Advanced Technologies New Cylindrical Grinding Capabilities. Titus grinder

US465737A. titus. Google Patents

Publication number US465737A US465737A US465737DA US465737A US 465737 A US465737 A US 465737A US 465737D A US465737D A US 465737DA US 465737 A US465737 A US 465737A Authority US United States Prior art keywords wheel shaft grinding machine casting Prior art date 1891-12-22 Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Expired. Lifetime Application number Publication date 1891-12-22 1891-12-22 Application granted granted Critical 1891-12-22 Publication of US465737A publication Critical patent/US465737A/en 1908-12-22 Anticipated expiration legal-status Critical Status Expired. Lifetime legal-status Critical Current

Links

• 238000005266 casting Methods 0.000 description 26
• 241000239290 Araneae Species 0.000 description 24
• 230000036633 rest Effects 0.000 description 6
• CSDTZUBPSYWZDX-UHFFFAOYSA-N Amyl nitrite Chemical compound CCCCCON=O CSDTZUBPSYWZDX-UHFFFAOYSA-N 0.000 description 2
• 210000003746 Feathers Anatomy 0.000 description 2
• 230000000875 corresponding Effects 0.000 description 2
• 239000000428 dust Substances 0.000 description 2
• 238000000034 method Methods 0.000 description 2
• 230000002035 prolonged Effects 0.000 description 2

Images

Classifications

• B — PERFORMING OPERATIONS; TRANSPORTING
• B24 — GRINDING; POLISHING
• B24B — MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
• B24B3/00 — Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
• B24B3/36 — Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades
• B24B3/46 — Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades of disc blades
• B24B3/466 — Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades of disc blades of cultivator disc blades

• Y — GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
• Y10 — TECHNICAL SUBJECTS COVERED BY FORMER USPC
• Y10S — TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
• Y10S451/00 — Abrading
• Y10S451/902 — Brake abrading

Description

IVOR R. TITUS, OF HUNTINGTON, VEST VIRGINIA, ASSIGNOR TO HIMSELF AND ELY ENSIGN, OF SAME PLACE, AND FERDINAND E. CANDA, OF NEW YORK, N. Y.

Be it known that I, IVOR R. TITUS, of Huntington, in the county of Cabell and State of Vest Virginia, have invented a new and Improved Grinding-Machine, of which the following is a specification, reference being had.

to the annexed drawings, forming a part thereof, in which- Figure 1 is a plan view of myimproved 1o grinding-machine. Fig. 2 is a vertical section taken on line ’00 w in Fig. 1. Fig. 3 is a vertical transverse section of the clutch-wheel for revolving the wheel being ground. Fig. iis a horizontal section of the support of the grinding mechanism. Fig. 5 is a vertical transverse section taken on line y y in Fig. 1, and Fig. 6 is a vertical transverse section taken on line 2 z in Fig. 1.

The object of my invention is to construct a simpleand efficient machine for grinding the peripheries of car-wheels.

My invention consists in a rigid frame car- 2 5 rying a spider provided with three guidingrolls, one of which is furnished with a clutch for engaging the flange of a car-wheel for rotating the sameduring the process of grinding, grinding mechanism provided with a wheel adjustable laterally and vertically, and means for suspending the wheel during the operation of grinding.

It also further consists in the combination, with the grinding-machine, of a crane for lift- 3 5 ing and placing the wheelin the machine, all

The body-castingA is made circular in form with a section removed, forming the opening B for the admission and removal of wheels or other articles to be ground. The casting A rests upon three supports a, which raise the machine to a height convenient for the operator. On the top of the body-casting A and bolted firmly thereto are three upright supports 1), upon which rests the spider C, which is bolted firmly to each upright support. The spider O is provided with three arms 0 c c, the arms 0 0′ being provided with longitudinal slots 01 d, in which are inserted and 5c clamped the studs e e, upon which are mounted the centeringrolls ff. The third arm a is provided with a longitudinal slot 6 and the walls of the slot and the top and bottom of the arm 0 are planed, forming a ratdial guide for the cross-head D, which is arranged to be moved back and forth by the screw g, swiveled in the end of the spider and entering a nut in the cross-head.

In the forward or inner end of the crosshead is journaled a vertical shaft E, provided atits upper end with a bevel-Wheel h and at its lowerend with a roll i, secured to the shaft and furnished with a friction-clutchj, which is presently to be described. The upper end of the shaft E and the bevel-wheel h are inclosed in a turret F, in which is journaled a shaft 7t, carrying a bevel-pinion Z,whicl1 engages the beveh-wheel 71. Upon the end of the shaft’k, projecting through the side of the turret F, is mounted a pulley m for receiving the belt by which the shaftE is rotated. Upon the lower end of the shaft E, which is prolonged beyond the roll z’, is loosely mounted a clutch-collar a, which is prevented from tu r11- ing upon the shaft by means of a slot and feather. The clutch-collar n is provided with a chambered boss 0, containing aspiral spring p, which is pressed upwardly against the clutch-collar by a nut “I”, mounted on the threaded lower end of the shaft E. The upper surface of the clutch-collarn is concaved to adapt it to the inner surface of the carwheelfiange. The clutch thus constructed engages the flange of the wheel with a powerful friction, at the same time allowing irregularities to pass without straining any of the parts. 1 l

The turret F is provided with a cover, which excludes grit and dust from the gearing and from the bearings of the shaft.

