Sharpening System - David Reed Smith
Sharpening System
Wet or Dry, Coarse grind to Hone, Instant grit change, with sharpening jigs.
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by David Reed Smith
Download Free Plans from
Costs about $250 to make
Introduction
Sharper is Better
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|A magnified view of a roughing gouge straight from a bench |A roughing gouge sharpened on my system. |
|grinder. | |
Sharper is better. And that’s pretty much sharper is better, Period. A sharper tool cuts with less effort, is easier to control, and leaves a surface that needs less sanding. The less pressure you have to use to cut the less chatter you’ll get on the work and the less edge damaging heat you’ll generate. The question isn’t whether you need sharp tools but what is an unobtrusive way to get them. This article tells you how to make a sharpening system that has done that for me. It is inexpensive, quick to use, accurate, and capable of both extremely fine honing and moderately heavy grinding.
The system is based upon a cheap 8 inch Drill Press. The Drill Head is mounted upside down. The platform is mounted above it and supports the rest of the system. The drill press is used to drive a quick-change set of abrasive disks. Lubricant cooling is provided for all but touch up sharpening. Accuracy is insured by using the same jig for everything from the roughest grind to the finest hone. Three different jig supports are included. A multiple-angle platform sharpens roughing gouges (also works nicely on chisels and plane irons), skews, and scrapers. A V-Block Analog sharpens detail spindle and bowl gouges. A Straight Line Reference sharpens a variety of other tools.
Jigged grind and hone versus freehand
It is possible to sharpen turning tools freehand and do it well. Once you’ve learned to do it freehand you can sharpen with little interruption to your turning. It does, however, take a lot of practice, and most of us don’t even practice turning enough. If you are a beginning turner you are further handicapped by not having enough experience to know whether you’ve gotten it sharpened correctly or not.
Using a jig solves this problem as the jig enables you to sharpen correctly with much less practice. It can, however, trade one problem for another, because now you have the bother of finding the jig, resetting it correctly, attaching it to the tool, and adjusting the jig on the grinder. I’ve tried to avoid this problem using jigs that either don’t need adjustment or are contained in the tool handle where they don’t get lost.
Freehand Honing is also a skill that requires practice, if not as much practice as freehand sharpening. The Tormek system avoids this problem by using a relatively fine, re-gradable grinding wheel. The cost of this approach is that any heavy metal removal takes forever. I’ve avoided both of these problems by using the same jig for honing as grinding, and by allowing for practically instantaneous grit changes with a range from 36 to 3000.
I have had too many epiphanies (along the lines of “So THAT”S how it’s supposed to cut!”) after first sharpening a tool with a jig to ever go back to freehand sharpening and honing.
Flat versus Concave Bevel
There are differences between a flat and a concave bevel, but it’s unlikely that either your tool or the wood will notice the difference. There MUST be a clearance angle for the tool to cut, so the only part of the bevel that rubs is the first tiny fraction of an inch or so where the wood deforms (Look at the photographs on pages 34 and 35 of Mike Darlow’s Fundamentals of Woodturning). Rubbing the bevel is a metaphor. Just because it is a very useful metaphor that will help you keep your clearance angle small to maximize control and minimize surface defects doesn’t mean it is literally true.
You, however, may notice the difference between a flat and concave bevel. The main advantage of a concave bevel is that it is easier to hone by hand, as less metal needs to be removed. If you do not hone you will slightly increase the minimum clearance angle attainable. If you do hone the wood sees a flat bevel in the only part of the tool in contact. If you do manage to bring the heel of the bevel in contact with the turning wood you will scar the surface by compression. This will be worse for a concave bevel than a flat bevel.
No Fuss Jig Set-up
Jigs can be a great aid to better sharpening. Unfortunately the fuss of setting them up can also be a barrier to timely resharpening. First you have to find the jig, then reset it for the tool you want to sharpen (assuming you remember), adjust the jig on the tool and then adjust the jig to the grinder. You do not need to use the jigs in this article as other jigs such as the One-Way (what’s the name?) or Tormek jigs will work with a little modification for use with a flat grinding wheel. However I hope you will consider making my jigs for your tools. Most of my tools have the jig as part of the handle or stored in the handle. This makes them easy to find. They don’t need adjustment to the tool as they’re tool specific and only mount one way. This leaves only adjusting the jig to the grinder. I’ve found that the simpler it is to set up to sharpen the less likely I am to continue to work with a dulling tool.
No Fuss Abrasive Change
Being able to quickly change abrasives can be very handy at times. Profiling a new tool on a grinder as slow as the Tormek is torture to my mind. Restoring a nicked edge is close. Bench grinders use coarse stones, so you must hone by hand or use a coarse edge. With my sharpening system you can change abrasives literally in seconds. A much wider range of grits is available as you can use any 8 inch abrasive disk. I’ve found 60, 120, 220 and a honing disk to be most useful, but you can use 36 or 3000 and every thing in between. For routine edge touch-ups I use one disk with 220 grit on the outer half and a honing compound impregnated surface on the inner half. This requires NO time for abrasive change.
