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| Examples of Jigs |
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| Finest abrasives. | ||
| Microbevels front and back. | ||
| Use a jig. | ||
| Copyright (c) 2002-10, Brent Beach |
- My Jigs
- The Competition
- Jigs made by visitors to my sharpening pages
My Jig Designs
The Original
This is one of my first jigs based on the idea of just sliding the jig on the glass. The screws heads are counter sunk into the short jaw, the nuts on the tall jaw. Tightening the nuts causes the screws to turn, so you need a screw driver and a wrench at the same time as you are holding the jig. I developed a weird screw driver that made this a little easier. I used this jig for years. The F stands for Front, to remind me which side the bevel went on - the jig was not exactly sized. You can see a little wear on the edge at the bottom. Not much wear for having done hundreds of sharpenings.
Grinding Jig
I usually grind my irons using a 1" belt sander. Having limited bench space, I do not have permanent bench top room for the belt sander, so it spends most of the time hanging from the ceiling (joists). Rather than use it, I built this jig to try to use a variation on Quick Lap for grinding irons. Quick Lap is a Scary Sharp variation that uses very low grit Alumina Zirconia belts to flatten plane soles.
This jig holds the iron in the usual way, but rather than slide back and forth in front of the abrasive sheet, it slides on either side of the abrasive. I glued a 2-1/2" wide (?) belt to a piece of glass and tried it out. The abrasive is represented by the blue line in the picture.
Looks like a good idea. I wonder why I have not used it since then?
Side Holding Jig
Got to thinking about jigs on a long drive one day and come up with this version. It is much like the eclipse jig, side holding with the tension provided by a bolt and a nut (well, piece of threaded metal). The difference is that the rod that aligns the jig is on the other side of the screw, away from the blade. This jig has a slightly different geometry - the back bevel angle (you knew it supported back bevels, of course) depends on the blade thickness in this one.
The blade position is shown by the green line. The dowel at the top is fixed on the left side, slides on the right side. This jig works fairly well. The bolt should perhaps be closer to the blade position to reduce racking. In this orientation it is positioned to do the back bevel.
Skew Jig
This jig is used for wood turning skew chisels. Standard idea, but both sides get the same bevel.
Water Stone Version
I tried out water stones (What is all the fuss about?). You can't slide a jig on a water stone, so this took a little doing. I built a pond with wooden sides on which I could slide the jig. The pond doesn't actually have any water in it, just the water stone sitting on a couple of wedges. By sliding the wedges together I could raise the stone to the level of the sides of the pond.
The problem with this jig is you cannot use it to put back bevels on the iron (the short jaw would have to be U-shaped, just like the tall jaw). Didn't get a lot of use. Still don't know why people bother with water stones.
Tiny Version
This is the smallest jig I have made. The tall jaw is only 3/4" tall. This is the size to use for irons under 4" long. I think Steve Knight planes originally came with short irons.
Japanese Irons
Japanese irons are short and tapered. They are short enough to present particular problems for sharpening with a jig. This design attempts to get around the shortness issue by grabbing the iron at the end with a sort of pliers action.
The iron is represented by the green line. The screws pull the jaws together (force along the yellow line), with the jaws pivoting around the small wooden slip on the right end of the top jaw (red arrow). The jig slides on the bottom of the darker piece of wood at the right when working the main bevel.
When doing the back bevel, it slides on the small slip at the right end of the upper jaw (blue arrow). It is adjustable for main bevel angle only by shimming at the back of the iron (right end of the green line) to change the projection of the blade. I still use this jig.
Some other Jig Designs
The Eclipse Style
My first jig was store bought. The jig is a side clamping style with a roller. It was bending my wide irons and scratching the glass. It did however have one crucial characteristic - you set the angle by setting the projection of the edge from the front of the jig. It even has the projections in raised lettering on the side of the jig.
Veritas Style
Bought this shop made jig from an old coot, who made these and a type of Jorgenson style wooden brace and sold them at his garage sale. Grabs the blade top and bottom and keeps the blade flat, but the blade slips and it has a roller. Any jig that holds the blade with a single pressure point in the middle of the blade is probably an error - the blade cannot be held firmly enough to prevent slipping, or turning, during use.
Veritas Mark II
Veritas has made significant improvements in the second version of their jig.
As shown here -- with the extension setting attachment in place -- it can be seen to combine many of the features of my jig:
- The extension setting attachment replaces the combination square. This may look better than a combination square, but it only has fixed locations for some angles -- 25 and 30 degrees, but not 29 degrees.
- The microbevel knob and roller builds in my two wooden slips. Again, you get to use the microbevel angles they chose. I personally believe that a first microbevel at +2 degrees, and a second at +1 more degree is better than their selection of +1 then +1 more degree.
