Of Grit and Grain

It seems that every article on sanding begins by saying how much woodworkers hate this chore. But the bottom line is that we usually don’t.

We can break sanding down into two categories, gross and fine. The former is done by big machines and the latter by hand-held tools, and also just by hand. Feeding boards to a wide belt sander, or having a CNC follow up a milling pass by changing tools and lightly sanding an MDF door is no big chore. The painful part of sanding is either in very small shops where there is inadequate equipment, in one-off art furniture where shapes can be infuriatingly complex, or in the finishing booth anywhere because coatings can become truculent and argumentative. Something as small as an eyelash can wreck your day there.

Let’s start by taking a look at where much of our woodshop sanding is headed – to the kind of technology that is already being adapted to CNC heads and will soon be common on collaborative robots. Then we’ll take a pass through some abrasives, scan the big solutions that are out there for panels and doors, and then wrap up with a family of intricate machines that can take the tedium right out of sanding.

As noted above, sanding is a matter of scale and that’s never more obvious than when it’s being done by a CNC router. Some of the smaller desktop models may have some challenges holding the work, reducing and maintaining the appropriate speed, accommodating larger diameter hubs and tools, and so on. But for most commercial CNCs, improved controls and better dust collection over the last few years have had a big effect. The ability to program for a lighter touch, switch heads easily and extract fines efficiently have made it possible for manufacturers to create a whole new arsenal of sanding tools.

The German company Benz Inc. (benztooling.com) operates a North American wood division that’s located in Grand Rapids, Mich., and the company offers a number of CNC sanding solutions. Among its innovations is the Collevo belt sanding unit, which takes 100 x 560 mm belts (about 4” x 20”). It has an HSK F63 connection and an SK 30 for Biesse is available, so it fits many spindle brands. If a belt isn’t solving your problem, Benz’s orbital sander, the Simolo, is available in HSK F63, HSK E63, SK 30 and SK 40 connections, This head handles a number of disc diameters and grits. And Benz also makes the Zucco vibrating pad sander, which has an HSK F63 connection. The company can provide custom solutions, too. That is, a woodshop can order small modifications to the standard heads, or even work with Benz to create a highly complex sander for specific tasks.

Flex Trim (flex-trimusa.com) in Queensbury, N.Y. makes sanding heads for CNCs and other machines. These are sanding strips backed by brushes on a shaft, and changes in the height of the brush can deliver any result from polishing to aggressive brushing, or just normal wood sanding. They can be delivered in any length or diameter, and the shape can be customized. For example, they can be configured to reach into deep profiles. The sanding segments can be replaced without dismantling the shaft and the head – a woodworker just has to remove an O-ring. And the sanding head’s core is resistant to chemicals, so it can be installed in a lacquer room. Flex Trim comes in a cup format for surface sanding and a hub for edge sanding.

According to California-based Voorwood (voorwood.com), its Turbosand line of rotary sanders offers “the lowest cost per foot of any rotary sanding system”. With more than 4,000 stock profiles available, it has a range of head diameters and widths to accommodate almost any edge detail. Turbosand is available for CNC routers and also shaper/sanders, single and double ended tenoners, and other types of machine. It has a simple, two-piece sanding head and works vertically and also at tilt angles. Strip changes are quick and easy, and heads are available for edges, raised panels, and complex profiles. They’re also available for HSK or ISO toolholders to match specific machine spindles, and they come in 3” to 8” diameters and 1/2” to 3” widths. There’s even a Turbosand rosette head for CNCs which can sand small grooves, slots and decorative features. And the Turboflex Pro is a rotary head that’s matched to a specific contour, and comes in six grits and three different levels of brush stiffness.

Peak Toolworks (peaktoolworks.com) offers the Riverside Tool Supersand system. This head has a lightweight aluminum body and a soft, profiled foam core. Rather than using flaps (strips), it has a durable, rubberized abrasive that’s infused in the foam, so it’s actually non-directional. It fits HSK 63F mounts, and custom arbors are available, plus it can be used on other machines such as shapers to sand profiles such as raised panels.