You also don’t have to worry about dishing the abrasive or dressing the abrasive when it gets clogged or dished. Just peel off the PSA abrasive disk and slap on a new one. I have no idea of the relative cost of a new grinding wheel versus the number of PSA disks that will do the equivalent amount of grinding, but even if the PSA disks are a little more, it’s worth it to not have to dress them.
No Edge Overheating
For each touch-ups with fine grit no cooling is needed. For heavier grinding I find lubricant cooling to be helpful. I don’t have to worry about overheating the tool, and I don’t have to breathe fine steel particles and silica dust. I started out using water, but adding a machinist’s coolant additive reduces the problem of rust and seems to clog up the abrasive less.
Suit refinement to the task
Because the abrasive can easily be changed you can suit the degree of edge refinement to the task. If you are cutting green wood with edge destroying dirt in the bark you may want to use a moderately coarse abrasive for quick edge restoration. On the other hand if you’re working a dry hard to sand wood you’ll want to take the time to work up to fine abrasive for the best surface off the tool. If for some reason your turning club has a cosmetic bevel contest, with a little extra time on a honing disk you can have a mirror bevel you can shave in or with.
Un-copyright
The sharpening system and the plans are not copyrighted. You can copy and distribute the plans as you wish. If you come up with improvements to the system I hope you will feel morally bound to freely share them, but as I do not wish to copyright the plans I cannot require it.
Safety
There are some obvious safety considerations. I use an electric tool in a fashion it was not designed for. Adding liquid lubricant to a system without special electrics adds some shock hazard. The on-off switch ends up upside down. There is some potential for the abrasive disk holder to be launched Frisbee fashion. I do not feel unsafe using the tool, but certainly I would not suggest using the tool if your spouse is an OSHA inspector. You, however, may have different work habits and different concepts of risk, and will have to make your own determination and take responsibility for it.
It is possible to modify the plans to reduce the appearance of risk. You can relocate the on-off switch and shroud the motor to shield it from lubricant, or alternately forgo using lubricant. You could forgo some speed of abrasive change in exchange for a more secure disk attachment. If you do not wish to use the quick-change disks, simply buy extra extra Aluminum Grinding Disks from WoodCraft. Do not add setscrews on the rim. Adjust the fit of the ½” drive shafts so that all are of exactly equal length. Put you abrasive disks directly on the commercial grinding disks and change the whole unit as needed. Making an extension for the chuck key will make change-over go more smoothly.
Making the System
Modifying the Drill Press
The first step is to buy an 8 inch drill press. I bought a Delta, but I imagine they’re all pretty much the same, or can at least be made to work. There are two tasks in this section: modifying the drill press so that the head can be mounted upside down, and removing part of the support column to provide clearance for the coolant collection system. I’ll describe what I’ve done. Feel free to add steps for a neater end result if that matters to you.
Allowing Head inversion
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|The modified Head |
The first step is to remove the top belt cover. A brief attack on the hinges with a hammer and cold chisel or diagonal cutters will suffice. I feel that when the head is inverted and mounted close to the base that this adequately isolates your fingers from the belt drive. This also makes changing speed easier, but I very rarely do that. If you wish, you could cut a wide slot in the cover to allow it be opened despite the support column.
The second step is to cut a hole in the bottom belt cover to allow the support column to go through it. I attacked it with a hammer and cold chisel until sufficient clearance was had. If you want neat you can perhaps remove the entire assembly.
The third step is to remove the drive pin that serves as a stop for the support column. It is inside the head. Just twist and pull it out with a pair of pliers.
Support Column Modification
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|The modified Support Column. |
Temporarily assemble the drill press. Attach the support to the base if it isn’t already done, and slide the head upside down on the column until the pulleys are about a half-inch from the base. Mount the drill chuck if it isn’t already done. Slide the table (right side up!) down the column until the table is about a half-inch above the drill chuck. Take a marker and mark the upper level of the table on the support column. Remove the table and head from the support column and the column from the base.
Make another mark two inches above the first mark. Use an angle grinder and cut off disk (or a hacksaw if you feel under exercised) to remove the front third of the column between the two marks. Clean up the worst of the burrs so that you can reassemble the unit. Remount the support column on the base. Install the belt so that the lowest speed is obtained. Slide the head assembly upside down on the column until the belts clear as before and lock it securely in place.
