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Sharper is better. And that's pretty much Sharper is Better, Period. While there are occasions when it might not pay to hone a woodturning tool after grinding, such as using it to hammer-drill holes in concrete, or turning Australian Wombat Wood (which measures about 7 on the MOS scale) in the ordinary course of woodturning what you should be asking yourself is not whether it pays to hone, but rather how can you hone more efficiently. Having sharper tools has many benefits. You can remove wood more quickly. Your tool will leave a better surface, cutting down on sanding time. You can cut with a lighter touch, reducing vibration. It just plain feels better. In this article I'm going to tell you an easy way to hone your woodturning tools quickly with minimal interruption in the flow of work.
Last year I got interested in modifying a Makita wet grinder to sharpen turning tools. I was using a 120-grit wheel to speed up the process, but it left a somewhat coarse edge. I had heard about and tried ideas for mounting a honing compound coated MDF wheel on a grinder. I didn't like the idea much, as you have to be able to walk around the grinder (not likely in my shop) and it seemed hard to control. But I made an MDF wheel to fit over the Makita wheel anyway, and I liked the way it worked. It was the slower speed and being able to work on the flat as well the rim of the wheel that made the difference. The Makita system turned out to be a rather jig-intense major project (if you're interested, check out my web site, www.DavidReedSmith.com) but the idea of a more slowly driven MDF wheel translates very well to being used right on the lathe. I've read many cautions about grinding on the lathe, but you don't have to worry about that here, as MDF disks don't tend to shatter into lethal projectiles, and you're going to use it when it's turning slowly anyway.
It works best with a variable speed reversible lathe , but I'm sure you can adjust. If you don't have variable speed, adjust the size of the disk until it's comfortable. If your lathe doesn't reverse the only problem is it will be a little harder to see what you're doing.
Please try this. It's easy, it's quick, it's unobtrusive, and even if you mess up you can't hardly hurt yourself or your tools like you can with grinding mistakes. You can easily put a mirror edge on your turning tools (or for that matter your pocket knife) in very little time (15 seconds a side does amazing things to a utility knife blade). Sharper really is better, the only danger is you'll probably never want to go back to just ground tools.
This is a microscopic image of my 1/4 inch beading tool. On the left it's been ground on a standard bench grinder. On the right is after honing.
Figure 1 shows a skew and spindle gouge. They were ground on the Makita, so the bevel is flat, and the honing disk polishes the whole bevel.
Figure 2 shows a roughing gouge ground on a 6 inch bench grinder and then honed. Only the lead and trailing edges of the bevel are polished.
Making a Honing Disk
The first, and probably hardest, step in making an MDF (Medium Density Fiberboard) honing disk is finding the MDF. Particle Board is more common but is coarser and less suitable. I found some MDF shelving at Home Depot. I don't remember what it cost, but it wasn't much, $5 would probably make 6 of the honing disks.
Mounting the MDF on a faceplate is the easiest way to try this out. Just cut out a circle of MDF on your bandsaw. It really doesn't matter all that much what size you use if you have a variable speed lathe, you just use a smaller wheel at a faster speed. Eight inches is a good place to start. Next you need to mount it on a faceplate. I suggest square drive screw with their deeper threads, but what you have will work. Make this a two-step procedure, as some of the MDF tends to push up as you drive the screws in. Drive the screws in once, then remove them and the faceplate. Cut off the protruding MDF with a chisel (or skew if you've never done flat woodworking) and then remount the faceplate. It will mount truer this time.
Now mount the MDF wheel on your lathe and turn the rim. As MDF has all sorts of chemicals that we weren't intended to breath and comes off in fine particles you should wear a dust mask and run your dust collector the whole time. You can experiment with different shapes for the rim. I've found it easier to hone gouges (both bowl and spindle) on a cove shaped rim.
After turning the wheel, you need to apply some honing compound. I got a stick from Lee Valley (1-800-871-8158, cat # 05M08.01, $6.50) years ago. I imagine any honing compound would work, but as I fell and about killed myself going down the stairs to the basement in my stocking feet to get their catalog so I could include a reference to them, I feel I should recommend it. To apply the honing compound, just hold the stick up against the wheel as it spins. If you slow it down first you'll waste less.
Figure 3 shows my faceplate mounted honing disk mounted outboard on my old Myford ML8. I added a Crepe block to clean sandpaper. I cut 4 inches off a 2x2 crepe stick, then cut it in half, then cut each half into a 4 inch semi-circle. I mounted the Crepe to the disk with wood screws, I kept driving until they recessed a bit. The hardest part was cleaning the melted then deposited crepe rubber off my lower bandsaw wheel after I was done.
