jointer sole length vs. stock length? ratio?

[Will Blick]

Neanders can get techie, I felt this was the best place to ask this question...

Whether a hand jointer, or a power jointer....

to get a straight edge on stock, what length does the jointer beds need to be, in relationship to the stock?

For example, a hand plane jointer 24" long, can not assure an 8ft wood edge will be straight.... if the edge started with a dip in the middle, the hand plane will follow the slight dip as the bed length can not reference the entire board.

So what is the relationship between board length and jointer bed length. I assume it makes no difference if its a power jointer or hand jointer?

TYIA

[Johnny Kleso]

The longer the fast if flattens the stock..

You can joint a board with a No.5 and a straight edge..
Start buy knocking the high spots down first and the more you plane the flatter the board gets..
The longer the plane the more it just knocks the highs..

I am not sure if there is some rule as to what plane to use but I always start with a No.5 or No.6

[Will Blick]

Agreed Johnny... a straight edge would be the necessary tool to assure straightness with hand planing a 8ft edge.... however, where do you get 8ft straight edge?
I realize these problems have been dealt with for hundreds of years, but in this case, I think the reference issue was always difficult.

[Matt Evans]

... however, where do you get 8ft straight edge?
.

Easy. . .taut string is a straight edge, and rolls up very small. . .is pretty cheap too. FIshing line, good thread, etc.

Also, your eye is more accurate than you might think. If I remember to I will post some pictures of long edge gluing I am doing this week, all done by hand with no 8' straight edge, just by eye and feel.

[Rick Cicciarelli]

8' straight edge can be found at the big box stores. Used for setting up a straight edge to cut plywood with a circular saw.
They come in two 4' sections and are joined together. I use it quite often.

[Jim Koepke]

For example, a hand plane jointer 24" long, can not assure an 8ft wood edge will be straight.... if the edge started with a dip in the middle, the hand plane will follow the slight dip as the bed length can not reference the entire board.

This seems like a case of the worker letting the tool do all the thinking.

The tool takes the shavings, the worker determines where the shavings need to be removed.

jtk

[Zahid Naqvi]

You can always borrow Derek Cohen's plane (6 foot something) that he just built :D
I suspect the woodworkers of yesteryears were less obsessive about perfect flatness than we are. Wood fibers have enough flex/give that clamping pressure will eliminate minor imperfections. I think fluctuations in moisture and temperature will cause more damage to glue joints than any slight error during construction. But I am not an expert in these things, the longest stock I have handles for a project was about 6' long bed rails made from laminated Walnut.

[Chris Fournier]

This seems like a case of the worker letting the tool do all the thinking.

The tool takes the shavings, the worker determines where the shavings need to be removed.

jtk

I couldn't have said it any better! Spot on.

[george wilson]

A long cooper's jointer really only touches the curved staves very near the mouth of the plane. We were always repairing their worn mouths. Unless they were making buckets,which were made from balsa-soft cypress, they didn't use much any of the length. A floor plane would be pretty long (for planing floors).

[Will Blick]

Interesting responses, even though none revolved around my original post....
Yes, I realize you can use string, BORG carpenter 8ft edges, your eye, etc.
I was curious about the relationship between bed length and assured flatness, i.e. no thinking, the tool would be fool proof...
As an example... my power jointer has 40" beds on each side... when I joint a board 40" or less, I am ASSURED straightness as the reference surface is as long as the stock... I was curious if there was any rules-of-thumb regarding this relationship... I think you can still be assured straightness using longer boards vs. the reference surface, but not sure how much longer...

> I suspect the woodworkers of yesteryears were less obsessive about perfect flatness than we are.

Fully agreed with this.... the internet, books, forums, I guess it makes us more curious creatures than yesteryear....

Interesting note of a floor plane....how long are those soles?

[john brenton]

I think the responses all touched on your original post, although there was no if surface"x" is so long, your jointer should be "y". Unless you're talking about a massive plane, you would need to plane the surface smartly to avoid simply following the existing contour. As you stated, even if you have a massive plane I don't know that it would give you "perfect" flatness. Even jointing a 5 ft. board with a 24" jointer plane doesn't guarantee "perfect" flatness.

Most people's longest plane is going to be 24", and with that you can do most anything, mostly limited by width more than length.

As the other posters said, I don't really concern myself with flatness outside of it's necessity. When it comes to it's affect on joinery I shoot for it, but other than that no.


