Struggling with sharpen plane blade after cambering

[Tony Wilkins]

With grinder at last installed on stand, cambered the O1 blade for my LV 5 1/4w. Grinding went well I think. Got the 8” radius I wanted. But I’m struggling with sharpening. In my LN jig I could get the middle but. In the corners, no matter how much pressure I applied, I count get on the stone. Tried freehand but with neuropathy I’m not the greatest to feel bevels. Edge just is t getting sharp.

Suggestions?

FWIW using king 1k & 6k water stones

[Derek Cohen]

Tony, I will take a stab at this, but recognise that I do this freehand (I only use a guide for BU plane blades).

First point - an 8" radius is quite strong, and I doubt that you will use more than the central third of the blade. This means that the outer thirds are going to go unused, and do not need to be as sharp.

Second point: David Charlesworth provided a model (don't think of it as a method) for cambering a blade in which he divided the blade into sections - hone the outer sections three strokes each .... etc. In your case, keeping in mind that you have an 8" radius and are not trying to create this from a straight edge, hone only the centre, and then "swipe" from the centre the remainder of the third on one side, and then repeat it on the other.

Thirdly: Use the guide as a pivot and don't try and run it back-and-forth. You are seeking to hone along the secondary bevel leading edge, which is a curve. If you want to additionally hone while moving the guide back-and-forth, that is okay, but the movement you are looking for is to polish on the curved leading edge. This is what I do freehand.

Finally: remove the wire on the back of the blade.

A thought about the King stones. I used these 20+ years ago, and the composition may have changed. If you create a slurry, the stone cuts more strongly. If you remove the slurry, you may get a finer polish.

Regards from Perth

Derek

[Jimmy Harris]

I'm not aware of a jig that'll work for cambered blades. Paul Sellers have a video about making a scrub plane and he shows two different methods to sharpen a cambered blade by hand. The figure 8 method he does is kind of difficult to master, but the other method he briefly shows might be easier if you haven't tried that. It's pretty similar to the method shown in the Lie Nielsen scrub plane sharpening video, but turned 90°, which also might be worth a look at. Either one of those would be a lot easier than Rob Cosman's method of going around in circles.

Otherwise the best thing I can think of would be to hollow out a channel into a piece of wood with the correct radius and glue some sandpaper to it. Then make a jig to hold the blade at the correct angle and run it back and forth. That sounds like a huge headache to me and hard to get right. So maybe send it off to a sharpening service?

Personally, I'd just keep practicing the free hand method and try it a bunch of different ways until you find what works best for you. It's a scrub plane. It doesn't need to be razor sharp.

[Tom M King]

I use an old Record guide that only has a ball under it. I can hone a Scrub plane iron with it. It's the red one in this picture just to show it but I'd never sharpen the narrow chisel with it.

Otherwise, the only other choice I know of is freehand. My helpers could sharpen the short radius cambers with the Record guide, but Zero chance by hand.

Just a note about King stones: I'm not familiar with the whole line, but I do have one 300 that doesn't require a slurry. I have no idea about the 1k and 6k in question.

edited to add: Here's a later version of the one I have.

https://www.ebay.com/itm/39510228280...Bk9SR8Tx8bubYw

[Tony Wilkins]

Tony, I will take a stab at this, but recognise that I do this freehand (I only use a guide for BU plane blades).

First point - an 8" radius is quite strong, and I doubt that you will use more than the central third of the blade. This means that the outer thirds are going to go unused, and do not need to be as sharp.

Second point: David Charlesworth provided a model (don't think of it as a method) for cambering a blade in which he divided the blade into sections - hone the outer sections three strokes each .... etc. In your case, keeping in mind that you have an 8" radius and are not trying to create this from a straight edge, hone only the centre, and then "swipe" from the centre the remainder of the third on one side, and then repeat it on the other.

Thirdly: Use the guide as a pivot and don't try and run it back-and-forth. You are seeking to hone along the secondary bevel leading edge, which is a curve. If you want to additionally hone while moving the guide back-and-forth, that is okay, but the movement you are looking for is to polish on the curved leading edge. This is what I do freehand.

Finally: remove the wire on the back of the blade.

A thought about the King stones. I used these 20+ years ago, and the composition may have changed. If you create a slurry, the stone cuts more strongly. If you remove the slurry, you may get a finer polish.

Regards from Perth

Derek

I use the DC method for smoothing and jointer blades but this seemed to be too severe for that. I think the wheel on the LN guide is too wide to get the pivot all the way to the edge with that radius. I’m using that much of a radius because I’m planning to use it as a traditional fore and rough work. Felt what I thought was a wire edge but when I took it off the edge was still not sharp.

