Micro Bevel vs Straight Bevel

[Mike Holbrook]

I am having an issue with the initial sharpening of Lee Valley plane blades on a Tormek sharpening system. Tormek advocates a straight bevel. They state that the only reason for a micro bevel is to reduce the time needed to sharpen hard to sharpen devices like plane blades. The LV plane blades all seem to come with a micro bevel.

I am having a problem reestablishing a straight bevel on the LV plane blades. Even after carefully measuring the grinding angle, making sure the blade is 90 degrees to its support devise etc., I get a new top bevel line that is not perpendicular to the two sides of the plane blade. Regrinding a whole new plane edge at the normal angle is proving to be a very time consuming undertaking even on a Tormek.

It is possible that imperfect pressure across the surface that is in contact with the stone would cause this. However, I do not seem to have this problem with the older plane blades that I have hand sharpened without micro bevels. I also do not seem to be able to reverse this bevel problem by altering the pressure. The only thing I can come up with is the small micro bevels are off a small amount that gets magnified when that small edge is ground off in the very early stages of sharpening.

I have talked to both companies. Lee Valley sent me a new plane blade, the first ones leading edge was not perpendicular to the sides. Tormek has tried to help with general information about using their equipment which has not helped much with this specific problem.

I wonder if others have experienced this problem? I am also wondering how those here feel about micro bevels vs straight bevels?

[Mark Stutz]

Mike,
I was having a similar problem. I've found that it is easy to slightly offset the blade in the jig as you tighten it. If you have not dressed the wheel with the diamond dresser, that may be the problem. That seemed to fix my problem with it.

Mark

[Dave Anderson NH]

In regard to Tormek's comment about the only reason for using a microbevel to be cutting the sharpening time on "difficult" to sharpen edges, they are dead wrong. I suspect that part of their point of view comes from the fact that their system is a very slow one, provides an edge which still needs further refining, and that their system doesn't provide a reliable system for making or maintaining a microbevel. "Where you stand on a issue often is aa result of where you sit."

A microbevel does take less time to sharpen, but the most important benefit is that it adds thickness and strength just behind the cutting edge. This is a reinforcement and can often delay chipping and dulling and other degradation of the edge. It also removes less steel and lengthens blade life and the time between major bevel reshaping. A side benefit is that the slightly higher angle can contribute to bending and curling the chip earlier which means the shaving exits the mouth more easily and the plane is less likely to clog at the mouth. Some would argue that this also helps prevent tearout, though I'm not yet convinced.

[Mike Holbrook]

Mark,
I do not have the diamond dresser yet, although I have been thinking about getting one. The people I got mine from seemed to think that the stone in the base kit works to flatten the stone. I can not see an error in the wheel surface using the Tormek method of lowering the tool bar onto its surface. My double square also indicates that the wheel surface is flat and perpendicular to both sides. I have checked and double checked the angles right after set up and after a period of brief usage. They are about as accurate as I can make them using the devices I have.

Dave,
I sort of thought there was another side to the micro bevel issue. It would seem to me that it would be possible to set the plane at a much steeper angle after grinding the base angle and achieve a micro bevel. I am not sure what angel the micro bevel would be ground at though. The Tormek Angel Master goes up to 75 degrees.

I understanding the planes cutting angle is determined by adding the blade angel to the plane's bed angel. The idea of adding another angel to that formula confuses me. Maybe the micro bevel is not relevant to the overall angle of the plane. It would seem logical that the micro bevel would effect both chip clearance and how the blade interacts with differing types of wood? I have seen a fair amount written about how various planes with there normal angles interact with wood. I have no idea what a micro bevel might do to the performance of these various planes.

I was also wondering what happens when a blade with a micro bevel does become dull. Is the blade sharpened on the micro bevel again? It would seem that each time this was done the amount of plane surface with that bevel would increase a fairly large amount since such a small surface is being ground down.

Since I had a fairly large number of questions regarding the micro bevel I elected to sharpen them on the normal bevel to start with.

[Dennis McDonaugh]

The microbevel may make a more durable edge, but I'd bet most do it because it makes sharpening easier. Same principle as the hollow grind from the Tormek. I grind the bevel with my Tormek then use waterstones to hone the edge. It only takes a few strokes to polish an edge just off the Tormek. Touch ups take progressively longer as the edge gets wider between grindings. The initial bevel is only polished 1/32" or so. I usually regrind when it reaches 1/8". Sometimes I have a problem grinding a bevel on the Tormek and it stems from three areas. The first problem I had was placing the tool in the holder. You have to tighten both knobs equally or it can cause the blade to cant slightly and you get a funky bevel. Second is the wheel, it has to be square to the bar thingie. Technical term you understand. I found out I was really wearing the wheel unevenly because I pushed harder on the tool when traversing right to left than left to right. Probably because I am right handed. The third problem is caused by uneven downward pressure on the tool when grinding. I have to make sure I don't press harder on one side or the other.

