I went into one of Brain Beresford’s sheds in the South West of Australia to see a mate and on stand 6 or 7 was this guy shearing away with bare feet using the thinnest Heiniger Rapier combs I had ever seen in use. Illustration by James Provost If you sharpen a chisel against the edge of a rotating wheel on a bench grinder, the resulting surface will take on a concave shape – referred to as hollow ground. The motors are mounted on x-y vices to adjust the tracking and tension.... No Weld Grinder Detailed Plans to Build Knife Grinder. Your email address will not be published. 2x 100mm 30° CBN coated steel wheel - better than diamond Sharpening 10 seconds and hollow grinding Between 0 ° and 70 ° sharpening angle available Fan cooled 375 Watt 240V motor 500mm x 300mm x 400mm Table top, 42kg Stainless Steel construction. Jantz Hollow Grinding Fixture With Elevator Our newly redesigned and improved Jantz Hollow Grinding Fixture allows you to grind straight or recurved blades quickly and accurately with your 2” wide belt grinder (some adjustments may be necessary to fit your machinery). by Phil Jones | Jul 21, 2017 | True Stories | 0 comments. The blade needs to have a hollow (concave) grind and in order to produce this discs which are used are machined to within very tight tolerances. I came across “the stone of truth” some 30 years ago when I was trying to work out why my sharp combs and cutters allowed a hand piece to run cool whereas another shearer’s sharp combs and cutters made it run hot. Hollow grinding machines (double side) series SV are designed to make high precision concave grindings for cooking knives, sport knives, flick knives, swords and hand tools. A hollow grind is produced when you use a wheel to sharpen the edge of a knife. “When you paint the kid’s bedroom and make one wall a different colour you can stand back at the end of the job and see how good a job you did. Hollow grinding is produced by introducing the blade between two grinding wheels, whose cutting faces are angled at 45º. This type of grind… • Sharpens blades up to 10” (254 mm) long. A hollow-ground knife can be incredibly sharp, but it can greatly benefit from a bit of stropping. “To get a good grind you need one of these” and Mal produced a flat aluminium oxide stone normally used for sharpening knives, I think, telling me it was flat and he never ever let anyone else touch it. Since this method results in a very sharp taper of the blade towards the edge, hollow-ground blades are very sharp but not particularly sturdy. Best of luck. If the blade starts to get hot, dip it in some water before it burns. When you sharpen a comb, you can see if it’s sharp but you can’t see where the hollow is. Attempting a specific job with the wrong grind on your blade will make that job much more difficult. Flat grind — The blade tapers all … The blades are sharpened using discs that are coated in a removable material that takes the smallest amount of metal off to produce the desired result. Web: http://www.3riverblades.com Twitter: https://twitter.com/3riverblades Facebook: https://www.facebook.com/3RiverBlades Instagram: https://instagram.com/3... New hollow grinding jig on Bader grinder. If you hollow grind you have to use a wheel so you have to be careful not to lose the temper in the steel. The light went on. It was a day I will never forget and a day that helped me more than anything else to learn about grinding / sharpening sheep shearing equipment. Your email address will not be published. T o sharpen the Scandi grind by hand, place the bevel flat to the sharpening stone and work on the whole edge. The stone of truth is simply a flat – very flat – aluminium oxide stone. Sharpening Machines. By shifting a comb or cutter over the stone of truth you will mark the comb or cutter at the highest points on the ground surface; the more you rub it the more it reveals the hollow, and the shape of the hollow, and in fact if you have a hollow or not”. The depth of the hollow will depend on the circumference of the wheel. Luckily for you, you're decades beyond being stuck with technology that mandates using a grinder to speed up the sharpening process. As I shall demonstrate, there is the ability to create the ultimate micro bevel. For knives, scissors and circular knives; For mincing plates and knives; Spare parts and consumables; Knife Manufacturing Machines. When grinding your blade use a light pressure against the wheel and keep your blade moving back and forth across the wheel. It is for a reason that almost all classic straight razors have a hollow grind. Bob Van