Clearance in BD plane

[Stewie Simpson]

David; thanks for the reply. What is your minimum clearance angle before you regrind the primary.

Stewie;

[Kees Heiden]

There s probably an optimum for the bevel angle, a balance between maximum clearance angle and maximum sharpening angle. For a bevel down plane it is probably between 25 and 35 degrees

[Normand Leblanc]

Patrick,
I was using for many years LV BU planes then I got a few Woodriver and finally just a month ago I bought a LN 4-1/2 and I immediately noticed a large difference in edge retention. This noticeable difference got me to make my own little study http://oldchips.blogspot.ca/2016/05/...iron-with.html and the results that I was getting with the BU kept me from publishing until I was able to figure it out.
Yes, the blade was lifted on the way back.
Yes, a strop was used but very lightly with the blade in a sharpening guide.

David,
A 35 degree bevel will work just fine. What I'm saying is a 10 degree RA won't last as long as a 12 or 15 one.

Kees,
Your tests have help me a lot understanding what was going on.

[david charlesworth]

Stewie,

What I have on (almost) all my bench plane blades is, grind 25deg., coarse stone 33deg., polish 35 degrees.

Nice and easy with an Eclipse type jig.

David

And naturally ruler trick for polishing stone on back.

[Stewie Simpson]

Thanks for the feedback David.

Stewie;

[Steve Voigt]

Definitely an interesting topic. I tend to think that Normand (and Kees) are right about the relationship between clearance angle and wear bevel, but I can't say for sure.

One thing I want to point out is that trying to maintain an absolute minimum clearance angle is probably incompatible with the type of "freehand grind the primary, freehand hone the secondary" sharpening method that I and many others use. Most of the time I aim for 25° primary and 30° secondary, but both can vary a couple degrees, so I probably have a total variance of 5° or so. Since my normal clearance angles are probably 12°-17° or so, it's not an issue, but if I were trying to "redline" an 8° clearance angle, it would matter.

My point is that worrying about the ideal angle to maximize blade life, much like worrying about what "wonder steel" will maximize blade life, is only an issue when sharpening is an onerous or overly complicated task. An efficient freehand routine tends to make sharpening a welcome diversion from hard work, and obviates the sort of concerns being discussed here…my $.02, ymmv, and all that.

[Steve Voigt]

There s probably an optimum for the bevel angle, a balance between maximum clearance angle and maximum sharpening angle. For a bevel down plane it is probably between 25 and 35 degrees

A revelation! Who knew?

[Normand Leblanc]

My point is that worrying about the ideal angle to maximize blade life, much like worrying about what "wonder steel" will maximize blade life, is only an issue when sharpening is an onerous or overly complicated task. An efficient freehand routine tends to make sharpening a welcome diversion from hard work, and obviates the sort of concerns being discussed here…my $.02, ymmv, and all that.

Sure! I hand sharpen and it's very quick but if I know that the angle I'm getting is causing a problem then I will change my procedure. In this case all I have to do is to have a few more degrees of RA and my blade will last much longer.

[Steve Voigt]

When I went and looked at my spreadsheet (I know, laugh away) I discovered that I'd grabbed the wrong spare blade, and the one I'd used was set up with a 35 deg secondary bevel.

I'm not laughing; I think there is an issue generally with folks who have busy lives and can only squeeze in a couple hours of shop time a week. It's easy to lose track of where you are if you haven't picked up a plane in a few days, and you waste a lot of time just retracing your steps.

I'd suggest, however, that the solution for folks in that predicament is to go in the opposite direction and simplify. I basically do all of my bench planing with three planes. I might make that four if I start using a shooting plane more regularly. I have no spare blades. And I sharpen all but the shooter at the same angle. I spend a lot of hours in the shop, but even if I didn't it would be easy to keep track of this limited information.

More importantly, as Warren Mickley has pointed out many times, there is a fluency and a familiarity that comes with working with (and mastering) a very limited set of tools.

(not that you (the OP) necessarily want or need my advice, but I imagine lots of folks out there can relate to the problem, even if they don't use spreadsheets…)

[Jim Koepke]

More importantly, as Warren Mickley has pointed out many times, there is a fluency and a familiarity that comes with working with (and mastering) a very limited set of tools.

This is one advantage in the column for the minimalist among us. Learning to do more with less is a great tradition.

In the other column resides the person who can not turn down a bargain on an old tool. At least then when something doesn't work they know where lies the fault.

A better way is to master the tools as you acquire them and continue to learn as your tool accumulation grows.

One example would be the Stanley #55. Many think of it as a useless 'boat anchor.' Some, myself included, suggest one fully master the Stanley #45 before attempting to move up to the #55. The #45 can be a bear to get set and working right. Once one can get it to work reliably the #55 isn't as difficult a challenge to conquer.

jtk

[steven c newman]

Hmm....mine are sharpened as a single bevel @25 degrees. never messed with all the other bevels....haven't the time, when honing up a blade to mess with more than one bevel

jack plane.jpg
Stanley No. 5, type 17. OEM blade, sharpened @25 degrees, single bevel. Cutting through pine knots as well as just pine. Chipbreaker set 2mm back from edge. bevel down as designed. It does make a mess on the floor, though..
shavings.jpg
means I have to sweep the floor..again..since I had fired Igor for not sweeping up.

[Brian Holcombe]

Sometimes it seems like the more time you spend in the shop the less you want to spend thinking about how you setup such and such planes. So you don't want four finishers, etc, you want one.

For guys who don't spend a lot of time in the shop I think they should take apart their planes every day, sharpen and reset until it is such a redundant task that they can set them in the dark.

For or more it's more than three bench planes but only because I refuse to sell the one I don't use.

[Jim Koepke]

As with many things in life there is a point of diminishing returns. The bevel angle on a bevel down plane is another.

We know there must be some clearance angle behind the edge of the blade. If close attention is paid to the video by professors Kato and Kawai it is clearly seen there is some rebound in the wood after the edge passes.

As the edge wears the clearance angle is reduced.

Normand Leblanc points out the failure due to wear determined by actual use.

After all is said and done, my blades will likely not see any changes to what has been working for years.

If someone is happy with what they are using, it is an uphill battle to get them to change.

jtk

[Jim Koepke]

For or more it's more than three bench planes but only because I refuse to sell the one I don't use.

It can always be sold tomorrow, though once it is gone, it is gone forever.

jtk

[Steve Voigt]

Sometimes it seems like the more time you spend in the shop the less you want to spend thinking about how you setup such and such planes. So you don't want four finishers, etc, you want one.

For guys who don't spend a lot of time in the shop I think they should take apart their planes every day, sharpen and reset until it is such a redundant task that they can set them in the dark.

For or more it's more than three bench planes but only because I refuse to sell the one I don't use.

Just to be clear, I too have a lot of bench planes. Partly it's an occupational hazard, but I also have Stanleys 3-7, a bunch of old woodies, and if someone offered me a mint Bedrock right now, I wouldn't say no. The issue, though, is not how many planes you own, but how many do you use day in, day out. On that, I'm pretty sure we agree.