width, bar diameter, overall length, tolerance
- Offset from center (working with thick lines requires more spacing in the center)

Feel free to flattr this if it makes loose ends meet for you.