|Examples of Jigs|
|Microbevels front and back.|
|Use a jig.|
|Copyright (c) 2002-15, Brent Beach|
If you landed here from a search engine, you could jump to the Sitemap/Contents page which will connect you to pages of interest to you. Start here for an overview of how I sharpen edge tools. If you are interested in jig designs for a variety of edge tools, you are in the right place.
I am currently using two designs almost all the time. For honing, the standard square jig discussed in these pages. In fact, I think I am still using this jig. That picture was taken Feb 27, 2006. These jigs turn out to be pretty durable. For grinding, the same slanted jig used in my grinding video. That picture was taken Sep 17, 2006. Neither jig has been repaired since it was made.
As well as discussion of my jigs, I have included here pictures of jigs made by people who were inspired by my jig. Quite a variety of approaches.
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?
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.
An interesting video showing how to make improvements to the Eclipse jig. If you are using an Eclipse jig, these small adjustments might help.
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.
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.
George Bell has put the eclipse jig onto a sled and uses it with PSA abrasives. He has slips that allow micro bevels, but has no back bevel option.
As shown here -- with the extension setting attachment in place -- it can be seen to combine many of the features of my jig:
Even though lacking a few essential features, it does well on the Buck Rogers rating scale.
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 are honing microbevels, you use 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.
While it side sharpens - uses a side to side motion - it will not put a camber on the blade the way the side to side sharpening using a jig does.
Large Jigs like this that do not roll on the abrasive have two main advantages over the smaller jigs that do.
Similar in concept to the Millers Falls, the tool is held near the end in a clamp, the tool and jig riding on the tool edge and a roller. The angle determined by the height of the jig above the roller.
The angles possible are limited by the fineness of the threaded rod.
This image is from US Patent 1,047,126 granted on December 10, 1912, patented by J. M. Hance, but assigned to the Stanley Rule & Level Company.
The patent image is interesting because it shows the tool/jig resting on a round abrasive - a grindstone of the circular revolving type. From the patent, it appears that it was intended that the operator actually spin the grindstone while the tool and jig were in contact. Quite ingenious.
This jig has two ways of adjusting the sharpening angle. You can set the extension - not mentioned in the patent application - or you can adjust the height using the threaded rod.
Early patent for a jig to be used on a grinding wheel.
Again, the tool is held by a screw pressing down on top, the movement of the jig accommodated by a wheel.
Not a lot different from the preceding Hance design.
The only way of adjusting the sharpening angle is by setting the blade extension.
John used neodymium magnets and "the blade just snaps in."
I have often wondered whether magnets would work in jigs for knives. The problem - some stainless steels are not magnetic. All of my stainless steel knives are magnetic. John makes his knives of O1 steel so they are magnetic.
Check your knives before building a jig that uses magnets.
Because these knives are skewed, John is able run the jig beside the abrasive and still have the abrasive move across (rather than along) the cutting edge.
In this model the glass and the abrasive are integral, meaning that you would need an entirely new jig for each abrasive grit you used. It would make more sense to design this so that glass with the abrasive could be switched as needed. Variations on the Stone Vice would work.Michael wondered about how this would work with a incannel adze - and he has one. He thought of putting the jig on the handle. I am not sure if this would work. Just because making sketchup models is fun, I made one for an incannel adze. This looks a lot more like my stone vice. In stead of a stone, the vice captures a tube of appropriate diameter (just less than that of the adze) with adhesive backed abrasive on the upper surface.
Putting a back bevel on the outside of this incannel adze would require that the back jaw be semi-circular. See the jigs made by Tom Culver below.
Chris bought the Harbor Freight belt sander and made a tool rest out of 1/4" Polycast acrylic and an angle bracket.
It looks a little big to me - a bit wide on the left side. Chris says it is 4" wide. My fingers are only 2 1/2" long, so anything more than that I cannot reach. You have to move the tool to the right far enough so that the left side of the tool is on the belt. For larger tools, this can be a problem if the tool rest is too wide. My tool rest is about 2 1/2" wide. You should not need more than 3" wide. Nice thing about Polycast acrylic - if it is a little wide you can trim a bit off easily with a hand saw.
I made an all acrylic version of this jig for my belt sander. A variant can be used on my grinder as well (replacing the crappy tool rest from General).
Richard write: "Works great so far. If it proves out over time I will make one from steel just like it."
If it works in MDF, why not make one in some exotic wood? Why steel? I have some small bits of wood around ...
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.
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 vice 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 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.
I think the jig should be made out of wood but George assures me that the jig works just fine.
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."
George has also made a very good version on my stone vice, again out of machine aluminum. George's version has a couple of important improvements over mine.
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.
The magnets are strong enough to hold the blade in position without any pressure from the other jaw.
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!
Rather than glass as the sliding surface, Wilbur has used a melamine covered board.This is how Wilbur makes his knobs.
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.
The box at the top holds the plates, jigs, extra sandpaper.
Since there are just models, there is no assurance that they can be made, or if made, that they will work as intended.
The thickness of the wood can be varied depending on what you have in hand. The lengths of the sides give you the angle you need, given the height of the jointer blade itself. You have to add screws through the top of the jig that hit the blade to hold it in place. Machine screws will self-tap into most woods if you drill a hole slightly smaller than the screw diameter. Try drill holes on scrap before you do it on the jig to avoid splitting the wood.
The dimensions of this jig will allow you to hone the existing edge at 45 degrees. You could add slips to get microbevels. Slightly increasing the angle would allow you to use a very fine abrasive (3, 1, or 0.5 microns) right at the edge. This would produce a very good edge.
Adding microbevels to improve the honed edge does increase the included angle at the edge - as compared to the original blade. Will it reduce the included angle compared to the dull blade? Wear bevels are rounded, not flat. A worn blade thus has a larger included angle at the edge. Honing these wear bevels to re-establish a flat bevel right to the edge will thus reduce the included angle from the worn condition. It will not return to the original blade included angle.
If increased included angle is an issue, you might try grinding the primary to an angle less than 45 degrees, then add microbevels with the last at 45 degrees. Grinding the primary on a blade that is 4 to 8 or 10 inches long can be a very slow process. If you try this, be very careful that the grinding operation does not reach the existing edge. In that way, you do not shorten the blade. Since these devices rely on all 3 blades being the same height, taking care to change the blade height as little as possible is important. (Magnetic blade setting jigs make this less of a problem, but why make setup any harder than it has to be.)
Honing only the front leaves the blade half sharp - it will still have all of the back wear bevel. You can flatten the back at the edge - replace the rounded wear bevel with a flat microbevel, at 2 degrees or so. This would improve performance. You will need something in addition to this jig though. [I am reluctant to promote side sharpening, but if there is no alternative it might be appropriate in this case. Put a strip of masking tape about half an inch (10mm) from the edge on the back face. Using this as a slip and the edge on a fine abrasive, slide parallel to the edge of the abrasive. Check the back face at the edge - has the wear bevel been removed? You may need 2 or 3 thicknesses of masking tape to get a large enough angle to remove the entire wear bevel. Test first on a blade that is otherwise too dull to use.]
Before going to the trouble of making this jig, check the type of steel in your blades. Some very hard blades may be very difficult to hone. Super hard High Speed Steel or Vanadium Carbide blades will be very difficult to hone.
So, the cross piece slides on the glass strips on either side. The jig sits on the cross piece and must be able to move side to side as you go back and forth to ensure even use of the abrasive.
The advantage is that you can use the full length of the abrasive without the jig bumping into the abrasive or the tool going off the near end.
The design appears to have a couple of problems.
If someone builds this, send pictures and your experience for others to see.
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