The grinding mechanism is located on one side of the body-casting A, between the arms 0′ c of the spider G. The hood-casting G is fitted to ways on the right-angled support II, which allows the hood to slide back and forth while preventing it from moving laterally. In a similar way the right-angled support II is fitted to ways on the body-casting A, so that it may be moved in a vertical direction.

In a hood-casting Gr is journaled an emerywheel shaft I, the upper end of which pro jects through a bearing in the hood-casting halves ofthe plate are forced together and and is squared, the lower end being journaled in the lower part ofthe hood-casting. The said emery-wheel shaft I is provided with a pulley s and with a collar t for clamping the emery-wheel u in the position of use.

The hood-casting G is provided with a nut jonrnaled in a frame j, secured to the body-. casting 1A. Upon the same shaft ismoun’te’d’ a’worm-wheel Z, which is engaged by aworm m on the shaft n, which is also journaled in the frame j. The shaft 17. is provided with a hand-wheel 0, by which it may be turned in one direction or the other to raise orlower the right-angled support’H to adjust the emery-wheel u to the work being done.

The spider O is provided at the center with a center plate J, formed of the halves p 10 pivoted to the spider at the rear of the slot q in’the spider which is opposite the center of theopening B in the body-casting A. To the halves p p of the plate J are piv oted the levers 0″ r which are oppositely arranged with respect to each other and provided with curved slots.9 for engaging the studs t t projecting from the spider. By moving the levers r r rear’wardly the halves p’p of the plate J are drawn apart. By moving’said levers in the’opposite direction the locked.

The center of the’plate isfurnished with a central aperture for receiving the suspensionrod K. The said rod is provided with aball L, whi’ch rests in a hemispherical cavityin the plate J,and’with an eye-nut M on the upper end of the rod for receiving the hook of the chain belonging to the crane, presently’to be described.

fitted a collar 0, having a convex cavity adapted to fit the head of the rod K and provided with a flange it for supporting the wheel while being ground.

At the side of the machine are arms P P, which are attached to or formed upon one of the standards b of the body-casting A. These arms are bored vertically to receive the shaft Q of the crane R, the said crane consisting’of a right-angled arm secured to the shaft Q, provided in its free end with a sheave “u and having formed in its vertical portion a windlass S, consisting of the shaft or drum T, which receives the chain w, the spur-wheel (0 mounted on the drum or shaft, the shaft 6 provided with the pinion c engaging the which’the crane is operated. The free end The lower end of the rod’K-is” furnished with a convex head N, to whichis” of the chain ’10 is furnished with a hook a for engaging the eye-nutM.

The operation of my improved machine is as follows: The levers r ‘r are moved rearwardly, thus separating the halves p p of the plate J. wheel to be ground-and the eye-nut M is connected by the hook e to the chainj w. The wheel is raised to the proper height, and the rolls ff are adjusted with their peripheries removed from the center of the machine a distance equal to one-half the diameter of the wheelto be ground, the roll 2′ being withdrawn a’ sufficient distance toadmit of putting the wh’eelin the machine. WVhen the wheel has reached a central position and is in contact with the rolls f f the-halves pp of the plate J are closedand locked by moving-thelevers in the manner already de’ scribed. The roll is’moved forward toward thecen’ter and brought into engagement with the periphery of the wheel by turn’ing the screw g, and the clutch-plate n is brought into engagement with the flange, and thehook e is detached’from the eye-nut M. The shaft is being in motion, rotary motion is’imparted to the roller 5, thus revolving the wheel.” The emery-wheel being set in motion isthenmoved forwardand adjusted vertically, as

may be required, to bring itin to proper rela tion with the-periphery of the Wheel, when the operation proceeds until the wheel is reduced to a circular form.-

IIavin g thus described my invention, I claim as new and desire to secure by’Letters Patent 1′. In a grinding-machine, the combination,

with a’wheel-support, of guide-rolls and a driving-roll arranged to engage the periphery of the wheel, substantially as shown and described; g

The combination, with the parts 19′ p of the plate J ,of the locking-levers 0” r pivoted to the parts 10 p and furnished with the curved slots 5 s and the fixed studs t t pr0- jecting into thecurved’ slots, substantially as specified. spur-wheel a and the hand-wheel d by 6. The combination, with the drive shaft E and driving-roll i, of the springpressed col- The rod K is inserted in the I engaging the flange of the car-wheel, and the adj usting-screw g for moving the driving-roll, substantially as specified.

