Tom Bowman is an expert when it comes to cutters — how they work, what they do and how to design and build them. 

The owner of Bowman Tool Company & Systems has been in the business for 25 years and still runs the shop and designs the cutters his company releases. 

Bowman says cutters are important to have when expanding into pipelining and rehabilitation. Once the lining process is finished, a reinstatement cutter reconnects the laterals to the mainline. 

“You put a bit onto the cutter and you go into the pipe and grind away sharp protruding edges and protruding laterals to smooth out the interior of the pipe,” Bowman says. “The cutter cuts those protrusions off and grinds them smooth to the pipe, so when you reline, you don’t have any sharp edges or mismatching pipe.” 

Other cutters clear away debris to streamline the lining process. 

“If you have really stubborn root problems or concrete left from past pipe work sometimes you can’t jet them out, you have to go in and get them out with a cutter with a carbide or diamond coated cutting bit,” Bowman says. 

Percussion Milling Cutters from Enz USA are designed to remove deposits such as concrete, injection cement and heavy mineral deposits. The tools have a combination of carbide and diamond teeth and use rotating percussion power as a way to remove hard debris and deposits. The cutters offer 600 to 3,000 impulses per minute and up to 12 tons of impact force. They clean pipes from 4 to 24 inches.           

Learning what works

Being in the business for 25 years, Bowman has come to learn what works and what doesn’t work when it comes to cutters.

He says contractors interested in purchasing cutters need to look at what the total maintenance cost for a year would be if they are operating it 40 or 60 hours a week. 

“I would look to see if there was any warranty and what the life expectancy of the internal parts are and if they are covered by some warranty as well,” Bowman says. 

He also suggests looking at how quickly a cutter can be taken apart and cleaned and put back together again. 

The Dominator 430 from Bowman Tool Company & Systems can be disassembled and reassembled quickly. “You can take it apart, clean it and put it back together in about 30 minutes,” Bowman says.           

The 72-pound reinstatement cutter is designed to operate in 6- to 30-inch lined pipe. It has only eight moving parts and all electric motors are isolated at the end of the cutter in a watertight chamber, eliminating water damage and allow for easy access. There is no external air tube, giving the cutter a streamlined design. The Dominator 430 has a 2.5 hp geared air motor, which reduces reinstatement time by 80 percent, according to Bowman.

Bowman also recommends those looking to purchase a cutter determine how many units they need on a truck — in case one goes down — and also to talk with other contractors. 

“I would call others that have cutting machines and talk to them and get it right from the horse’s mouth on how dependable the machine is,” Bowman says. “Do your research.”    

Taking control

Cutters can come with several different controls. Some have one joystick that controls all three axes, while other cutters have two joysticks. 

“There are controls that require the use of both hands and both thumbs,” Bowman says. 

The Digital Tap Cutter Controller from RS Technical Services is a single-conductor module that is compatible with all RST single-conductor mainline systems and operates multi-conductor cutters and other robotics. 

The unit can control and monitor up to 10 functions, a proportional joystick control and programmable current limits on the motors to protect them from damage. It also offers test modes and equipment operations, and an on-screen status display of settings is easy to read and interpret. 

Bowman notes that it’s important to look at each cutter and it’s controls because not everyone is comfortable with the two joysticks and not everyone is comfortable with the one joystick. 

“Everybody likes their own thing and technology is changing all the time,” Bowman says. 

(All products from Cleaner Product Focus, October 2012.)