Smoother Pulleys

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So when I was installing the pulleys on the X-axis i ended up stripping 2 of the holes. I figure this is due to the small size of the threads combined with the soft aluminum, when I did the first few turns it simply shared the threads and made it impossible to get a strong hold. I went to Home Depot and bought some #8 bolts and nylock nuts to replace it with and seeing as they were slightly too small for the bearing I put 2 pieces of heat shrink around the shaft of the bolt and then slid the bearings over it. This turned out to be better than stock since the heat shrink had a tight fit on the inside of the bearing and so now it only rotates based on the bearing rather than rotating on the shaft and bearing, making the rotation smoother. In addition  to that it is a tighter fit since its not metal on metal and it now has virtually no wobble whereas it originally had a small amount of wobble. its really a pretty simple process, just get 1-2 pieces of heat shrink roughly 11mm long and slide them all the way to the end of the bolt, then heat and put on the bearings and shim as you normally would. In hindsight it would actually be best to use a 15mm piece so that it goes all the way through the hole and gives it a firmer fitting on the mounting, with this however it may be too tight for both pieces of heat shrink so I would do a fitting with just one piece and see how tight it is, then add either an 11mm or 15mm piece on top depending if you need a tighter fit or not.

This may be overkill as it is not a very big difference however i suspect after a lot of use having metal on metal contact with no lubrication between the inner bearing and bolt it would wear down and increase wobble, so with this setup it should eliminate that issue.