Interesting responses, even though none revolved around my original post....
Yes, I realize you can use string, BORG carpenter 8ft edges, your eye, etc.
I was curious about the relationship between bed length and assured flatness, i.e. no thinking, the tool would be fool proof...
As an example... my power jointer has 40" beds on each side... when I joint a board 40" or less, I am ASSURED straightness as the reference surface is as long as the stock... I was curious if there was any rules-of-thumb regarding this relationship... I think you can still be assured straightness using longer boards vs. the reference surface, but not sure how much longer...

> I suspect the woodworkers of yesteryears were less obsessive about perfect flatness than we are.

Fully agreed with this.... the internet, books, forums, I guess it makes us more curious creatures than yesteryear....

Interesting note of a floor plane....how long are those soles?

[Chris Fournier]

Interesting responses, even though none revolved around my original post....
Yes, I realize you can use string, BORG carpenter 8ft edges, your eye, etc.
I was curious about the relationship between bed length and assured flatness, i.e. no thinking, the tool would be fool proof...
As an example... my power jointer has 40" beds on each side... when I joint a board 40" or less, I am ASSURED straightness as the reference surface is as long as the stock... I was curious if there was any rules-of-thumb regarding this relationship... I think you can still be assured straightness using longer boards vs. the reference surface, but not sure how much longer...

> I suspect the woodworkers of yesteryears were less obsessive about perfect flatness than we are.

Fully agreed with this.... the internet, books, forums, I guess it makes us more curious creatures than yesteryear....

Interesting note of a floor plane....how long are those soles?

Your speculation is not correct. You are not yet ASSURED straightness just because your table length is the same as the board length. Your tables could not be parallel or the cutter could be too high/low and you will not get a straight board.

The responses to your first post don't hit the bullseye for you because the question that you asked doesn't really make sense from a theoretical or practical point of view. The responses that revolve around your post are trying to help you get a straight edge but answering the original question won't get you a straight edge at all.

The fact is that there is no relationship between bed length and assured straightness - I guess that this is your answer, however unsatisfying!

[john brenton]

I think this question was asked not too long ago, too, and with the same result. The longer the tools, the straighter they SHOULD be, but that doesn't mean anything without experience...there is no "set and forget" as far as I know.

I remember the first time I tried to plane a board...it was fantastic. I couldn't believe how easy it was, or why people would say it was hard. Then I REALLY remember the next time I tried to plane a board flat...same plane, but hours later I was shin deep in shavings and no better off than I was before. It was a particularly twisted and bowed board, yes, but looking back now I could flatten it without wasting all that energy and wood.


Your speculation is not correct. You are not yet ASSURED straightness just because your table length is the same as the board length. Your tables could not be parallel or the cutter could be too high/low and you will not get a straight board.

The responses to your first post don't hit the bullseye for you because the question that you asked doesn't really make sense from a theoretical or practical point of view. The responses that revolve around your post are trying to help you get a straight edge but answering the original question won't get you a straight edge at all.

The fact is that there is no relationship between bed length and assured straightness - I guess that this is your answer, however unsatisfying!

[Jim Koepke]

Interesting note of a floor plane....how long are those soles?

According to Patrick Leach, the Stanley #11-1/2 floor plane was 7" long.

jtk

[Bob Stroupe]

It seems like i read somewhere that to flatten a surface your plane should be 2/3 the length of the work, or maybe it was 1/3. I couldn't tell you where I read that. Shoot, I might even be making it up... whoever wrote it probably did.
You could practice with say a 2' piece of scrap and a smoother. When you can get the 2' piece flat use the same technique with your 8' chunk of wood and your 24" jointer.

[Will Blick]

> Your speculation is not correct. You are not yet ASSURED straightness just because your table length is the same as the board length. Your tables could not be parallel or the cutter could be too high/low and you will not get a straight board.

OK, I should have spelled out the disclaimers..... i.e. assuming plane is finely tuned, flat, etc. In other words, removing the planing instrument itself as a variable.


> The fact is that there is no relationship between bed length and assured straightness - I guess that this is your answer, however unsatisfying!

Who's fact is this? Yours? Like most facts, they exist, sometimes hard to find. Just because one does not know a given fact, does not suggest it does not exist. If I had to wager a guess, based on my years of ww'ing and being an engineer, I would think this part of Bobs post below, would be close to accurate...


> to flatten a surface your plane should be 2/3 the length of the work...


longer would be even more fool proof, but you start entering into diminishing returns...

