Harbor Freight Engine/shop Crane

[abrace]

All,

I purchased the HF 2-Ton engine/shop crane to lift my new Grizzly G4003G lathe. After putting it together there is a gap between the base and the crane post. This gap is there because the spring bars in the back were too short. I researched this and read that it is done this way intentionally to "pre-load" the spring bars. Now, the gap is on the side facing the load, so that is better than in the rear I would think, but it still has me concerned. Is this crane safe like this? Will it settle after I put it under load? I have tightened the bolts pretty tight, I would say they are probably near 100 ft pounds.

This type of engineering is way outside my area of expertise.

I am attaching a photo for review. The gap is somewhere between 1/16" and 3/32" at the front, and it is flush in the back.

---Aaron

 

[epanzella]

That looks Ok to me. The base joint by itself would be lucky to hold 200 pounds without bending. The spring bars are doing all the real lifting.

 

[joshua43214]

Those bolts need to be tight!

Where the column meets the base is a pivot point. If those bolts are loose, the column can rotate. Ever see an engine crane fall over sideways?

Loosen every thing up. Make sure the column supports are about as loose as you can make them. Tighten the column to base bolts. There should be enough slop in the bolts that hold the supports to allow the column to be drawn in tight. Then tighten the supports. The actual length of those supports depends on the bends in them, they do not all bend perfectly so they are not always the perfect length.

Watch the column and arm closely while tightening. It is really important that the arm run directly down the center of the legs.
I was a mechanic for many years. I have seen countless engines hit the floor from people thinking "it is good enough." I wish I had a dollar for every time I have seen someone standing on a crane leg to keep it from falling over sideways while yelling for help.

 

[abrace]

Those bolts need to be tight!

Where the column meets the base is a pivot point. If those bolts are loose, the column can rotate. Ever see an engine crane fall over sideways?

Loosen every thing up. Make sure the column supports are about as loose as you can make them. Tighten the column to base bolts. There should be enough slop in the bolts that hold the supports to allow the column to be drawn in tight. Then tighten the supports. The actual length of those supports depends on the bends in them, they do not all bend perfectly so they are not always the perfect length.

Watch the column and arm closely while tightening. It is really important that the arm run directly down the center of the legs.

The 2 bolts in the back are flush, the leg bolts with 4 bolts.

I tried what you suggest and this is as good as I could get it, I will give it another shot and see.

I think those spring bars are just a bit short and I am worried about stripping out the chinese fasteners. I suppose I could always replace them with some grade 8's if that happens.

 

[joshua43214]

I wouldn't bother with replacing the bolts.
Just test it to make sure it holds and does not shift.
Raise the machine about 1 or 2 inches off the ground and really shake the arm. Shake it side to side, and up and down. Don't be gentle.
Put wood under where the machine will land just in case it falls (or better, leave it on the pallet). Falling 1" onto a block of wood will not hurt anything, unless the hook breaks (it won't). The machine will describe and arc as the hoist falls over and soften the landing.
take the load back off and make sure the arm did not go out of alignment.
If the arm goes out of alignment, add some washers in the gap so all 4 bolts can pull down tight, and try again.

These things tend to fall over at the worst possible time, when the load is at it's highest point. It will happen so suddenly that you will become aware of the problem about the same time it hits the floor.

Back in the day, when I had to pull V8's attached to automatic transmissions, I would put all my weight behind rocking the assembly when it was raised just off the engine mounts. Saved my butt on more than one occasion when I could feel the crane starting fall over.

 

[abrace]

I wouldn't bother with replacing the bolts.
Just test it to make sure it holds and does not shift.
Raise the machine about 1 or 2 inches off the ground and really shake the arm. Shake it side to side, and up and down. Don't be gentle.
Put wood under where the machine will land just in case it falls (or better, leave it on the pallet). Falling 1" onto a block of wood will not hurt anything, unless the hook breaks (it won't). The machine will describe and arc as the hoist falls over and soften the landing.
take the load back off and make sure the arm did not go out of alignment.
If the arm goes out of alignment, add some washers in the gap so all 4 bolts can pull down tight, and try again.

These things tend to fall over at the worst possible time, when the load is at it's highest point. It will happen so suddenly that you will become aware of the problem about the same time it hits the floor.

Back in the day, when I had to pull V8's attached to automatic transmissions, I would put all my weight behind rocking the assembly when it was raised just off the engine mounts. Saved my butt on more than one occasion when I could feel the crane starting fall over.

I was only going to replace the bolts if my new attempt at tightening stripped them.

I must have had a couple beers this morning and forgot. My leg only has 2 bolts, not 4...hehehe.

Anyways, I loosened everything up and tightened everything back up again. I didn't use a torque wrench, but I used my snapon 1/2 drive ratchet...the long one, the SL80A (15" handle), plus my long box wrench and really reefed on those leg bolts. I got it to take up a bit more, the gap at the front is somewhere around .070 now based on my feeler gauge.

I don't want to use my impact wrench, I am worried I will strip the crap out of those bolts...if you think I should I will.

I estimate I probably got them north of 200ft lbs now by hand.

---Aaron

 

[chips&more]

I would do exactly what “joshua43214” said to do.

 

[tq60]

It should bolt flush.

Ours is.

Remove the spring arms and see if it fits properly.

It should seat well finger tight.

The other parts may not be correct length or maybe placed wrong.



Sent from my SAMSUNG-SGH-I337Z using Tapatalk

 

[abrace]

It should bolt flush.

Ours is.

Remove the spring arms and see if it fits properly.

It should seat well finger tight.

The other parts may not be correct length or maybe placed wrong.



Sent from my SAMSUNG-SGH-I337Z using Tapatalk

I can bolt it flush no problem without the spring arms. When it is bolted flush without the spring arms, the spring arms holes are 3/8"-1/2" out of alignment with the holes at the top of the leg. To put it together I have to connect everything real loosely, and then tighten the leg as tight as I can. The spring bars pull very tight at that point. Then I secure the spring arm bolts with a ratchet to bring them in.

I think they make it tight intentionally to pre-load the spring bars, but they got a little carried away with mine.

---Aaron

 

[yendor]

Can you file the holes slightly Oval ?