turig tool sharpeig 201 kig heiple cwt 2007

TUR�I�G TOOL SHARPE�I�G 201 KI�G HEIPLE �CWT 2007 Keeping your turning tools cutting easily and cleanly means you have to accept that they will often need to be re-sharpened as often as every 10-20 minutes. Particularly for bowl gouges on harder woods. That means you need to master the techniques for re-sharpening them quickly and skillfully in 60 seconds or less with most of them. Only a skew generally takes a bit longer but fortunately needs it less. The tools covered here for spindle work are the Spindle Roughing Gouge, Spindle Gouge, Detail Gouge, Parting Tool and Beading & Parting Tool. For bowl or faceplate work the Bowl Gouge and both Flat and Round Nose Scrapers and several specialty scrapers. Once you are comfortable with these, other odd tools you may acquire will not be a problem. A couple of the special scrapers are included for interest. GRI�DI�G WHEELS A�D JIGS: Although you can master free hand sharpening for all of these, it is only marginally faster and will almost never be as uniformly repeatable and satisfactory as using a jig or platform support! You need an 8" grinder with aluminum oxide wheels. Most of us in the beginning pick too fine wheels, typically a 60 grit and 100 grit. These are OK for chisels and carving tools, but over fine for lathe tools. They grind too slowly and heat too much. And the white aluminum oxide wheels are soft [H hardness] and wear quickly, but are cheap. Cost about $30 apiece. Hardness levels for wheels are H, I, J, K of increasing hardness. The gray wheels that come on most inexpensive grinders are way to hard. Much better are SG Ceramic grinding wheels by Norton in 46 and 80 grit. They are K hardness and are great but cost $100 apiece! The club has them on its grinder, [I do not.] I use a Norton intermediate hardness aluminum oxide wheel [you can order from Production Tools on Brookpark.] 8x1x1-1/4 [straight, not recessed] 32A46-IVBE. The 46 is the grit, the I is hardness. one step harder that typical white H wheels. The 32 & BE are mfg. numbers and will differ by mfg. The A mean aluminum oxide. C would indicate carbide. You might also want the 32A80-IVBE, the 80 grit, for scrapers and parting tools only, on the other wheel. These wheels are about $50 but far better than the white wheels in most turning catalogs. The Oneway Wolverine jig is the "standard". Four of five others now do essentially the same thing. The Oneway Vari-Grind attachment for $48 is the core and worth getting rather than making your own. The Basic base unit is $80 but you can build your own for $5! Here are the plans or go to Google: 'King Heiple's Shop Built Sharpening Jig' and you can down load a pdf file of them from Fine Woodworking. You should own a diamond wheel dresser. A cupped non-flat wheel is hard to sharpen tools well on. The single point dressers are hard to control. A 1" flat one can be found from $20-35. General sharpening concepts re woodcutting tools. Fine carving tools for soft wood can have cutting edges as fine as 15-20 degrees but will be very delicate. Wood chisels depending upon usage may be sharpened with angles of from 25-40

of 11TURNING TOOL SHARPENING 201 KING HEIPLE 2007

5/30/2009http://www.ncwt.org/tips/HeipleSharpening/%20Turning%20Tool%20Sharpening%20201...

degrees. 40-45 cuts well and is a durable edge in wood. Obviously thinner edges chip more easily. Lathe tools generally have edges from 40 degrees for a skew up to 75 degrees for the nose of some bowl gouges to 80 degrees for a scraper edge. Learn to use a black magic marker to judge your grinds initially. Getting the edge angles you want. If you have trouble with edge angles, you can buy a Veritas bevel gauge from Lee Valley Tools

for $6.00 it measures from 15o to 45o in 5o increments. A very useful gadget. And also very useful are several triangles cut carefully on your table saw with the miter gauge and labeled. They help in setting jigs or just eye matching angles you want to achieve.

Figure 1. Veritas gauge and wood angle guides. THE SPI�GLE ROUGHI�G GOUGE In general the bigger this gouge is the easier this tool is to use. Mine is 1-3/4". You need only rest the butt end in the pocket of the slide. Pull the slide out far enough to give you a 45 degree sharpening angle of the edge. Slowly spin the gouge in the socket watching your edge contact. In front view you want to keep it ground straight across not swept back at the corners or dished in the middle. Your profiles should look like this when you are done. No need to de-burr this tool. Figures 2-A-C.



