Sealey SMS01 Drill Bit Sharpener Grinding Attachment

Product Information

I built this from scrap so it was necessary to take some liberties with the design, plus some minor changes would make it easier to build with the tooling I have available. If I were building again I'd try a 3/8" body rather than 1/2" to make cutting the slit easier - I don't have a 1/16" end mill so I used a 1/16" Woodruff cutter to make the slots - a thinner body would make this easier. I used a 608ZZ bearing so it was necessary to use a bushing to fit it to the 1/4" internal shaft. This powered 4/6 facet drill sharpener of my own design covers the range from 1/2" down to 1/16" for 118° and 135° point angle drills. This sharpener is reasonably easy to build and works well so in July 2011 I submitted an article to HSM magazine; it was the cover article for January 2012 - part 2 is in the next [March 2012] issue. The article describes construction of the motion control which can be used with various grinders, as illustrated below. I put a video on YouTube describing the controls and demonstrating their use. (Village Press has run out of magazines containing plans for my sharpener so if you would like to build one, here is a 5.8mb ZIP file containing the sharpener plans.) For those with a 3D printer, see this. Design Concept Bob Rawlins from Australia also used a more powerful grinder for power. Construction is mostly aluminum. My simple prototype drill point splitter is shown at left. Point splitting is a special method of web thinning that extends the cutting lips almost to the center of the drill face. This improves cutting efficiency and reduces the thrust required while drilling. Building and using the Four Facet and HoneDrill sharpeners along with the Pit Bull provides a practical education in drill sharpening. The HoneDrill in particular is educational and also thought provoking. The combination of the Pit Bull plus Derek Brown's collets is reminiscent of a Champ Sharpener's dual bed. Since building the Brooks cutter grinder I've added a HoneDrill inspired jig to it for sharpening larger drills. Motorized 4 facet grinders are available but expensive (see Christen or Optima) so I recently built a 4/6 facet sharpener with a much different design.

An eccentric was added and calibrated to allow setting the primary relief angle easily by tilting the trunnion table. The 4 facet sharpener works well for drills from 1/2" down to about 0.060=#53; smaller drills can be sharpened with 2 facets ( see below). On the left is an 0.080 test pin ground to evaluate alignment of the wheel to the trunnion table axis; here the primary facets (silver) don't meet properly in the center - the wheel needs to be a couple thou farther from the table to correct this.On the less bright side, the model is a tad too loud for our taste. It's not necessarily deafening. You won't need earbuds. But the engine is a little too loud considering that it is not that powerful in the first place. The relatively low maximum RPM means it will take some time to sharpen larger drill bits. Another thing to consider is whether the sharpener has an adjustable angle. A good sharpener will let you adjust the sharpening angle to suit each individual drill bit. Drill point angles can vary from 118 to 135 degrees. However, if you want a sharpener that’s more portable, you might want to consider a manual one that uses your power drill to drive it. This means that if you have no access to electricity and you’re faced with dull drill bits, you can still sharpen them and get the job done. Why we like it: This multifunctional sharpener is smaller than most grinders, meaning it won’t take up much space on your workbench while still giving you an edge. It’s possible to hone the point on these, but it’s not recommended. This is because these bits come with a special coating that gives them their hardness. When you file these bits, the grinding wheel is likely to remove this coating. You can still use the bits, but they won’t be quite as tough. Which drill bits are better – Titanium or Cobalt?

When this happens, you generally have no choice but to throw them out and go and buy new ones. However, with a drill bit sharpener, you can easily solve this problem and save your old bits from adding to the landfill problem.

Versatility – Drill bits require different angles for different purposes. Can your chosen sharpener create the right angle for your needs? Overall, the Pit Bull type sharpener is inexpensive and does a reasonable job sharpening larger drills, 1/4" to 1/2". It works from 1/8" to 1/4" but is shakier in that the alignment is more difficult to do accurately so it is possible to have the lips differ -- this results in wander when drilling deep holes; using the larger collets described above reduces this problem. Using the Pit Bull jig was part of my learning process but has been superseded by the 4/6 facet grinder. I considered building the Duplex design but decided against it because it handles only 118° point angle. The 4/6 facet sharpener described below is simpler to build and has more capability: 118° and 135° point angles, SPA's and split points. On the construction subject, this product seems and feels pretty tough. Plus, there are slots on the bottom that you can use to mount the machine to just about any workbench. This way, you'll be able to reduce vibrations and make this sharpener much more practical since you won't have to support its frame with your second hand.

Why we like it: This sharpener can handle most drill bits that you are likely to use in a professional setting without the professional price tag. John Lamb made a "few modifications" while keeping the underlying concept. His version allows adjusting the point angle through a considerable range, allowing him to sharpen lathe bits and he also plans to sharpen end mills. He reports the diamond wheel rapidly sharpens drills.The Darex M3 doesn't include point splitting as their more expensive M5 does so when needed I split point drills with the 4/6 facet sharpener's point splitter. I no longer used the Darex after completing the 4/6 facet powered sharpener so I sold it in January 2012. Here the grinder is fixed to a wood base and the trunnion table is raised to the wheel's center height. This provided space for a nice drawer to hold the collets and other tools. The DEWALT 6-inch grinder is on the smaller side for grinders but is more than adequate for your home sharpening needs, whether you are sharpening knives, drill bits, or lawnmower blades. It won’t overstep your budget. I often use #1 center drills for starting holes but find them relatively fragile. Should the tips snap off they can be re-sharpened to resemble a spotting drill (but with 4 facets) -- and are much less fragile than they were originally. Random Thoughts On Drilling

Titanium bits have a special coating that gives them extra durability. They are said to last six times longer than a high-speed bit. However, cobalt bits are designed to drill into hard metals such as titanium, hardened stainless steel, and cast iron. These are, however, not designed for general purpose drilling. Which is better – Carbide or Cobalt? The 11/32" drill shown at right has small SPA's added making it 6 facet. These extra facets cause the drill to have a stronger self centering action plus the shearing action often produces a better finish in the hole. The sharp outer point on the cutting lip, a common failure point (pun), is eliminated so the drill remains sharp longer. It requires only one additional hole in the tilting table to produce SPA's, where the size of the facet is set by eye; SPA facet size isn't critical so simplicity won out.John Baron made the table wider so the left table support is outside the wheel. He used ER16 collets rather than the original ER20's. The motor is reversible, accounting for the two switches on the top of the box. Lots of little differences from the original design but it keeps the original concept where the drill center is on the trunnion pivot line so it works fine. He also made the jig to set the drill extension from the collet and the lips horizontal