Rope size on a pulley????????????

lenray · Jul 10, 2021

I am driving down a 2 inch well casing using my Ford 9N.Have a rim bolted to my pulley and run a rope around the pulley. Pull on the rope a little and it lifts a 100 lb. weight. Does the diameter of the rope make a difference???? In the past I used a bigger dia. rope and it seemed to pull easier that the smaller Dia. rope I am using today...Or am I just older today ??????

rustred · Jul 10, 2021

Definitely the larger diameter rope is easier. That would be about 1 1/2 rope. Same as cat head set up on drilling rigs. But no longer allowed. Used them a lot. Just dont get to many wraps on the rim. As the cat head is flatland shiny and use about three wraps , four wraps tops for the heavy collars. Any more and u get yourself in trouble. In ur situation a would say two wraps be lots for 100 lbs.

Janicholson · Jul 10, 2021

Smaller rope, though more flexible, has less surface area than a larger rope where it contacts the rim flange. thus less friction surface at the contact. Rope fiber material also makes a difference. If it is working all good. a pair of rope grippers might be usable. Jim
one idea.

rustred · Jul 10, 2021

Think u get in trouble pretty fast with them things on the rope. The number of wraps control the weight. Plus the rope has to be the size to fit in ur palm of hand and have a good hold on it. 1 1/2 would be minimum even 2. Small rope wont pull or be hard to pull. Plus u need control going down thats why # of wraps matter. Plus u cant sit there with the weight gor too long as it will get hot. Plus its a slow turning drum. Plus u need to wear gloves for sure. Could lift 8-10000 lbs with a cat head and rope picking up drill collars off the catwalk and mouse holing them.

guido · Jul 10, 2021

lenray,

Smaller rope will be deeper in the pulley, much harder to pull. Ideally the rope should be level with the groves, or just a bit into them.

Guido.

old-9 · Jul 10, 2021

I used a one inch rope. As a retired electrician have used capstan drives to pull a lot of cable, use the smallest number of wraps as you can and Don't let the rope cross! Do you have a helper to run the clutch if you get into trouble? joe

bc · Jul 11, 2021

Size the rope according to the weight you are picking up and pulling. Allow extra for the initial pull. Preferably use a manilla rope of at least 3/4 and up depending upon the weight. Used a cathead all the time to pick up drill pipe & collars, etc. On the big triples and jackups I used in the middle east back in the day we used air hoists and steel cable.

Nylon rope can get hot and lose its grip on the cathead plus it can stretch and not work as good for what you want to do assuming you will have the rope on the cathead all the time and stand there pulling and releasing the end to hammer your pipe down. Poly rope may melt on you. For what you are doing using just a short piece of rope then you can make about any size work but the bigger the better. Just have to figure how much weight.

In Pakistan I seen them digging a well using a 3 pole tripod with an anchored horizontal wood pole used as a spring pole. Basically a manual cable tool rig.

I bot a bunch of electric fence wire at a sale. Guy used old wheel rims with extensions welded on made of 3/8" round rod. Then had spacers welded on so he could mount them.

Rope size on a pulley????????????

lenray

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rustred

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Janicholson

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rustred

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guido

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old-9

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bc

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