Dkye. • Unique spiral-shaped honing/edging stone design assures consistent, smooth, sharp edges. The stone of truth doesn’t allow you to hide a result. “No, you use it to check the quality of your grind” Mal went on to explain. Once a shearer has sharpened their combs and cutters, sliding them over the flat stone of truth will reveal the highest surface of the comb or cutter ground surface; the rest of the surface hollows away in some fashion from these points. Single-bevel sharpening on Duo-Sharp Red grit after hollow-grinding with a hand-crank grinder. This video shows my double wheel grinder. Knife making at the Dan-D shop (1828 Bowie), Homemade grinder contact wheel constructed from MDF and measuring 14.375. The advantage of a hollow grind is that the edge can become incredibly thin. The advantages and disadvantages of these types of grind, in part five of this 8-part series answering your questions about sharpening. This is called a hollow grind, and in Japan, chisels are sharpened that way on purpose, because it makes it easier to sharpen them the next time. Basically, blade grind refers to how the cross-section of the blade is shaped to produce the cutting edge. Normally you will only need to grind about 0.5mm from the edge, unless you need to grind out a chip in the edge. The hollow grind is achieved by holding the blade to the grinding wheel at a right angle, which "hollows" the blade. I really do not think a surface grinder is the tool you need for this work. The diameter of the wheels never changes with the cupped wheel system which allows knives to be taper ground at the same angle throughout the life of the wheels. For decades sharpening with grinders was the only option for woodworkers. I remember saying it will take a long time to grind up using that. TwinsTM Sharpening System Hollow grinding wheels Honing/edging wheels Twins™ Sharpening System • Consists of identically sized HG4S Hollow Grinder and HE4 Honer/Edger. Mal had just shown me a method to learn about the hollow when grinding. You can use a bench stone or diamond plate but you can also use the side of a true grinding wheel. Join our mailing list to receive the latest news and updates from our team. By shifting a comb or cutter over the stone of truth you will mark the comb or cutter at the highest points on the ground surface; the more you rub it the more it reveals the hollow, and the shape of the hollow, and in fact if you have a hollow or not”. It means that every time you re-grind, you remove a tiny and constant thickness of steel, extending the life of both your tools and grinding wheels. A straight razor has a hollow grind. I just finished sharpening one flat on a stone. The Hollow Grind has been a historically popular type of grind, especially in the hunting community. The founder and director of the Connecticut Valley School of Woodworking answers questions from readers about … Therefore, they can be sharpened with a sharpening stone, or with a sharpening system. It simply reveals the truth about hollows ground into the comb or cutter grinding surface with the sheep shearer’s grinder. This will minimise the chance of burning the blade. How do you ensure the bevel is “flat”? This is characteristic of straight razors, used for shaving, and yields a very sharp but weak edge, which requires stropping for maintenance. Mal was shearing these hoggets with Rapier, very narrow, plates they were ground out well past the tip radius with no curved clearance to be seen giving his comb the longest teeth ever, and he had around 4mm of lead gauged on the middle tooth. The hollow ground blade has a characteristic concave grind to the edge, so that both sides of the knife have a bevel that is bowing inward until they meet. The concave offers hundreds of sharpenings made easier than … For the first time in some years I have reorganised my grinding/sharpening system. The result is a really sharp edge that is easy to renew many times before any re-grinding is indicated. Required fields are marked *. Despite what you may have read or been told, hollow grinding isn't a necessity; it's simply an unavoidable by-product of using a bench grinder. After honing the bevel, you may notice a slight recess on the flat side. To make a hollow grind, the blade blank is applied to the surface of a grinding wheel or a belt passing around a wheel, taking a concave scoop out of the blade. It is two 1/2 HP motors running 1x42 belts. The world’s best belt grinders Australian Made Award Winning Precision Machinery Exported to Germany, the USA & 20 Countries Worldwide. When sharpening a clipper