Hybrid Profile for Freehand Sharpening BU Plane Blades

[Derek Cohen]

A new article on my website. This one is about freehand sharpening a camber on BU plane blades. Hope you find it useful.

http://www.inthewoodshop.com/WoodworkTechniques/HybridProfileforFreehandSharpeningBUPlaneBlades.ht ml

http://www.inthewoodshop.com/WoodworkTechniques/HybridProfileforFreehandSharpeningBUPlaneBlades_ht ml_87d5041.jpg

Regards from Perth

Derek

[Terry Beadle]

Thanks for another great post. Good info and technique.

[Jim Neeley]

Derek,

It's prbably me but I had a tough time figuring out what's going on. I think I may have it now and would like to synopsize what I think is going on. Please correct me when I misspeak. It may assist others as well.

First, a 25* hollow grind is placed on the 3/16" thick blade, followed by a 50* secondary. The secondary only goes back until the blade is perhaps 1/16" thick. Thus, the 1/16" makes less thickness to camber and the 50* lets you get away with less camber. The hollow grinds remove more of the metal where you'll be cambering, further reducing the hand work.

Am I close???

This looks like a good use to the rattailed monster to decrease the Armstrong sharpening while leaving you trackless.

Jim

[Derek Cohen]

Hi Jim

The aim is to reduce the amount of steel to hollow grind, so that there is less steel to remove when honing a camber on 50 degree bevel.

Reducing a 3/16" thick blade to one about the thickness of a Stanley blade is the goal. Working with a blade that is thinned by a 25 degree primary bevel is preferred over a 50 degree bevel. The former is thin, and the latter is thick.

Hollow grinds are traditional for those that freehand hone blades. The aim here is to create a hollow grind on the thin section of the bevel, rather than having to do so on the full thickness of the blade.

An observation about the contents of this article ...

It strikes me that those who are dedicated freehand sharpeners (essentially to whom this article is aimed) are less likely to use a BU plane, either because they attempted to freehand the 25 degree primary bevel (that the plane comes with) and consequently obtained horrible results (well what do you expect with an included cutting angle of 37 degrees?!), or because they became frustrated at needing a honing guide for a specific, higher secondary bevel.

Then we have the dedicated group of honing guide users who are comfortable with their BU planes because they require the same attention to detail as their BD planes. For this group I anticipate that they are unlikely to appreciate the difficulties with freehand honing and BU plane blades. (This is not a criticism of using a honing guide).

So one group lack experience with BU planes, and the other group are short of experience with freehanding issues. As a result of this, the relevant information in the article is likely to missed by most. It's probably a small group that want to freehand their BU plane blades to a high angle and include a camber at the edge.

Regards from Perth

Derek

[Jessica Pierce-LaRose]

Just bringing a couple of tools to my fathers to use the grinder (I need to get one for myself) and it occurred to me that the other place this could really help free-hand grinding is mortise chisels. On the ones I've been using, I really like a 20-25 degree primary, which I feel aids in penetration as the chisel gets really sunk into there when doing heavy chopping, but I put a 35 degree secondary bevel on there for a durable cutting edge. I find if I freehand hone these, I end up with a steeper and steeper cutting angle, which isn't a problem until you've gone to far. This second grinding, leaving another, second hollow grind to help register the chisel when free hand grinding would be really helpful. Especially on those days you find yourself doing a whole lot of mortises. I don't know why I didn't think of this earlier.

[Pam Niedermayer]

...It strikes me that those who are dedicated freehand sharpeners (essentially to whom this article is aimed) are less likely to use a BU plane, either because they attempted to freehand the 25 degree primary bevel (that the plane comes with) and consequently obtained horrible results (well what do you expect with an included cutting angle of 37 degrees?!), or because they became frustrated at needing a honing guide for a specific, higher secondary bevel....

Derek, there are certainly more than your two reasons for not using bevel up planes. For example, I don't put a chamfer on my LN 62, use it only for shooting. Period. So I'd appreciate it if you were to not make such all encompassing assumptions. There lies the path to complete hubris.

Pam

[Derek Cohen]

Derek, there are certainly more than your two reasons for not using bevel up planes. For example, I don't put a chamfer on my LN 62, use it only for shooting. Period. So I'd appreciate it if you were to not make such all encompassing assumptions. There lies the path to complete hubris.

Pam

Pam, what I wrote was "It strikes me that those who are dedicated freehand sharpeners (essentially to whom this article is aimed) are less likely to use a BU plane...". That is not all-encompassing to me.

Actually it could be the basis of a really good discussion (about the honing preference of BU plane users)! :) Would you like to say why you think I am incorrect in my opinion?

Regards from Perth

Derek

[Pam Niedermayer]

Pam, what I wrote was "It strikes me that those who are dedicated freehand sharpeners (essentially to whom this article is aimed) are less likely to use a BU plane...". That is not all-encompassing to me.

Actually it could be the basis of a really good discussion (about the honing preference of BU plane users)! :) Would you like to say why you think I am incorrect in my opinion?

Derek, I quoted the pertinent part: It strikes me that those who are dedicated freehand sharpeners (essentially to whom this article is aimed) are less likely to use a BU plane, either because they attempted to freehand the 25 degree primary bevel (that the plane comes with) and consequently obtained horrible results (well what do you expect with an included cutting angle of 37 degrees?!), or because they became frustrated at needing a honing guide for a specific, higher secondary bevel.

You gave two reasons for freehand sharpeners to not use BU planes. The first because those people tried to freehand and obtained horrible results and the second because they became frustrated.

I think you know that I sharpen mostly freehand, although "dedicated" is probably a strong word to describe me on this issue. I think you know I only use one BU plane, the LN 62. And I think you know I don't use microbevels or secondary bevels. At most I chamfer some of my BD smoothers.

Therefore, reason one is blown to bits. I never obtained horrible results, never even tried, don't want to try, have no need for the results. As to your second reason, frustration in creating a secondary bevel, again blown. I never, with any blade except one very large chisel, use secondary bevels. Nor would I hesitate to use a honing guide for whatever reason, I just generally don't. My major point is that you've assumed we all want the same things you want; but we just haven't been able to produce. This is wrong, wrong, wrong; and incredibly presumptuous to make such assumptions.

Pam