Is it possible to maintain a camber on the jack plane indefinitely

[tibi]

Good evening,

Disclaimer: This is not a pure sharpening thread about what technique is the best for splitting atoms with the blade, so only popcorns up to 300 ml in volume are allowed.

I am grinding a camber on my jack plane with a rather pronounced radius on a bench grinder for fast wood removal. However, after a few sharpening sessions on the stones, my camber approximates to zero. I try to apply more finger pressure at the ends of the blade and less in the middle, but eventually I get a flat edge anyway. Is this normal and I have to regrind the camber after it becomes flat or I am not doing it properly and I should be able to create camber only once and then just maintain it indefinitely?

I am able to maintain slight camber on a smoothing plane, where only few hundreds of mm are needed, with finger pressure, but I am not able to maintain a bigger camber of jack plane without making the edge straight by consequent sharpening sessions.

I do not mind using the grinder, but my blades would become too short too soon.

Thank you.

 

[raffo]

You could try marking the flat side of the iron so you can see the existing curve when you resharpen it. It'll help you no overgrind the crown of the camber.

 

[Jacob]

Keep a camber by swiping the blade slightly sideways (say 45º angle across the stone) and twisting slightly, so you start the grind on one corner and finish on the other, but at 30º to the stone all the time as near as you can.
May sound odd but it's very easy.

 

[AESamuel]

You should be able to maintain it. Are you using a honing guide? I find honing guides fine for mild cambers, but freehand is the way to go for more extreme cambers.

 

[tibi]

Keep a camber by swiping the blade sideways and twisting slightly, so you start the grind on one corner and finish on the other May sound odd but it's very easy.

Hi Jacob,

This is exactly what I did. I discovered this sideway sharpening method as I have seen it mentioned somewhere on the internet and figured out that I can achieve a burr faster this way. Maybe I was not twisting enough so I have honed off the middle of the blade quicker, so it became flat sooner. I am glad to hear that this technique works, but I need to perfect it more.

By the way, I have found in the statistics of this forum that you are the second most active member of this forum by the number of messages. Maybe half of them are a friendly discussion with D_W

 

[tibi]

You could try marking the flat side of the iron so you can see the existing curve when you resharpen it. It'll help you no overgrind the crown of the camber.

That is a good idea, but I should scribe the line instead of marking it, because I would immediately erase it when removing the burr.

 

[tibi]

You should be able to maintain it. Are you using a honing guide? I find honing guides fine for mild cambers, but freehand is the way to go for more extreme cambers.

No I sharpen freehand. I had a honing guide, but it was out of square by manufacturing fault, so I threw it away last year. Maybe I will buy a better one, once I will buy a bevel up plane or any speciality plane , if ever.

 

[Jacob]

Hi Jacob,

This is exactly what I did. I discovered this sideway sharpening method as I have seen it mentioned somewhere on the internet and figured out that I can achieve a burr faster this way. Maybe I was not twisting enough so I have honed off the middle of the blade quicker, so it became flat sooner. I am glad to hear that this technique works, but I need to perfect it more.

It's not really a "technique" it's just doing it the easy and obvious way. Sidways makes twisting easier but you could twist it to and fro if you want to.
These things get over-thought - best to just do it, head-down brain off!

By the way, I have found in the statistics of this forum that you are the second most active member of this forum by the number of messages. Maybe half of them are a friendly discussion with D_W

No not at all. It may look like that but I've got our slim american friend on 'ignore' most of the time!
It's just that I've been on this forum for a very long time, since the beginning - 2007 perhaps? Cant remember!

 

[raffo]

That is a good idea, but I should scribe the line instead of marking it, because I would immediately erase it when removing the burr.

Draw an outline below the edge, so that there's a thin strip of bare metal between the edge and the ink, stay away from the ink. Alternatively, cut a template of the curve you use for your camber, compare as you sharpen. Just a couple of thoughts.
.

 

[tibi]

Draw an outline below the edge, so that there's a thin strip of bare metal between the edge and the ink, stay away from the ink. Alternatively, cut a template of the curve you use for your camber, compare as you sharpen. Just a couple of thoughts.
View attachment 126530.

Thank you, it can be done this way as well.

 

[raffo]

It may look like that but I've got our chubby american friend on 'ignore' most of the time!

What a condescending and rude thing to say.