[Alan Turner]

I had similar problems with my Tormek, at first, and I think they were probably caused by uneven pressure on the bar during the process. When I retrue the face with the diamond tool, I make sure to cant the bar to one side or the other (there is a little play there) and then cant it to same side each time I set it up, and that cured the problem for me. I put an arrow on the tool to remind me which way to do it.
I use the Tormek rarely, and promarily only to establish a bevel on a new-to-me tool. I sharpen often enought that none of my tools now have a hollow grind; all are flat accross. I do not use a micro bevel, but have no comment on whether I should or not.
Alan

[Mike Holbrook]

I believe I am hearing here that some feel the Tormek is not the fastest system and from others that they have the Tormek but use other methods too. I would like to hear about the other methods that might be complimentary to what I have been doing (trying to grind a single flush bevel).

What method would you guys use to surface a new blade or resurface an old one? It is taking me a very long time to grind my blades to the point that the entire surface of the blade is new and polished. Maybe others do not do that? I think I have to on the two LV's because there are two different bevel lines at this point.

[Joel Moskowitz]

I use a regular high speed dry grinder to form a hollow (about 2 1/2 minutes including grinder setup time) then onto either oil or waterstones to hone the actual edge using a primary and then microbevel and strop (another 90 seconds or so). This of course implies that the back of the tool is in good shape before I start which on a new tool it may or may not be. For a new tools I will first do the first 1/4" or less of the back using either a coarse diamond stone or water based diamond paste on a lapping plate (water base is easier on my hands) let's say 3-5 minutes including setup time. Further refinement of the back is done during the regular sharpening sequence above).

[Mark Singer]

I have the Tormek and when I sharpen I color the edge with a blue felt tip marker. Then with the blade or chisel in the jig , I hand turn a few rotations of the stone. This shows the precise place the grinding will occur. If it is off set or not at the edge, I adjust and try again by hand. Once the grind area is acuratley located I turn on the machine and grind.

[Steve Wargo]

I put a micro bevel on all of my planes, except my smoother. I figure it takes such light passes that the eadge seems to hold well without.

[Geoff Irvine]

Like Mark I colour the bezel and check where I am grinding but I also place a line, with a permanent marker, a couple of millimeters off the leading edge on the back for reference during grinding. I only use the Tormek for the primary bevel and finish off with a waterstone - LN do a nice 1000/8000 combination. Whilst we are on the topic of honing has anybody got any experience of a thing called 'The Sharpening Sled' - I saw a advertisement for this in February 2005's Fine Woodworking (page 111). Looks like the roller assembly runs beside the stone as opposed to on it. Might be interesting. Thanks

[Mike Holbrook]

Great idea Mark, Geoff, I have seen them use the marker in the demo but did not think of it for this problem. I will try that.

What would you do if the grind is not straight and the old square says the front edge is not perpendicular to the two sides? LV says that since they have screws to hold the blade in place it should not matter that the front edge is not quite perpendicular to the sides. That philosophy worries me, I have been trying to square the front edge to the sides.

[Keith Christopher]

I believe I am hearing here that some feel the Tormek is not the fastest system and from others that they have the Tormek but use other methods too. I would like to hear about the other methods that might be complimentary to what I have been doing (trying to grind a single flush bevel).

What method would you guys use to surface a new blade or resurface an old one? It is taking me a very long time to grind my blades to the point that the entire surface of the blade is new and polished. Maybe others do not do that? I think I have to on the two LV's because there are two different bevel lines at this point.

I use the scary sharp system myself. I have no trouble with the microbevel because the LV jig I have is AWESOME, but befor that I would just all a playing card spacer to lift it about 1deg to add it.


Keith

[Mike Holbrook]

I finally coughed up the money for the diamond sharpener for my Tormek. It immediately indicated that the wheel was high on the left side. I dressed the stone for a good while and put my plane iron back in, the stone immediately started working the opposite side. So that was apparently my big problem.

Lesson here, although I was checking the stone with an accurate square, it was apparently still off enough to cause a pretty major error. I think the diamond surfacing stone is definitely needed for this piece of gear. It also roughed the stone much better than the roughing stone did allowing me to grind much faster.

I also took Mark Singer and Geoff's suggestion to color the edge of the steel to be ground to see where grinding will take place. This method removes most doubt about what will happen.

Thanks for all the help and suggestions!