Unistrut Bridge Crane

[Muckin_Slusher]

Why the hell not?

A friend built a 12x20 skidoo shop. Used 2x6 for ceiling member with the intention of putting a 2x8 up there with some eye bolts for lifting spots. Laying in bed last night I was thinking how it would be sweet to be able to move in at least one direction with a hoist, or even 2 directions.

So, plan for now is to buy a sleeve of 100 608-ZZ skateboard bearings and some 5/16 roll pins and make 8 of these:



Then attach two lengths of standard unistrut to the ceiling perpendicular to the rafters, attached with those fancy new-style lag bolts. Probably 5 feet apart.



Then span those with a bridge of two strut side by side with some tubing to stiffen the bridge.


The trolley is rated at 600 lbs and I'll be using 4 to hang the bridge, and another 4 to hang the hoist.





Should be a dirt cheap way to have a super low profile 3 axis crane. Should easily lift anything snowmobile and small engine related (<1000 lbs). Snagging a 800 4-stroke engine out of a skandic and setting it on the workbench would be childs play.

Change my mind?

 

[bgaidan]

Do it. And take videos. It'll either be awesome, or make a sweet vid of you dying. 🤣

I don't think I'd stand under the load, personally....

 

[Stingray]

I think the way unistrut works is by the straps holding it together, I would be concerned of it spreading under load and having the carriage you built falling out.
but I'm no engineer.

 

[B-rock]

We use this at work to lift and move 100 HP motors or tube bundles that are being replaced. We use the double strut the trolley slides in. Works so well I'm planning on doing this in my workshop that's a 10x20. but only spanning 10 feet.

 

[Johann]

Attach it where it crosses every rafter for maximum deflection prevention. There has to be a uni strut spec for how much weight it can take on an unsupported length before the "U" fails. That it is distributed to four roller contact points probably helps too.

But I do know for a fact that a 14' 2x12 drilled centerline with a 1" steel dowel through it can support a 1.5 ton chain fall and an iron Spitfire 4 cyl engine no problem. The chain fall was just suspended from the dowel on a short length of chain bolted together. I may have even had the trans on there as well. It's been a while.

 

[Muckin_Slusher]

.....and we're a go!

Time to source 608 bearings, 5/16x1.375 split pins, and spacers.

Any suggestions as to what I should use to space the bearing out from the plate? I don't think it needs it, but I could weld the spacer to the trolley plate to stiffen things up a bit.

If only I had a lathe to square up some spacers.

Oh, and we're doing the full length of the shop, so 20 feet long, 5 foot wide.

 

[jeepnmatt]

how thick do the spacers need to be?

Or, just increase the thickness of your plate to locate the bearings correctly in the unistrut

 

[Muckin_Slusher]

how thick do the spacers need to be?

Or, just increase the thickness of your plate to locate the bearings correctly in the unistrut

Math says the spacers on either side should be 0.305 inches for exact fit, so I'm guessing a 1/4 inch spacer on each side should be about right. I suppose the easiest thing would be to add a 1/4 inch strip on either side of the plate, weld in place then make my holes.

 

[Muckin_Slusher]

Harrington makes this sexy little chain hoist. 1/4 ton, looks to be the same size as 1/4 ton lever hoists.

Pricey though, (compared to the levers).

 

[Muckin_Slusher]

I guess I should be looking for coil-pins instead of split pins?

 

[PAE]

Local place down in Oroville sells the part with the bearings of various types.

And the Steel.

They are called "All Metals". Edit valley Iron bought them out and as of a year ago 9.15.2022 or so they stopped selling any hardware, local customers are pissed.

https://www.allmetalssupply.com/product/strut-roller-4-wheels-4-plate/

Part #

ZH820-0115

 

[Spiritof76]

I did this same thing in my old garage, just in one direction, and used it as an attic hoist with a 1,000# warn 120v winch on it. Wokred perfectly. I had it over an attic scuttle, so I could use it in the garage, or use it to pull items up into the attic and slide them over to the decking up there for storage.

 

[GLTHFJ60]

Seems like a perfect solution for a light-duty overhead crane for sheds and whatnot.

Post many pics, I may do this in my shed as well.