Fig. 2-A Set up Fig. 2-B 450 profile Fig. 2-C Straight across grind

THE PARTI�G TOOL A�D BEADI�G & PARTI�G TOOL These can both be sharpened semi-free hand or with the butt in the socket of the slide. The included angle of the edge should be between 45 and 60 degrees. It is not critical. Just keep aligned with the stone to keep the cutting edge square to the blade. Touch down equally from both sides until the grind just comes to the cutting edge. Again no need to de-burr but you need to pay attention to keep the edge square across to the axis of the tool.

3-A Parting 3-B Beading tool 3-C Beading tool THE SPI�DLE GOUGE Set your Vari-Grind jig angle at 130 degrees [or 50 degrees if you measure the other way from 90!] Scratch the setting in so if it slips you know where it was and lock it down and never move it again! The exact degree setting is not critical, you just don't want it different every time you re-sharpen the tool. Most new spindle gouges come very poorly sharpened. Usually too blunt in profile and too large [blunt] an edge angle. Getting a new tool right is much more work than re-sharpening. Here are the steps. Put the new spindle gouge face or flute down against the grinding wheel in the slide or over a bar rest at about 20-30 degrees from the long axis, like A. below. Grind down the face of the gouge at this angle, checking the face frequently until you just see the complete profile of the flute demonstrated, B and C below. The angle you put it down will determine the length of your profile and its arc. The shallower angle the longer and narrower the tip. Essentially your choice. This one is "medium".



Fig. 4-A Set up Fig. 4-B Initial "flats" Fig. 4-C Complete flute profile Check the grind after each touch-down to keep it even and watch the "flats" on each flute develop. Stop as soon as you see a complete profile of the flute as in Fig. 4- C. When the complete profile is exposed, cool it and put it in your Grinding Jig with exactly 1-3/4" protruding beyond the face of the jig, D. This could be 2", but must remain constant in re-sharpening to avoid changing your grind with every sharpening! Mark 1-3/4" somewhere you can easily set the length protruding from the jig. Set the slide such that the angle of grind is

450.. This should be checked after a bit of grind, adjusted and then marked on your slide with magic marker. Some turners who do mostly very small and delicate items will make the included angle of the edge 40 or even 35 degrees. But these are too delicate edges for most work. It should be obvious that you need to be grinding much more on the sides than on the tip. You are making the final profile match that of the flute one you exposed. The sweep of the jig needs to be smooth and uniform to avoid flats in your grind. Although the jig makes it possible to do well, it still takes a bit of practice and learning. Learn to stand in such a position that you do not have to move your feet during the complete swing of the tool.

Fig. 5-A Set up Fig. 5-B Partially ground, Fig. 5-C Finished grind

note flats remaining.

Fig. 5-D Profile of Fig. 6-A Tip of Fig. 6-B Profile of spindle gouge detail gouge detail gouge Deburring Although not absolutely necessary, for the best wood surface right off the tool with



spindle gouges, the burr should be either buffed off on a buffing wheel or touched off with a round edge diamond or ceramic slip stone. THE DETAIL GOUGE A detail gouge is simply a slightly different spindle gouge. Usually what are sold as detail gouges have a slightly shallower flute which makes them a bit stiffer than an ordinary spindle gouge the same size. You see both 1/2" and 3/8". You can find a 7/16" which I think is ideal. Figures 6-A and 6-B is a ground 3/8" detail gouge. The initial face down grind is shallower making a longer flute contour. You want a much narrower arch that will do details on small work easily. Note the longer sweep back on the sides. THE SKEW This is one tool that performs much better when not hollow ground, i. e. with flat bevels. The jig sold for doing this with the Oneway does make it less hollow ground but better is to use the side of the wheel lightly and make the bevel completely flat. This is the only time you will use the side of the wheel, but with a light touch. Although you can learn to do this free hand easier than with the gouges, you can rig your own jig as shown in Figure 7-A. Your skew will come with the cutting edge about 15 degrees off of square to the blade length and this works well and should be maintained. The jig is just a 15 inch strip of half inch plywood with a pocket for the skew handle at each end as shown. This can be clamped to your slide with a C-clamp. Only a 30 minute job to make one. Be sure you have the slide out far enough that the tip of the skew will not touch the disks holding the wheel! You will have to set the pocket out far enough to give you a 20 degree angle to the side of the