- The blade is held with a plate across its full width, rather than by a single pressure point in the middle. This greatly reduces the chances of the blade turning in the jig.
- The knurled knobs on the tightening screws replace the screw driver. It does mean though that you cannot simply flip the jig over and do the back bevel as an integral part of the honing operation.
- If rolls rather than slides on the glass. A bit or grit under the roller and the glass is scratched.
- It cannot be used for both front and back bevels in a given setting.
- They have missed the baby oil delivery mechanism.
Even though lacking a few essential features, it does well on the Buck Rogers rating scale.
Abrasive jig
Garret Wade sells this jig, but does not give it a name other than honing jig.
Quite ingenious, the tool lies flat and the jig, which has diamond hones slotted in, moves past the tool.
If used to hone only, this could be quite a good hone. It would only hone a single microbevel and would not help with back bevels on plane blades, but it might be a quick way to hone and then touch up a chisel.
Notice however that you only use a very small part of the abrasive. If you hare honing microbevels, just 0.01" of the abrasive. You buy and abrasive that is 0.5" wide and use only 2% of it. Even with diamond, this will wear fairly quickly.
Jigs made by visitors to my sharpening pages
Some designs of shop made jigs, most recently received first.Bob Jones
Bob Jone made a stone vise using plywood offcuts, as well as slanted jigs for grinding. Bob also intends to try using abrasive sheets on glass the same size of the coarse stone to hone in the same setup.
Bob reports that the coarse stone worked well right out of the box - no need to recondition the surface on concrete. He went one step further and rubbed the back face on concrete and found that it did not work as well as the other face! So, before assuming a new coarse Norton stone will not work, be sure to give it a good trial. Let's hope that Bob's experience is the new normal for these Norton stones.
Tom Culver
Tom Culver has adapted the basic jig design to curved carving chisels. I use a straight bodied jig for straight edges. These pages include several designs of jigs with rounded bottom edge to allow honing of rounded (cambered) edges on straight blades. With carving chisels you almost never have a straight (flat) blade, let along a straight edge. You could be putting a straight edge on a rounded blade, or a rounded edge on a rounded blade.It looks like Tom got the tall jaw height from the extension calculator, then used that as the radius of a circular tall jaw. This is a reasonable approximation to the jig shape. The actual honed angle will vary from the middle of the chisel to the edge, but only by a few degrees. A more complex calculation (with resulting more complex lower jaw shape) is needed if you want precise angles on rounded gouges with straight or rounded edges.
Sizing of these jigs works the same as sizing for any jig derived from my basic model. You decide first how much blade you can have extending in front of the jig (the blade length minus the jig thickness) and the angle you want. Take these to the extension calculator. You cannot put the extension into the calculator - you have to try various values for the tall jaw height until you find those that produce suitable extensions.
For very short carving tools you will have the added excitement of making a slanted jig.
This jig is rounded to handle the 1 1/2" gouge. Tom must have spent some time with the extension calculator, using the length of the chisel and the honing angle to find the right size for this jig - which happens to be 1 1/2" radius circle. The base has a V-groove 5/8" wide and 5/16" deep to steady the gouge. Without the groove, the small contact area between the gouge back and the jig means very high pressure with likely burnishing of the wood. Once burnished the wood no longer holds the chisel in place well. The screws go into holes tapped in the base. Tom used Cherry.
Same idea but for a much smaller 1/4" gouge. In this case, the radius of the base is 3/4".
These are the only jigs Tom uses for all of his gouges.
A little hard to see, this is actually a V-tool. Again, with the size of the tool and the angle you want, use the extension calculator to determine the basic jig size.
The V-tool has a 75 degree angle - so does the jig. The base is notched to accept the tool. The sliding faces are slightly rounded.
Threads tapped into base as in all the other jigs. I have been using a plane iron jig made of mahogany with threads tapped into the base - the threads show no signs of loosing strength.
Tom even does incannel gouges. The half-round has the same radius as the gouge, so you need one half round for each gouge radius. One jig works for any gouge.
The upper jig jaw is notched as in the other jigs. The lower jaw has an elliptical indent based on the largest gouge radius. Tom uses flexible plastic on the half-found to raise the jig - flexible plastic slips.
Tom can use his incannel gouge to pare cross-grain on pine and redwood with great results.
Tome spends the last hour in the shop each week sharpening all his tools. He marks any problem tools with masking tape and gives them a little extra jig time in the next sharpening session.
For small things - knickers, pencil sharpener blades - Tom uses vise grips to hold the tool and this jig to hold the vice grips. Tom notched the base to hold the back of the pliers. Some adaptation was also required on the upper jaw of the jig.
