Daily Regrind, The

Today’s technologically advanced grinding machines allow high-quality tool regrinding to be done at a relatively low cost, whether the job is outsourced or performed internally.

Most large shops regrind their own cutting tools, because they have the resources to invest in machinery, staff and training. That’s not always the case with small to medium-size shops.

Before committing to an in-house grinding program, they need to consider a number of factors. These include tool consumption, the costs associated with in-house grinding, their company’s management style and the skill level of their operators.

Tool Use, Cost Considerations

The number of tools used from shop to shop varies widely. Kaddis Manufacturing Corp., a Rochester, N.Y., screw-machine house, consumes a lot of tools-approximately 25,000 a year.

"We do about 50 to 60 jobs a week, with some of them involving multiples of six or eight [tools]," said Kaddis’ toolroom manager, Tom Krest. The company regrinds all of its tools in-house on its six grinders.

When asked if he’d ever consider sending tools out to be reground, Krest replied, "No. The shipping costs alone would be incredible."

According to Ron Peruski, marketing and sales manager for Elk Rapids (Mich.) Engineering, a subsidiary of Star Cutter Co., "One of the things that almost nobody considers when they outsource is the cost of shipping." And, over the course of a year, these costs can really add up for shops that consume large numbers of tools.

Peruski said that some companies spend as much as $200,000 annually on shipping-enough to buy a new CNC tool grinder.

Timing is another critical issue for shops that use a lot of tools. The turnaround time for resharpening a standard tool is about a week, according to regrinding services interviewed for this article. A week can seem like an eternity to a shop running large lots for an extended period of time with specialized tools.

"It’s similar to farming out machinery work in the middle of the process," said Bill Freese, president of grinder manufacturer Rush Machinery Inc., Rushville, N.Y.

Freese said that a company considering the outsourcing option needs to realize that its tooling costs will rise, "because while one tool is out being sharpened, you’ll need a replacement to keep the machine running."

That fact doesn’t seem to bother Borisch Manufacturing Corp., a Grand Rapids, Mich., electronics manufacturer. It goes through approximately 200 tools a year and has always had them reground by an outside vendor.

"For a shop our size, it’s a matter of cost," said Borisch’s shop manager, Gary Hallman.

Not surprisingly, costs deter many shops from refurbishing tools internally. The biggest obstacle usually is the price of a grinding machine. Grinders range from a few thousand dollars to $250,000-plus.

Hallman said that staffing is another barrier. "If you grind in-house, you need to bring in someone who knows cutting tools," he said. "It’s really an art."

Borisch has had its tools refurbished at Melinn Tool Co. for years. Melinn, also of Grand Rapids, offers special services, including emergency grinding and local pickup and delivery.

The vice president of Melinn Tool, Dave Melinn, said that an advantage to outsourcing is that a shop gets its tools refurbished by a specialist.

"There’s nothing we haven’t seen or can’t do," he said. "We have guys here that have been in the industry for over 20 years, including myself." Melinn said that experience proves especially beneficial when customers send in tools with complex geometries.

Kevin O’Donnell, vice president of O-D Tool & Cutter Grinding Co. Inc., Mansfield, Mass., noted that a regrinding company’s know-how helps when it comes to standard tools, too. "Standard tools are pushed out like popcorn," O’Donnell said. "We can regrind tools and get them to tighter tolerances than when they were made."

Management Style

Management style is unique to each shop and will affect the decision about whether to regrind tools internally or outsource the job.

Certain managers like to have control over all aspects of manufacturing, including tool grinding. Keeping the job in-house allows them to track their tools, monitor quality and make on-the-spot engineering adjustments.

The latter is why Continental Teves grinds the majority of its tool in-house.

"We run all night," said Bob Hole, a tool engineer at Continental, Culpepper, Va. "So if I want to tweak a tool, maybe to improve a cut, I can just tell the night shift and it’s done in the morning."

Hole, whose company manufactures braking systems and consumes several thousand tools annually, also feels that his tools’ tolerances are too tight for regrinding services to handle. "We work with extremely close tolerances, like +0µm/-3µm, so we need to watch over quality very closely. It’s very difficult for regrind services to meet a tolerance that tight."

He conceded that he does send tools out when he’s flooded with work, but only those with less critical tolerances. "But they often come back different-like a mystery package," said Hole.

"We can regrind tools to tighter tolerances than when they were made." -Kevin O’Donnell

Hole cited what he considers to be another downside to outsourcing: Regrind services don’t always meet shipping schedules. "It might be that you told the service that you need your tools sent back overnight priority, then they forget to tell their people in shipping, or maybe bad weather in another part of the country delays your tools," he said.