I11 a grinding-machine, the combination of the spider 0, provided with adjustable guiding-rolls f f the cross-head D, fitted to ways in the spider, the shaft E, journaled in the cross-head and provided at its lower end with the drive-roll ‘6 and clutch j and at its upper end with the bevel-Wheel h, the turret F, inclosing the bevel-wheel, and the shaft 70, carrying the bevel-pinion Z for driving the shaft E, substantially as specified.

The combination, with the Wheel-support and Wheel-revolving mechanism constructed as herein described, of vertically and laterally adj ustable emery-Wheels, of dilterent sizes, for truing the peripheries of car-Wheels, substantially as specified.

The combination, in a grinding machine constructed as described, of the adjustable hood-casting G, containing the vertical shaft I and emery-Wheel u, and the verticallyadjustable supporting-frame H, substantially as specified.

11,111 a grinding-machine, the combination, with the revolving and grinding mechanism, of a crane and swivel-Wheel-supporting rod for placing wheels in and removing them from the machine, substantiallyas specified.

Advanced Technologies Drive New Cylindrical Grinding Capabilities

While cylindrical grinding has been used for some time, its capabilities may not be fully appreciated. New grinding wheel technology, controls, materials and dressing processes, coolant and pump options—as well as smarter software—make today’s machines worth getting acquainted with.

With multiple-wheel machines that allow a single setup for a complex process to probes that measure parts on the machine to maintain critical tolerances, cylindrical grinders have grown more flexible and easier to operate.

One process gaining traction is peel grinding, which removes a large amount of steel or carbide in a single pass using high feed rates and spindle speed in a manner reminiscent of a lathe.

Meanwhile, oil-based coolants are finding favor over water among some users. Improved chillers and heaters are maintaining stable processing temperatures vital for meeting the tighter specs required of aerospace, automotive and other components made with super-hard carbide, ceramic or coated materials. Programmable variable frequency pumps provide the exact amount of coolant when it’s needed most.

And, more sophisticated hinged or stationery probes can measure complex part features—length, shoulders, tapers, outer diameter (OD) and even internal bores—while compensating for temperature and wheel wear, all without unclamping the workpiece.

It all adds up to a contemporary lineup of cylindrical grinders that deftly handles parts as large as shafts and gears or small as ballscrews, threads and cutting tools.

Feeds, Speeds and Flexibility

The quest to accelerate grinding machine setup and part production and expand usefulness has led to notable modernizations.

For instance, the Studer machines from United Grinding North America (Miamisburg, OH) provide a new level of flexibility, said Hans Ueltschi, vice president of cylindrical sales. A contemporary part might be partly coated with carbide or another material via High Velocity Oxygen Fuel (HVOF), requiring a diamond wheel for that section. The alloy or steel substrate requires a different wheel. With a multiple-wheel setup, the grinder can process the entire part, avoiding multiple setups and runout issues.

Studer machines are also being asked to grind more bearings, especially for the aerospace industry. With one setup, the machine can grind the OD of the ring and interior of the race with the same clamping in the shoe system. Traditionally, Ueltschi said, bearing grinders would perform different functions on up to three or four machines.

He also noted that the Studer line features more accurate linear scales graduated in nanometers instead of microns.

Meanwhile, recognizing that some cutting tools initially require a round of cylindrical grinding, ANCA Inc. (Wixom, Mi), has refined its machines to allow them to spin the headstock at up to 3000 rpm or house a 10″ (254-mm) diameter wheel. ANCA machines also feature in-process gaging.

On tool and cutter grinders, the option for a cylindrical grinding first step “is a nice feature to have,” said ANCA President Russell Riddiford. It minimizes the number of setups or “hand-holding” of the tool from one machine to another.

ANCA’s portfolio includes the MX7 Linear and larger TX7 Linear, which can be used to grind a range of parts, including pinion gears for power steering shafts, journal bearings, helical gears and carbide blanks for cutting tools like end mills and drills. The MX7 features up to six wheel pack stations for configuring multiple operations; the TX7 cell features two to 21 wheel packs.

“You have a library of wheels you can call upon,” Riddiford said. “You can tell the machine to get wheel pack number 15 and do this particular operation, and that wheel change time is about 12 seconds.” Mounting and truing the wheels prior to operation can take about 15 minutes.

He noted that peel grinding with cylindrical machines is gaining traction for its ability to remove several millimeters of material in a single pass. “We’re doing a lot of development with grinding wheel suppliers,” Riddiford noted. “There’s a lot of FOCUS being put on peel grinding and the grinding wheel’s ability to hold the edge for long periods of time to allow this mass removal of material.”

The feed rate for peel grinding “is quite aggressive,” he continued. The machine calculates optimal spindle rpm when the operator inputs the job’s surface footage on the controller.

Parts and Processes

Among recent additions in the cylindrical grinding repertoire is the replacement of chrome plating with HVOF spray coatings, said Rob Titus, grinder product specialist for Okuma America Corp. (Charlotte, NC). The aerospace industry in particular is utilizing the process to great effect.

