edge jointing and the mysterious vanishing camber

[woodbloke]

For my straight blades, I've taken to using a small plane hammer for fine adjustment (toffee hammer would do as well) - didn't get raised eyebrows from Rob when I mentioned it the other week, so guessing this is OK, and it's certainly quicker than fiddling with the lateral adjuster.

Cheers
Steve

As Steve said, one of the many topics we touched on last week. Nothing wrong in using a small tapometer for fine adjustment...I sometimes use a nylon headed or small toffee hammer to adjust planes...just as long as it's very small 'tap' :wink: - Rob

 

[adrian]

I tried another board last night. Evidently I still have a problem with the lateral adjustment on my Clifton because I was having a lot of frustration getting and staying square to the face. But the plane was taking off the bumps, or at least almost doing so. Once I got the bump removed then it wouldn't be square and I'd square it and then there'd be a bump and then I'd remove the bump and then it would be out of square and .... around in circles for a while. I think I quit working when I found it wasn't square after the last bump removal. So I have not recovered the previous tool configuration where once it got square it just magically stayed square.

The only other observation is that I don't reach the point where, when I move one end of the straight edge it swivels on the other end. When the plane stops cutting I'm at the point where if I swivel one end of the straight edge it swivels on a point 1 inch in from the far end. I can't get beyond this. My suspicion is that this indicates that I haven't actually achieved the target of a slightly concave surface. But I'm not entirely sure how to interpret this. I could believe that it's a limitation of my non-flat plane sole. (I was wondering if slightly extending the blade might eliminate this problem, as the shavings seemed kind of wispy and might have been down around 1 thou---I didn't measure.)

 

[Chris Knight]

Adrian,
You can get some funny-seeming effects if the edge is not square to the face all the way along, or more generally if the edge is not in fact a plane surface but twists along its length - check this with winding sticks and ensure you remove the high spots to produce a plane surface before proceeding.

This should in fact be the first job in any planing you do.

 

[adrian]

Adrian,
You can get some funny-seeming effects if the edge is not square to the face all the way along, or more generally if the edge is not in fact a plane surface but twists along its length - check this with winding sticks and ensure you remove the high spots to produce a plane surface before proceeding.

This should in fact be the first job in any planing you do.

My general approach has been to bring in a coarsely set plane and try to remove the rough saw marks and gross irregularities. Then I check for square to the face and try to fix that. Then at least I try to remove the bump in the length. But, at least last night, the process of removing the bump is making the edge no longer square, so it twists here and there away from square. And then I end up in an endless cycle of fixing the edge to be square and than making it flat in length and then fixing it to be square and making it flat in length....

If a small amount of twist can throw this process off (nobody has yet suggested that this could be a problem) then the reason I seem to be somewhat less successful at removing the bump this time around might be that I'm introducing a small twist as I remove the bump, whereas before I wasn't (for some mysterious reason) doing so.

For face jointing it doesn't seem like you can check for twist before you establish straight lines across the width of the board---your winding sticks might rock, if it's convex. I tried this once when it was concave and then I removed too much material trying to correct it because the high spot wasn't very big...

 

[Paul Chapman]

I think the major problem, Adrian, is that you are grappling with several problems at once. One of the issues I have with the David Charlesworth method of planing the edge of boards is that the method becomes increasingly difficult the longer the boards are. If you add to that the problems you've been having with too short straight edge, then it's no wonder you're struggling a bit.

In your position I would seriously try the method where you plane two boards together - not necessarily on the boards you are dealing with at the moment, because you have already said that you don't want to do those that way, but on some practice pieces. I'm sure that will give you some extra confidence and help you to improve your technique.

The advantage of planing boards together is that you can forget about getting the edges at 90 degrees (that will take care of itself) and just concentrate on planing the boards straight in the length. I would suggest getting some boards about 3/4" thick and give it a go (any old stuff would do). I'm sure your technique will benefit.

I was taught to joint boards like that at school in the 1950s and never looked back

I can do it the Charlesworth way as well but it's not my preferred technique.

Cheers :wink:

Paul

 

[adrian]

I think the major problem, Adrian, is that you are grappling with several problems at once. One of the issues I have with the David Charlesworth method of planing the edge of boards is that the method becomes increasingly difficult the longer the boards are. If you add to that the problems you've been having with too short straight edge, then it's no wonder you're struggling a bit.

