Unistrut for overhead trolley ?

[mkepke]

James' thread on moving a RAS reminded me I'd been thinking about adding an overhead trolley to the shop for moving machines.

Does anyone know the 'best practices' for attaching unistrut/super-strut (I'm thinking the doubled-up P1001 type) to wood I-joists ? The thought of lag screws doesn't excite me. I'm thinking of some sort of hanger, but nothing jumps out at me looking through the Unistrut catalog.

-Mark

 

[Skymaster]

thru drill the joist, run threaded rod, fender washers and double nuts ?

 

[FlyingRon]

I'd not drill through the flange (the top or bottom). I'd bolt a 2xWhatever through the web (the vertical part of the I) and attach to that.

 

[Umich684]

Parallel or perpendicular to the joint span?

Totally agree on reinforcing the joist web, using a thru-bolt and strap hangar to not damage top/bottom cords.

 

[Deeptree]

I would recommend to line the strut perpendicular to the joists. This will distribute the load across all of the joists instead of just one.

On a side note, I bought a gantry on wheels a couple of years ago, that I use for moving big 16/4 slabs of wood, as well as heavy equipment. I like it because I can fold it up when not in use, and also take it outside, to the garage, etc. You can get them pretty cheap if you look around. I think I paid $800 for mine, and it will hold up to 1 ton. It is on heavy duty casters that make it easy to roll things around the shop.

 

[bobby g]

A pretty bullet proof method is to lay a piece of Unistrut across the tops of the joists in the attic. Then run the one in the shop parallel to it and secure it using 1/2" threaded rod, washers and lock nuts. This eliminates rotational forces on the joist that would be present with a strap hanger.

bobby g

 

[junquecol]

Instead of unistrut, consider barn door track. Lowes and Agi-Supply both stock it. Premade dolly wheel assemblies also.

 

[mkepke]

Thanks for the ideas.

This application happens to have runs that are both parallel and perpendicular to the ceiling I-joists (2 runs of track)

I finally found a random diagram (on fire-sprinkler installation) that showed the use of Simpson strap ties (LSTA/MSTA) placed at the top of the joists acting as hangers and will probably go with a similar approach.

The space above the shop is habitable , already floored with OSB, so I need to keep out of that area.

Bruce - common barn door track & accessories are too light-duty Typically maxes out at 400-500# max load - probably assuming a somewhat distributed load (like a barn door). I'm planning for something in the <1000# range. Lots of unistrut assemblies - like trollies - available, which is why it's strange I don't see a unistrut fixture for 2x wood members.

-Mark

 

[toolferone]

http://store.eberliron.com/products/unistrut_parts/unistrut_trolley_assemblies

Saw this????

 

[mkepke]

http://store.eberliron.com/products/unistrut_parts/unistrut_trolley_assemblies

Saw this????

Not that store specifically, but yes, those are the unistrut fittings I was planning to use. Unfortunately no guidance there on how to attach the unistrut to wood 2x members.

If you look at the .pdf brochure available on that site, it only lists beam hangers for steel i-beams (I wonder if that's a hint :wsmile. If I had an I-beam, I'd skip the unistrut altogether.

-Mark

 

[Gotcha6]

I once purchased some lag screw assemblies at the Mooresville Lowe's (haven't seen them at any of the CLT stores, probably a NASCAR thing) that was a 5/16" x 4" lag with a fitting on the end to accept 3/8' x 16tpi threaded rod in either axis. It impacts into a truss chord nicely. Not sure it would hold 1,000# and you'd want to design a Safety Factor in anyways, but several of these trapezed to the trolley assembly at each truss crossing may do what you need.
You could also lag screw a 2-3' piece of Unistrut onto the bottom truss chord parallel to it & hang from it using slot nuts.