In the past, end users would chrome-plate parts, grinding off some chrome to maintain durability in a final assembly. HVOF involves spraying a chromium carbide mixture on a part—mild steel, for example—that allows more even and consistent coating and greater wear resistance, he explained.

Titus noted that a potential hindrance to optimal use of cylindrical grinding is often the practice of using decades-old process specifications limiting adoption of current grinding speeds. Today’s superabrasive wheels can be fed at Q-prime rates in excess of 5 mm3/min, he explained, whereas aerospace specs crafted in the 1980s might be based on 2.5 Q-prime.

“Grinding technology is a little bit different than the rest of the machining world,” Titus explained, noting that there are features and practices that smaller customers or those who don’t use grinding as a primary process might not be using and benefiting from.

For instance acoustic emissions sensors have been in Okuma and other machine makers’ machines for 25-plus years. They listen for when the grinding wheel touches the workpiece to slow the wheel to grinding speed, as well as for when the dresser contacts the wheel during dressing. But Titus still encounters customers who have not heard of them.

In the automotive industry, grinders are adjusting to tighter tolerance features and lighter-weight components, said Shane Farrant, national product manager for grinders at Toyoda Machinery USA (Arlington Heights, IL). Toyoda specializes in camshaft and crankshaft production.

“Various industries are introducing new materials for us to work with, which is good to see and challenges us and the customers with application solutions. In many cases we look to our grinding wheel manufacturers for recommendations for handling materials outside of our typical mild and hardened steels and cast iron.”

Dressing for Success

There are numerous techniques for renewing the cutting action of or truing the wheel on a cylindrical grinder—including single-point, roll, crush—in-process while the wheel is in contact with a part, and postprocess, said ANCA’s Riddiford. Grinding wheel makers are developing units that minimize the number of dressings required and work longer and harder.

Aluminum-oxide wheels are the more conventional and relatively less-expensive option, generally used for steel and flexible in their ability to be dressed with various profiles and shapes.

“The makeup of those wheels in terms of their compounds and other chemical agents vary based on application,” Riddiford said. “You might use a larger grit wheel for a roughing application, then a finer grit wheel for finishing.”

Optimizing wheel life and output depends on a variety of factors, he noted: part run; listening to the wheel; examining parts coming off the machine; monitoring CNC controller data that tracks a wheel’s amperage draw, which increases as the wheel dulls; and using software that adjusts rpm to keep the wheel working within a given parameter range.

Grinding wheel suppliers like 3M and Saint-Gobain “will give you good information about a starting point in terms of speeds and feeds,” he said, guiding users on where their wheels work the best. “But then you put that grinding wheel on two different machines and it is likely to perform differently on both. It can depend on whether one machine is more rigid than another, for example.”

To facilitate wheel RD, two of ANCA’s larger machines are in the US labs of key grinding wheel manufacturers, who develop and test their products with them.

To keep grinding wheels working with optimum effect, United Grinding is unveiling the 2.0 version of its WireDress technology for metal-bonded diamond or cubic boron nitride (CBN) units.

WireDress is an EDM method for removing bonding material from superabrasive wheels, explained Ueltschi, allowing sharper wheels with easier-to-produce profiles. The smaller, less-intrusive version being introduced fits right on Studer machines. The technology allows better control over grinding wheel shapes, profiles and accuracies as opposed to traditional methods.

“On a conventional wheel, we mainly use a single-point dresser,” Ueltschi explained. “If it is a plated wheel, you cannot dress it—you cannot influence the shape or the geometry. If it is a vitrified-bond wheel, you can use a rotary disk-type dresser and dress the shape, but you are limited in what type of profiles you have—typically a straight shape or basic profile. If it’s a resin bond diamond wheel, you are reduced to truing the wheel with a silicon carbide grinding wheel.”

However, with the WireDress electrical discharge method, wire-generated sparks remove bonding between the diamond particles of a metal-bonded wheel to expose the diamond or CBN grit and hone the wheel’s grinding ability. “It clears the bond without pressure or deflection,” all with simple CNC programming.

It’s particularly useful for generating a very fine-pitch thread form on the wheel to produce a thread on a carbide workpiece, he added.

Keep Things Cool

Historically, said ANCA’s Riddiford, water-based coolants have been favored for OD grinding, but oil is coming to the fore for some users, being better for the wheels, surface finish and the machine overall.

“Oil now has a very high flash rate for fires,” he explained. “It’s much safer to use oil as your main part coolant, especially for peel grinding, which requires good lubricity.”

The importance of coolant goes far beyond just keeping the part cool.

“The position of the coolant is critical in all grinding operations, especially OD,” he said. “The nozzles that project coolant onto the wheel need to be in the right place” to allow cooling at the point of contact between the wheel and part. Proper coolant flow is required to remove the resultant particles, or swarf.