Making the Grinding Drive and Disks
Making the Grinding Drive
It is easiest to start with an aluminum plate with a ½” ID designed to mount PSI disks (see Sources of Supply). Flip the disk over so that the ribs and arbor mount are up. Us a pair of dividers or compass to mark out three equally spaced holes 1/4'" inside the rim. Center punch the holes and drill with a #7 drill. Then tap for 1/4x20 threads. Insert a 1/2" long 1/4x20 set screw in each hole and adjust so that it protrudes just less than 1/8" on the flat side of the plate. Screw on a ¼” nut from the ribbed side to lock the set screw in place.
Cut a 3” piece of ½” drill rod and debur both ends. File a flat to mate with the locking screw on the arbor. Make the flat about 1” long to allow you to adjust the projection of the rod.
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|The bottom of the grinding drive. |The top of the grinding drive mounted in the splash shield. |
Making the Disks
Make the disks to mount abrasive out of 1/8” thick aluminum plate (see Sources of Supply). The size plate you buy depends on the number of disks you want to make, which in turn depends on the number of grits you want to be able to easily use.
Lay out the disks. I used a CAD program to draw an 8” circle with three equally spaced holes and printed it out on 8.5x11 self stick labels. You could draw the circle and holes once, then copy them with a copier and use spray adhesive to attach to the aluminum plate. You could also use a thin line marker and trace the grinding drive disk.
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|Two finished disks. Abrasive has been attached to the one |
|underneath. |
Cut out the disks using a metal cutting blade on a hand held scroll saw. Center punch and drill the three holes with a 5/16” drill. Counter sink gently from both sides. It is best to approach this task slowly and clamp the disk down each time before drilling. Check and make sure that the disk will fit on the grinding drive disk in all six possible orientations (rotate 120 degrees three times, flip over, rotate 120 degrees three times). If your metal working skills are under precise, like mine, you will likewise have to fall back upon the methods our Revolutionary era Forefathers used: Come close and file to fit. Use a small round file to adjust the holes if necessary.
To attach the PSA abrasive disks, simply remove the backing, center on the aluminum disk, and press. If you want to use both sides of the disk, use a trash pair of scissors to remove notches so the pins can get into the holes in the disks.
Making the Support
Making the Center Support
Make the Center Support from plywood. Probably the easiest way is to rip a strip of ¾” plywood 5 ½” wide and at least 27” long. Then cross cut this into one 12” piece, two 2-1/2” pieces, and four 2” pieces. Cut out the center of the top piece as indicated on the drawing. Locate and drill three ¼ “ holes as indicated.
Select two of the 2” pieces as end pieces. As I have a ½” wooden tap and die set, and wooden threads don’t dent wood, I drilled and tapped for ½” wooden threads. You can install thread inserts instead. If you do use metal threads you may want to insert a piece of sheet metal to keep from denting the Sliding Support.
Assemble the pieces as in the drawing using whatever method you prefer. I used dowel cross pins and screws. But plain screws should also work if you drill pilot holes.
Once the Center Support is assembled, center it on the drill press table and mark the location of the three ¼” holes. Drill with a #7 drill and tap for 1/4x20 threads.
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|Dimensions of Center Support |Drawing of Center Support |
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|The Center Support mounted to the Drill Press Table. |
Making the Sliding Support
The slide support has three main pieces; two runners and a front piece. When making it, it is more important that it fits the Center Support you’ve already built than to fit my drawing. The length of the runners is somewhat arbitrary. I picked 22” and haven’t come close to wishing they were longer. Make them from a strong hardwood. My runners ended up being 7/8x2x22. Check the fit in your center support before fastening to the front piece.
The front piece should also be made of a strong hardwood, about 1.5x2x12.5. You can laminate two pieces if you don’t have a piece thick enough. Center the piece on your Center Support and make the locations for a mortise for the runners. Make the mortises about ¾” deep. Check the fit when dry assembled and then glue and screw together.
Drill two 5/8” holes in the front piece as indicated in the drawing, about 4 inches from the left side and 5 inches from the right. You now need to decide on a way to install threads to lock the SLR and VBA in place. I used threaded inserts but they haven’t held up well; the insert is being pushed out. You could install a cross pin of 3/8” steel rod and then drill and tap, or screw on a metal plate and drill and tap the plate.
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|Dimensions of the Support Slide |Drawing of the Support Slide |
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|The Support Slide |Detail of the Support Slide knobs & thread fixtures. |
Making the Cooling System
Making the Coolant Supply Support
The Coolant Supply Support is a simple turned piece (that fits in the top of the Drill Press Support Column) attached to a shallow box. Mount a 3 inch long piece of wood between centers on your lathe. Turn the last 2 ½ inches to fit the Drill Press Support Column (mine measures 2.68” right now) and leave the first ½ inch a little bigger. Test the fit in the Support Column. It should be tight enough that it won’t rattle around or move from vibration, but loose enough that you can easily turn it.
