Sharpening Your Lathe Tools

by Fred Holder

Sharpening tools seems to be one of the largest hurdles that a beginning woodturner must learn to leap. Of the many woodturners that I've met while demonstrating at craft fairs, most of those who declared that they were having trouble turning, were really having trouble sharpening. Several times, I asked a turner to bring in his tools and let me look at them when he had stated that he couldn't cut clean like I was doing. In every case, the tools were dull. At that point, depending on how the traffic in the booth was at the time, I often gave a brief sharpening seminar and sent the turner home with some sharp tools.

I normally grind my tools and take them straight to the lathe without honing, I then touch up the edge from time to time with a slip stone or a diamond hone. I sort of think of myself as being a student of Richard Raffan, because I have all three of his books and both of his videos. Richard says that honing is not necessary and he is perhaps one of the best if not the best turner in the world. Anyway, I normally grind on a 3/4" x 6" Aluminum Oxide Grinding Wheel mounted on a Craftsman grinder. I have two stones: a 60 grit and a 100 grit. (Note: a check of the Woodcraft Catalog shows that they only carry 60 grit and 120 grit now; however, Farris Machinery of Grain Valley, Missouri carries the 60 and 100 grit.) The tool rest that comes with the grinder is practically worthless, so I purchased a Veritas Grinder Tool Rest with the straight grinding jig and the skew grinding jig. This tool rest is large enough to allow your tool to move on the rest and still remain flat on it.

sharpening tools

The Veritas Grinder Tool Rest straddles the grinding wheel. This did not leave room for the normal guards that come with the grinder; however, the rest performs perfectly. You do lose the protection of the wheel guards if the grinding wheel should fly apart.

On larger chisels, I find the 6" stone is too small to give a good bevel. These tools I grind on my 4" belt sander. Many turners, Wally Dickerman is one, uses a belt sander to do all of their tool sharpening. I normally free hand the tool on my belt sander, but I could likely get better control if the belt ran vertical and I had a tool rest to enable me to obtain repeatable bevel angles. The belt must run away from you.

Michael Hosaluk, on the other hand, says the first two fingers of his left hand are the best custom made tool rest in the world. But then, Michael has perhaps sharpened more tools that most of the rest of us put together. Michael sharpens free hand. He says to bring the tool up to the stone with the tail of the bevel first, let it touch and then lift the handle until the edge is cutting. It seems to work pretty good, especially when grinding tools at a craft fair with a stone mounted on a mandrel and driven by the lathe.

Originally, I used a 1/2" bolt with the head cut off and two thin nuts and two washers. The 4" stone that I use at craft fairs was mounted on the threaded portion between the two nuts and the washers. The smooth part of the bolt was clamped in a Nova Chuck with the 25mm (one inch) jaws. This worked pretty good except that you had to dress the stone every time you mounted it. I later purchased a mandrel with a No. 1 Morse taper to fit my Carbatek headstock spindle. This works much better and it isn't always necessary to dress the stone when mounting it on the lathe. I use the tool rest of the lathe as a tool rest for grinding or I simply move the tool rest out of the way and use the custom designed tool rest, the first two fingers of my left hand, that I came equipped with. This rest works quite well if one uses the advice of Michael Hosaluk and brings the tail of the bevel up first and then rotates the tool until the edge is being ground.

sharpening tools

For use away from my shop, I have a 4" grinding stone mounted on a mandrel with a No. 1 Morse Taper to fit the headstock spindle of my Carbateck Mini Lathe as well as that of my foot powered lathe. This does not work as well on the foot powered lathe, but is better than no grinder at all.

Like I said, I don't do too much honing of my tools. I turn straight from the grinder, with a little touch up from time to time with a stone or a diamond hone. The diamond hone seems to work real fine to extend the time between grindings. This also helps make your tool last longer. There are a few turners that advocate honing. I'm sure you can get your tools sharper, because I hone my carving tools. My turning chisels would cut even better and would last much longer if I took the time to hone them .

[Since I don't hone or a regular basis, I hardly feel qualified to present any form of dissertation on honing tools. Therefore, I've borrowed the following information on honing lathe tools and edited it from Volumes II and III of Turning and Mechanical Manipulation by Charles Holtzapffel.]