Different materials produce different swarf, he added. For instance, OD grinding stainless steels produces stringy swarf, whereas a heat-treated blank will produce particles like fine sand.

While thicker synthetic or general cutting oils are available, the ideal oil is thin and low viscosity with high flash points, he advised. “A lot of the grinding wheels have been developed around oil-based coolant.” And, grinding oil makers like Oelheld and Blaser SwissLube are “constantly working on the chemical makeup of their coolants.”

Coolants are also application driven, he continued; carbide might require something different than stainless steel. Whereas a job shop might seek a coolant with average features for a range of grinding jobs, a production run dedicated to carbide alone would allow use of a higher-end coolant.

Oil is “absolutely” better for the grinding process, said Okuma’s Titus. “If you talk to a grinding wheel manufacturer about a superabrasive grinding wheel, he’s going to say, ‘I would love for this to be run in oil because it will perform much better and last a lot longer.’” That said, about 90% of the company’s customers prefer water as a coolant in light of the environmental impact of oil disposal. Also, the requisite fire-suppression equipment in the machines is an added cost.

Improved grinder design is helping reduce thermal displacement issues. Toyoda has changed its casting design to control heat fluctuations in the manufacturing atmosphere by isolating the casting from the coolant with a steel plate with an air gap, explained Farrant.

To evacuate coolant, Toyoda added a channel beneath the wheelhead to eliminate pooling around the wheelhead. “Being thermally stable helps reduce the number of offsets needed when operators return from a break or during the machine warm-up period,” Farrant said.

Software and Sensors

Calculating feeds and speeds, spark-out times and other process parameters to ensure desired accuracies and surface finishes requires grinding software to be more technology driven, advised United Grinding’s Ueltschi. A lack of skilled operators demands that software allow cylindrical grinders to calculate how to grind and how fast.

In addition to libraries of wheels and wheel profiles, United Grinding software offers a quick-set option that uses the machine’s probe system to measure parts without touching off each wheel to the workpiece and recalibrates the machine immediately. Setup time can be reduced up to 10% with one wheel and 90% with four wheels. And, the software can set feed and speed rates and grinding methods, resulting in a good part quickly without an operator taking half a day to dial-in the proper setup. A user could generate a part in 10 minutes instead of about 30 minutes, Ueltschi noted.

Another critical function software provides is wheel balancing, said ANCA’s Riddiford; his company offers a software suite that includes in-machine balancing to prevent vibration and harmonics. With its machines grinding parts anywhere from 20 thousandths up to 6″ in diameter, “we are constantly working on improving the software in terms of getting machines to grind quicker,” particularly by speeding setup.

Meanwhile, Industry 4.0 features appearing in all sectors of manufacturing are making their way to grinders, with sensors monitoring processes and component wear and predicting when machine parts must be repaired or replaced.

“We see more customers requiring some sort of automation system,” Ueltschi said. “In cylindrical grinding, with its short cycle times, you don’t typically talk about lights-out processing.” However, United Grinding’s flexLoad Automation Cell allows an operator to stock enough parts for the grinder to run 30 minutes to an hour untended.

Chevalier Machinery Inc. (Santa Fe Springs, CA) offers two proprietary grinding software solutions. The company’s conversational graphic program offers a “Q A” setup style that asks the operator what the job requires, then creates the program. “Anyone without experience in engineering, programming or CNC operating can use it,” said Johnson Lan, vice president of sales. Chevalier also offers the iMachine Communication System, which uses its MT-LINKi to monitor performance data, prevent downtime and forecast production issues. “Remote monitoring of the factory will not only increase productivity but also produce systematically controlled outcomes,” Lan noted.

Chevalier also offers two spindle sensors, one for automatic balancing and another for the spindle loading meter to determine the wheel dressing cycle. “Customers can leverage it as an indicator to maintain the machine,” Lan said.

According to Titus, Okuma’s grinders have joined its turning and milling machines in incorporating a Windows-based open architecture OSP-P300G control that is “very suitable for Industry 4.0.” With that comes a conversational CNC programming package, “reducing the need for a dedicated programmer for the machine. The operator goes through a series of menus and fills in the blanks, and that will develop a CNC program based on those inputs,” he said.

And at Toyoda, monitoring factories as a whole as well as machines individually has been a FOCUS for the past year or so, Farrant said. Many grinding-related issues can be identified before they occur by monitoring vibration, noise and temperatures of castings, coolant and lubricants.

Such monitoring is standard on Toyoda grinders in the form of the Toyopuc AAA module, which allows factorywide connectivity. The recently introduced Toyopuc-Touch control “helps facilitate the conversational aspects of the control with the operator,” Farrant said. From a maintenance perspective, the control allows faults to be easily traced in the ladder for quick diagnosis, for example down to a faulty wire, and the grinder’s manuals are available at the touch of a button on the control.

Ultimately, “we want to be able to hit cycle start and let that machine run as long as possible without any intervention.”