 

[tibi]

It's not really a "technique" it's just doing it the easy and obvious way. Sidways makes twisting easier but you could twist it to and fro if you want to.
These things get over-thought - best to just do it, head down brain off!No not at all. It may look like that but I've got our chubby american friend on 'ignore' most of the time!
It's just that I've been on this forum for a very long time, since the beginning - 2007 perhaps? Cant remember!

I have learned from both of you a lot, so I am thankful for that. David is more of a scientific guy and he can provide information that is hard to find, unless you study a lot of historical books, metallurgy, Japanese cap iron papers, etc. He is more of a hand tool guy like myself. You give advice how things were made in a proper British woodworking way, maybe more like Paul Sellers, if that comparison would not insult you in any way. So I keep both of you as valuable members that I can learn from.

 

[Sporky McGuffin]

You give advice how things were made in a proper British woodworking way, maybe more like Paul Sellers

I like Jacob much, much more than Sellers.

 

[Cabinetman]

This might not work as I’ve never had a camber on a plane blade, I just take the sharp corners off now and again, how about a combination type stone with the camber shape ground into it ? Ian

 

[Jacob]

This might not work as I’ve never had a camber on a plane blade, I just take the sharp corners off now and again, how about a combination type stone with the camber shape ground into it ? Ian

Thats how they end up anyway if you just keep cambering edges. I once flattened an old stone and found sharpening more difficult without the hollow.

 

[D_W]

I have learned from both of you a lot, so I am thankful for that. David is more of a scientific guy and he can provide information that is hard to find, unless you study a lot of historical books, metallurgy, Japanese cap iron papers, etc. He is more of a hand tool guy like myself. You give advice how things were made in a proper British woodworking way, maybe more like Paul Sellers, if that comparison would not insult you in any way. So I keep both of you as valuable members that I can learn from.

Jacob doesn't really have any information for you unless you're looking for a guy who worked back and forth from a shop where most of the stuff was cut with a slider and shaper. I had to go back pretty far to find him demonstrating something, and it was cutting half blinds. It didn't look like he'd done it before.

But the answer with a jack is simple - grind the jack with curvature and then draw and push the whole iron with rotation. while you're doing it and then work the tip of the tool with a finer stone to remove the burr (there's no good reason, even on a jack, to tear off a large burr - actually there's never any good reason to remove a burr with anything other than a fine stone or a strop that will hone most of it off and not tear it off).

Once you get a jack set up, it's good for a solid half hour of planing or so in hardwoods (and if working by hand, you absolutely do as much with it as you can to get close to a mark). If grinding is needed to push back the bevel more than once per very large furniture project, it would be unusual.

Generally want an iron that's on the moderate hardness side and not super hard, either - sharpening takes about a minute. Grind from time to time to keep the bevel from getting fat or the honed area from getting large, maintain the actual edge geometry with a middle stone and then work the tip of the tool with a fine stone. It becomes hard to maintain even work with a full bevel if you're not grinding the bulk behind the edge of shallower, and it's not really practical to try to do anything with the finisher other than finishing.

I was a bit surprised last week to see that Nichoslon prescribes the same thing (Grinding occasionally, not every sharpening), but I've not read much of nicholson's stuff before and the person who referred me to it insists that things only be sharpened with a flat (not sloppy sellars type, but flat bevel progressed through a set of stones at each interval. I think that's more of a carver's thing (and the person who mentioned that has tended toward carving for income over time).

 

[D_W]

Thats how they end up anyway if you just keep cambering edges. I once flattened an old stone and found sharpening more difficult without the hollow.

This is an example of making it up as you go along, at least if you're going to try to finish smooth anything at all.

 

[D_W]

I do not mind using the grinder, but my blades would become too short too soon.

Thank you.

You won't do any more honing with the grinder than without, by the way, and it may end up being less. You'll just complete the job more or less and have better clearance. It's exceedingly rare with any tool that you'd grind off the honed edge -there's probably something, but I can't actually think of anything short of actually manufacturing the chisel.

 

[Droogs]

You are all going about this the wrong way. What you need to do is grind your own slipstone with the convex radius you desire, then attach a honing guide to hold the iron at the correct 25 deg angle and you will always have your perfect radius and a really sharp curved iron.

 

[Vann]

...It's just that I've been on this forum for a very long time, since the beginning - 2007 perhaps? Cant remember!

Interesting. Have you done 21,000 odd posts as "Jacob" or does that include previous posts from the "Mr Grimsdale" and other non-de-plume eras?

...but I've got our american friend on 'ignore' most of the time! ...

I must try that. I find said slim "friend" drives me bonkers.

Cheers, Vann.