blade there is a lot of things that can go wrong. Cupped Wheels The HG3 Hollow Grinder uses two 6 inch (15.25 cm) cupped wheels to grind the knife blades. Since the bevel on scandi grind knives is so large and flat it is pretty easy to get the right angle for sharpening. If you use the same area too much, a hollow will develop there, and it won't sharpen edges as easily from then on. In addition, it is easier to sharpen a hollow grind blade without the edge getting thicker behind the edge. For me it is a tool that every learner should buy, understand and respect as it will tell them no lies, misconceptions or myths. Because there is less material directly behind the edge, this type of edge is less durable (although the degree to this is more theoretical than in actual practice). I do not sell, distribute or endorse this jig in any way. It helps then if you have at least a fundamental understanding of blade grin… Are the lines down the corners straight, did you go over the skirting boards at the bottom, etc. The hollow acts as a jig. The Hollow Grind – Knife Store **CLICK HERE FOR IMPORTANT LAYAWAY INFORMATION** We are knife collectors, aficionados, and enthusiasts with a dedication to the expertise and product line for every type of customer: every-day users, first-time browsers, or those seeking a specific knife for casual use, marital arts, military combat missions, or outdoor recreation purposes. Also look at hollow grinding jigs as used by knifemakers. To re-sharpen the Scandi grind you need a flat grind stone. This guy was getting a great cut. He went in to grab another sheep and I flicked his hand piece on and off and there was bugger all tension. My “why?” hat went on and I asked him “how do you grind”? Now, Mal wasn’t the fastest shearer I had ever seen, quite the opposite actually, but what Mal taught me that day was more than I had learnt in around 3 years of constant “why?” about grinding shearing combs and cutters. Sure, there are those that have no respect for the stone of truth at all but believe in the tension nut to make things cut. The cambered grinding wheel only makes contact in a small area, so you're sweeping the blade back and forth across that high spot on the grinding wheel. The blade of quality wood carving knives is often … Hollow grind — a knife blade ground to create a characteristic concave, beveled cutting edge. Even if you do have one. There was no thinking outside the square with Mal – there simply wasn’t a square of containment. Beveling, Serration and Granton edge machines; Flat bevel grinding, Hollow grinding and Sharpening machines; Sanding and Polishing machines; Machines for handles; Contact Hollow & Flat Grinding. Hunting knives have usually the edge angle between 35 and 40°. Also, if you use a Cbn wheel, it won’t burn the tool. Fast, versatile and precise belt grinders and accessories for shaping, finishing and sharpening. So who cares about the hollow? Mar 31, 2020 - A brief demonstration of how I do my zero bevel grinds on my puukko knives. • System can sharpen up to 400 blades per day. POWER KNIFE SHARPENER HOLLOW GRINDER. We carry everything you need to complete your project from start to finish: blades, blade stock, handle materials, components, metals, tools, equipment, abrasives, polishing and finishing supplies, YES, we have it all. The place to find all your knife making needs. The only markings on it say "Pat Pend"... nothing else. Well, Mal wasn’t shy at all and the explanations started to flow. This produces a thin and wickedly sharp edge but it’s not durable and needs constant maintenance. David Heim and Michael Dobsevage. A hollow grind is also economic of the steel. His name was Mal Walton. The video shows standard Tormek sharpening resulting in a hollow grind. It could also cause irreparable damage to the edge. Does anyone have a used hollow grinding made easy jig from jantz knife supply for sale or know of some one who may be selling the jig? Take a look around online for scissor sharpening jigs, and you will get a pretty good idea. Sharpening the Scandi grind. On top of this he had around ¼ worn cutters and he was getting a great cut. The majority of hollow grind knives made today feature a secondary V-shaped bevel at the cutting edge. I watched him for a couple of runs and he was using far less gear than some of the other guys but no more than anyone else. Cheers Trev Illinoyance, Paolo_MD liked this post 02-29-2016, 08:41 PM #5. josh623. It also means that the geometry of the tip won’t change, allowing your tools to display the same properties every time you use them.