About the author: Geoff Giordano has been a contributing editor for SME since 2016 and a manufacturing and tech journalist since 2005. Contact him at geoff@driveninbound.com.

Connect With Us

Grinder alignment

How to get the best tasting coffee from your grinder.

Exactly how much side by side the two burrs are placed in the grinder has importance for the particle distribution of the coffee grind. This is called burr alignment.

Such difference in particle distribution was measured in a project done by Christopher Hendon, Matt Perger and more, see https://baristahustle.com/grinder-paper-explained/ This graph is from Supporting Information. The blue curve is good alignement of the burrs with. They grey curve is bad aligned burrs:

What does it matter for the taste ?

The more alike coffee particles are in size, the more clear taste and aroma.

The more difference in particle size, the more both over- and under-extracted coffee (mix of bitterness, bad flavours, sour).

Where as fines is another story – see The taste of fines.

How can you tell bad grinder alignment ?

By taste

Good alignment makes the aroma characteristics of the coffee stand out more clear.

By how it looks when brewing

When making a filter brew you adjust the grind size according to the time it takes for the water to pass. Some aim at 2:20 minutes, others at 3-4 minutes. If the water takes too long to drain through, then grind coarser. Too quick then grind finer.

This photo is a V60 brew from a bad aligned grinder: 1) a little coarse grind is left high in the filter (called “high dry”)

2) the drain slowed down, when still 1-2 cm water stood above the grind in the filter. Very little coffee dripped through = too many fine particles clogging the filter.

So this grind had both too big particles (= boulders) and too many fine particles = typical for bad alignment of the burrs.

Paint with a whiteboard pen

Paint the burrs (do NOT use a permanent marker) and then run the grinder while gently letting the two burrs touch – you can hear the burrs making a chirping sound.

If the paint is not worn off the same all the way around → it means some of the burr is higher than others.

Here you can see the blue worn off in the front – whereas in the back it’s still all blue:

By sound

Matt Perger did this sound diagnosing of burr alignment of the EK43 grinder https://www.YouTube.com/watch?v=_jWlpz9mELM

Here you can hear the chirping sound of burrs touching with a Mazzer Super Jolly grinder https://youtu.be/xrNYzvXq8i0 First only by ajusting to zero. Later by pressing the adjustment collar on one side. Thats how sensitive the burrs are.

Waveforms The waveforms from the sound of chirping on a grinder looks like this. Jon have recorded the sound of his own Ditting grinder – and compared it to the recordings from Matt Pergers video with the 4 states of EK43 alignment:

Bad aligned burrs will touch once pr rotation – this makes a clear single peak in the waveform. peaks pr rotation indicates a better alignment, as more peaks indicates more contact between the burrs through the rotation.

Ideal aligned burrs would touch the entire rotation, making very long series of equal sized peaks per rotation.

Screaming burrs when grinding beans

If your grinder is making a terrible noise when you grind beans (at normal setting and not at low setting where the burrs touch) … you might have this problem:

A bean got stuck in the prebreaker. When new bean goes in, the burrs are pressed out of shape and touch on the opposite site.

How to do alignment of your grinder

For Mythos One – can be used for other grinders

Matt North have made this great guide to alignment of the Mythos One grinder Here he use the whiteboard-marker method.

Lido handgrinder from Orphan Espresso

Lido 2: https://www.YouTube.com/watch?v=npVWLJnBcAs combined with this http://coffee.stackexchange.com/questions/2515/how-to-fix-burr-contact-alignment-issues-on-an-oe-lido-hand-grinder-on-fine-grin/2516#2516 Extra: when you have aligned the burrs at fine setting, then go back to normal grind size and grind a handful. This will slightly push the burrs. Then test again at fine setting if the burrs touches.

Matt Perger using tin foil/ silver papir to adjust: https://www.YouTube.com/watch?v=5-cf0Iack5Q. Just be aware that this might deform the burrs, see below.

Note: how much the front screws is tighten also affects the alignment https://www.YouTube.com/watch?v=V02UBGeLSx8feature=youtu.be

A third point that affects the alignment – but ONLY do this if you are trained in such maneuver (or you will do more damage than good) https://www.YouTube.com/watch?v=r0RjPFi-Uzg

Socratic Coffee made this analasis of Ek43 grind from before and after alignment https://www.instagram.com/p/BVpA-vMj8YF/

Titus grinding just launched this alignment tool to measure the inner burr, here in May 2017.

Frank Durra describes the purpose like this: “It aligns / measures at the roots of the problem which is the axial alignment of the inner burr due to irregularities of the aluminum case”

Mahlkönig also lounched an alignment tool.

Flat-burr grinders: rotate according to screws

When aligning flat-burr grinders we normally use thin pieces of metal foil to align the burrs – but before using metal foil, another method is to start by mounting the burrs in the different positions, just by rotating the burrs. The burrs themselves should in theory have no differences in height around the burr, but in reality very small differences can occur.

