Reddit reviews Gates 7401-0076 Pencil Type Tension Tester, 30 lbs Deflection Force

Or buy one of these

Bought this belt deflection gage because I had a loose belt in my car.

As for the holidays, I just moved on my own, so I'm asking my family for the one glaring missing piece of my tool kit, a nice combo wrench set.

I bought a pencil style tension gauge but I'm not sure if it's accurate, or if the specs I found were really off but I tried to tension to those specs and it seemed unreasonably tight so I just ignored it. For the most part I've been pulling it as tight as I can around the drive pulley in the back and the idler pulley at the front, clamping them down then slipping the belt over the idler bearing just in front of the drive pulley. That seems to be working well enough for me and the prints I've shown were printed using that method. Not ideal, but it allowed me to focus on other issues. I would like to do it properly proper though, just not sure if my gauge is good and if so, what specs are needed.


The X belt lasted considerably longer and I suspect it was only due to my custom idler bearings wearing out and the walls breaking free since I had to make them from nylon which was the only thing I had available. I had to use washers to trap the belt and they didn't spin with the bearing so I'm guessing that's why they failed at all. I'm going to be making new idler bearings from delrin once I get a proper mini lathe. I tried using a Sinwise 6 in 1 machine but they are such garbage and are pretty useless as a lathe since the chuck wobbles lol I might still opt to go overkill on the X belt though since it would be more expensive to replace due to it's generous length, but I'll go with your recommendation if you think it would be wise to do otherwise.


Belt Failure

Y Belt Path

X Belt Path shortened for illustraion purposes, drive gear on right side of image, others are idlers

Belt Tensioner


So after weighing every part on the gantry and X carriage (steppers, extrusions, plates, bolts, nuts, washers, etc.), the weights are as follows:

gantry alone - 14.7 lbs

X carriage - 3.9 lbs

All - 18.5 lbs


I didn't factor the weight of the belts or pulleys in but I'm sure it won't be a problem just add a pound or so on the top.