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|Drawing of the Coolant Supply Support |The Coolant Supply Support from the top. |
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|The Coolant Supply Support from the bottom. |
The box is made from ¾ inch plywood. Cut a 6 inch square (or larger if you select a larger water reservoir than I did), two pieces 6 inch by 2 inches, and two pieces 7 ½ inches by 2 inches. Cut a 2 inch wide semi-circle from the middle of one of the 7 ½ inch long pieces. Then screw the 6 inch pieces to the sides of square, then the 7 ½ inch pieces to the front and back of the square. Last screw the assembled box to the turned support with two or three long (2 inch or so) screws. You could apply a coat or two of varnish if you wish.
Making the Coolant Supply
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|The Coolant Supply. The lid makes a handy place to keep |Detail view of the valve. |
|a bevel angle gauge and the drill press chuck key. | |
To make the coolant supply you need a plastic container, loc-line valve and hose, a ¼ NPT coupling, and a small scrap of wood (see Sources of Supply). Make a small vent hole in the lid of the plastic container. Then carefully drill a ½” hole in one side of the plastic container about 1” from the bottom.
Make a spacer from a small scrap of wood by drilling a ½” through hole. Mount it on a mandrel and turn to a small enough diameter that it won’t foul the on-off lever of the valve.
Snap a small tip onto 6” or so of Loc-line, and then snap the line onto the valve. After applying some silicone sealant, push the spacer onto the threaded end of the valve. Apply more sealant and push the threaded end of the valve into the hole in the container. Apply some more sealant inside around the valve on the inside of the container and fasten it in place with the ¼ NPT female coupling. Set aside to cure over-night.
Making the Splash Shield
To make the Splash Shield you need a 9” round cake pan, neoprene rubber sheet, ¼”
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|The completed splash shield. |This is the Toilet Tube Inlet in hardware store packaging. |
plywood, and a toilet tank inlet. Use tin snips to cut the height of the cake pan wall to about 1 inch. Then cut a 2” hole in the center of the cake pan bottom. Cut a 9” circle out of ¼” plywood. Cut a 2” hole in the center of the circle. Cut ¾” plywood or other scrap wood into a circle that fits inside the cake pan. Spread silicon sealant liberally on the bottom of the cake pan, then using the ¾” circle, protected with waxed paper, as a caul, clamp the cake pan to the ¼” circle. Allow the sealant to cure overnight.
Position the Splash Shield on the Drill Press Table, and drop the Grinding Drive in place to make sure the Splash Shield is centered properly. Mark the position of the left slot in the Drill Press Table on the bottom of the Splash Shield. Remove the Grinding Drive and Splash Shield. Drill a ½” hole (or whatever fits the insert of your toilet inlet) about 1” from the front of the marked slot. Drill a ¼” hole about ½” to the right of the center hole. Put the insert temporarily in place and replace the Splash Shield on the Drill Press Table. Again check position with the Grinding Drive, then mark the position of the ¼” hole on the drill press table. Remove the Splash Shield, center punch the marked hole, and drill (#7 drill bit) and tap it for 1/4x20 threads.
. Apply silicone sealant liberally to the pieces of the toilet inlet and insert the top piece through the Splash Shield and into the bottom piece. Place the Splash Shield down on the Drill Press Table and secure in place with a 1/4x20 cap screw.
Cut a strip of Neoprene Rubber (See Sources of Supply) about 1.5” high and long enough to go around the Splash Shield plus about 1” overlap (about 30”). Spread silicone sealant liberally around the inside wall of the Splash Shield. Press the Neoprene strip into place. Apply some more silicone to the overlap. Secure the Neoprene on the outside with duct tape.
Make a inner dam of silicone sealant about 5 inches in diameter. Then leave everything undisturbed overnight to let the silicone cure.
Making the Coolant Drain and Reservoir
This is hardly worth a separate heading, but it’s my outline, so humor me. Hook up some tubing (how much depends on how far away you put the reservoir) to the splash shield drain. Cut a hole in the lid of the second plastic container that matches the O.D. of the tubing. Thread the free end through the hole and replace the lid on the container.
Making the SLR
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|The completed SLR |
To make the Straight Line Reference you need 5/8” threaded rod, ½” (or 12 mm) drill rod, and a sliding nut (see Sources of Supply). Cut a piece of 5/8” threaded rod about 14” long and a piece of ½” drill rod 12” long. If you think you might like to try using Tormek jigs (which of course is strictly forbidden in their manual) use 12mm drill rod instead. Line up the drill rod and threaded rod so that the drill rod goes about 1.5” past the threaded rod on the short end. Make darn sure they’re at right angles to one another and weld together. After everything cools thread the sliding nut on the threaded rod.