skew so you end up with a 40 degree included angle. Initially by trial and error or cut a 20

degree wedge on your table saw and use this to approximate the initial setting. An easy rule of thumb is to grind such that the final width of the grind area is 1-1/2 times as wide as the thickness of the blade, this is very close to a 40 degree angle for any tool.



Figure 7-A -A Measure and mark how far the jig is set to the left and mark it. It needs to be set exactly the same distance to the right for the other side of the skew. [It does not work well to just turn the tool over!] If you already have a good angle on your skew you can find the correct setting for the jig by just blackening the ground side of the skew with a black magic marker. Set your jig by eye and just turn the wheel by hand with the blade against the stone. Inspection will show which way the jig needs to be moved. Fig. 7-B When one side is finished move the jig to exactly the same amount of offset for the right pocket and grind with light touch and occasional cooling. Fortunately the skew needs grinding only occasionally. Mostly just occasional touching up on a fine stone.

Figure 7-B Figure 7-C Figure 7-D Figure 7-B Blacken the side of the skew with a magic marker to help set your jig for regrinding. Figure 7-C Work out the grind marks on a medium and then fine stone. until the cross grind marks are entirely gone at least at the cutting edge. Keep the bevel flat. Don't rock and round



the edge. Figure 7-D A fine diamond stone is also OK. I finish with the charged leather hone, 7-D. You should be able to shave your arm with a properly sharpened skew! THE BOWL GOUGE Most bowl gouges come with the English style grind with a 45 degree nose bevel. Cheap and easy for them to do at the factory. We usually want to convert them to a medium to long fingernail grind and a blunter nose angle. Be aware that every company has a different profile of their flute cross section, and some are "unfriendly" to a fingernail grind. These are some of the common profiles:

Fig. 8-A Typical bowl gouge cross section. S lightly larger bottom radius and flared sides. These take a fingernail grind well. Fig. 8-B Cross section of Glaser [now Glaser HiTech], relatively narrow radius at bottom and flat flared sides, but takes a fingernail grind well. Fig. 8-C Several makes of bowl gouge have very vertical side walls, not flared. This makes the wings of the fingernail much too thin. They will chip or bend. Best for English style grind or a very short fingernail only.

Fig. 8-A Fig. 8-B Fig. 8-C Initial reshaping of a new gouge. Bowl gouges mostly come with a grind of the tip or nose angle about 45 degrees and it needs to be about 65-70 degrees. Grind off the tip to that angle free hand, but don’t get past 70-75 degrees as the tip can catch into the wheel. Then put the gouge face down on the wheel at 20-30 degrees and grind off the face until you see a complete fingernail profile of the flute as you do with a spindle gouge. Put the gouge in your grinding jig, protruding 1-3/4", lock firmly and proceed. Even more than with spindle gouges, you do most of the grinding on the sides. Go very lightly across the nose of the tool or you will make a "notch" in the tip and the tool will be very catchy and unfriendly.



Fig. 9-A Face grind to expose Fig. 9-B Finished grind Fig. 9-C 650 nose with

flute profile flat profile As you grind the sides, slide the tool slightly across the face of the wheel and keep the side view profile flat, not arched nor saddle shaped. The parabola you see as in Fig. 9-A & B should be a smooth arch, without any corners or flats if it is to cut smoothly.

Fig. 10 Top row: Short, medium and long fingernails. Regardless of the length you make your fingernail, keep the side profile flat. Bottom row: Avoid a swayback or unequal sides, or the nose ground away like the two on the right. Since all bowls need sanding, [it's only a question of how much] it is a waste of time to deburr a freshly ground bowl gouge. The burr will disappear in the first 30 seconds of use. SCRAPERS The scraper can be a magic tool. But only if you learn to sharpen for a fresh burr almost every two or three minutes. You can learn to do it in 20-30 seconds. Some woods will require it so often you just leave the grinder turned on! And some super hard exotics scrape smoother than any gouge will cut!



