Made a contraption

[Aukai]

I'm going to add another rolling box for the ACRA mill, and keep the rotary table, the 6" Kurt with swivel base, and 2 Glacern vises on the top. This contraption with the 200/400lb winch will lift, and move them to the table. I still have to mount the new winch. I threw the mount, and boom together from miscellaneous stuff I had leaning against the garage wall.

 

[matthewsx]

You mill is actually wearing Hawaiian shirts

 

[Aukai]

HAHA Walmart curtains.

 

[cathead]

I'm not one to be critical but question the physics of lifting something heavy supported only on one end
expecting the cable to support the far end.

 

[Aukai]

I'm hoping the vises do not stress the contraption too much, most definitely not for heavy lifting. We will see, the wall bracket is 3/8" through bolted through the 4" beam, and a Teflon pad under the arm the pin is 1/2". The gusset angle is pretty steep too, that's another minus.

 

[jwmelvin]

The load limit is the cable (perhaps the arm bending for a load in its center, but that seems fine). What are the horizontal length of the arm and vertical separation of the cable at the beam?

 

[cathead]

I'm hoping the vises do not stress the contraption too much, most definitely not for heavy lifting. We will see, the wall bracket is 3/8" through bolted through the 4" beam, and a Teflon pad under the arm the pin is 1/2". The gusset angle is pretty steep too, that's another minus.

Another consideration would be the torsion exerted on the beam the lift is mounted to. One way would be to test
it with the loads you intend and see how it holds up. The further out the load is extended, the more torsion on the
beam of course.

 

[JRaut]

The load limit is the cable (perhaps the arm bending for a load in its center, but that seems fine). What are the horizontal length of the arm and vertical separation of the cable at the beam?

Agree that the cable looks to be the weak leak (or really, those S-hooks and turnbuckles).

By my eye, looks to be about a 8:1 ratio from the wall to the tip of the tube where the cable is connected, compared to the vertical separation.

So that means (roughly) that if you're trying to pick up 200 pounds, the cable and its connections/S-hooks/etc. will need to hold 1600 pounds. Same goes for the bolts at the top of the bracket --- 1600 pounds between the two of them. No weak links allowed.

But you absolutely want a Factor of Safety (don't want a vise to fall from midair and land on your feet, and the boom to come crashing down on that beautiful mill). On something like that, your Factor of Safety certainly shouldn't be less than about 2, preferably a fair bit higher.

So we're talking the need for upwards of 3200 pound capacity on the cable/connections. That ain't nothing to sneeze at, and that's just for picking up a measly 200 pounds.

If I were you and intended to pick up a vise, I'd (1) size up the cable and beef up the connections; and (2) do a bit of a load test to at least 2x what you want to lift. Load it up carefully and slowly, and pay close attention to what's moving/stretching/bending. Stop, if you can, well before anything breaks.


(BTW I'm a structural engineer by day, so this is right in my wheelhouse.)

 

[jwmelvin]

^ yes, the various components in the cable link are probably more suspect than the cable itself. The small-angle approximation does seem fine for the geometry shown (at larger angles, the load does not scale simply as the ratio of lengths). I’d want that cable attached as high as possible on the beam, ideally up on the top flange. But since you are lifting pretty small weights, it’s likely okay; just realize the scaling that puts a large load on the cable link.

 

[mmcmdl]

Another easy option Mike would be go out and get yourself a die cart . It'll hold more weight than the rolling cart and can be lifted/ lowered for the mill table height . They are easy to move also . We use these in at work as you've seen in my pics I've sent you . Ask my former nightshift partner about his light duty crane experience . Dropped a 1300 lb. die onto the floor when one of the eye bolts stripped out and snapped the chain. It made a loud bang .