If you don’t have a welder, don’t know anyone that welds, and can’t find/are too cheap to use a commercial welder, you can assemble the SLR with a cap screw. Obviously I find welding superior. Start by clamping the threaded rod in a vise and use a ½” round file to match the profile of the end of the threaded rod to the ½” drill rod. Check frequently that a right angle is maintained. Use a #7 drill and 1/4x20 tap to drill and tap a hole about ¾” long in the center of the threaded rod. Be patient, as the threaded rod is likely work hardened enough to make tapping difficult.
Drill a recess for the head of a 1/4x20 cap screw about half way through the ½” rod about 1.5” from the end. Then drill through with a ¼” screw. Assemble with a TIGHT cap screw. Check to make sure the rods are at right angles to one another. Adjust with shims or a hammer if necessary.
Making the V Block Analog
A V Block is a long established sharpening for use with bench grinders. But with a bench grinder, the tool handle or jig is usually pointing over and up so that gravity assists in keeping the jig in the V Block. With my sharpening system, however, the handle usually points over and down. To make up for the loss of gravity as an assistant we can substitute a rare earth magnet. This will help hold any steel jigs in place. Adding a nail or screw to the end of wooden handles or jigs will accomplish the same thing.
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|The VBA and an earlier version. The head on the earlier version is |
|like the description, but is mounted on ¾” acme thread. |
To make the VBA cut a length of 5/8” threaded rod about 14” long. Find a piece of scrap wood that is approximately 2”x2”x2”. Drill a 5/8” hole about 1” deep into the bottom. Cut the front face inclined back about 30 degrees. Drill a ½” flat bottomed hole about ¼” into the center of the inclined face and glue in a ½” rare earth magnet into the hole with super glue. Drill a ¼” hole in the side of the block about ¾” up from the bottom to intersect the 5/8” hole. Insert the threaded rod into the 5/8” hole and mark the location of the ¼” hole on the rod. Then drill and tap the 5/8” rod for 1/4x20 threads. Reinsert the threaded rod and fasten in place with a 1/4x20 bolt and washer.
Making the Multiple Angle Platform
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|The MAP from the top |The MAP from the bottom |
The Multiple Angle Platform is optional, as all tools can be sharpened using either the SLR or VBA and various jigs. It does, however, make it much quicker to sharpen Roughing Gouges, Skews, and Scrapers as no jigs and almost no set up time is required. If you only do bowl turning, you might wish to make a single bevel platform for scrapers and mount it in the Sliding Support. One weakness of using a simple platform for sharpening when the abrasive moves away from the tool, is that the tool tends to be pulled away from the proper bevel. To make this less likely I use rare earth magnets to hold the tool down on the platform. This works very well when doing light to moderate grinding. During heavy grinding you may want to use the SLR instead. A minor drawback of using strong rare earth magnets is that your tool may become magnetized. This hasn’t bothered me, but if you wish to avoid this, then don’t add the magnets.
To make the MAP you need some ¾” plywood, some small pieces of ¾” or 7/8” inch thick hardwood, nine 1” rare earth magnets, a 1/16”x 1-1/4” x 18” strip of steel, two ¾” nuts, a ¾” bolt, and a 1/4-x20 set screw. See Sources of Supply.
Start by cutting two 5” circles of ¾” plywood. Drill and tap one circle for 3/4x10 threads. Make sure that the tap is kept at right angles to the disk when tapping. The best way to do this is to clamp the disk to your drill press table with scrap wood underneath and drill thru with a 21/32” drill (okay, it’s only wood, you can get away with 5/8”). Remove the drill without unclamping the disk. Chuck a Micro Tap Guide (See Sources of Supply) in the drill press and place the tap, attached to a tap wrench, in the drilled hole. Advance the drill press quill until the Micro Tap Guide engages the tap and the spring of the tap guide is compressed. This will hold the tap perfectly perpendicular while you turn the tap wrench handle to start the threads. If you don’t value spending $11.63 on such a spectacularly simple and effective tool then tap the threads by hand, chuck up a piece of ¾” bolt in your lathe, thread the disk on and turn the disk true to the threads. After you drill and tap one of the disks, use glue and four 1-1/4” screws to fasten the two disks together. Another alterative is to glue a smaller 1.5” disk on the bottom, drill a ¾” hole, use ¾” rod instead of a bolt and cross pin it in place with a ¼” bolt like the VBA.
Find a large ¾” bolt. You want one that has a couple of inches of unthreaded shank and at least 1-1/2” of threaded length. Cut the head off of the bolt. Cut the bolt so that abou5 1-1/2” of threaded portion remains. Thread a ¾” nut on to the bolt. Then thread the bolt in to the disk until it bottoms out. Lock the bolt in place by tightening the nut against the disk while holding the bolt so that it doesn’t turn. Clamp the other ¾” nut in a vise on your drill press. Drill out the threaded portion of the nut with a ¾” or 25/64” drill. Then drill and tap for 1/4x20 threads from one facet of the nut and insert the setscrew. This will be used as a height stop.