Also, as previous posters have mentioned... I have learned through the years, whenever I power joint, I look at the wood edge like a gun sight, find where the unflatness is, and work that section(s) of the board first. It can save a lot of passes. It's easy to get lazy and just zip the wood through. I typically use my hand planes to clean up any jointer marks vs. jointing the board from scratch, unless its a small piece, then I hand plane the edge flat. Of course, this level of flatness I refer to is always for an exposed cosmetic glue joint.... otherwise, as stated previously, not a big concern. I find near perfect joined glue lines have a more seamless look, which I like...

[Chris Fournier]

You don't say what kind of engineer you are Will but if you're a mechanical engineer you may be familiar with the technique used in building and repairing very precise machine tools which is called "scraping". This technique yields (if done by a practised operator), straight, flat and registered surfaces and the tool used to scrape is sorta like a chisel - no bed at all - the cutting edge is directed by hand. The bed length is zero.

So lets take any intended work surface length of any value from .001" to 1 mile and divide this by the length of the scraping tool bed - 0" and we have infinity! This is your answer in goofy theory (me being the goof) and practice too. The relationship of your jointer bed to the length of your workpiece is infinitely variable.

[Jon van der Linden]

A perfectly set up and perfectly operated plane or planer will result in a flat or minutely concave surface. Why concave? Because you can't reference off a convex surface, at least not with normal tools.

As far as the bed length goes, with machines a lot of it has to do with the practicality of being able to support the work without it jiggling around, so it really depends on the weight and length of the material and whether you use feeders or not, etc.

With a hand plane you can get a very flat surface without too much trouble with any plane about 15" or more. (Personally I like the 5 1/2 size.) It's a two part process, first getting rid of all the highs and lows, then a final pass to bring it exactly to where you want it to be. It really has more to do with your ability to verify flatness and anticipate the result of your next planing pass than anything else.

[Johnny Kleso]

With out something to check your work like Winding Sticks and a Straight Edge you are just guessing its flat..

If you want flattness you have to check it and make corrections..
As someone said there is no set and forget.

Lets say the ratio is 1:1 or lets say it 3:1 or 10:1 whos ratio is that??
The experts or a novice?
With the power jointer set perfectly or the out feed table too high or low?
How do you know its set perfectly?

Who ever is making a ratio is just giving an opinion in my opinion :)

[Jon van der Linden]

Johnny, you just touched on a few interesting points. A power jointer will need adjustment of the outfeed table due to blade wear, the only way to really know if it's set perfectly is by judging the results, and those will change over time even if the settings don't.

When working by hand I don't think that we're really aiming for flat, but minutely concave. I.E. just concave enough that we can verify that it's not convex. I do this by using a straight edge and the super accurate wiggle method! If you can actually measure it with a feeler gauge then the gap is probably too big. (It's not difficult with practice to get this below .001".)

While it might seem like having a ratio provides a nice guideline, it really doesn't. Fortunately we don't need different jointing planes for each and every length of wood. Which is good because that means there's more money left for all those tools we really need!!!

[Jim Koepke]

Fortunately we don't need different jointing planes for each and every length of wood.

Please, don't ever tell my wife that. :eek:

Often I use two jointers on the same piece of wood. One is taking the bulk of the shavings and the second is set to take as thin a shaving as it can and the blade is kept sharp with less use.

This is also done with a few other sizes of plane.

Of course, this is not necessary, but neither are a lot of other things.

jtk

[Will Blick]

Chris, your Scraping scenario transfers the bed length to the blade movement tolerance, over the material. This is similar to metal working machines, which flatten material with NO beds as well. The machine moves the material over the blade. Assuming a FLAT cutting surface, the tolerance of flatness will be limited by the tolerance of the movement system. Different animal...

Johnny, yes, of course a reference is required to determine if the end result is FLAT. As to the ratios, 1:1, 10:1, you refer to.... its obvious that if the bed length on each side of the blade is long, or longer than the material, you will be assured flatness (assuming all other variables are within an acceptable tolerance). So this is a logical max. starting point, we know the beds do not need to be 10x longer.

Agreed on all the techniques to narrow down the process of getting an edge flat, winding sticks, a reference flat edge, etc. etc. I don't often work with really long boards, but a few times I have, and I struggled getting the edges dead flat. Of course, I could get them close with enough effort.... I knew the problem was, my reference surfaces were simply not long enough for 8 ft boards I was working with..... my power jointer which is very precise with ultra flat beds, verified by 5ft Starrett straight edge did a much better job than my 22" hand jointer plane.... (which as jon correctly mentioned, produced slightly concave edges) no surprise there... of course we also have the time factor here... I could have improved my hand jointed edges if I spent several hours tweaking each one of them.

