Jib crane hook modification

The Photo Album is a place for "Shop Shots" as well as pictures and descriptions of projects that we are working on. Show off your Shops, Machines, and your Projects!

Moderator: Harold_V

Post Reply
User avatar
Harold_V
Posts: 20231
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Jib crane hook modification

Post by Harold_V »

Some time ago I built a jib crane for use in handling a ladle of molten metal, as well as heavy molds. If you care to see what it looks like, here's a link that provides a picture https://www.chaski.org/homemachinist/vi ... 4&start=72 . Scroll down a few posts to see the picture.

I have the capacity to melt 100 pounds of iron, so some means of handling the weight was necessary.

I was not happy with the hook assembly, which did not allow the hook to rotate freely, so placing a heavy load as desired would have been a little more difficult than necessary, and could complicate efforts to install the cope on a mold. As a result, I decided to rebuild the hook and block assembly, so it would float, plus I wanted to add some weight so the cable wouldn't bird nest when the crane was used without a load.

I had considered a few different designs, and settled on one that used a thrust ball bearing for the hook. It would require building a cone end, in which I could add weight, plus a long housing to which the cone would attach. The long housing allowed for more weight, plus it provided a little protection from injury. The original design made it all too easy to get a finger in the hook/sheave assembly. I settled on a design that allowed the existing assembly to be installed inside a piece of 4" schedule 40 pipe. That required the bottom end of the sheave assembly to be shortened, and the original hook removed. The new hook, which would be mounted with the thrust bearing, would be installed in the cone, which, in turn, would be installed in the end of the pipe with a thread.

I began the project by machining the cone from a piece of 4½" mild steel. Once machined, the end was single point threaded 4¼"-16, using thread wires to determine proper pitch diameter. With that part finished (it would be needed for fitting the internal thread of the housing), I was now ready to machine the housing.

The housing necessitated work on the 9-1/8" long piece of schedule 40 pipe. To do the necessary work, I turned to the "magic bullet" of lathe holding, soft jaws.

DSC00048.JPG

With the jaws made, installed and machined, I was ready to start work on the piece of pipe. It was faced, then turned and bored to clean up, so I had a round and straight piece to work with. Thanks to the use of soft jaws, I could now grip the machined end to machine the second end, and result in a straight, round and concentric piece of pipe. With that done, I then bored and threaded the end to fit the cone.

With the housing now finished, I had to turn the corners on the block assembly so it would fit inside. By making a holding jig for the block assembly, the corners were machined in the lathe such that the block body was properly centered within the pipe, and machined to provide enough clearance for the assembly to fit

I was satisfied with the end results, so it was time to add weight. Using the cone as a mold, and a core installed to create the required cavity for the shank of the hook, I cast the bottom weight.

DSC00052.JPG

I made a couple more simple molds and cast side weights and a center weight. Overall, I managed to add 24 pounds to the assembly. Enough to prevent bird nesting, which was my goal.

DSC00053.JPG

I added an exterior safety stop to the body, to prevent the assembly from contacting the bottom of the hoist. It's the strange looking projection at the top of the housing, which you can see in the picture of the installed hook assembly. I am now well satisfied with the hook, as it rotates effortlessly and there is no more bird nesting of the cable on the drum.

DSC00054.JPG
H
Wise people talk because they have something to say. Fools talk because they have to say something.
User avatar
Steggy
Posts: 1976
Joined: Tue Jun 28, 2011 9:19 pm
Location: JB Pritzker’s Hellhole
Contact:

Re: Jib crane hook modification

Post by Steggy »

Harold_V wrote: Fri Oct 23, 2020 1:20 amSome time ago I built a jib crane...I was not happy with the hook assembly...

Pretty slick, Harold!

While on the subject of hooks on lifting devices, I really detest what is done with cheap cherry pickers. I've seen a few from a certain country on the other size of the Pacific in which there is a nut welded to the hook shank, and that is the load-bearing component. Needless to say, there's quite a bit of friction in such an arrangement, which makes controlling the load that much harder.

Overall, I managed to add 24 pounds to the assembly.

Just don't let it smack you in the head. :D
———————————————————————————————————————————————————————
Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
User avatar
liveaboard
Posts: 1970
Joined: Sun Dec 08, 2013 1:40 pm
Location: southern Portugal
Contact:

Re: Jib crane hook modification

Post by liveaboard »

A thrust bearing for few hundred pounds load, crazy overkill, I love it.

Another work of engineering art by Harold.
Patio
Posts: 1369
Joined: Wed Oct 06, 2010 3:14 pm
Location: Centralia Wa

Re: Jib crane hook modification

Post by Patio »

Another piece of the puzzle!
Looks nice Harold. That will make pouring into the flasks much easier.
Live for the moment!
Prepare for tomorrow!
Forgive the past!
jcfx
Posts: 713
Joined: Sun Aug 09, 2009 1:24 pm
Location: NY

Re: Jib crane hook modification

Post by jcfx »

oooo !
Harold, Can you do a thread on how you made those sweet soft jaws for holding the pipe ?
They look like they're cast ?
User avatar
GlennW
Posts: 7284
Joined: Sun Apr 15, 2007 9:23 am
Location: Florida

Re: Jib crane hook modification

Post by GlennW »

I like those jaws!
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!
User avatar
Harold_V
Posts: 20231
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Jib crane hook modification

Post by Harold_V »

jcfx wrote: Tue Oct 27, 2020 11:30 am oooo !
Harold, Can you do a thread on how you made those sweet soft jaws for holding the pipe ?
They look like they're cast ?
Interestingly, my original intention was to do a post about the soft jaws, not their purpose. Then I figured it might be interesting for others to see how I solved the puzzle of a floating hook that had to be out of the way, yet heavy enough to prevent bird-nesting of the cable.

Sure, I'll do a post about the jaws. As I took no pictures of the jaws being made, all I will be able to show is the finished jaws. I'll try to get to it in the next day or so.

I own a blast cabinet and have a habit of blasting things to improve their appearance. The jaws look like they're cast because of their exposure to aluminum oxide.

Glenn---
I originally made a set of jaws from the gripping portion you see in the picture, but years ago (more than 45). I had removed them from the base and kept them on hand in case I had a future need, which turns out to be a good idea. The original jaws had a single gusset, a round rod, in the center. It complicated installing the jaws, so I elected to use a pair of thin gussets this time, one on each side of the mounting bolt holes. They were originally built because I had to turn a long piece of aluminum pipe (I recall it was 18" long) and too large in diameter to fit my steady. The jaws worked perfectly well for that purpose, but the chance I'd need them again was slim. By removing the gripping portion, I was able to re-use the bases for other projects. That's the advantage of making soft jaws from steel instead of aluminum if a guy doesn't have TIG capabilities (I didn't at that time).

H
Wise people talk because they have something to say. Fools talk because they have to say something.
Post Reply