To make the three platforms; start by cutting three pieces of ¾’-1” hardwood 4” wide and 7” long. Cut two pieces 4 inches wide and 2” long. Glue the short pieces onto the ends of two of the long pieces. The next step is to cut the required bevels on each. The bevels I recommend are 70 degrees for scrapers, 30 degrees for roughing gouges and 17 degrees for skews (at 15 degrees the handles will foul on the other platforms). You can easily cut the 70 degree bevel on your table saw. Just set the angle of the blade to 70 degrees and cross cut using your miter gauge.
|[pic] |[pic] |
|A simple homemade jig for cutting bevels on the band saw |Sawing a bevel. The jig has to be advanced partially past the |
| |blade before the wood is clamped to the fence. I’m cutting |
| |plywood here. It didn’t hold up on anything except the 70 degree|
| |bevel. |
The other bevels are more difficult to do on the table saw. They are easier and safer to do on a band saw. Mount the widest blade you have on your band saw. Make a temporary sliding jig that slides in the miter gauge slot by screwing on a piece of ¾”x3/8” hardwood onto a piece of plywood. Run it through the saw to trim the piece exactly to the cutting line. Draw a baseline for the angle you want to cut on the jig, then fasten a scrap piece of 2x4 narrow edge down so that it is on the line to make a fence. Run the jig through the saw to establish the exact cutting line on the fence. Now clamp the piece of hardwood to the fence and saw. Change the angle of the fence for the other piece and repeat.
Adding the Magnets. If you have a tilting drill press table or a vise that will open to 4 “ you can simple drill three 1” holes 1/8” deep in each piece and super glue the 1” magnets in place. Place the magnets as close to the beveled as you can without risking drilling through. If you don’t have a tilting table or a large vise, or simply want the greater magnetic power that comes from backing up the magnets with steel; first cut a dado 3/16” deep and 1-1/4” wide on each beveled face. Cut three 4” pieces of 1/16”x1-1/4” steel. Find a scrap block 1-1/4” wide and 4” long. Drill three 1” holes about ¾” deep in this block. Then rip three 1/8” slices off the block on your table saw. Take a steel piece, a wood piece, and three 1” rare earth magnets and assemble with super glue, then super glue into the dado in the bevel.
To mount the beveled platforms, set your table saw miter gauge to 30 degrees and cut the back end of each platform so that the cutting line runs through the midline of the platform. Set the miter gauge to 30 degrees the other way and repeat. You’ll now have 120 degree angles that will nest on the circular base. Glue and screw the three platforms on to the base.
Make a mount for the MAP: Cut a 2 ”x 2” x 2-1/2” block of hardwood. Drill a 49/64” hole through the block (alternately drill a ¾” hole, pop the mounting bolt for the MAP in a chuck in your lathe, and file it down to easily slide in a ¾” hole) Make a mount for a locking knob like you did for the sliding support. Then fasten the Mount to front edge of one side of the Center Support.
Using the System
The general steps (details for each kind of tool will be given in the next section) for using the system are:
▪ With the motor OFF set up the SLR, MAP, or VBA and/or jig.
▪ Turn on the motor
▪ Adjust the position of the coolant nozzle so that it over the center of the disk. Open the coolant supply valve so that a slow stream of coolant flows.
▪ Grind the tool.
▪ Turn off the coolant and swing the nozzle out of the way by turning the Coolant Support.
▪ Turn off the motor. If you reverse these last two steps you’ll make a mess.
If it is necessary to change to a finer abrasive:
▪ Rotate the MAP out of the way if necessary
▪ Change the abrasive disk
▪ Replace the MAP if necessary
▪ Turn on the motor
▪ Swing the coolant supply nozzle back to the center of the disk and turn on the coolant.
▪ Grind the tool.
▪ Turn off coolant.
▪ Turn off motor.
Lubricant
You can use water as a lubricant, but this is false economy. Using a commercial lubricant prevents rust both on the system and your tools, is less messy, and the abrasive will clog less and is easier to clean. A lifetime supply of concentrate is $29.95
Grit Selection
For quick touch-up sharpening, a disk with two (a donut and an inner circle) grits will work well. You can use 220 and 20 micron 3M microfinishing, or if you are willing to forgo lubrication, 220 and cardboard with honing compound.
For serious initial shaping and restoration progressing to a mirror finish you can start with 60 Blue Zircon, then 120 Blue Zircon, then 220, followed by honing compound or 20 micron. As the grits get finer, the disk is marginally thinner which can change the angle slightly. I have found the effect to be negligible; if any thing it increases sharpening efficiency by introducing an imperceptible micro-bevel.
