Tech Tip: Linear Slides Twin Rod Series - Rebuild from AutomationDirect

Re-building a Twin Round Shaft Slide can be a little tricky, so we’re going to quickly walk through the process in this video. We’ll be following the instructions located on the product page, under product inserts. This is the one for the twin round shaft slide. It has a parts list, torque specs, tools required and step by step instructions. Here we go. Remove the retaining ring from the ball screw. Loosen the drive coupler screw closest to the slide and remove the four motor mounting screws. I like to loosen the side screws and slide this out a bit to make reaching these two screws easier. Just be sure to slide it back and tighten those screws when done. Remove the motor and coupler. Loosen the two support screws on the support bearing lock nut and remove the nut. You’ll need to hold the carriage still to prevent the screw from turning. Remove the four screws holding the bearing flange in place. Remove the two screws from the carriage to release the drive screw nut. Push the end plate bearing out and remove the bearing. Remove the ball screw from the base – DON’T remove the bearing block from the drive screw yet – there’s a trick for that and if you don’t do it right you will have little ball bearings everywhere! While we have this one open, you can see how this works. If I put a couple ball bearings in the thread and rotate the unit, the balls hit this little protrusion and are guided into a tube where they are transferred back down the screw several threads so they can work their way back up again. We call these recirculating bearings. Again, don’t remove the bearing block from the screw just yet … we’ll show you the right way to do that in just a minute. Remove the spacer sleeves – one of them may have already come out with the drive screw. Discard both. We’re going to discard the screw and bearing block, but we need to re-use this nut block. I had to put the bearing block in a vise and use a large open end wrench to separate these, but since I’ve already loosened them, I’ll remove the nut block by hand. Just know that it took a fair amount of effort to get these apart. And remember, if you take this bearing block off the screw you’ll have ball bearings everywhere. Remove the bearing support. It may come out easily, but if not you can punch it out with a hammer and a socket. Ok, time to re-assemble everything. Get the new flange bearing unit and insert it. If it is tight, gently tap it into place or press it in. Install the flange bearing unit screws. We need to put this ball nut onto the screw. To do that, cut the zip tie and remove it but DON’T remove the cardboard tube – it’s holding the bearings in place. Slip the cardboard sleeve over the ball screws machined end. Now slide the ball screw into the nut. You’ll need to rock it a little and then turn it to engage the ball bearings. Keep rotating the screw until the ball nut is all the way onto the screw and then down the screw a little ways. Make sure you keep the sleeve tight up against the ball screw shoulder until the screw is all the way through the ball nut to keep the balls from falling out. Screw the nut block onto the ball block. Now make sure the ball return tubes are BELOW the top edge of the nut block. If they aren’t, then remove the nut block, flip it, and put it back. The ball returns should now be below the top edge of the nut block. When that looks right, go ahead and clamp it in a vise and tighten it with a wrench. Install one of the two spacers onto the screw and slide the screw into place. Put the bearing on the screw, insert the screw into the motor end and press the bearing into place. Align the carriage to the lock nut and attach with the original screws. Install the second spacer sleeve, Install the bearing lock nut – make sure the raised edge of the lock nut is pressing on the bearing. And then tighten the two set screws. Loosen the motor plate and slide it out a little to make inserting the lower screws easier. Slide the motor assembly onto the screw and attach with the four screws. Slide the end plate back into place and tighten its clamping screws. Tighten the drive coupler. Finally, Install the retaining ring Apply a light coat of grease onto the ball screw and then move the carriage the full length of the screw several ties to spread the grease. If you need any help, please contact AutomationDirect’s free award winning support team during regular business hours. The will be happy to help. And don’t forget the forums. There are lots of folks there that love to share their years of experience. Just don’t post any questions directed at AutomationDirect’s support team there, they don’t monitor the forums on a regular basis.