Won't any method become increasingly hard as the boards get longer? The fact that I'm using a short straight edge should make it easier to conclude that things are OK...I'm not sure that's really a major problem. (Though I am planning to get another long straight edge.)

I think the fact that I successfully jointed six boards is a wonderful success. Clearly the technique is workable. It's not my confidence that needs help, but my actual technique. How can I reproduce the setup that lead to that initial success? I seem to have had great luck with the initial setup of my plane and now something (lateral setting? blade profile? blade extension?) is different.

In your position I would seriously try the method where you plane two boards together - not necessarily on the boards you are dealing with at the moment, because you have already said that you don't want to do those that way, but on some practice pieces. I'm sure that will give you some extra confidence and help you to improve your technique.

I'm curious about why this will give me extra confidence. Switching to technique B after initial success with technique A doesn't seem like an obvious confidence building method to me. Maybe I'm not sure I understand what you mean, but I never got a straight edge until I used the Charlesworth method. I gave up trying to get a straight edge and used a powered router to do my edge jointing the last time around. (And the boards were only 2.5 ft long--I couldn't even get that straight.) So the Charlesworth method is actually working, which seems like a pretty big advantage. If I were to clamp the boards together I'd still be using that same method of stop shavings to try to get the board flat in length, because I don't have any other method to use! (Well, ok, so I had some success in the past with a method of deliberately creating a large hollow in the middle by taking shavings across the grain and then trying to cut off the high points at the ends, but it wasn't a very reliable approach.)

One thing that has puzzled me is that when I look in books that talk about jointing, they usually dismiss the job as trivially easy (all sweat and no technique): you just plane the surface and it turns flat. That just has not been my experience. (Do I have the wrong tolerance?)

The advantage of planing boards together is that you can forget about getting the edges at 90 degrees (that will take care of itself) and just concentrate on planing the boards straight in the length.

This is only true if waterhead37 is wrong. I'm inclined to suspect that twist matters, that it alters the way the plane rides the edge. I've had experiences in face jointing that would be explained by twist playing a role. So if twist matters, then in order to get a straight edge on the pair of boards clamped together I actually need to get the edges in a plane, just maybe not one that is 90 degrees to the board. A job for the winding sticks, I suppose, but I don't have a ready, reliable way of removing twist. It's not obvious that this is easier. In other words, either way, I still need to remove twist. In one case I have to use winding sticks to find it and in the other case I find it with my try square. I think the try square is easier.

I'm curious: what to you do at the final edge, where the board won't be joined to anything else? Doesn't this edge have to be square to the face?

 

[Chris Knight]

You can use a couple of mini G cramps to clamp a piece of wood to the side of the plane to make a fence to hold your plane square to the face of the board (it will need rebating to create enough stand off to allow the blade to full meet the edge of the board).

I did lots of edge jointing this way before I became proficient in the use of a cambered blade.

I never got on with clamping two boards together like Paul does; my boards are invariably of different widths and I found it very difficult to get long boards into position in the vice.

Adrian, where are you based? Someone may be able to show you if they know where you are.

 

[Paul Chapman]

Adrian,

Planing is rather like riding a bike - one minute you can't do it, the next minute you can, but you can't work out why :? :lol: The bottom line is that it comes down to practice and technique. I am only suggesting the method whereby you plane two boards together because I find it very simple that way and it might help you. We could debate it for hours but that wouldn't do much good. Try it some time when you have an hour to spare - you might find it works for you.

Cheers :wink:

Paul

 

[Mr Ed]

I think Pauls right, you have to try all techniques until one clicks for you.

Also, whilst its good to discuss technique up to a point, you can over analyse things and sometimes its just better to spend the time doing it.

Cheers, Ed

 

[Mr T]

Hi Adrian

I would agree with both Paul and Ed. It is easy to over intelectualise a process that can only come with practice. It is also very difficult to write about. However if an experienced woodworker could actually see you planing they may be able to spot the problem, a bit like a golf professinal observing a golf swing.

Chris

 

[adrian]

I have to admit that part of my reluctance to just try planing two pieces together as a test is that I doubt that I have two similar sized pieces that are jointed flat available to use for a test. (Most of the scraps I have lying around are either narrow or short, hence unsuitable. Anything long is also rough and thick.) So I'd have to joint the faces first....or....buy new wood. Hmmm. (I'm also a bit limited in that I have only one plane blade left that doesn't have a camber.)