On the other hand, O-D Tool’s O’Donnell said there are shop managers who prefer to send tools out to a service so that they can focus all their attention on production. He said one well-known cutting tool manufacturer sends him between 500 and 600 endmills a month. "They don’t want to be in the business of resharpening," he said.

Outsourcing the tool regrinding function allows a business to direct capital back into its manufacturing process, said O’Donnell. He added that turnaround time is faster with repeat orders, because the correct geometries for customers’ tools are stored in computer memory and can be instantly recalled by O-D Tool’s CNC grinders.

No Experience Required?

Some contend that today’s CNC grinders are so easy to operate that the need for highly skilled toolroom personnel is disappearing.

Elk Rapids Engineering’s Peruski said that current technology virtually eliminates human error. "You set up the machine once and it grinds the same way every time," he said. "It really brings parity to the process."

Greg Less, vice president at Cutting Tools Inc., a tool manufacturer in Bensenville, Ill., added, "You used to have to pay someone a lot of money to do specialized work. Now you don’t need the guys with all the experience."

However, Borisch’s Hallman argued that complex tool geometries still prove too difficult for many inexperienced toolroom workers.

Krest, of Kaddis Manufacturing, agreed, "You’re always going to need guys to do the specialty stuff or the manual one-offs. It’s hard to find someone with the finesse."

Regardless of how easy CNC grinders are to operate, their use by small and medium-size shops still depends on price, according to Less. He said that even though some CNC grinders cost less now than in the past, buying one still represents a significant investment.

"CNC machines are still $250,000, and that’s a big chunk for a small or medium-size shop," he said.

Regrinding Costs: In-House vs. Outsourced

A shop that consumes a large number of cutting tools can save a bundle by regrinding them in-house—even if it purchases a CNC tool grinder.

We compared the cost of regrinding tools internally to the cost of having an outside service perform the work. For purposes of comparison, we assumed that a fictitious shop regrinds 24,000 endmills annually. All of the tools are 3/4" in diameter; half are made of HSS and half are carbide.

Walter Grinders Inc., Fredericksburg, Va., supplied information about what it would cost to regrind the endmills on its Helitronic Mini Power CNC tool grinder-a $199,500 machine. According to Walter’s North American marketing manager, Ed Sinkora, there’s little difference between the time needed to regrind an HSS endmill and a carbide one. If the endmills were reground in lots of 10 by an operator earning $12 an hour, the per-tool cost would be $3.86, or $92,640 annually.

Based on information gathered from tool regrinding services, the average price to regrind a 3/4" endmill would be $4.46 for HSS and $11.15 for carbide, excluding shipping and discounts for lots over 50.

If the shop outsourced its endmills, the annual cost would be $187,320-a hefty $94,680 more than if it did the job in-house.

Companies that can justify the cost of a CNC tool grinder often realize substantial savings on regrinding costs.-D. Phillips

Benchtop Backup

With all the talk about high-ticket CNC grinding machines, you’d think it takes a million bucks to grind your own tools. It doesn’t. There are plenty of inexpensive alternatives. Among them are benchtop grinders, some of which can be purchased for less than $1,000.

Manufacturers of benchtop grinders understand their place in today’s world of CNC equipment, according to Roberta Nobile, marketing director at Precision Service Grinding (PSG), Franklin, N.J. When a customer’s big CNC grinder goes down, she said, "we’re like a lifeboat."

She also pointed out that benchtop grinders are relatively small and light, making them easy to move. Plus, compared to CNC machines, they’re easy on the pocketbook. PSG’s machines cost between $999 and $1,900.

Denise Montamble, customer service representative for Darex Corp., Ashland, Ore., credited low prices for the continued interest in her company’s benchtop grinders.

"Our most expensive machine runs $6,500," Montamble said. "That’s a lot less expensive than a CNC."

According to Montamble, Darex’s E-series grinder is the company’s most versatile. It’s geared for shops that consume fewer than 200 tools a week. Prices start at $2,198.

"These are everyday grinders," Montamble said. Each machine comes with a CBN wheel; diamond wheels are available for grinding carbide tools.

Darex also offers a line of grinders specifically for sharpening drills. Montamble said that they grind points on drills ranging from 1/16" to 1" in 30 seconds. The SP 2500 costs $2,498 and comes with a 135° wheel to split points.

Nobile added that standard tools aren’t a problem, but benchtop grinders can’t do everything. "We don’t do the fancy stuff," she said. Drills with specialized points and high-performance endmills may be difficult to resharpen with a benchtop grinder, due to the tools’ complex geometries.

Nobile believes that people look for repeatability and precision in a benchtop grinder, along with the sense of security it provides. If the ship goes down, it’s always nice to have a lifeboat around.

-D. Phillips