For rough turning green wood, or turning abrasive wood where the edge will not last you might wish to use only a medium abrasive such as 120 or 150.
Making and Using Jigs
Roughing Gouge
|[pic] |[pic] |
|With the MAP |With the SLR |
|The MAP is the quickest way to sharpen a roughing gouge. Turn the |If you don’t make the MAP or need to do heavy grinding to reshape |
|MAP so that the 30 degree angle bevel faces the grinding disk. |your roughing gouge (to get it to a proper 30 degree angle, for |
|Place the gouge on the MAP, advance it forward until grinding |instance), you can use the SLR. The ferrule will ride against the |
|starts, and then rotate the gouge from side to side. |SLR. Adjust the extension of the Support Slide and the height of the|
| |SLR until the bevel rubs the abrasive approximately in the middle of |
| |the disk. Turn on the System and roll the gouge from side to side. |
|[pic] |[pic] |
|With the VBA |A jig for the SLR |
|If you wish to sharpen the roughing gouge with the VBA, you’ll need|A simple jig for use with the SLR made of plywood. Cut a flat-topped|
|to place a small screw or finishing nail in the end of the handle. |side, cut a triangle shaped hole in the middle, big enough for your |
|Adjust the extension of the Support Slide and the VBA so that the |biggest roughing gouge. Drill and tap for a thumb screw in the top. |
|bevel contacts the abrasive. Turn on the system and roll from side|In use you can fasten the jig anywhere along the gouge blade. |
|to side. | |
Skew
|[pic] |[pic] |
|With the MAP |With the SLR |
|Turn the MAP so that the 17 degree bevel faces the grinding disk. Place |With the SLR you can use a built in handle jig or a separate jig. |
|the skew on the MAP and advance the skew until grinding starts. Turn |With the built in jig adjust the Support Slide and SLR height until |
|over and repeat for the other side. |the bevel contacts the grinding disk. Turn on the system and sharpen|
| |one side. Flip over and sharpen the other side. |
|[pic] |[pic] |
|With the VBA |Built in Jig |
|To use the VBA to sharpen a skew you’ll need to insert a finishing nail |Secure the handle in a vise or mount it in your lathe and lock the |
|into the handle so that it protrudes about 3/8”. Put the nail into the |spindle. Use a ½” round file to make a groove on each side that |
|magnet recess and adjust the Support Slide and height of the VBA to that |matches the skewedness of your skew. |
|the bevel contacts the abrasive disk. Turn on the system and sharpen one| |
|side, then flip and sharpen the other. | |
|[pic] |[pic] |
|A simple jig for sharpening with the SLR. A block of wood is cut so that|A drawing of the jig. |
|the angle of one face matches the skewedness of your skews. A | |
|rectangular hole is cut into the middle that is at least as deep as your | |
|biggest skew. A cross pin and thumb screw are added to hold the jig in | |
|place. | |
Bowl & Spindle Gouge—Swept back
|[pic] |[pic] |
|With the VBA & Homemade Jig |With the VBA & Commercial Jig |
|This is a very simple and effective homemade gouge jig—a piece of dowel|You can also use a commercial jig. This photo shows One-Way’s |
|rod with a screw in the end to engage the magnet in the VBA. I drill a|Varigrind. I had to increase the set-back from the tip so that the jig |
|hole in the end of the gouge handle to store it. Since each gouge has |didn’t contact the abrasive disk. Make a gauge to set the setback |
|it’s own unique jig, less set-up is required; you just pull it out of |consistently; I’m using 3-1/2” here. Once you set the jig on the gouge,|
|the end of the handle, insert in position, then set the Sliding Support|set the Slide Support and VBA height so that the bevel contacts the |
|and VBA height so that the bevel contacts the abrasive disk. Start the|abrasive disk. Turn on the System and rotate the gouge from side to |
|System and rotate the gouge from side to side to sharpen. |side to sharpen. |
| | |
|To set up the jig in the first place, drill an angled hole in the |Since I’ve used less space on this side, I’ll preach a little about |
|forward part of your handle. The length of dowel determines how much |using gouge jigs. What they do is set and/or maintain the grinding |
|set back there is to the grind. Cut a length of dowel longer than |angle at the tip and wings. What they don’t do is determine the shape |
|required (or drill rod if the dowel is too whippy for the length |of the gouge. You determine that by how long you grind in each spot. |
