X Carriage Belt Tensioner

I am having issues installing the belt clamp on the left side of this [url=http://www.thingiverse.com/thing:12481 x carriage[/url]. I am using a M3x22mm bolt as instructed, but it doesn't seem long enough. Does anyone have any good suggestions?

Yeah I hate the while x-axis belt tensioner thing most of these carriages seem to use - the bolt and nut arrangement etc. I find it isn't that hard to take up a bit of slack in the belt and do it without the tensioner anyway. I'd like to see a good design with the tensioner in the idler end.
For the one you are describing the bolt needs to be more like 35mm long and ideally you need to make a cap for the end of the thread where it presses on the belt to prevent it punching through.

Edited 1 time(s). Last edit at 10/05/2012 10:17PM by Wired1.

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Richmond, New Zealand
Thingiverse ~ YouTube

I did this: [www.thingiverse.com] for a completely different purpose, but it might be used for tensioning the belt on x-axis of a Prusa.

Great minds think alike I did something similar on this carriage I designed recently [www.thingiverse.com] I wanted to only have the machine screws on one side and I was worried about the belt slipping out. It works amazingly well and gets the belt in closer to the correct line. The carriage has recessed for the belt teeth so the screws are only holding the belt in position, not clamping it.
I was also wondering about putting a stand-alone belt tensioner in the middle of the belt as the middle never reaches the pulleys at either end.

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Richmond, New Zealand
Thingiverse ~ YouTube

Sorry for the late replay, but everyone in my house got sick over the weekend. I’ll probably just go to Lowes or Home Depot and see if I can get some longer screws. Once my printer is up and running I’ll probably look at some other options. Thanks for the advice guys, I appreciate the help.

I finally got some free time to work on my 3D printer. I ended up ordering M3x35 bolts, but I just noticed that the belt is wider than the notch that the belt goes through. Is that what Wired1 was talking about when he said "make a cap for the end of the thread where it presses on the belt to prevent it punching through?"

Do I widen it or do I bend the belt so that it fit as is?

No I was talking about the bolt that pushes on the belt - probably misunderstood what you were talking about. The standard belt arrangement for a lot of x-carriages has one side where the belt is held between the carriage and the "toothed" clamp, and the other side where the belt passes through a slipping clamp on top and is held in a toothed clamp below and the tensioning is done with another machine screw at right angles coming through the carriage and pushing directly on the belt to tighten it up. This is where I was suggesting you add a cap for the pushing screw to stop it punching through the belt. Hard to describe sorry, I must find a photo

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Richmond, New Zealand
Thingiverse ~ YouTube