That was several years ago... then for another project I bought the Festool TS75 saw and LONG rails.... I don't have a 9ft reference to check my long rail, but after testing the final cut, with all the means I have available, winding sticks, 85" jointer bed length, eye sighting, using 5ft Starett in overlapping checks, etc, this was the straightest edge I could possibly get, (with minimal amount of time to boot) and glue ready cut as well. And the ultimate test IMO is when you join the two edges that will be glued, how does it look to your eye? when you join two long flat surfaces, errors are magnified over length, they become ultra obvious. Of course now, any long boards that need a STRAIGHT edges, I just cut with this track system.

Anyway, I strayed off the original question I was curious about, but thought this info would be useful... I too always seem to find suitable solutions.... my original question was a curiosity question, not a "I can't solve this problem" type of post...


191276

[Jon van der Linden]

Please, don't ever tell my wife that. :eek:


jtk

LOL Jim, you're safe with me... you really need different setups i.e. blade bevels, handsaws with different ppi/rake combos, etc. for dealing with different woods and different grain configurations within those types of woods. Doesn't mean it can't be done with a just sharpened & hardened screwdriver, but that would turn any project into a 200 year multi generation work!

If you need an alibi, I can send you a $200k + "required" tool list no problem!

[Johnny Kleso]

Will,
You made me think when I wrote 1:1 or 3:1 or 10:1 as you are correct I was not even thinking what I was writing and more than 1:1 is useless..

I think any power tool use can save a lot of work by just checking a board or pannel for flattness with some type of straight edge and knocking the high spots down with a No.5 before running it through a planner or jointer

[Will Blick]

In my pre Festool days, this was my strategy as well... very sensible. Then, after I bought the Festool saw/rail system, if an edge is too unruly from the start, I forget all this, just lay board on table, clamp on rail, cut, done. The older I get, the more I appreciate the "ideal" tool for the job...in this case, simplicity and perfect end result first try.

Of course, if the wood has a decent edge to begin with, I will just hand joint or power joint....

[Russell Sansom]

This is a cool discussion. In an aerospace lab, this is the kind of question that comes up constantly. It's pretty common for electrical and mechanical engineers to be involved with the clipping off of wave forms. Sometimes people simply know the answer ( like the theoretical maximum speed of a displacement boat hull ), and sometimes people pop in and out of each others' workspaces all day with scribbled out competing theories.
I can't resist giving this one a little thought tonight.

BTW: Where did the first straight edge come from is a fairly easy one. I just made three 5-footers from scratch, though it did take considerable effort.

[Will Blick]

Russell, I'll take the bait....so where did the first straight edge come from? ;-)

In my younger, more alert days, I would find this an interesting quandary to tackle. Of course, like all mechanical issues, their is a tolerance relationship... so the answer would read something like this....

Stock length vs. Bed Length = theoretical flatness
1 : 1 = TRUE FLAT
1 : .9 = .0001" flatness tolerance
1: .8 = .0003" flatness tolerance
........

of course, Bed length is the length of the bed on ONE side of the blade, for a hand plane, its more complicated, as the two sides are not equal....much easier to calc. if both sides are of equal length.

Now, how to calculate this table? Someone with the proper mental horsepower could probably rip this out in a few hours....for me, a few days, maybe longer :-(
Have a "go" at it!

[Johnny Kleso]

I'm guessing standing water like the ring around a tub..

[Russell Sansom]

Will...
I didn't mean to tease anyone. I'd heard for years about a math proof in which 3 (arbitrary, non-flat ) planes are presented to one another in round robin fashion. One is rubbed against another and the high spots are taken off. There's a simple strict protocol to the round robin. The result is 3 flat planes...flat down to the resolution of the flattener.
Even though a straight edge is a long narrow plane, it's still a plane and the proof holds. On the internet I found a couple machinist's references to flattening steel plates. There's also one article on creating a wooden straight edge. A good deal of searching found little else, and very little practical help. There were drawings, but no pictures. In fact, some of the details made it clear that the author probably hadn't actually made a wooden straightedge himself. Just to mention it, Christopher Schwartz's article on the subject is useful, but a horse of a different color.
Since I needed a 6' straight-edge to align the tables of a new jointer, I set out to discover the practicalities of doing this in wood and did so after two enjoyable days of puzzle solving.
In the light-headedness of the moment I wrote an article about the adventure. It turned out to be 8 pages or something, so I haven't trimmed it down and published it here yet. I'm certain that some of the SMC clan could take advantage of a few faint road signs to success that I found.
In my own younger and more alert days I would have searched out the first proven flat plane and have the details on the tip of my tongue. No longer being in the competitive atmosphere of a research lab, I'm content with just having performed the exercise and knowing how it had to have been done in the first place.
And, Johnny, I hear you, but generally speaking, I can't come up with a way to transfer that bathtub ring to a length of wood.

