Belt installation and tension

So I saw the videos about tips and tricks when it comes to the belt, like using shrink tubing so keep it from slipping etc.

But, I’ve also read on the forum that the belts will loosen up the first couple of days. So, my question is; Should I even care about shrink tubes and all that now when assembling a new x-carve, since it will loosen up anyhow? Won’t I have to essentially take it off and shrink tube it again after the belt has reached the limit of how much it can stretch?

Or will that not be more than what you can adjust with the belt clip?


The belt will stretch a small amount, but if you leave the Max amount of travel left on the screw adjustment you can tighten the belt back up.


there is a difference between belt stretching and belt slipping.

Stretching is just that. the belt gains a very slight amount from being under tension. This does occur with new materials but is very limited and easy to account for as the prior post has stated.

Slipping, the action of the end of the belt where the teeth mesh to create an anchor point is what I used the shrink tube to prevent. It keeps the teeth from jumping over one another causing the belt to lose tension.

Another solution to keep belts from slipping is to route the belt as shown below:

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that’s the way I route it. But I still fasten them.

I’ve run them this way for months with no other fastening.

Thanks all! I ended up routing it as they show in the instructions, but with added shrink tubing. It’s quite tight now, but with the tension lost the first days I think it’ll work.

Thank you all for quick answers!

I heard if you do that, an angel loses its wings. Just sayin.

My wings are still securely attached. …just sayin… :innocent:

Has anyone experienced differences in ambient temperatures having effects on the belts? So far it’s been pretty cold (<40 Fahrenheit) consistently while I’ve been milling. Curious as to what will happen in the next few weeks as it warms up.

My garage is 40 degrees unless I am in there all day and put the heat on and then it can get toasty - 70 degrees or higher. I did not notice any difference in belt tension at either temp. But I run my belts pretty tight. Twanging tight.

I have heard of people having problems with the Delrin nut shrinking in the cold. That can cause the Z axis to bind and lose steps.

That’s good to hear. I had my belts super tight (i think too much) at the start but let it sit for a day or so and they softened up and since then motoring has been peachy clean. Now if i can just get one of the stinkin offset nuts to stick in place so it doesn’t drop the vwheel I’ll be golden.

order yourself some eccentric spacers, slightly longer bolts and lock nuts. I’ve slowly replaced all mine on two machines. It makes tightening a joy and they rarely move afterwards. Plus, its good to begin to collect spare parts.

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My shop here in the hinterlands of northern Minnesota is heated via a wood stove when I am out there and it gets quite chilly (~25 deg F or colder.) if I dont light a fire every day or two. I have experienced no issues with the x carve. My shop laptop however definitely does not care for the cold, especially the battery whether plugged in or not.

FYI - I am headed to Mille Lacs for the DU Fishing for Ducks competition on the 19th. Hopefully will be using handmade x-carve lures!

Mille Lacs = The dead sea lol

I’ve thought so as well… but THIS year, appears to be different. This event is more about drinking and winning gear anyway. I have no idea where people are going to park. The ice is not good enough for 1,500 trucks to park on it.