Damage to cord galvanizing using piano or hook knife methods.

Posted in: , on 23. Apr. 2006 - 10:27

On a recent thread Mr Nordell mentioned


2. REMA Stripper (RS or its equivalent) does minimize scraping damage to cord galvanizing verse piano or hook knife.

I’d like to hear comments on:

1/ How much damage is actually done.

2/ Which has the most damaging affect on the cables, hooking or piano wiring.

3/ What long term affect it has on the cables / splice.

4/ Can it be minimized using these methods and if so how. ■

Regards Bruce Baker Conveyor Consultants & Project Managers http://www.conveyor-services.com ________________________________________ "Professional Service" As Consultants our Customers expect and demand the right knowledge, expertise and experience and over the last 26 years we've proved we can do this time and time again, we guarantee it. "Worldwide Installations" We've worked all over the world and in all circumstances and conditions, from the Tropics of North Queensland, Australia to the Deserts of Saudi Arabia. "Expert Training" With 26 years experience, our customers bank on our extensive knowledge and expertise when they ask us to conduct training, we create a training programs customized to suit your specific requirements. ________________________________________
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Re: Damage To Cord Galvanizing Using Piano Or Hook Knife Method…

Posted on 23. Apr. 2006 - 11:18

Hi Bruce,

There are a few basics we must always consider when we are spilcing a steel cord belt and they are;

1) The splice strength, everything else being equal, is related to the surface area that is to be bonded. In other words a square section of rubber has a greater surface area that a circular section if the parameters are set by the cable diameter. A simple calculation using 7mm cable surfices to illustrate that the surface area is potentially 25% more if you have a squared section rather than circular and this translates directly to theoretical splice strength.

2) The bond we rely on in splicing is the zinc sulfur bond so any device that potentially can damage or remove the zinc coating from the steel cable filaments must be avoided if you want to maximise splice strength

3) The splice strength is all about bonding rubber to rubber preferably. While we can get very good bonds with the zinc galvanising we get better outcomes if it is rubber to rubber so we want to avoid exposing cable if possible if we want to maximise splice strength.

Against all this is the time required to individually fillet each cable as was done traditionally so many "labour" saving devices have been developed that ease the workload and reduce splicing time. Of all these devices the one that seems to maintain the basic integrity of the splice best has been the various cable ploughs of which the REMA system is one example. We get away with a lot when we splice because we use conservative safety factors so many of our short cuts never get exposed. When you have to work on very high tension belts where splicing is absolutely critical then these issues become factors that must be considered.

All the best

Col Benjamin

Gulf Conveyor Systems ■