Spindle Thread Mounted
I've found it more convenient to mount the MDF directly on the threaded spindle nose. All you have to do is cut out a circle of MDF, drill a hole in the middle about 1/8th inch less than your spindle nose diameter, and then tap it with a tap that matches your spindle nose thread. My own opinion is that every turner should have a tap to match the spindle nose thread, as I've found all sorts of uses for it. But then I'm an inveterate tinker who will jump at any excuse to buy another tool.
Once you've tapped the threads, screw the MDF disk on to your lathe. It's very hard to get the threads completely true, so you will have to turn the rim and the outside face true. If your lathe has nose that is partially unthreaded, turn a recess for it at this time. Put in a spacer if you need to avoid fouling your tools on the spindle itself. Then reverse the wheel and true the other side, then apply some honing compound.
Figure 4 shows the spindle thread mounted disk I made. I glued two pieces of MDF together, so I could turn a rim with both convex and concave profiles. If you grind your tools on a bench grinder, you'll find the convex profile handy to remove any resulting burr.
The idea to the honing disk is that you can easily use it when ever your tool starts to dull a little. The spindle thread mounted disk works well like this when working between centers, but you can't use it with a chuck or faceplate. The dimensions I'll give work well behind my One-Way Stronghold chuck, you may have to play with the sizes a bit if you use something else. To make a honing disk that can be used with a chuck, start by cutting out a 5 inch circle of 1/4 inch plywood. Drill a hole in the middle that matches the diameter of your spindle nose next to the flange. Mount the disk on the spindle and screw a chuck or faceplate on to hold it. Turn the lathe on and turn the rim of the disk true.
Next cut a circle (I used 8 inches) out of MDF. Draw a 2-5/8th inch circle (big enough to clear the rear flange on your faceplate or chuck) in the middle of the disk and then cut it out using a scroll saw. Then mount the disk on my Stronghold chuck by expanding the jaws into the cut-out and turn a 1/4 inch deep recess to match the plywood disk. Remove the disk from the chuck and glue the plywood disk in. Once the glue has set, slip the Honing Disk onto the spindle and screw the chuck or faceplate on. Turn the lathe on and shape the rim to your taste, then apply some honing compound.
Figure 5 shows the completed Behind Chuck Honing Disk.
Using the Honing Disk
The first step in using any of the honing disks is to have an edge that's ready to hone. While you can rehone an edge that's gotten just a little dull, if it's seriously dull or has any nicks that need attention, grind it first on the grinding system of your choice. Reverse the direction of your lathe if you can, and slow the speed down. You can use the tool rest if you like to help steady the tool, but it's not necessary. You might want using the rest the first time you try this, but afterwards it will interrupt the flow of work to move the rest. Make sure that the wheel is turning away from the cutting edge of the tool. Bring the tool up to the honing disk making contact with the trailing edge of the bevel first. Swing the handle until the whole bevel is in contact(this is easier to see if you can reverse the rotation of your lathe), then increase pressure. With a bowl gouge I find it easier to hone the nose on a concave rim and the wings on the flat side.
Figure 6 shows honing the nose of a bowl gouge on the concave rim of a Honing Disk.
Figure 7 shows honing the wings of the bowl gouge on the side of the Honing Disk.
Figure 8 shows honing a roughing gouge on a spindle mounted Honing disk while a turning square is still mounted.
Figure 9 is a drawing of all three honing disks.
One area of sharpening that's easy to overlook is the inside flute of gouges. I doubt if you can find an article or book on sharpening chisels or plane irons that doesn't tell you to start with the back. If you would like to make your gouges a little bit sharper yet, clamp the gouge in a vise. Dribble a little honing oil into the flute and then take a slip stone and have at the last couple of inches until it looks uniform. Then use a honing disk with a convex rim or bead at least a little smaller than the inside of the flute and hone it until you get a mirror polish.
Smoother is Better Too
Sharper is Better, but smoother is nice to have too. That's one of the reasons I like the flat polished bevel I can get using the Makita and then a Honing Disk. I don't want a coarsely ground trailing edge of a bevel dragging across my freshly cut surface. So even if you use a bench grinder take the time to make sure both lead and trailing edges of the bevel are polished. Another area that can benefit from a little polishing is the shaft of the tool. If you hold the last few inches of the tool up against the side of the honing disk for a minute or so, you'll get a nicely polished shaft that will slide along your tool rest more easily.