and why not make the switch to the lawsy carriages? your printer will run so much smoother once you do - it is well worth the time it takes to make the change.

there was so much of an improvement on the our 1st SD4 that when we got the second one I made the switch immediately. ordered the bearings and smooth rods the same day the printer was purchased, printed out another set of the carriages and had everything ready to install by the time the printer arrived.

I lowered my bed and looked into it. I was under the impression there was a spring-loaded tensioner in the long screw/captive nut area. I figured out there was not. I was able to fix it using what remained of the old belt. It was tight, but I think the way it came was a little long to begin with. I did get some x-axis shifting in my first print, but I had problems with the model slicing. I am hoping a little adjustment and it will be ok.

this pic is of the stock carriage from my 2nd SD4 - it is the same basic layout for the ones that use the bushings and teflon blocks - verified by checking the carriages from my 1st SD4...

I have had a couple of belts split out at the screw hole now - it is not hard to change them if you have new belt on hand.... or you could take a leap of faith and try the fishing line mod. I have not yet successfully done this one, but I do have line on hand for when I have time to mess with it..

if using new belt, cut it to the correct length using the old one to measure. I use a silver sharpie to mark where I want the screw hole to be on the smooth side of the new belt to ensure it is centered. Using some scrap wood, i made a little jig to drill the hole in the belt - using a 3mm drill bit, i drilled a hole in a thinner piece of wood (1/4 in thick) to make lining things up easier. I place the belt down on a thicker scrap piece, line up my jig hole with the mark I made on the belt, hold firmly (or clamp), and drill the hole in the new belt.

the reason jago said to hold the belt is that they like to twist when turning the screw to tighten the tension.

it is basically the reverse of disassembly - 3mm cap head screw with 3mm washer goes through a hole in the belt (tooth side of belt facing the washer) and screws into the carriage. thread belt around the pulleys making sure everything is straight, and then the same on the other end - cap head screw & washer through hole in the belt and screwed into the carriage. there are more than likely captive nuts for the screws to thread into (definitely is if using the lawsy carriages) I can verify this shortly on the stock carriages...

yes, stock carriages use a captive nut on the tensioning side and a threaded insert on the stationary side - pics coming...

I was finally able to get in enough to get my X-axis belt tight enough to work properly--for a while. Fairly shortly after that the noise came back and the belt was loose again. I assumed it needed to be tightened again, and possibly the tension screw was stripped.

After tightening as much as I could, the belt was still loose. I printed off a tensioner instead of buying a spring. Guess what happened? I broke the belt. Sometimes you just have a bad day.

I am hoping replacing the belt will not be very difficult. My biggest concern is that I can find very little information on replacing it other than do the opposite of what you did to take it off.  Specifically, how do I reassemble the tension adjusting side of the belt?

Any links or resources would be appreciated.

https://youtu.be/9tevYebc58M

Update:

I have printed off back-ups for both x and y carriages.  Turning that screw has greatly decreased the noise. Because of the position of the screw, I have been having a hard time getting it completely tight without slack. My screwdriver literally pushes the belts apart stopping them from getting any tighter. However, I am still having some of the same squeaking, just not as badly. I feel like it should be tight enough, based on how tight my y belts are. Am I just not going tight enough? Maybe I overdid it? Any other ideas?

can you shoot a short video? squeaking could be from the bushings on the x rods (maybe they need lubrication), or the pulley that goes around the M5 screw on the right may need some lube. there shouldn't be any "twang" in the belt, but it shouldn't be so tight it's stretching either.

The issue with the screws on the X axis is that they are not easily seen, so some don't even realize they exist.

they are not needed when a simple turn of a screw will take up any slack in a belt.

and for the record, I did try them, on my Folgertech 2020 Prusa i3 - did NOT like them. designed an adjustment screw based tensioner for the X axis and found another on thingiverse for the Y axis to get rid of them.

Okay, I understand, but I'm wondering why Morganism was having so much trouble with those little screws, if they are So Great ??
It seems that a simple 'spring' could Solve that type problem ?

The CTC, and other makes, come from factory with those springs Already installed and they work Great !

and for the record, I did try them, on my Folgertech 2020 Prusa i3 - did NOT like them. designed an adjustment screw based tensioner for the X axis and found another on thingiverse for the Y axis to get rid of them.

EagleSeven - those springs are completely unnecessary on a Solidoodle. There are screws for adjusting the tension on the belts.

Those Springs will Help Any printer that has Loose Belts !
( Try It, You will Like it ! ) LOL

But I'm still wondering if it may be a problem with a Bushing or Pulley, not the belt ??