EDIT: Found some docs. This is pretty impressive.
https://www.unistrut.us/assets/unist...olley_Broc.pdf

https://www.unistrut.us/products/1-5...aming/trolleys

https://www.youtube.com/watch?v=7V5toTT3gbo

 

[DirtRoads]

I'd like to see the parts list for the next size up of this concept. Like big enough to lift an LS engine and trans.

 

[CarterKraft]

Sliding garage door track is another option.

 

[arse_sidewards]

I'd like to see the parts list for the next size up of this concept. Like big enough to lift an LS engine and trans.

Yeah. ~1000lb capacity and I'm in. Less than that and I'm gonna stick to my plan of waiting for some cheap 6" I beams to come along.

 

[Muckin_Slusher]

Yeah. ~1000lb capacity and I'm in. Less than that and I'm gonna stick to my plan of waiting for some cheap 6" I beams to come along.

Mill a slot in the welded side of a 2x2x1/4 tubing. That'll get you 1000 lbs easy.

 

[CarterKraft]

Mill a slot in the welded side of a 2x2x1/4 tubing. That'll get you 1000 lbs easy.

Might as well go 6 or 8 section height and use a metal circular saw to make the slot instead of the mill.

edit: or maybe just stitch weld 2x2 to lighter gauge 2x6 tubing cause 2x6x1/4 wall is gonna be pricey.

 

[DirtRoads]

Might as well go 6 or 8 section height and use a metal circular saw to make the slot instead of the mill.

edit: or maybe just stitch weld 2x2 to lighter gauge 2x6 tubing cause 2x6x1/4 wall is gonna be pricey.

And here I was considering how many cases of 4.5" cutoff wheels I was going to burn since I don't have a mill

 

[GLTHFJ60]

I'd like to see the parts list for the next size up of this concept. Like big enough to lift an LS engine and trans.

You're already there. Use multiple trolleys with the wider unistrut clamp things and you're well over 1000# lift capacity. The track itself has ratings for how much it can support based on the span between supports in the docs I quoted in my last post. 24" between supports with 1 5/8" track is almost 1200# rated.

 

[arse_sidewards]

I'm looking to cover a 13x13 space. This would be for moving things around my basement machine shop. How much you think the table or knee on my Cincinnati weighs? Those and engine trans combos are the biggest kinds of things I need to move gracefully. Used shapes are so much more readily available used than tubing or unistrut that I have a hard time justifying not going that route and having overkill. I can get 10ft sticks of 4x5.4# C-channel for $30ea. The local scrap yard goes as low as $0.40/lb depending on the desirability of what you're buying.

 

[GLTHFJ60]

I'm looking to cover a 13x13 space. This would be for moving things around my basement machine shop. How much you think the table or knee on my Cincinnati weighs? Those and engine trans combos are the biggest kinds of things I need to move gracefully. Used shapes are so much more readily available used than tubing or unistrut that I have a hard time justifying not going that route and having overkill. I can get 10ft sticks of 4x5.4# C-channel for $30ea. The local scrap yard goes as low as $0.40/lb depending on the desirability of what you're buying.

I'm right there with you, but vertical height and installing overhead beams are concerns there. Installing unistrut is way, way easier. I built a gantry crane with a S-beam from the scrap yard for pretty cheap, but standing it up was tricky without a larger crane or a forklift of some kind. A unistrut single-line crane would make sense for ~1000# if you can support it at least every 24" across the length. Bridge crane style would be tricky, because the transverse beam would be unsupported in the middle. Take a 10' piece of 1 5/8" unistrut supported just on the ends and you could deflect it quite a bit just with your body weight.

How much does your Cincinnati weigh total? Probably 1/4 to 1/3 of that weight is in the full knee assembly I'd imagine. A table and knee for a bridgeport style mill would be much less.

Specs for the unistrut crane applications here:
https://www.unistrut.us/assets/unist...olley_Broc.pdf

https://www.unistrut.us/products/1-5...aming/trolleys

https://www.youtube.com/watch?v=7V5toTT3gbo

EDIT:

Using the 3 1/4" tall unistrut as an example, the max uniform load for a 120" span (10') is 1000#, so that might work in a bridge crane application. Almost 3/4" deflection at that load though.

https://www.unistrut.us/product-details/p5000

 

[arse_sidewards]

I'm right there with you, but vertical height and installing overhead beams are concerns there. Installing unistrut is way, way easier. I built a gantry crane with a S-beam from the scrap yard for pretty cheap, but standing it up was tricky without a larger crane or a forklift of some kind. A unistrut single-line crane would make sense for ~1000# if you can support it at least every 24" across the length. Bridge crane style would be tricky, because the transverse beam would be unsupported in the middle. Take a 10' piece of 1 5/8" unistrut supported just on the ends and you could deflect it quite a bit just with your body weight.

