I bought a used xxl and went through the Z carriage today. There was considerable sawdust buildup on the v wheels and the rails. I cleaned the rails with mineral spirits and the white 3M non-woven sanding sponge. I had ordered a xxl maintenance kit and two of the v-wheels has some chatter marks on them so I replaced them. Some of the v-wheels had 5mm washers and some did not so I went to Ace Hardware and bought 10 5MM washers. I replaced all of the washers to make sure they were all the same thickness and saved the originals. I made one mistake by installing a washer on the idler pully and installed it backwards. I moved the z carriage and the belt kept coming off. I realized the mistake and re-installed the idler in the proper orientation. Since I was working on the z carriage I replaced the belt and saved the old one. Because I installed a washer behind the idler the carriage would not go all the way home and activate the switch. There was just not enough room for the bolt that holds the idler to hit another bolt head. I removed the washer and the carriage was perfect. The main reason to disassemble the z carriage was when tramming I was getting slight groves on the Y axis and I shimmed the bottom of the router mount with two layers of heavy duty Reynolds aluminum foil. I re-trammed the spoil board and got the same groves but in the X axis this time. I have a 123 setup block coming tomorrow and will reset the router mount and try tramming again. I made 3 new spoil boards from plans on youtube from Myers Woodshop. The new spoil board have 2x2 inch spacing for 1/4-20 5/16" Tee nuts. The spoil boards should work well. The plans include fences for the front and left sides as well as L stops and cam clamps. I have a Shard Pro Plus HD and made the spoil board with T-slots and 1/4-20 Tee Nuts. The T-slots are not practical because the MDF distorts when tightening 5/16" T bolts and are unusable with 1/4-20 bolts. I will make a new spoil board for the Shark using the same principles used by Myers Woodshop. The new spoil boards are machines and ready to go as one wears out. I bought a whiteside 6210 1" 3 wing cutter to tram the spoil boards. I emailed Whiteside about the feeds and speeds and they recommended 100 IPM and 15000 RPM. I set the IPM at 80 IPM and set the router on 4 (Dewalt 611). The Whiteside that I added to the bit library set the speed at 4 IPM and it took 4 hours to complete the first Tram. I changed the speed in the file and recreated the gcode. The second tram took 20 minutes to cut a 32x32" spoil board. That was a considerable difference in speed. After I get the router squared I will tram one more time. I did have a low spot on the front left corner and one more tram should get the spoil board flat.