Linear Slides Techniques

I’m trying to help my middle school EDR team. They have decided to build a short rack and pinion style linear lift for getting the mobile goals into the 10 and 20 point zones. We’ve watched a number of videos and understand the concept, but seem to be having a problem with technique. The slides feel tight when we assemble them without the gear box or motor yet. It’s not that a bolt head is interfering with the movement. Rather moving them by hand, the motion through the length of the movement is smooth but takes a lot of strength to move. Does anyone have some good step by step instructions for assembling the slides? Thanks in advance

If you could post a picture of what it looks like, that would be helpful. There are several things that could be wrong that a picture would help the community in assisting you.

If its the full metal slide system then I recommend a small amount of grease to reduce friction. For the new system, I’ve noticed you have to adjust the spacing to get the metal to slide just right. Also make sure you’re using the correct pieces. There are two different plastic pieces for which side of the rail you are using.

For the all metal linear slide, we would put the inner slide in a bench vice and squeeze it very slightly. Not too much, or it will be loose and rattle around, but just enough to give it some extra clearance.

I all honesty skip experiments with linear sides and move on to DR4B its easier to make and its much quicker and the height is unmatched

no, stop discouraging designs, there is no universe where a rd4b is undoubtedly king. The problem is that alot of people are encouraging rd4bs when linear lifts are just as viable, please op, go explore and better the world of linear lifts

I’m not trying to discourage anyone I am saying from my personal experiments with linear slidesthat its not worth it

A linear lift is much better than a DR4B for scoring mobile goals. A DR4B might be ok for scoring cones, but not for mobile goals. Height is a non-issue when you only need to do 4", and you need to use different lifts between cones and mobile goals, since mobile goals outweigh cones by nearly an order of magnitude.

On Topic:
Make sure all your trucks are lined up properly. If the ends don’t line up, it can be very problematic. Try loosening the trucks and seeing if the slides are easier to move around. Then tighten the trucks with the slide on them.

AS you have a lever arm of the mobile goal, it causes some torque about the linear lift from that attachment point. That can drive the linear lifts to not slide real nice.

Thank you to everyone offering advice!

I appreciate the help but my kids did a comprehensive brainstorm and evaluation as part of their design work. They felt they didn’t need to lift very high so a single stage linear would be good. And they wanted to do separate mechanisms for mobile goals and cones since the requirements are different and they could learn about 2 different mechanisms.

Oh, that’s a good idea! Thank you

Thanks for that. I’ll be prepared for when they get to the next stage

For a newer team especially, I completely disagree. Even for experienced teams, we don’t all need to have the exact same robot.

Double-Reverse 4 Bars aren’t really easy to perfect or even make. Also, Chain bars are pretty fast too.

A picture will really help.

But off hand - are you looking at similar mobile goal lifter like 8059z?

J u S t u S e Dr FOUR BAe 10/10

One thing my team does to make the linear slides smoother is when using the new slides that go on the inside, we sand them to make slightly smaller. Also, I believe it is legal for competition to use graphite lube powder to make them slide smoother as well. I’m also glad someone else is considering using a linear lift. I don’t like design convergence at all that’s why I’m pushing my team to use something besides a DR4B.

Thanks everyone for the input. We got a lot further at practice on Saturday.

For anyone else with similar problems, the advice that helped the most was from Silicon to loosen the trucks (or not install them too tight in the first place) then install the rail and tighten as you make sure it can continue to slide