A shop can also reduce the need to sand by using other CNC tools a little more creatively. For example, master furniture builder Russell Crawford (cherryleaf-rustle.com) suggested on the Vectric.com forum that sharp edges on plywood cutouts can be chamfered before the profiles are cut. He recommends using a 90-edegree V-bit and cutting on the line at a shallow depth (perhaps .05”). Then the woodworker can go back and profile outside the line, using a good compression bit.

The 3M Co. (3m.) is based in St. Paul, Minn. and has been making woodshop abrasives for about a century. The company’s Cubitron II Hookit Clean Sanding Paper Discs have a property called Precision Shaped Ceramic Grain, which has earned high praise from users. Comments such as “the backer wore out before the grit” are common. The manufacturer says that Cubitron’s triangular shaped ceramic mineral is designed to slice through the substrate, rather than gouging or plowing like conventional abrasives, and 3M says that results in a disc that cuts up to twice as fast and lasts up to four times as long as conventional abrasives.

The Finnish company Mirka (mirka.com) offers about three dozen different sanding abrasives for wood processing. Among the newest additions to the line is WPF Next Gen. This is an ideal paper abrasive for effective hand sanding, both wet and dry, on multiple surfaces. It is very flexible, fully waterproof and has great grain adhesion. Produced with new coating technology, the abrasive surface doesn’t clog up easily, so a woodworker can sand faster and the abrasive lasts longer. The finer grits are optimal for fresh clear coats, and also make polishing easier.

In late 2018, Mirka launched two new abrasives families, Iridium and Novastar. These are premium products with new optimized grains, new coating and curing techniques, and new multi-hole patterns. Developed in parallel, the abrasives are similar but not the same. They both have a unique dust-repellent surface that doesn’t clog, so the grains stay sharp longer. The paper-backed Iridium comes in 80-600 grits and is ideal for cabinet shops, sign makers and furniture builders coating with paint. There are 125 mm and 150 mm discs as well as 81x133 mm and 70x400 mm strips. The longer strip has a center perforation, so it fits 70x198 mm sanders as well. Novastar is film-backed, waterproof and non-clogging, and it can be used on composites. Here, the grit range is also 80-600 but it only comes in the 125 mm and 150 mm discs.

Back in the good old days, every woodworker had a small block plane in his apron. Shopsmith thinks that was a great idea and has come up with a modern equivalent, the Finishing Block. Located online at shopsmithabrasives.com, it’s just a soft, palm-shaped block with a Velcro hook and loop bottom for quick paper changes, and a hidden platen called a weighted reinforcement plate that lets the woodworker apply a little pressure when needed. It’s the perfect solution for breaking the edges on doors, face frames and drawer fronts.

The German abrasives manufacturer Klingspor (klingspor.com) has been in the sanding business since 1893. The company operates a manufacturing facility in Hickory, N.C., and sells to businesses only through the website shown above. (Retail customers are served through Klingspor’s Woodworking Shop.) Its new GreenTec sanding discs have been developed to meet the needs of industries where significant loading of the abrasive occurs. These include cabinetmaking and solid surfaces. In testing and in production sites around the country, GreenTec has been proven to dramatically reduce loading in even the most stubborn applications. A patented, proprietary coating named T-ACT is designed to minimize loading.

Located in Bethesda, Md., the online retailer 2Sand.com has more than a decade of experience supplying coated abrasives to industrial purchasers, and its warehouse stocks a large variety of abrasives including brands such as Performax belts and Rhynogrip.

SuperMax (supermaxtools.com) offers half a dozen drum sanders, a couple of brush sanders (single and double head), and two combination units.

Laguna Tools (lagunatools.com) offers the 25” Compact Widebelt Sander that features Automatic Pneumatic Oscillation, two feed speeds, and an industrial cast iron bed sitting on four Acme threaded screws with center alignment. The bed is adjustable with an electronic motor for gross movement and a manual handle for micro movement. The platen is fully adjustable so it can run in combination with the 4” rubber drum for optimum results. Raise it and use the drum alone to dimension wood, or lower it to sand sensitive material such as veneer without the risk of going through the material.

