Over a Barrel

The shop has five cylinder service bays, one for suspension cylinders, one for lift cylinders on small loaders and three for high-force cylinders. “We can replace the barrel, rod, rod eyes, head/seal areas, hydraulic lines and connections, or custom fabricate new cylinders to spec,” said Michael Carter, the service coordinator.

There are four hydraulic cylinders on the average Cat machine, so the shop stays busy, processing about 1,000 cylinders in 2011. “During the summer, we may have a hundred or more cylinders outside our shop waiting to be rebuilt, because our indoor storage is full,” added Carter.

HONING CYLINDERS FOR CUSTOMER SAVINGS AND SHOP PROFITS
The shop’s old hone consisted of a drill motor on a sliding carriage that lacked the power, capacity and rigidity needed for doing serious work, according to Carter. “It could produce a surface finish, but not remove metal.” Whayne agreed to beta test the new all-electric HTA cylinder hone and later purchased the machine with a 12 ft (4 m) part capacity.

The HTA tube honing system handles parts weighing up to 8,000 lb (3629 kg) with ID ranges from 2.5 in to 21 in (63.5 mm to 533 mm). This machine is designed for resurfacing and repair work where light-duty stock removal up to 0.030 in (0.76 mm) is required. Standard models are sized for 6 ft (2 m) and 12 ft (4 m) part lengths, and custom lengths are available.

The HTA is equipped with a Siemens drive and PLC control with touch-screen HMI for setting machine parameters such as stroke reversal point, spindle/stroking speed and crosshatch angle calculation. The control features a load meter to determine areas of bore tightness, and provides the ability to dwell the tool in multiple areas to correct part geometry.

A touch screen-controlled hone provides a safer working environment and reduces operator fatigue. It also provides better quality parts by producing a controlled crosshatch pattern, which allows the honed surface to retain oil or grease, ensuring proper lubrication and ring seal of pistons in cylinders.

“We were not sure about downtime for a new machine, but it has proven extremely reliable and we’ve used it to hone cylinders from 2.5 in to 17 in (63.5 mm to 432 mm) diameter, and 6 in (152 mm) length to over 21 ft (6.4 m),” noted Carter. “We simply created a table with an adjustable-height V-block to support parts that overhang the machine. We have used up to a 21 ft drive-shaft length on the machine, and we can hone from both ends of the part if need be. Our cycle time for most barrels is about 30 minutes, which includes setup, honing and washing the part.”

Whayne uses both roughing and finishing abrasives to remove scratches and rust and imparte a specific crosshatch surface finish on the barrel bore. “We can increase the cylinder bore diameter up to 0.254 mm (0.010 in) in relatively short time, removing rust and all but the worst scratches, and remain within Cat machine specifications,” stated Carter. “Our old hone simply could not do this. The HTA hone is easy to setup also. The control calculates the correct crosshatch angle. It’s been a very reliable system, too, with no appreciable downtime.

“We scrapped a lot of hydraulic barrels or sent them out to other shops prior to acquiring this machine,” smiled Carter. “Now we can salvage a cylinder with honing, and the cost and time for the customer is a fraction of replacement. In the current economy, our customers appreciate this.”

Sunnen Products Company, 7910 Manchester Road, St. Louis, MO 63143, 800-325-3670, Fax: 314-781-2268, [email protected], www.sunnen.com.