[Norman Hitt]

That's how they leveled the bases for the Pyramids, ........ water in ditches, (or at least that's what I have read).

[Johnny Kleso]

Tub of water is what they use to test levels..

[Will Blick]

Interesting post Russell....

So, getting back to the original issue, and applying what you have learned...what would be your estimate of hand plane length vs. board length. Assuming all the obvious things are done, such as lowering the high spots, at some point, you can not stop a shorter plane from concaving a longer board.... I am interested in your thoughts...

[Casey Gooding]

I believe the general rule is a plane can accurately joint a board approximately 2.5 times it's length. I think the important thing is not so much that a board is perfectly straight, but that two edges match up.

[Roderick Gentry]

There is an inherant relationship that will create a straight edge without measurement, automatically. It has been referred to, there is a relationship between blade projection and sole length that will give a certain degree of concavity for a given sole length and blade projection, and for a given shaving size. The length of the board does not affect this. But while it might be within an accuracy/length limit of a thou over 22" it is a lot more than that as the 22" segments are connected, but in my experience it yields sufficent performance to joint edges over say 7' table lengths. One can tighten the specification if one is willing to reduce shaving thickness but it eventually gets impractical. So another option would be to lengthen or shorten the required sole length to get back in the sweet spot.

If one is jointing, rather than shooting an edge, the width of the board or it's aspect ratio also comes into it. As boards get wider their stiffness increases, so the joint will tolerate less spring. So a plane that might be fine for a board with an aspect ration of 1:14, say for a table plank, would not be fine for a guitar plate that was nearer 1:2.

So the relationship has a few factors in it, but it could be said to exist, and if one prefered to express it in the form of sole to board length with the other variables assumed, it could be done that way.

[Roderick Gentry]

So imagine you have a board whose edge has a 30 foot longitudinal concave radius to it, or call it 3 foot if that helps. Run a jointer plane along that edge and it can't cut. Now take a piece with the same radius, but convex. The plane will be able to cut into that. Somewhere between those two extremes the plane goes from taking a cut to not taking a cut, and that is the point of automatic "straightness". It is a function of blade pojection relative to sole length.

[Will Blick]

Fully agreed, great contribution....

I like your point about board thickness as well, or more importantly, board flex... we often forget about the downward pressure applied when hand planing....the shorter the plane, less area this force is spread over, the more flex. A power jointer has a big benefit here due to much longer beds.

and agreed, thickness of shaving plays a very significant role also.... so it make sense to finish joint planing with thinnest shavings... I will start implementing this.... thx

[Andrew Pitonyak]

Let B = the bed length of the plane. Let B=24"


Where is the cutting edge of the blade? I will assume that it is 25% from the front, so 75% from the back of the plane. For our example, this means 6" and 18".


Let D = the blade depth = distance from the bottom of the sole to the cutting edge = shaving width along a flat board. Let D be a very thick shaving of say 0.01"


Assume a perfectly flat board and place the front of the plane firmly on the board and take a shaving. I expect the shaving to have thickness D while the front of the plane is held firmly in place.


Take a shaving for a bit until the entire plane is over the wood. If the front is held down firmly, then the back 18" of the plane is of height D above the board. Now, let the back end drop to touch the board. The plane is now at an angle. I assume that the uncut portion directly in front of the blade is touching the uncut portion wood and the back end is now a depth of D (0.01") lower. So, what is the angle? The angle is given by asin(D/18). This yields the tiny angle 0.0318 degrees, which tilts the plane and changes the cutting depth to sin(90 – 0.00318) * D. The difference in height is about 1.54E-09 = 0.0000000054"


The main advantage of the long sole is that the plane rides of the hills and valleys of a board that is not straight.


Sometimes the length is a problem, not because of the length, but because of the weight. I have some twisted and cupped boards. If I use my #8, the weight of the plane flattens the board so the cup and twist is gone. To some extent I can avoid this by putting weight down on the rear of the plane so that the cutting edge reaches the hill before the weight pushes the board flat. I can also use a lighter plane, which means not as long.