I do have a future project list and the project after next will feature raised panels with thin wood, and I will certainly try the clamping together method then. At my current rate of progress, though, it will be a great long while before I get to the project after next.

I actually have the Veritas jointer fence...but since I put the camber on my blade I think it unadvisable to use it.

Sometimes practice is the answer. There's no question about that. But no amount of practice with a bad method is going to be as good as switching methods. When I'm trying to get something done and I'm frustrated because I don't understand what's going on, more time spent in this state of frustrated confusion does not make anything better. Cutting dovetails is comparatively easy. Yeah, they might not come out perfect. And I can see how this or that could have been better, but I don't recall ever wondering "why isn't this chisel cutting the wood" or "I just don't understand what to do next to finish these dovetails". These things happen when I try to plane wood flat. At least for me, I need some kind of analysis of how and why they happen so that I have some idea what to do about it. What changes might make a difference? If I can't find anything to change then everything grinds to a permanent halt.

In answer to the question of where I am located, the answer is that I'm rather far away in the small town of Vienna at the outskirts of Washington, DC.

 

[tnimble]

I have had the bump in the board problem a couple of times. I'm near 100% certain the not planing whilst on the bump is unrelated to sole flatness. My no 5 and 6, which are my favourite planes for tis job, are a tiny bit concave with a slight relief at both the toe and heel. The concavity is delibarate and measured as beeing flat (I do my measurements with Mitutoyo caliper and indicator calibrated and rated for max 0.03mm deviation with 0.01mm repeatability, starrett straight edge, Moore and Wright feeler strips and gauges, gauge blocks all grade 00, and well stored and cared for)

When analysing such a board is reads as beeing two slight concave boards. Also the height of the bump seems not to matter much as other bumps that are either lower or higher are planes away without problem. Also when having a bump in the board switching to another board without resharpening or readusting the plane does not show the same problem as with the other board.

I am to believe that the unplanable bumb must be related to either a specific bump profile, change in wood hardness, grain direction or combination. I have had success in removing the bump when opening the mouth and with switching to my no 3 or my LV edge plane. Setting to blade to a more agressive cut has not helped me by much, at the point where the plane does start to cut it immediately goed from not cutting at all to digging in badly.

I use the Charlesworth method for sorting out an edge to be slightly concave along the length of the board. I use my LV edge planes for squaring up, I find this the most fast and repeatable way. I usually give the board a few swiped with one of the edge plane first to sort out most of the twist and squareness. Then I plane the length using stop shavings, plane 1 full shaving, and finally plane 1 shaving with the other edge planes which is set very finely. If the board misbehaves with slight tearout I swap the last two steps.

 

[Paul Chapman]

In answer to the question of where I am located, the answer is that I'm rather far away in the small town of Vienna at the outskirts of Washington, DC.

Oh well, a visit is out of the question then When I have a moment I'll take some photos and show you how I would do it.

Cheers :wink:

Paul

 

[adrian]

I am to believe that the unplanable bumb must be related to either a specific bump profile, change in wood hardness, grain direction or combination. I have had success in removing the bump when opening the mouth and with switching to my no 3 or my LV edge plane. Setting to blade to a more agressive cut has not helped me by much, at the point where the plane does start to cut it immediately goed from not cutting at all to digging in badly.

Thanks for your report. Do you find that the unplanable bump is unplanable both with your #5 and your #6, or does switching between these make a difference? (If the problem is that the plane sees it as two hollows then I would think that switching to a different length plane ought to make a difference.)

I use the Charlesworth method for sorting out an edge to be slightly concave along the length of the board. I use my LV edge planes for squaring up, I find this the most fast and repeatable way. I usually give the board a few swiped with one of the edge plane first to sort out most of the twist and squareness. Then I plane the length using stop shavings, plane 1 full shaving, and finally plane 1 shaving with the other edge planes which is set very finely. If the board misbehaves with slight tearout I swap the last two steps.

Do you sharpen your #5 and #6 straight or cambered for this task?

 

[adrian]

For a while I seemed to be getting along OK using my #7 and my LV 5 1/4. When one plane wouldn't cut I found I could usually move forward by switching to the other one.

Lateral adjustment remains something of a challenge, but at least I had the #7 adjusted so the cut was sort of close to the middle, off to the left half an inch. But then I discovered that the #7 was no longer cutting in that same spot. The location of the cut had shifted to the far left edge. I tried to adjust it and I could get it to cut at the far right or far left, but nowhere else.