When the turning chisel for soft wood is sharpened with its double chamfer and the oblique edge; the extreme point of the turning chisel requires to be made quite keen, that it may be used for turning flat surfaces. The chisel is conveniently sharpened with its shaft held in the right hand with the left wrapped around it and with the shaft of the tool presented at a horizontal angle to the side of the stone that the oblique cutting edge may lie nearly square across the latter the hands are traversed parallel with the length of the stone, the main pressure being given as the edge of the chisel travels forward or from right to left upon the stone. The one bevel completed, some merely turn the tool over in the hands, others reverse the horizontal angle of the shaft and the positions of the hands to sharpen the other; the tool in the latter case is then held in the left hand with the right wrapped around it, the main pressure being then given as the tool travels from left to right.

The turning gouge, when sharpened upon the flat oilstone, is held in the same manner as the cabinetmaker's gouge, but to sharpen its elliptical edge the tool is traversed in a more concave sweep, much like the path of the parabola, upon the face of the oilstone, whilst the gouge is twisted in the hand. Sometimes both the outside and inside of the turning gouge are set with the oilstone slip; in this case the gouge is held in the left hand, and rested against the popit head, or any convenient part of the lathe, whilst the flat surface of the oilstone slip is rubbed lengthways all around the external chamfer of the tool, and then the round edge of the slip is rubbed within the concave flute. The wire edge left by the grindstone upon the gouge must be entirely removed before the tool is fit for use, it is expedited by drawing the chamfer of the tool through a notch cut by itself in a piece of wood as hard as beech, a few touches of the oilstone slip will then render the edge perfectly keen and fit for use.

Flat tools for hard wood and ivory when sharpened upon the oilstone are usually held in the right hand, the forefinger straight out along the face but also bearing slightly on the side of the blade, the thumb on the opposite side and the other fingers beneath the blade, the handle passing, the palm of the hand, and the left hand, knuckles uppermost, is wrapped round the whole nearly or quite covering the right forefinger. The tool is traversed straight along the stone which is placed with one end towards the operator, and the above named positions of the hands are a considerable assistance to maintain the tool at one uniform inclination throughout its sharpening.

Small round tools from about a quarter of an inch wide downwards, and the small round slide rest tools, drills and cutters used in ornamental turning, in their socket handles, are held and sharpened after the same manner, but with only the two first fingers of the left hand placed on the forefinger and thumb of the right to give the pressure.

Flat tools of moderate size are conveniently sharpened held in a different manner; the shaft of the tool is grasped in the right hand, all the fingers wrapped around it with the thumb stretched out upwards pointing along the handle, the thumb, the face of the tool, and the end of the stone all towards the operator. So held with the wrist a little bent to incline the shaft at the appropriate angle to give the edge its cutting facet, the flat tool is steadily traversed to and fro along the stone, its true position upon which is readily felt by the manner in which the edge bites or hangs to the stone as the tool is traversed towards the operator, the strokes by which the sharpening is principally effected.

Round tools, perhaps the most difficult of all tools to sharpen because it is necessary to arrive at a regular curvature as seen on the face, and an equal cutting bevel all around such curvature, are most conveniently sharpened held in a different manner, and with the long side of the stone towards the operator. The shaft of the tool is held like a pen with the forefinger stretched out along its face, the handle free and above the hand, with the left hand wrapped around the right, the fingers all above and the thumb below the right thumb. Thus held the round edge is traversed in a flat curve from six to eight inches long from end to end of the stone, the wrists twisted backwards and forwards to cause the entire round edge to meet the stone, with the upper arms kept in contact with the body for steadiness.

Small round tools from about a quarter of an inch wide downwards, and the small round slide rest tools, drills and cutters used in ornamental turning, in their socket handles, are held and sharpened after the same manner, but with only the two first fingers of the left hand placed on the forefinger and thumb of the right to give the pressure.

The round drills for ornamental turning are also, sometimes held by their necks between the finger and thumb alone, the wrist twisted as before during their traverse. Right and left side tools, and the sides of flat tools, have their side cutting edges traversed at right angles to the length of the stone, with their shafts horizontal. They are held in the right hand after the manner of the flat tools, but with the clenched left hand placed above the right forefinger and thumb to give the pressure. Their end cutting edges are sharpened like flat tools.