How the plane behaves with respect to a hill or valley depends on where pressure is applied to the plane. Pressure applied to the back will PROBABLY (no testing done) allow a 24" plane to ignore valleys that are easily 12" wide... until the back of the plane enters the valley.


If you consider what occurs when the front of the plane enters a valley and pressure is applied to the front of the plane, the equations change... Also, the front is not as long, so the angle will be greater for the same depth.

[Roderick Gentry]

"The main advantage of the long sole is that the plane rides of the hills and valleys of a board that is not straight."


I don't believe that, though it is the dominant view. The reality is you can't tell what length of plane will interface with what wave train of bumps most effectively (just running the boards, I guess the next part of this post is an analysis of fit, but who does that and picks up a specific plane). So imagine a 10' boards. Having bumps even 1" A block plane would get 'er done pretty much just as well as a jointer. But there would be a board where the longer sole would work better, maybe 10" spaced bumps. And because of that the longer sole plane is the better choice as you say. But the reality is that the jointer when used properly would straigten any board just as well regardless of what the bump pater was so long as it is being used for it's default cut. And as far as that is concenred a plane half the length with half the balde projection would work just as well as the longer jointer, but would take a long time to get the result because of the finer shaving.

The constant is that for a given effective cut, a given blade projection and sole length will produce a given "strainess" of board regardless of what board you start with. (That is an approximation if you want to get super picky about it, but the principle is correct). And this principle remains true regardless of what board you start with. I didn't make this up, I learned it in the Krenov plane video.

I don't want to overstate my point. I guess the length of plane sole, and it's effects, is default function also, but it varies depending on the board you start which while the default function relative to blade projection is a constant.

[Roderick Gentry]

Fully agreed, great contribution....

I like your point about board thickness as well, or more importantly, board flex... we often forget about the downward pressure applied when hand planing....the shorter the plane, less area this force is spread over, the more flex. A power jointer has a big benefit here due to much longer beds.

and agreed, thickness of shaving plays a very significant role also.... so it make sense to finish joint planing with thinnest shavings... I will start implementing this.... thx

On board flex I was thinking of something different than your equally valid point. My point is that in setting up a plane:

- The default cut is concave, length of the board, until they start to make very subly convex plane soles.

- The default cut will create a sprung joint, unless you back it out.

- While you can close together a sprung joint, or as you point out regulate it with blade projection aspect ratio, this needs to be regulated not only in terms of board length but width to length aspect ratio.

So take my original example. except let's consider the guitar plate only. 20 inches long, 10 inches wide, and 1/8" thick at glue up along the 20 inch side. aspect ratio 1-2. Now cut out a strip that is aspect ratio of 1-14, otherwise similar. That would be a strip 20 inches long and 1.42 inches wide. The guitar plate 10x20 is 345 times stiffer than the 1.42x20 strip as far as closing the edge joint. So when working with the plane's defaul setting one has to account for that.

The take away is that the crossgrain stiffness of boards rises exponentially with width, and you may have to alter your approach to deal with it. You don't need math except to realize how significant this factor can get. It isn't practical to use planes and their default settings on guitar tops, which is why we have shooting boards and sanding boards, etc... But there are many other situations where the default planing ability of planes is very useful.

What this has to do with the original question is that you can meaningfully set plane length in terms of board length, but width ratio also has to be considered, and you can set that in terms of felt flex, or reasonable clamping pressure.

[Will Blick]

again, great post.....

I was mostly thinking of edge jointing, whereas the edge was thinner than the blade width...otherwise, a power jointer is the ideal solution... or as you mention, sandpaper on FLAT surface.... assuming you have a flat surface large enough

valid point regarding material strength, which is a function of the wood type and dimensions.... again, a power jointer solves this, as you push the wood on the large flat beds, so the wood is always supported, vs. a hand plane where some of the wood is being flexed at different amounts based on hand pressure, and position... obviously center has potential for most sag, so clamping strategies also come into play...

What this thread has made me appreciate is.... reference surfaces are the key, as we know 1:1 will assure flatness equal to the tools tolerance, i.e. 100% of the wood touches the beds, throughout the entire cut. The further we stray from this ideal, the more risk the board not being straight. A well tuned and FLAT power jointer truly can earn its wings in this regard. Of course, its the wood length that is the significant factor here... 5ft board you must deal with differently than a 1ft board, assuming your goal is max. flatness. Although I never thought about this much in the past, I have always instinctively used my neander tools on smaller length boards, and my power tools on larger boards. Of course the marriage of the two is ideal... a single pass of hand plane after power edge jointing gives you a glass like surface, vs. power jointer.... although when I put new blades on my jointer, it can match my hand plane surface, but it doesn't last long....