Upon removing the blade I found the same thing that happened before: the blade is concave in the center. It actually has two bumps, about 1/2 inch in from each side. So despite a claim to the contrary, I am indeed losing my camber in use, somehow. (This is kind of frustrating because I don't have a quick easy way to create the camber. I didn't think I'd have to make a new camber every time I honed the blade.)

 

[newt]

If you are losing the shape of the camber during use and producing a concave blade with two humps on each side of the centre, then the blade must be very very soft. Does this happen with the blade in the other plane. If this is happening due to use I would then expect as the blade became concave that it would become very blunt and not cut. Are you sure that the blade is not concave after you have honed?

 

[tnimble]

Thanks for your report. Do you find that the unplanable bump is unplanable both with your #5 and your #6, or does switching between these make a difference? (If the problem is that the plane sees it as two hollows then I would think that switching to a different length plane ought to make a difference.)
[/qupte]
As the bump is always relatively high it happens with the no 8, returning to diagonally srub planing the board (if the board permits it (sizewise)) or only the bump resolves all.

Do you sharpen your #5 and #6 straight or cambered for this task?

All my bench planes except the ones use for shooting have cambered blades. Per jointer I've 2 blades ready with different cambe sizess for smaller/thinner and wider/thicker boards.

Upon removing the blade I found the same thing that happened before: the blade is concave in the center. It actually has two bumps, about 1/2 inch in from each side. So despite a claim to the contrary, I am indeed losing my camber in use, somehow. (This is kind of frustrating because I don't have a quick easy way to create the camber. I didn't think I'd have to make a new camber every time I honed the blade.)

What make (and type) of blade, how many has been sharpened/honed off in total from its original length?

If the blade has been ground back behind the heat treated part, or it has losts its hardening due to over heating while grinding it (by previous user for instance) or when a blade is very very new I can imagine this happening. If neither is the case a bad production blade (skipped the heat treatment) or planing, planing, planing and planing with a dull blade without honinh for a long long long time could cause this.

 

[adrian]

The blade is the original stock Clifton blade and was new when I bought the plane. The amount of blade "used" is negligible. Does Clifton use very soft blades? I suppose I could replace the blade. I was thinking I might raise the bevel angle a bit---I have it at 28 or 29 degrees.

It has not happened to the other plane. Studying the other blade, I found that the camber was less than I thought...but I last sharpened that one a couple months ago so I don't recall exactly what camber I managed to apply. It's possible it had a larger camber and wore down but not enough to become concave. It's also possible I had a small camber and nothing about the edge geometry changed. There was a glint visible on the back of the blade along the center of the edge indicating some sort of edge failure, I assume. (And this glint was pretty hard to remove at the stones.)

Regarding the concave blade, when I sharpened the last time I compared the blade to a straight edge and found it to be convex. It would rock, for example. It won't rock now.

But also note the change in the behavior of the plane. Freshly sharpened, it would cut a shaving near the center. There was a period where the blade would "mysteriously" cut only the edges of the board I was working and not in the middle---behavior consistent with a concavity in the center of the blade. Right before I took the blade out I could not adjust it to cut near the center, only at the far extremes. So clearly something changed. As far as I noticed it was cutting fine and then it abruptly stopped cutting in the center. I didn't notice a period of poor performance before it stopped entirely. (I may not be very good at recognizing when the blade is starting to dull but still cuts reasonably well, though.)

In an effort to describe the amount of planing I did that caused this:
My total number of boards is 10 four foot boards and 9 two foot boards. So the only other way I can describe the amount of use is to note that I sharpened the jointer after planing 6 of the four foot board edges flat. And I have since then planed all the rest of them flat and then gone back, after figuring out how to arrange the boards, to touch up and make sure that the boards that will be glued together fit well. And I've worked through all but 4 of the four foot boards. The American cherry is a soft, easily worked wood that is friendly to the tools.

 

[newt]

I think we must assume that the blade is at fault, either to soft (most likely) or so brittle that the edge broke off. How easy is it to sharpen? One thing you could do is to get a small file and stroke it on a peice of mild steel and note the sound then do the same on the side of the plane blade it should skate over the surface and be much more difficult to mark.

 

[Mr Ed]

I think you must have ended up with a blade that somehow missed its heat treatment. That or the temper having been drawn through over heating whilst grinding are the only logical explanation for wear at the rate you describe.

Cheers, Ed