How much does your Cincinnati weigh total? Probably 1/4 to 1/3 of that weight is in the full knee assembly I'd imagine. A table and knee for a bridgeport style mill would be much less.

Specs for the unistrut crane applications here:
https://www.unistrut.us/assets/unist...olley_Broc.pdf

https://www.unistrut.us/products/1-5...aming/trolleys

https://www.youtube.com/watch?v=7V5toTT3gbo

EDIT:

Using the 3 1/4" tall unistrut as an example, the max uniform load for a 120" span (10') is 1000#, so that might work in a bridge crane application. Almost 3/4" deflection at that load though.

https://www.unistrut.us/product-details/p5000

The runway beams don't count against my head room since they go up between the floor joists. I could do three runway beams and cut the unsupported span down to 6' but that's likely still to much for strut channel. I could add even more runway beams but at some point it gets kind of silly to not just use a better traveling beam. Also worth noting that the Cincinnati doesn't leave much headroom between the top of the head and the floor joists. I could possibly double or triple up on the traveler.

I don't have delusions of being able to lift the complete Cincinatti knee (mill is 7500lb overall) but I need to be able to remove and reinstall the table and knee. At the very least the table will have to come off to get it inside anyway. I'd also like to be able to put large logs on my lathe for wood turning operations.

Considering how the "1500lb" Home Depot shelves turned out I don't want to both push the limits in terms of working load, while overhead lifting, with things I care about all simultaneously. I'll do any two of the three though.

 

[Dethmachinefab]

Bolt an angle to the backside of the bridge one to reduce deflection.

 

[Muckin_Slusher]

I think at work we have a crane load cell. If I have time I can do a test for science and see how much a solid strut can take before it shits out the trolley. Any other thinks I can test while I'm at it?

 

[Dethmachinefab]

I think at work we have a crane load cell. If I have time I can do a test for science and see how much a solid strut can take before it shits out the trolley. Any other thinks I can test while I'm at it?

Make sure you traverse the trolley while testing. It may hold more static, and roll right out when loaded down and moving.

 

[GLTHFJ60]

I think at work we have a crane load cell. If I have time I can do a test for science and see how much a solid strut can take before it shits out the trolley. Any other thinks I can test while I'm at it?

Use 1 5/8" square unistrut in one test, and 3 1/4" unistrut in the next test. The 3 1/4" stuff should be much stronger.

 

[Muckin_Slusher]

Use 1 5/8" square unistrut in one test, and 3 1/4" unistrut in the next test. The 3 1/4" stuff should be much stronger.

I don't have access to that tall stuff. All we have is regular and back-to-back double. Since mine will be anchored every 16 inches, I'm not concerned with it's span strength.

By the way, strut is super floppy (great crane material!). I've had fun just trying to use it for mounting security cameras. If you use it as an unsupported pole, you need to guy wire it, AND you need to bolt on a torque tube to prevent twisting (just like the torque tube in long trailers).

In my bridge crane application, the bridge will be stongbacked by some kind of steel square tubing.

Again, just to be clear, sideways bracing is a huge factor, just like with an I-beam or S-beam, you need a much, much heavier beam if it doesn't have any sideways bracing.

 

[Muckin_Slusher]

Never got around to doing anything with this yet. People die and life gets busy.

Anyway I'm back looking for trolleys. Amazon has the 4 wheel assemblies with solid axle pins in 4 packs for $108 CDN.

Also found these pics.

 

[Muckin_Slusher]

Make sure you traverse the trolley while testing. It may hold more static, and roll right out when loaded down and moving.

I made this one earlier this year (and yes it's a repost) specifically to hand my welder on a shelf, but to help keep the strut from spreading I added gussets at the hangers.

I'm thinking for a 3 axis bridge crane it would be easier to add side plates on the trolleys that would ride outside the strut to prevent it from spreading, probably also with roller bearings to cut down on wear and make things roll easier.