Scott’s Workbench

When is it really time to replace a cartridge?

We have heard many stories of an installer that has had the same cartridge in his CPT tool for year and it still works great. The truth is either they don’t use the tool that often or they just don’t realize how worn the blades are until they replace it with a new one. We’ve all experienced this at home with a knife we thought was sharp until we replace it and realize how bad it really was. So how long should a cartridge last and what are the signs that it needs to be replaced?  The life expectancy of a cartridge can be affected by many things.

  • Braid coverage
  • Jacket materials
  • Temperature
  • Flooded cables 

First off you should know the blade in the RBC (Replacement Blade Cartridge) and are NOT razor blades like found in other tools in the industry. Those types of blade dull quickly cutting facial hair, so cutting metal braids obviously isn’t a good match nor is it what they were intended for. We use a very high grade of tool steel designed specifically for cutting the metal braids in coax.

Braid coverage:

Its common sense that a blade cutting a 60% braid cable will last longer than a cartridge used on 95% braid quad cable. This is simple math ,45% more braid is being cut. Newer bonded tri-shield cable designs add another factor that was not present just a few years ago. The tool now must cut through a layer of metal foil tape that had been bonded to the underside of the jacket. Non bonded cables did not require the blades to cut completely through the foil 

Jacket Materials and temperature

There are two common types of cable jacket materials used in drop coax .PE (polyethylene) and PVC (Polyvinyl Chloride).PE jackets tend to be softer and more flexible but don’t offer the durability requirement for certain applications, PVC jackets are much harder and more commonly used for direct burial, messenger cable and Plenum applications were fire retardant jackets are required. PVC jacketed cables being much harder will certainly play a role in lower blade life expectancy but, temperature also has a major effect. Both PE and PVC become much harder as temperatures drop and in turn reduce blade life. This factor can be eliminated with the use of a Cable Prep Heat Prep tool.

Flooded cables = Maintenance:

Many people are not aware that maintenance can be done to the cartridge of a prep tool to increase the life and performance of the tool. When flooded cables are used cleaning of the cartridge is a must. The flooding compound builds up on the blade surface and on the cartridge radius. The sticky compound attracts dirt and debris to the radius of the cartridge and can reduce the depth the blade penetrates the cable jacket. The effects can range from scalping or failure to remove of the jacket to severe reduction in blade life.

If the tools stop removing the outer jacket do not assume that the blade is dull, first check to see if any jacket material has been wedged next to the jacket stripping blade. If material is found, using the center conductor of a prepped cable simply drag the trapped material away from the side of the blade. The trapped material will reduce the depth the blade can penetrate the cable. DO NOT USE YOUR FINGERS. This should always be looked for when scalping of the cable jacket occurs. Scalping of the jacket can happen if the tool is removed from the cable before the blades have completely cut through the jacket.

What is scalping:  This occurs when you attempt to remove the prep prior to the blades completely cutting through the jacket causing the blades to skim over the top, scalping a small piece of jacket and wedging it next to the jacket blade .

Cleaning the cartridge using a Q-tip dipped in Cable Clear or alcohol works well to remove cable flooding from the cartridge.

Warning signs of a dull cartridge.

  • Braid wrapping around the center conductor
  • Braid not cut / leaving long strands
  • Uneven or pyramid like tearing of foam
  • Excessive rotations required
  • Jacket not removed
  • Pitching the tool closed to get the jacket cut to come off

All these issues can be cause by a worn-out tool body as well. Even a new cartridge cannot make up for a worn tool body. Eventually the tool just must be replaced.

 


© Copyright 2020 Ben Hughes Communication Products Company. All rights reserved.

Cable Prep, the Cable Prep logo, Tools You Trust, the Cable Prep Tools You Trust logo, the CPT logo, FOCUS, the FOCUS logo, Gator, the Gator logo, Super CPT and Wing Ding are registered and common law trademarks of Ben Hughes Communication Products Company. Cable Prep® products and tools are covered under one or more of the following patents. U.S. Pat. Nos.: 5,561,903; 5,647,119; 5,749,270; 7,849,589; 7,232,235; 7,322,713 and other patents pending.