|required) Lay the gouge with dowel attached on a table with the gouge | |
|tip at the edge, and the gouge at an angle to the table. About 30 | |
|degrees for a spindle gouge and 45 degrees for a bowl gouge is a good | |
|angle to start. Cut the dowel at the point it crosses the edge of the | |
|table. Add a screw in the end. Drill a starter hole so you don’t | |
|crack the dowel. | |
Bowl Gouge—Straight Across
|[pic] |With the SLR |
| |To sharpen a bowl gouge that is ground straight across, use the ferule |
| |to register on the SLR. Adjust the Support Slide and the SLR height so|
| |that the bevel contacts the abrasive disk. Turn on the system and |
| |rotate the gouge from side to side to sharpen. |
Scraper
|[pic] |With the MAP |
| |To sharpen a scraper turn the MAP so that the 70 degree bevel faces the|
| |abrasive disk. Turn on the System and place the scraper on the MAP. |
| |Advance the scraper until grinding starts, then follow the shape of the|
| |scraper to sharpen the whole edge. |
| | |
| |You can hone the face of the scraper after sharpening and use it that |
| |way. You can also use a slip-stone or the Veritas Scraper jig to |
| |ticket a burr on the scraper. While both ways will give a very nice |
| |surface, it is my experience that a scraper with a burr requires less |
| |pressure to cut and thus will give better results if the work is thin |
| |enough to chatter. |
Parting Tool
|[pic] |[pic] |
|With the SLR |With the MAP |
|To sharpen a parting tool with the SLR, adjust the Slide Support |To sharpen a parting tool with the MAP, turn the MAP so that the |
|and height of the SLR so that the bevel contacts the abrasive |30 degree bevel faces the abrasive disk. Turn on the System and |
|disk. Start the System and grind one side. Flip over and grind |apply the parting tool to the MAP. Advance it until grinding |
|the other. |starts. Flip to the other side and repeat. You will have to be |
| |careful to keep the parting tool exactly on edge as you have very|
| |little surface to register to. |
|[pic] |
|To turn your parting tool handle into a jig, use a ½” round file to make semi-circular grooves in the handle. This is easier to do|
|if you mount the handle in a vise or between centers on your lathe. Make sure they’re straight across, equidistant from the |
|ferule, and perpendicular to the width of the parting tool. |
Pyramid Point Tool
|[pic] |[pic] |
|With the SLR |Making the Handle into a Jig |
|Adjust the Support Slide and SLR height so that the bevel |To make your pyramid point tool handle into a jig, mount the |
|contacts the abrasive disk. Turn on the system and sharpen. |handle between centers. Lock the spindle and make a semicircular|
|Flip to each new face and repeat. |groove with a ½” round file. Turn the handle 120 degrees and |
| |lock the spindle and make another groove. Advance another 120 |
| |degrees and repeat. |
Contact Me
Please feel free to contact me with any comments, questions, or suggestions. My email address is David@. If you prefer telephone, I’m home most mornings. My phone number is 1-410-374-5318.
Parts and Sources
Woodcraft, 1-800-225-1153, :
Aluminum Sanding Disk, PN 09L33, $15.99
MSC, 1-800-645-7270, :
1/8” Aluminum Plate, 12x24” enough for 3 disks, 32004871 $15.35
Loc-line ¼” Male NPT Valve, 097777210, $9.89
Loc-Line Adjustable Coolant Hose, 09777012, $7.89
Micro Tap Guide (optional) 95267472 $11.63
Neoprene rubber sheet, 1/16 thick, 36” wide, 1 ft, 31936057, $4.61
½” drill rod, 06000327 $6.11
12mm drill rod (optional), 06005128, $8.58
5/8” threaded rod, 06056204, $3.66
5/8” Fast Thread Knurled Nuts, 01603000, $6.35 x 2 = $12.70
½” round file, 80758410, $9.89
Knobs, 1/4x20, 06816201, $.67 x 3 = $2.01
Flat Stock O-1 Steel, 1/8x1/2x18”, 06108054, $4.71
Flat Stock O-1 Steel, 1/16x1-1/4x18”, 06104129, $5.59
Amazon,
Delta Drill Press, 11-900, $99.99 (or buy locally to save shipping)
Lee Valley, 1-800-871-8158,
½” rare earth magnet, 99K31.03, $.80
½” magnet cup, 99K32.53, $.50
1” rare earth magnet, pack of 5, 99K32.13, $8.95 x 2 = $17.90
Honing Compound, 05M08.01, $6.50
80 grit Zirconia Disc, 05M30.15, $4.75
120 grit Zirconia Disc, 05M30.16, $4.75
220 grit Aluminum Oxide Disc, 03M30.21, $2.50
500 grit Aluminum Oxide Disc, 05M30.23, $2.50
Grizzly, 1-800-523-4777,
Cutting Fluid, G7897, $29.95
Local Store
Rubbermaid Servin’Saver 3 qt. (2)
¼ NPT female coupling
Silicone sealant
9” round cake pan
Toilet tank inlet $3.09
¾” nut (2)
¾” bolt
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