[Johnny Kleso]

I have made high precision parts for over 30 years and high precisionmachines..
No matter how big or expensive the machine you always haveto check the part for accuracy, there is never a given in a machine shop..

When you'er figuring formulas where your accounting for the wood, badly tunedplane as well as user experience?
I know where must be some relationship and ratio that longer is better but I think its futile tothink you don’t have to check yourwork..
There is no such thing as FOOL PROOF as fool are so Ingenious :)

[Will Blick]

I doubt you will get an argument from anyone with comments like, "check you work", or "check your tools", etc....

I have a 5ft starett straight edge, its straight to .0002" per ft... this was the best investment i made in my shop....
It enables me to get my long jointer beds, as close to dead flat as one could expect for ww. The finished wood is equally as flat....
As I mentioned, the key is proper starting reference, otherwise you will tune tools that will be poorly aligned, but with no knowledge of such...

As for user experience.... a thread like this gives people info to think about, hence the value of forums...

[Darius Ferlas]

I read somewhere, possibly on this forum, that a reasonable ratio is 1:1.5 (combined table length to the length of material) and this is what I had no choice but test with my 6" jointer - 54" long table. The longest piece I ran thrugh it was 80" long. It worked but it was a serious chalenge and I think the fact that the pieces were bed rails helped me in deciding the quality of the cut was good.

The longest pieces that I was able to verify as to their straightness were 60" long boards for a table top glue-up.

[Brad Pearce]

I have both a 6" machine jointer [46" bed] and a 22" hand jointer plane [Lie-Nielsen]. The hand jointer is absolutely true as far as I can discern. The machine jointer is as true as I can make it, which is within 4 thousands of an inch infeed and outfeed. This is measuring with a Veritas 50" straight edge. With wood pieces shorter than 25 inches the machine jointer works fine and is very fast, with longer pieces it fails, just a bit, but it magnifies with additional cuts. Then I need to take it into my own hands with the hand jointer, where it all goes square. I could not live in woodworker's world without both tools... Also, the hand jointer is indispensable with larger stock [i.e. My shop can’t accommodate an 8” jointer.].

[Eddie Darby]

I was curious about the relationship between bed length and assured flatness, i.e. no thinking, the tool would be fool proof...
As an example... my power jointer has 40" beds on each side... when I joint a board 40" or less, I am ASSURED straightness as the reference surface is as long as the stock...


Even with your 40" board on 40" beds you need to 'know' the general state of your board, since how you hold the board, and where you put pressure on the board as you feed it, will affect the outcome. Knowing if a piece is cupped or bowed, twisted all must be factored in so you can run the board correctly through the jointer.
Sorry you will just have to accept that in woodworking you have to use your brain.

[Will Blick]

> Sorry you will just have to accept that in woodworking you have to use your brain.


hmmmmm.... I run CAD, I have a plethera of metalworking measuring devices I use for ww, setting up tools to better than .001" in most cases, I have cross-check references for just about every ww task I perform, I design and build many custom jigs to simplify tasks... many fellow ww's sort of laugh at the level of neurosis I have towards perfection....

but yet, it appears by your post, my problem is, I did not realize I must use my brain during simple ww'ing tasks.... gosh, it all makes perfect sense now, thx for the great contribution Eddie!

[Eddie Darby]

> Sorry you will just have to accept that in woodworking you have to use your brain.


hmmmmm.... I run CAD, I have a plethera of metalworking measuring devices I use for ww, setting up tools to better than .001" in most cases, I have cross-check references for just about every ww task I perform, I design and build many custom jigs to simplify tasks... many fellow ww's sort of laugh at the level of neurosis I have towards perfection....

but yet, it appears by your post, my problem is, I did not realize I must use my brain during simple ww'ing tasks.... gosh, it all makes perfect sense now, thx for the great contribution Eddie!
You are welcome!
Just curious as to why you wanted to have the job done with "no thinking" if you pride yourself on all your excellent skills?

[Will Blick]

> Just curious as to why you wanted to have the job done with "no thinking" if you pride yourself on all your excellent skills?


The reason is, curiosity.... The same reason so many tools are designed in the first place... to reduce the amount of thinking, the amount of steps, calculations, etc. to perform a given task. The OP was a mathematically quandary..... a way to further exercise our brains.... but somehow, you interpreted as:

sorry dummy, you gotta use your brain.... (??)