Do not switch the lower burr with the upper burr. The lower burr should always remain the lower and vice verca – this alignment is about rotating the burrs individually to different mounting posistions.

If your burrs has screwholes, rotate the burrs individually to the different screwhole/burr combinations to check if some combinations are better aligned than others. If your burrs has no screwholes, simply rotate the burrs individually to different positions to check if some positions has better alignment than others.

This is the fixed burr on the EK43: first paint with a non-permanent white bord marker

Then collect and run to chirp the burrs. After opening up you see how the chirp has worn off the blue paint. Here it is nicely worn of the whole way around:

This alignemt was achieved only by rotating the burr; one position was perfect. The two other positions not.

Weakness of metal foil / silverpaper method

When the burrs crush coffee there will be a great force on the burrs. If you have placed metal foil only at one point there will be a bit of space on each side – here the burrs can be deformed by the pressure of the beans during grinding.

Therefor place thinner metal foil on the sides of the highpoint.

Mahlkönig Vario Home / Baratza

The question is how much you can align the Vario since the construction is not that strong. This alignment I did with Andreas. He found the alignment did make a small difference: more clarity and sweetness in his filterbrew coffees. But he let the burrs touch too much – and ever since the grinder has been much noisier when running.

Procedure: First test the 3 positions how the upper burr is fixed in the white holders. Test by seeing at what point on the setting you get the chirp sound.

Paint both upper and lower burr. In this case the blue marker on the lower burr was nicely worn off the whole way around. So no need to do anything here.

Then try the 3 position of how the upper burr is attached to the burr carrier (loosen the 3 screws).

Here you can see markings from rotating the upper burr (the fixed burr).

In the first position the wearing off area was marked by two red L’s; one at each starting point and pointing in the direction of the wear off. It was almost 80%.

The black marks (one L and one l) is in the second position. Here only 40% of the circle was worn off.

The third position is where the blue marker is worn off. It’s almost 50% of the circle.

So the first position was the best.

When placing metal foil / silver paper – be aware that it doesn’t curl up on the sides.

Grinders.

If you’ve read the preceding posts, you know that I believe the grinder is the single most important piece of coffee equipment, or if skimped upon, the largest setback. There are a few adages when it comes to grinders, mainly because it’s so hard to get yourself to justify spending a lot on your first, or even second one. Those preaching these adages are only trying to save you some coin along what could be the inevitable and never ending upgrade path.

You can make better espresso with a 200 machine and 1200 grinder than you can with a 1200 machine and 200 grinder.

The grinder is especially important in espresso because the grind fineness and consistency need to be such that it can withstand 130psi water coming at it. We’ve all heard that water is lazy and will take the path of least resistance. Well, if your grind is inconsistent, that means channeling and over extraction in some areas and under extraction in others. This example applies to brewed coffee as well; if you have grinds made up of boulders and dust, you’re going to have the boulders be under extracted and the dust be over extracted, you’ll never get a balanced cup.

Spend as much as you can on a grinder.

Take how much you want to spend on a grinder and double it.

Hand and Motorized Coffee Burr Grinder options under 100, aimed at manual and pour over brewing.

These are all popular sentiments on the coffee forums, and there’s a reason for them. All of the forum members have learned how important a quality burr grinder is to unlocking the potential of the coffee.

So, I’ve probably harped on enough, now let’s get my personal list of recommended grinders. There are certainly other options out there in each category, but these are all grinders that I feel most comfortable recommending based on ownership, experience, feedback, or research. I already covered an under 100 option here

Without further ado, my first recommendation over 100:

Baratza Encore

Baratza’s site states, “The Encore is lauded by coffee experts as THE go-to entry level grinder for those brewing coffee at home,” and I would not disagree with them. Baratza’s grinders are routinely regarded as outperforming their price tags and their burr size. The Encore is sure to satisfy all brewing methods with a home friendly footprint and user friendly design. Their customer service and after sales support is also incredibly good.

If you’re looking for additional features, such as timed grinding, you can work your way up their product line, but as far as bare bones, solid, motorized grinders go, the Encore just works. It will not grind fine or consistent enough for espresso needs, but any brewing methods will be well served.

129 available at most coffee equipment retailers and Amazon here.

Orphan Espresso Lido 3 (E or T)

The OE Lido is a hand-held hand grinder on steroids. OE’s hand grinders deliver grind quality and consistency at a price that electric grinders can’t sniff, if you’re willing to put in the sweat equity. The Lido, and its variants the E (espresso specific) or T (travel specific), and incredibly versatile for all brewing methods and really not bad to crank for a hand grinder.

The Lido 2 is still listed on OE’s website for 175, click through via the picture OR, the improved Lido 3 is available online for 195: Prima Coffee

Baratza Sette Sette W (pending)

The just announced Baratza Sette just might be the game changer for the entry into a home (motorized) espresso grinder. Still plenty qualified for grinding all other methods as well, this grinder is looking to have the potential to bring a home friendly footprint, user friendly design, minimal retention, and great grind quality at a very reasonable price. I hope to have more feedback and experience with this one soon!

