Proof testing cable clamps

[STRR]

As a cable bends either over a sheave or on/off a drum, the wires will move past one another. Thus it is imperative to provide some lubrication to minimize wear and allow for easier movement. The down sides are: Pain in the a$$ to do, attracts dirt, and is messy to handle.

Related to cycles, no more than you are telling me you will be using the hoist, lubed up, that cable might out last the life of the furnace. I am not sure of the engineering put into 3/16" cable but I know 3/4" and larger are designed to make 100,000+ cycles with proper D/d, lubrication, and handling. I would bet good money 3/16" cable would be good for at least 5,000 cycles with proper care/use.

SO, it looks like you're good to go for quite some time.

If you are compelled to do a load test, fill the furnace (cold) with as much as possible. drape scrap over the top of the furnace until you reach your test load weight. Then hoist the furnace 1 INCH of clearance. The first few inches will be the greatest load on the cable and winch. As you go higher more weight will transfer to the bearings until the furnace is empty. We load test for 30 minutes. I suggest you might consider load testing the amount of time you will have a load on the cable when doing a pour. I kind of doubt that will be longer than 30 minutes or so. I like to make the cable dead end tail, a specific length. This can be whatever you want, say 4". Knowing this, it will be easy to measure the tail prior and after a pour to see if any movement happened. Check the torque on your clamping bolts. As long as that doesn't change and the tail length is the same, you're safe. Generally speaking: Once a cable has taken a "set", it will stay in that "set" until a great amount of energy is exerted to change the "set".

We use a socket and wedge on the end of our hoisting cables. Once the cable has taken a "set" around that wedge in the socket, it's easier to cut the end off than it is to straighten it out again.

Good Luck Harold,
Terry

[Harold_V]

Thanks, Terry.

I'm somewhat more at ease over this topic now. The great input I've received has been very helpful, and I finally came to realize that weighing the furnace wasn't beyond my capability. I started thinking about the 1,000 pound capacity scale I have, the one I use when mixing my foundry sand (one must use precise measurements of the additives, including water). Why not weigh the lifted half? Shouldn't be all the difficult, so I moved the scale behind the furnace, then lifted it high enough for the lifting bar to extend out enough to stand on some 4 x 4's. I tared the lumber, than stood the furnace on the two pieces, which bear on the scale. 310 pounds with an empty furnace. That tells me that the predicted weight of 700 pounds is quite representative of actual weight, considering this furnace melts 70 pounds of iron.

Here's a picture of the setup---with the furnace tilted about 28°.

Thanks for the great guidance I received.

H

[STRR]

Harold,

Great news. When you get into production, I may be one of your first customers. I have a wheel pattern ready to go. You could get some practical experience and make some money at the same time, while I get castings to machine for my Quick Draw McGraw cartoon train.

I love good news in the morning.

Thanks,
Terry

[GlennW]

Something to ponder that you might find this interesting.

This is the lifting sling for a 1850 pound engine and calls for 1/4" cable. I meant to post a picture of a new one that I have in stock in case I ever need to replace my forty some year old one. I had them made at a wire rope and sling operation.

[Harold_V]

Thanks, Glenn. Not only interesting but encouraging! The 3/16" cable on my lift looks rather frail, but everything indicates it should function in an acceptable fashion. I've been lifting the furnace with the same cable with my jib crane and it has been without issue. Knowing I'm lifting no more than 400 pounds gives me considerable comfort.

Terry----I have experienced numerous failures with the venture, although the vast majority of them are related to the metal cooling too quickly. If this tilt system solves the problem, as it's intended to do, I would entertain the idea of pouring wheels for you. I wouldn't want to undertake that project unless I was perfectly satisfied that I could provide acceptable quality.

I'm using recycled rotors for material. I use ONLY those made without ventilation (single disc without air space between two surfaces). They are capable of being fully cleaned before melting, which I do by quartering, then tumbling the sections in an old cement mixer, along with some gravel. Works great and doesn't take much effort on my behalf. I have to quarter the rotors in order to get them in the furnace, anyway.

Melting rusty materials isn't a great idea, as some of the rust reports in the casting, degrading the quality.

H

[Harold_V]

Chains get very hot around induction furnaces. We used fairly fast cable hoists to tilt the furnaces.

Jim B

Jim,
I've had no end to issues with the foundry setup. The jib crane had a problem (bad switch), then when I got it repaired and tried to run the furnace the original KVAR meter had stopped working. I, fortunately, found one that could be used, albeit made by Westinghouse instead of Hickok. The specs were virtually identical, so I made the purchase and got it installed. There was a cautionary note on the face of the meter that a given external device was supposed to be used but it was referenced only by a number that had no meaning without literature from Westinghouse, which is not available. I took my chances and installed the meter, which operated quite nicely until the magic smoke got out. I'm going to address that with a new thread, one about fixing a meter, so I won't go into any details here.

The one thing that surprised me today (when I did a test drive on the meter I repaired) was that the cable I am using to empty the furnace started smoking. The furnace had been operating long enough for the chamber to be up beyond red heat, with the smoking starting when I increased wattage. I cut power and started thinking---knowing I couldn't continue the course. A Faraday cage quickly came to mind, so I placed a thin sheet of aluminum between the furnace and the cable and was pleasantly surprised to discover the cable returned to cold. I was successful! The tilt mechanism works a treat, although I'm going to increase the speed, which is a touch slow.

H

[rrnut-2]

Well Harold, it sounds like you are getting there. Is your lifting yoke on the furnace insulated? If it isn't, that will give you trouble. Also, on most of our furnaces, the rear most angle on the top of the furnace is aluminum, that cuts down on problems.

Jim B

[Harold_V]

Well Harold, it sounds like you are getting there. Is your lifting yoke on the furnace insulated?

Yes, it is. I made a new one to shorten it due to limited height. It mounts on both ends through fiberglass bushings, so it's isolated from the entire furnace. Even the lifting supports are isolated. Anyway, the piece of aluminum solved the problem so I'm no longer concerned. It does serve to demonstrate how critical proper material selection is, though. Induction heating is a whole different world.

H

[rrnut-2]

Induction heating is a whole different world.

Yes it is. You would be amazed at some of the things that I have seen involving induction furnaces and their power supplies.

Jim B