Because the tool is much larger away from where it is held, top slit the top at the screw in the font of the picture to make a quick release top. It looks like a shadow to the right of the front screw but that is the quick release slot.
In order to work with very small tools like nickers, Tom filed off a bit of the nose of the pliers.
Tom has shown considerable ingenuity.
Scott McLagan
Scott McLagan built some wood/metal jigs - one sized for the short Lee Valley block plane blade. The wooden part is hand-me-down Lignum Vitae - his dad was a ship builder and these bits followed him home. I have some similar blocks of Lignum Vitae I bought from a ship builder who worked on wooden hulled mine sweepers in Vancouver, BC, during the second world war. This wood sits around for a long while before finding just the right use.
Scott appears to have use larger and thicker glass sheets than I use. He is also not using a backing board. The edge of the glass look nicely eased though.
On the short jig for the block plane iron, a narrow jig with a wooden back would probably work well. If the t-nuts partially overlap the blade in the area in which the blade is held, there should be no problems with the wooden jaw flexing.
Scott later sent me a picture. The email said "The pic is of a pine shaving, certainly only a few cells thick." I saw the jig, the two slips and the plane and was wondering where the picture of the shaving was. Wow! The shaving is resting on the plane! Very nice.
George Daiber
George Daiber has a complete machine shop - he made this jig out of aluminum.
I think the jig should be made out of wood but George assures me that the jig works just fine.
- Glass wear - George assures me there is no wear problem with aluminum sliding on glass.
- Blade holding - You can just see that George notched the top of the thick jaw to help keep the blade square - the blade does not turn in the jig even when twisted hard.
- Thin jaw - George has no flex in the thin jaw. He made the jig just wide enough for a 2" iron.
From George: "I brought a shirt pocket full of chips into the house to measure, with the range of chips being the .0015 down to the .00035. This technique is very effective even right out of the box and me not having the experience with this sharpening method."
Dave Gilbert
Dave Gilbert built his version of my jig using brass! The screw holes were tapped with 8-32 treads. Dave also made a jig from high density PVC.
Running the screws through counter sunk holes in the thin side into tapped holes in the thick side would work for hard woods as well. I suspect that slanted jigs for chisels and for grinding plane irons might be more easily made this way.
Edi Malinaric
Edi Malinaric used brass and olive wood. A 3mm brass plate with square stock silver soldered to that. Edi says he has no problems with scratching the glass. The shaving below is spruce, though it looks like lace. Edi made (is making?) a cello.
Jerry M. Honeycutt
Jerry M. Honeycutt added a couple of rare earth magnets to a standard jig design to make it easier to hold the plane blade during extension setting. Shallow holes with a Forstner bit, then epoxy to hold the magnets in place.
The magnets are strong enough to hold the blade in position without any pressure from the other jaw.
Jerry Alexander
Jerry Alexander has built a complete set of jigs. Great edges cannot be far behind.
These look so much like my jigs you might suspect that I made them. Jerry lives on the other side of the continent from me and we only met through google!
Wilbur Humphrey
Wilbur Humphrey made this slanted jig for chisels. Rather than screws and t-nuts, Wilbur uses hex head screws which he glues into the wooden knobs. He threads the hole using a tap designed for use with metal. I have tried this a couple of times and it seems to work. I have actually stripped a couple of t-nuts over the years (on my jig for sharpening saws only, but they are easy to replace) so taping threads may be an option.
Rather than glass as the sliding surface, Wilbur has used a melamine covered board.
This is how Wilbur makes his knobs.
Randy Klein
Randy Klein made two very interesting alterations to my jigs.
First, notice the rounding on the top and bottom (ignore the extra thickness for a minute). Randy wanted to put a bit more camber on his blades. If you camber the jig the same amount as you want to camber the blade, you can easily get camber.
For example, you might want to have 0.003 camber for a jack plane. By putting this much camber on the jig - both sides - you can easily hone to that profile.
It turns out that for small cambers a flat sided jig works fine. Just press a bit more on the corners of the edge as you hone. It will cause the jig to tilt but will hone to the cambered profile. For larger cambers, this type of modification to the jig works well.
These are Randy's abrasives. He attaches plate glass to MDF of varying thickness. The abrasive is on the plate glass. Having abrasives of known height, where those heights differ by the thickness of the slips you want to use, can remove the need to use slips when honing. The height difference is built into the abrasives instead.
To compensate for the fact that the abrasive surface is off the plane on which the jig slides, Randy thickened both parts of the tool jig. The amount you have to thicken depends on the exact jig geometry. You can see a sketchup model of a modified sharpening jig near the bottom of this page.
David Dack
David Dack has a metal lathe! This infill jig pinches the blade up against a metal plate. The thin plate is less flexible than a wooden jaw of the same thickness, allowing David to have smaller back bevels.
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