Baratza Vario

The Baratza Vario was my entry level recommendation for a motorized espresso grinder, but the Sette may just change that. In the meantime, the Vario is still a great grinder. It is extremely user friendly, versatile, has minimal retention, and has the ability to grind fine and consistently enough to meet espresso needs. This was my first grinder and one that I still use daily, though it’s now dedicated to brew grinding duties. It is capable of grinding coarse enough for French Press and fine enough for Espresso, though it’s not recommended to be frequently switching back and forth; you’ll have to spend some time re-dialing in and resettling into the tight demands of the espresso range. The Vario does have a few drawbacks, such as you don’t want to be switching back and forth between coarse and fine grinding, though no grinder is really meant for that, and that it can struggle a bit when grinding some demanding light roasted coffees for espresso. But other than that, it may be the most grinder you will ever need. The Vario-W does offer weight based grinding, which could be useful if you’re going to keep the hopper full and grind into the grinds bin. I personally use it as a single doser, weighing out how much coffee I want, and grinding just that quantity until it has run through. The Vario’s retention (amount of coffee that doesn’t make it out of the grinder) is very minimal, usually around.1 grams.

The Forte is Vario’s beefed up brother. All of the same functionality but in a more robust chassis able to serve commercial needs as a brew grinder or maybe as a secondary espresso or decaf grinder. If you can swing the price difference to the Forte, it might be worth it if you have a strong preference for really solidly built machines. Not to say the Vario is flimsy, but the Forte is robust.

from most major coffee equipment retailers or on Amazon here.

00

Moving into full on commercial territory things get a bit more complicated. There are some fantastic grinders in this category, and you can have the piece of mind that you’re getting the best out of your coffee you can by using a fantastic grinder. Being that many of the the grinders in this category and beyond were primarily designed for commercial use, each of their pro’s and con’s, which make some better suited for your particular usage and needs than others. I will continue to update the grinders I prefer in this category, but encourage anyone that would like to discuss options in this range to contact me!

Anfim SCODY ii

This first one is a bit of a wildcard because it is a relatively new model to the market, and it’s less common in stateside specialty coffee shops than the usual suspects from Mazzer and Mahlkonig, but Anfim is a 50 year old company that is actually owned by Mahlkonig’s parent company, and the SCODY, or Super Caimano On Demand is now in its second generation, hence the “ii”. There aren’t a ton of bells and whistles on this on demand grinder (meaning it grinds what you need on-demand versus a doser), but it does boast some impressive specs for the price. It features very large 75 mm flat steel burrs that are upgrade-able to titanium coated burrs that are said to increase longevity and thus grind consistency in commercial environments; that is to say a home user may not see any benefit. The layout is very clean, everything you need and nothing you don’t with two timed grind settings programmable to.1 second, and an easily accessed manual button on the lower left of the machine. Programming appears very simple and straight forward, and the manual on/off button seems to be well thought out in its placement. The stepless worm gear adjustment should be extremely easy to use and fine tune your grind fineness. The grinder has a real utilitarian charm to it, and represents about the least amount of money you can spend for a big flat burred grinder. The 450 W motor isn’t going to be the fastest or most powerful, but should have no issues cranking out shot after shot with its built in cooling fan (which is probably a bit overkill for the home user). Prima Coffee states that it can accept the short hopper of the CODY ii, which should make this grinder come in around 17″ tall, meaning it should be cabinet friendly for most home users.

The CODY ii is a little more suitable to the home user, removing the cooling fan (that will only increase ambient noise in the home), equipped with only the short hopper, and available in either white or black. The motor, controls, and overall look are pretty much the same as the SCODY, but burrs are slightly smaller at a still impressive 64 mm. The Cody ii is available from Prima Coffee for 925 here.

On-demand grinders like these are great for someone that doesn’t want to do the extra steps of single dosing, and would rather walk up and grind, tamp, and go. This suits the home user that likes to stick with one coffee for awhile and thus doesn’t need to keep dialing in the grind and thus burning through beans. The only drawback to on-demand grinders, such as these Anfim’s is that there will be some coffee left in the grind path, or the space between the burrs and the chute, or in the chute itself. This is called retention, and that retained coffee will stale in prolonged periods between shots. Many home users work around this by purging and discarding a bit of coffee to clear out yesterday’s grounds before pulling their first shot of the day. The CODY ii and SCODY ii both have relatively straight forward and short grind paths, but still expect to have about 5-6 grams of retention.

So, like I mentioned at the beginning of this section, there is some give and take with the larger more commercial grinders, so it’s important to determine your preferences. The SCODY ii still represents a great value in being able to get a reputable, well built grinder with massive 75 mm flat burrs for 1,175 from Prima Coffee Equipment here.