Tools for turning hardwood and ivory are sharpened upon the oilstone much the same as the corresponding tools for soft wood, the principal difference being that they are held upon the stone at a greater angle, according to the material upon which they are to be employed; the appropriate angles and forms for the various materials have been fully explained with the illustrations.

Finishing tools for soft wood are sometimes burnished with the back of the turning gouge applied at an angle, to throw up a wire edge which is used with a scraping action. The broads, figs 372 and 373 are thus employed for flat surfaces. Right side tools, fig. 382, ground at an angle of about 30 degrees and burnished, serve for interiors of boxes, and ordinary paring chisels are used in like manner for finishing cylindrical and convex works.

Editor's Note: The line drawings presented here were borrowed from Volumes II and III of Turning and Mechanical Manipulation by Charles Holtzapffel. Some of the drawings relate to tools for use in turning softwood. Softwood in Holtzapffel's terminology might be woods such as maple, elm, etc. whereas hardwoods are very hard woods such as Lignum vitae, box wood, African Blackwood, Desert Ironwood, etc. The tools for turning hardwood are somewhat different as you will note when studying the drawings. Note that hardwood turning tools do not use as long of handles as the tools for softwoods.

sharpening tools

Application of the Soft Wood Gouge to the wood to be turned. Grind Angle is 20 to 30 degrees.

sharpening tools

Basic Soft Wood turning tools (tool angle is 20 to 30 degrees): the gouge and the chisel. Figs. 362 and 363 show the gouge. Figs. 364 through 367 show the chisel. The chisel is normally ground 25 to 30 degrees for soft wood and 40 degrees for hard woods. Tools of one inch or more in width have handles 15 to 24 inches long. Tools less than one inch wide have handles of 8 to 12 inches in length.

sharpening tools

Hook tools for softwood (sometimes called inside gouges. The blades are 6 to 12 inches long and the handles run 12 to 15 inches in length. They are sharpened from the point around the hook as far as the dotted lines, mostly on one, sometimes on both sides. The hook tools follow very nearly the motion of the gouge in hollowing. The rest is placed rather distant and oblique. The tool is moved upon the rest as a fulcrum.

sharpening tools

The Broad, represented in Figs. 372, three views, is required to be held downward, or underhand, at about an angle of 40 to 50 degrees from the horizontal in order to bring its edge into the proper relation to the plane to be turned. Another form of the Broad is shown in Fig. 373. The stem is cylindrical with a triangular disk of steel screwed onto its end. It is sharpened externally.

sharpening tools

Tools for cutting the insides of cylinders. Fig. 374 is the side tool, it is generally sharpened on both edges and applied horizontally. Fig. 375 is a tool that serves for both sides and bottoms of deep works. Fig. 376 is another form of the same tool. Figs. 377 and 378 are threading tools for softwood that must be used with a traversing or screw mandrel lathe. Fig. 379 is a parting tool for softwood. It has an angular notch or groove on its upper surface. The two points serve to separate the fibres by a double incision.

sharpening tools

Hardwood turning tool is placed horizontal and has a grind angle of 60 to 80 degrees. This fits the scraper defination that we normally use for our so-called hardwoods.

sharpening tools

The Handle Configuration for Hard Wood and Ivory Turning Tools is much shorter than those for soft wood turning tools. These tools have a grind angle of 40 to 80 degrees and are applied horizontally at the center line of the work.

sharpening tools

Figs. 382 and 383 are right and left side tools. Fig. 384 is the flat-tool. Fig. 385 is the point tool. Figs. 386 and 387 are bevil tools. Fig. 388 shows the general thickness of these tools. Fig. 389 is a parting tool. Fig. 390 is a small side tool for small and deep holes. Fig. 391 is an inside parting tool used for removal of rings of ivory from the interior of solid works, in preference to turning the materials into shavings. It is also useful in some undercut works.

sharpening tools

Fig. 392 is the round tool. Figs. 393 and 394 are the quarter round tools. Fig. 395 is the bead tool and Fig 396 is the astragal tool. The quarter hollows, Figs. 397 and 398 could be used in forming loose rings. Tools such as Fig. 399 can be ground to make a particular shape of cut. Figs. 400 through 403 are inside tools. Fig. 404 is an inside screw tool and Fig. 405 is an outside screw tool. The edge of the screw tools may be whetted at a slope as shown in Fig. 406 or nicked on the grindstone as shown if Fig. 407.