All,
I replaced the X axis idler with a smooth pulley assembly. To make up the space to keep it aligned, I used 5 spacers that are 1mm thick and 1 of the 1.4 mm washers. Actually, one of the plastic spacers that were used in the lid hold up were about the right size. I wanted to use the metal spacers because it would add some stiffness to the design. I put the larger metal washers on either side of the plastic mount to add some more support.
The hole bart made in the plastic was just undersized enough that you had to screw the machine screw into it, which was really good because it ensured good contact and alignment.
Here's a pic of the setup.
- Smooth Idler setup
In my opinion, this is a huge improvement, even over putting a precision shaft in place. The shaft was fine, but the plastic pulley on the shaft was one of the cheaper ones and not precision made so there was minimal belt wobble even still. This however, is VERY smooth and the belt doesn't even move side to size when the cart travels. By sandwiching the plastic part with larger washers, the connection is very solid and can take a lot of stress. By undersizing the hole, the shaft is aligned well. Over all, I am very happy with this. I like it better than my shaft setup.
BTW, an upgrade kit will have to include M5 machine screws and nuts. I found that the x axis idler could use a 35mm shaft and be just fine (I reused the screw from the lid holder I took off). I was able to get a flat and lock washer on the back with a nut and the end just barely protrudes. The other shafts are going to need 40mm screws.
This is a great upgrade. When I move the car by hand, there is absolutely no pitch change in the motor and everything feels nice and balanced and smooth! You can sight down the belt and everything is very nice and strait!
This is great! I can't wait to get them on my y axis. I don't have enough 1mm spacers to properly space the bearings out from the plastic holder, so I will probalby use the 2 plastic spacers that came from the lid support.
I will try to get that done tomorrow and report, but I am expecting really good stuff.