Tech Tip: Linear Slides Compact Series - Rebuild

Re-building a Compact Series Linear Actuator can be a little tricky, so we’re going to quickly walk through the process step by step in this video. The rebuild kit comes with Lubricant, bearings, washers and nuts, a lead screw nut and sliding bearing elements. You’ll need an imperial and metric set of Allen wrenches. Loosen the coupler on the lead screw side and remove the four motor mount screws, remove the motor assembly. Loosen the sensor plate set screw and remove the endplate, then loosen the other sensor plate set screw and remove it. Loosen the lock nut set screw and remove the lock nut. This should be finger tight, but if you need a little help a ½ inch or 12mm end wrench fits this too. Loosen and remove the lock nut on the other end too. Remove and discard the four bearings from both sensor plates. Remove the lead screw from the carriage, remove the carriage from the base and remove the sliding bearings. Remove the lead screw nut from the carriage and discard the nut and Bellville washers. Clean and inspect all components. Alcohol or acetone works well on all of the Anodized aluminum parts just don’t get any of it on the plastic bushings or lead screw nut. Install the leadscrew nut with this extended part facing the motor end of the carriage. Put a dab of grease on the nut to hold the new Bellville washers in place and then insert the screws taking care not to knock the washers off. Don’t tighten the screws yet –we’ll do that later when we align everything. If you have large fingers consider using the lead screw to hold the nut in place inside the carriage. Lloosen the four top adjusting screws about one full turn each and also loosen the two side adjusting screws on each side – again about one full turn each. Put a dab of grease on the back of the large plastic slide bushings to help hold them in place and insert them into the carriage. You should feel the bump on the back drop into the groove on the carriage. Hold the plastic slide bushings in place, and making sure the lead screw nut is positioned away from the drive end of the base and carefully slide the carriage onto the tube. Move the carriage around to make sure the plastic bushings are fully seated. Slide the carriage to the drive end and expose as much of the carriage as you can without taking it off the tube. Insert one of the small slide bushings in the top of the carriage until the bump on the back snaps into the groove and do the same thing with the other small slide bushing. Move the carriage back onto the tube and move it around vigorously to ensure all the bearings are fully seated. The carriage should move freely up and down the slide. If not, then double check the placement of the slide bushings. You may feel a few tight spots on the slide – that’s ok, we’ll adjust those in just a minute. Tighten the side adjustment screws until they make contact, then add another sixteenth turn. You want these to make slight contact with the tube. Anything more is unnecessary and will increase wear and shorten the life of the slide. The top adjustment is VERY sensitive and critical. Tighten one screw until the carriage is difficult to move, then back off until it does move. Repeat that for the remaining three screws. Now vigorously move the carriage around the slide and continue to adjust until it feels smooth but not loose. In general, for fast operations you will want a slightly looser or smoother adjustment. If you need more rigidity, you will want a little firmer adjustment. There is no science here – it is all about how it feels to you. Just remember – the tighter you make these pre-load screws, the fast everything is going to wear out. Once you are happy with the feel, check the alignment with a height indicator. A good adjustment can be as tight as 2 thousandths of an inch across the carriage top relative to the base. The carriage will rock a little in the roll direction – that’s normal because the carriage rides on a tube instead of dual rails. Continue to adjust everything until you get it the way you want it. Just remember that SLIGHT adjustments make a BIG difference. So be careful as you tweak things. Install the lead screw into the carriage making sure the motor end of the screw is on the motor end of the base. Install a new bearing with the flange side up against the machined shoulder on the lead screw. Add a new washer, the bearing holder – again with the flange side facing the leadscrew. Add another new bearing, with the flange facing the other way this time. Insert the lock nut with the raised shoulder facing the bearing, and finger tighten the lock nut. Move the carriage to test for ease of motion and readjust the preload screws as needed. Double check that all bearings are fully seated, and that the lock nut is finger tight. Insert the set screw bushing, apply thread lock to the set screws and tighten to a snug fit. And do the same thing on the other end. Move the carriage to one end and loosely tighten the screws on the lead screw nut. Move the carriage to the other end and finish tightening the screws on the lead screw nut. Move the carriage back and forth several times and make sure there isn’t any binding. If there is, continue to tweak those pre-load screws. Install the sensor mount brackets on both ends. Make sure that the sensor screw hole aligns with the adjustable flags on the carriage. Tighten the set screws. Install the new coupler and motor bracket assembly. Lubricate all outside surfaces of the slide tube and the lead screw. Move the carriage the full length of the slide several times to distribute the lubricant. Wipe away any excess. Step by step instructions are available on the product page under product inserts. These are the instructions for this slide and have everything you need to rebuild the slide including parts lists, tightening torques, tools required and step by step instructions. I should point out that we didn’t follow these instructions exactly as shown here, but it should be close enough for you to follow along. Also, I didn’t put any thread locking compound on the screws in this video because I had to remove the screws several times during the recording of the video. You will definitely want to add something like Loctite to keep screws from vibrating out so use these instructions to see which screws need it. 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.