The Laguna lineup also features 37” and 43” wide belt sanders, and the top of the line 51” equipped with an 8” primary roller and a second (4”) roller followed by a wide platen. This allows shops to use a rougher grit on the first roller that will absorb most of the impact and do the dimensioning, while the small roller with the platen can be set up with a finer grit. The configuration saves time because there’s no need for a second pass and a belt grit change. Plus, the large motor means the machine is capable of dimensioning even wide boards and slabs, which is important for shops that don’t own a wide thickness planer.

Minnesota-based Timesavers LLC (timesaversinc.com) offers solutions for almost any aspect of woodshop sanding, including heavy stock removal, panel sanding, wide belt sanding and calibrating, orbital sanding, veneer and lacquer sanding, brush sanding and more. One aspect of this sanding veteran company’s line is versatility. For example, the mid-sized 2300 Series planer/sander is customizable with either a 75” or 103” belt length, and up to three heads (knife, drum or combination). It’s also available in three widths (37”, 43” and 52”) and runs at 15 to 45 feet per minute.

Martin Woodworking Machinery in Charlotte, N.C. (martin-usa.com) also offers a range of wide belt sanders. There are five Weber models in the catalog, ranging from the 51” wide LCS that accommodates either one or two belts, to the industrial and very speedy KSL model. This latter has reinforced construction, contactless work-piece detection, and high-speed electronics. It has operating widths of 1350 and 1600 mm (53” and 63”), can be combined with up to eight machines, and has infinitely variable speed from 3 to 25 meters (10’ to 82’) per minute. The belt length is approximately 103”, and the machine has segmented platen pressure technology that adjusts the sanding pressure of individual segments to the workpiece size, using electronic controls.

Biesse America (biesse.com) offers a full spectrum of eight Viet brand wide belt sanding options, ranging from the S211 which the company bills as “the most compact, high-performance machine for calibrating and sanding in its category”, to the Valeria, which is a calibration-sanding center that was designed for large-scale industrial applications. This latter is ideal for heavy-duty processing, so it allows precision machining on high-speed production lines.

Also available from Biesse is the Narrow model, which is especially well suited to making narrow parts and components such as beams up to 400 mm (15-3/4”) thick, or flooring, disassembled window elements, or other long and narrow pieces. It can be configured with vertical rotating sanding brushes for profiles and sides.

The Felder Group (felder-group.com) has seven showrooms strategically located around the country, and the company offers ten Format4 and Felder wide belt sander models. Seven of these have touch screen control as standard or as an option, and three of the machines are new to the lineup. These include the Findustry 1352 and 1354. Options include a cross-section unit, contact-bars-module, combination sanding unit, Superfinish-unit, sanding pad units (EP/ESC), planer cutter-head unit and various varnish packages.

Felder also offers three edge sanders, including the new Hammer HS 950, which is billed as the perfect entry-level machine. Oscillation makes use of the entire sanding belt surface, and the sanding unit can be tilted continuously to 90 degrees. The open design also allows easy sanding of long workpieces.

Global Sales Group in Chico, Calif. (globalsalesgroupllc.com) offers several brands of wide belt sanders including Castaly, Cantek, Dotul and Safety Speed Mfg. The Castaly CA-1554 is an affordable open-sided machine that has a combination head configuration with a drum and platen, a pneumatically controlled oscillating belt, and easy pressure adjustment for veneers (more details at lobomachine.com). And another entry-level machine, the American-made 3760 from Safety Speed (safetyspeed.com) comes with either a 10-hp single-phase or a 15-hp 3-phase motor and photo-electric belt tracking, for under $13,000.

Remember that teaser about a family of intricate machines? Well, Opti-Sand Inc. in Geneva, Ill. (opti-sand.com) builds finish and sealer sanding machines that use flexible finger abrasive technology. These include models for sanding moldings, trim, flooring, linear parts, entry and cabinet doors, drawer fronts, face frames, MDF parts for powder coating, and more. An example of this company’s versatility is the WB12 Wire Brush that is used for texturing or distressing the surface of wood parts including paneling, siding, flooring and frames. And Opti-Sand’s UTS (Universal Table Sander) has a spindle that tilts from vertical to horizontal and is designed to allow woodshops to manually finish sand, sealer sand or de-nib parts.

Now, that’ll take the tedium out of sanding. 

This article originally appeared in the September 2019 issue.