[Tony Wilkins]

I have a vague recollection of the Paul Sellers video you’re talking about. I’ll go find it. The 90* thing is what I was trying at the end and felt the best but the cutting edge just wasn’t sharp.

[Derek Cohen]

Okay Tony, I recalled a guide I built many years ago as part of "The 10c Sharpening System". https://www.inthewoodshop.com/Woodwo...%20System.html

It looks like this ...



Designed by Brent Beach ...



It is just two pieces of wood screwed together.

The scrub plane modification would be to saw the bottom to a Vee to act as a pivot, or shape a camber there. Even a nail below would work - just run it on a scraper blade.

What made me recall this was this "upside down" method I used for the LV Mk 2 before Lee Valley produced a cambering kit for this guide ...



Regards from Perth

Derek

[Tony Wilkins]

Okay Tony, I recalled a guide I built many years ago as part of "The 10c Sharpening System". https://www.inthewoodshop.com/Woodwo...%20System.html

It looks like this ...



Designed by Brent Beach ...



It is just two pieces of wood screwed together.

The scrub plane modification would be to saw the bottom to a Vee to act as a pivot, or shape a camber there. Even a nail below would work - just run it on a scraper blade.

What made me recall this was this "upside down" method I used for the LV Mk 2 before Lee Valley produced a cambering kit for this guide ...



Regards from Perth

Derek

I do have a mk 2 with camber roller. Not my favorite guide but I could try it if it will work?

[Derek Cohen]

Tony, try the Mk2. Remember, you do not need to hone more that the centre third of the leading edge since there is already a steep camber.

Regards from Perth

Derek

[Rafael Herrera]

Tony, an 8" radius is quite extreme and, as Derek pointed out, in production you're more likely to only use the middle third of the blade.

I'm guessing here, but if your neuropathy makes it difficult holding the iron when free hand honing, a contraption like the one shown in the picture might help. I actually use that block to abrade the flat side of irons when I refurbish them. The block is out of a 2x4 off cut. It doesn't need to be that big, just big enough for a comfortable grip.

20240105_232337.jpg

[Rafael Herrera]

This is my scrub plane and its iron.

The scored line on the bench is an 8" radius arc. My camber radius if longer than that.

I don't do a lot of rough planing, but when I do this plane is plenty aggressive for my taste.

My guess is that, unless I'm planing green wood, I might cause damage to the board if I try to plough through with an 8" camber.

20240105_234008.jpg20240105_234138.jpg

[Derek Cohen]

I would call an 8" radius on a scrub plane "moderate" since the typical radius on a Stanley #40, the LN and Veritas scrub planes are 3" radii - that is "severe"! These blades are also only 1 1/2" wide. 8" would be a "severe" radius on a jack plane. I found, as Rafael pointed out, that this is too great for the hardwoods in my location, cutting too deeply to avoid great tearout. Consequently, my jack uses a 10-12" (closer to 12") radius.

Regards from Perth

Derek

[Bob Jones 5443]

I’ve no need for an 8” radius, and don’t know what such a need might be. For typical flattening and smoothing — about all I use hand planes for — I’ve found the David Charlesworth sharpening and cambering method produces excellent results, surprisingly quickly, easily, and reproducibly (and the 1/2” wide wheel on the Eclipse guide enables fine edge control).

And cheaply: I don’t go in for honing guides or systems that cost over a hundred dollars. The Eclipse and its Taiwanese imitators fit the bill nicely. David was always a parsimonious fellow himself, one of many reasons I admire him.

[Tony Wilkins]

I’ve no need for an 8” radius, and don’t know what such a need might be. For typical flattening and smoothing — about all I use hand planes for — I’ve found the David Charlesworth sharpening and cambering method produces excellent results, surprisingly quickly, easily, and reproducibly (and the 1/2” wide wheel on the Eclipse guide enables fine edge control).

And cheaply: I don’t go in for honing guides or systems that cost over a hundred dollars. The Eclipse and its Taiwanese imitators fit the bill nicely. David was always a parsimonious fellow himself, one of many reasons I admire him.

Does it work for you on very rough sawn boards? It’s my preferred way for pre planed lumber but figured it would be too slow for the rough stock and uneven panels I’ve been working on.

[les winter]

LeeValley to the rescue! I own this and use it for scrub plane blades and compass plane blades. Works perfectly for this task.

https://www.leevalley.com/en-us/shop...e?item=15M1001