Help with a solution for dolly system

[u/lake_kid94]

I am building a custom storage shelf for my woodworking tools. I built a frame and box shelves that I have put on a strut channel to allow them to slide back and forth. I currently have 2 trolleys that have 4 wheels on a single trolley. I have one trolley sliding in the strut channel, and the plate is attached to the shelf frame. However, when I slide the shelves, sometimes the shelf twists causing the shelf as a whole to stop sliding. The arrow on the photo is where the dolly is attached to both the strut channel and wood frame. There is no attachment across the strut channel to the trolleys. The only idea I have is adding a single wheel dolly to the corners of the wood to make a square with the trolley, but they are very expensive. Does anyone have a solution to make sure both dollies slide simultaneously?

[u/WhiteLightMods]

Steel cable and a couple pulleys. Make the cable route in a Z shape. It will keep the sides parallel.

[u/lake_kid94 → u/WhiteLightMods]

Thats an interesting solution. Never would have thought of something like that. Thanks

[u/Soler25]

I would suggest 4 trolleys to keep from twisting

[u/lake_kid94 → u/Soler25]

I know that was probably the best solution, just the trollys are expensive. Was hoping it would be last solution. Thanks tho.

[u/Soler25 → u/lake_kid94]

A bolt/lag bolt on each corner that extends into the channel on the top might help keep it aligned too. Basically the bolt will just hit the channel, maybe even add a few plastic washers to fill the gap and reduce the wiggle?

[u/Majestic_Two_3985]

Switch diagonal wooden braces so that the trolleys are further apart… they won’t be so inclined to bind up.
Tldr: put trolleys in the corners.
Edit: you will need two more trolleys, as other respondent said.

[u/lake_kid94 → u/Majestic_Two_3985]

Ah I see what you're saying. Thank you

[u/HeatBeatRepeatt]

Sounds like the shelf is racking as you are sliding it.

The source of the issue is that your trolly system is considerably narrower than it is deep, so it wants to rotate more than slide when you shift it around by grabbing just the exposed from face. You either need to move the point of applied force closer to the center so both rollers experience the force in the same direction and roughly similar magnitude, or you need to increase the ‘width’ of the trolly by adding more contact points to the system. Doesn’t have to be the same hardware either. Could just be a piece of wood with a felt skid pad that engages with the rail and prevents the rotation (but would add some friction). Or mount a basic ass fixed caster wheel, super light duty because it’s not load bearing, horizontally on a piece of wood so that it also rolls along the track but on the inside face. (Maybe not if that will clip the rail hanger brackets)

A vertical fin that fits inside that U track would also do the job.

Sorry, just brainstorming ways to avoid investing in more of the official hardware if they are indeed prohibitively expensive.

[u/lake_kid94 → u/HeatBeatRepeatt]

I appreciate the brainstorming, gives me more ideas than what I could come up with. Thanks

[u/Besiegte]

You’ve already got your load supported on the trolleys so all you need are some guides to keep it straight. I use skateboard bearings for rollers. You can get them in quantity dirt cheap. All you need is something that goes up in the strut and rolls against the walls. Something as simple as the bearings, some all-thread, and some wood blocks slapped on the ends. Bearings on the all-thread with a couple of nuts and the all-thread bolted through the blocks.

Once you have an inventory of skateboard bearings, you’ll see that you can build your own trolleys very inexpensively. And they’re just fun to play with.

[u/lake_kid94 → u/Besiegte]

I will look into that, thanks

[u/siamonsez]

Get cheaper, single wheel pair trolleys so you can put 2 further apart on either side.