SLIDE

551 985 70 SLIDE this piece is essentially a guide, you know, one of those surfaces that lets the drill head or maybe a feed carriage move back and forth without binding up. It's not a bearing, per se, but it takes a lot of the side load and keeps things aligned as the rig extends or retracts. Think of it as the low-friction interface that keeps everything tracking straight and smooth during the feed cycle.

When this SLIDE starts to go, you'll usually notice some slop in the system. The drill head might feel a bit loose, or the feed carriage could start binding up, especially when it's under load. Sometimes you'll hear a distinct grinding or squealing noise as the metal-on-metal contact increases, or even just a general increase in vibration coming from the feed system. If you see uneven wear patterns on the mating surfaces, that's a dead giveaway you've got a problem brewing.

Replacing these isn't usually a huge job, but it's critical to check the mating surfaces for damage or scoring before you put a new one in. A lot of guys just slap a new SLIDE on, but if the rail it runs on is chewed up, you'll be back doing the job again real soon. Make sure everything's clean, properly aligned, and don't forget to apply the right grease or anti-seize if the spec calls for it – sometimes that gets overlooked and you end up with premature wear on the new part.