If you have used a cabinet scraper you know that it must be leaned away from you to cut with its burr. The same with scrapers on the lathe, is must point downhill to cut properly. you are dragging the burr on the work. Note the burr is "pushed up" by the grinding wheel and occurs on the top of the tool, not the bottom! It is delicate and will only cut for a very short while before disappearing. If you are getting dust instead of very fine shavings your burr is gone and you will get significant tear-out. A good burr will catch your fingernail as you drag it across. The shaving a scraper burr takes is only a few thousands thick. As soon as you push on the scraper even the slightest it will stop cutting a shaving and start plowing and creating tear-out. You stroke the surface of the wood with a scraper as with a feather! The burr needs to be supported by firm metal so the sharpening angle for a scraper is 75-

800 ! I.e. only 10-150 back from 900 if you think better that way. If you make an edge much

sharper than that is will bend as it encounters the wood at less than 900 or else push in too far and catch severely. Use the flat plate platform to grind scrapers. It is obviously best if you can set it and lock it so that you always hit the grinding wheel at exactly the same angle. This saves both time and much expensive metal. And this setting will work for all your scrapers. For best results with all scrapers it pays to flatten and polish the top surface on a very fine stone before grinding. Make sure that your wheel is flat, set and lock the plate platform and slide the flat scraper lightly across the wheel until you get a clean grind across the entire width of the scraper. As soon as you do so you are done. It shouldn't take more than 20-30 seconds!

Fig. 11-A 15o tilt to platform Fig. 11-B Carry the edge back

the tool worked flat the sides a bit. Most round end scrapers as they come are not round enough. Make the end into a half circle and even sharpen back up the sides for a quarter of an inch, "cone shaping" it a bit, Figures. 11A & 11-B. It works in tight quarters much better. Most work will be easily accomplished with a 1/2" and a 1" round end scraper. Wider scrapers are not really better, they just grab harder!



Exterior scraping on bowls is done much better with a square ended scraper and 1" or 1-1/4" is as wide as you ever need. It may be simply ground square across at your 15 degree back angle. Special Scrapers There are three special scraper shapes that are worth mentioning in a sharpening demo. They are included since many have not encountered them and they are extremely useful. First you can make a 1 inch scraper much more versatile by modifying the two corners very slightly. First by grinding a very tiny radius on the left corner of the tool with the grind coming back the left edge of the blade a quarter of an inch. And then put a very short 10 degree chamfer on the right corner. Both of these are shown on the scraper in Figure 12.

Figure 12. Note the degree of polish to the top edge of the scraper. Slight radius to left corner and chamfer on right corner. A straight scraper modified such as this will do all your exterior bowl scraping quite well and in addition will work a flat bottom on a tray or platter, sliding smoothly sideways in both directions without raising a burr in either direction. In addition the left corner is ideal for making the entering plunge cut on the interior edge of a natural edged bowl. Tenon and recess scraper Although you can make a tenon for a scroll chuck or a recess for expansion with a square

scraper, a much better solution is a corner scraper. A 1/2" or 3/4" scraper ground into a 85o

point tool is enormously useful in making tenons and expansion recesses for gripping bowls. And this shape can be sharpened indefinitely, it just gets shorter unlike sharpening the side of a square end scraper. Figure 12.



Figure 12 Just grind off one side at 45 degrees and then turn 90 +5 degrees and grind off the other to meet in the middle. Note again that the top of the tool was polished first, although not very important for this usage. Recess truing scraper

Figure 13 There is no more awkward task than truing up an expansion recess in a rough turned bowl after it has dried and is now out of round. This recess truing scraper is the solution. Just pin the out of round bowl to a padded scroll chuck with a live center and this scraper will reach in to flatten the out of round bottom as well as true up the recess and its bottom for the expansion jaws. It is easily ground from an stout old file. Just grind off the teeth on the top edge first and grind the shape using the corner of the grindstone and tape the rest of the file. You only need a 1/4" of reach for a good expansion recess.



turig tool sharpeig 201 kig heiple cwt 2007

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