Don't worry, not surprised, I am used to internet forums by now.... no thread can go unscathed without misguided or sarcastic comments such as yours.... my other big curiosity has always been...when someone like you, reads a thread like this, and has nothing sensible to contribute, wouldn't it be more prudent to just "move-on". Why do you feel compelled to introduce sarcasm / misguided comments into a peaceful thread? Since I answered your questions, maybe you can be fair, and do the same for me...

[Eddie Darby]

> Just curious as to why you wanted to have the job done with "no thinking" if you pride yourself on all your excellent skills?


The reason is, curiosity.... The same reason so many tools are designed in the first place... to reduce the amount of thinking, the amount of steps, calculations, etc. to perform a given task. The OP was a mathematically quandary..... a way to further exercise our brains.... but somehow, you interpreted as:

sorry dummy, you gotta use your brain.... (??)


Don't worry, not surprised, I am used to internet forums by now.... no thread can go unscathed without misguided or sarcastic comments such as yours.... my other big curiosity has always been...when someone like you, reads a thread like this, and has nothing sensible to contribute, wouldn't it be more prudent to just "move-on". Why do you feel compelled to introduce sarcasm / misguided comments into a peaceful thread? Since I answered your questions, maybe you can be fair, and do the same for me...

I think the problem that you are experiencing is one of 'Implied vs. Inferred', and also a misunderstanding as to why threads are saved for future reference.
At no time did I use the word "dummy", so I can only conclude that you inferred it.

The sarcasm that you are reeling against was not directed at you, but at the subject of 'no thinking', and the answer was not just for you, but for anyone who in the future should view this thread looking for a way to avoid thinking.

That you see the sarcasm as an attack on yourself is one of inference, and was not the goal of the response, nor was it intended to be implied, but merely an attempt at failed wit.
Not all sarcasm is an attack on a person or persons, nor is it always negative.

*If* you are offended in any way, then please accept my apology, as it was not the intent of the response. I have, on numerous times, run into threads here and at other forums, by beginners, trying to let the tool do 'all' the work, and so pointing out that thinking is necessary was meant to be a help to anyone who so thought this.

[Will Blick]

You quoted what I wrote, then below it made the sarcastic comment. Common sense says, your sarcasm was directed to the author of the quote... if you were not responding to the quote, or author of the quote, why not preface your post with such ??

Anyway, its gracious you accepted responsibility for your post and apologized, so thx for that.... (rare on any forum, not just ww forums)

time to move on.....

[Ron Willmert]

I would say, at least for a power jointer, the piece would need to be half the bed length for it to be '100% automatically' flattened. If the piece is the same length as the the bed, you start and finish cutting with half the board off the table. To reference the whole piece, all the time, it can only be half the length of the table. And you still have to start out with any bow in the arch position instead of a 'U' position.

[Will Blick]

Agreed Ron, I referenced a bed, as one side of the blade,.... so we are on the same page.....
for a hand plane to accomplish the same, at a min., the rear bed must be as long as the work piece... :-)

[Larry Feltner]

I'll throw in my 2 cents on your hypothetical question. I'm going to interpret your question to mean how long would a plane need to be if we remove the human element from the process of planing. Removing the human element, and assuming the blade was in the middle of the plane length wise, wouldn't the plane have to be twice the length of the board. In other words, wouldn't you have to have a situation where the plane is always in contact with the full length of the board to ensure a perfectly straight edge, if you remove the human element in the operation of the plane? Otherwise, some portion of the plane will follow the contour of the board which would require human intervention to correct.

[Will Blick]

> and assuming the blade was in the middle of the plane length wise, wouldn't the plane have to be twice the length of the board


Yes, you are stating the same position I, and others mentioned above. Ideally, both sides of the blade will have beds equal to, or longer than the wood. But if there was a compromise, it should be the bed in the front of the handplane (opposite for power jointer) as the goal is to keep the post-cut bed to be equal or longer than the wood. This IMO, is why jointer hand planes have the blade located very near the front of the plane. With power jointers we don't see this, my guess is, cause you need to support the wood so it does not fall off the infeed side.

[Pam Niedermayer]

...This IMO, is why jointer hand planes have the blade located very near the front of the plane...

Slight amendment: Japanese jointer plane have the blade located near the back of the body.

Pam

[Will Blick]

Very Interesting.... very curious why they place the longer sole in the front.... I would think, its not as effective vs. the traditional longer rear sole, but, I have been fooled b4 :-)

[Jim Koepke]

This IMO, is why jointer hand planes have the blade located very near the front of the plane.

Actually, this does not sound correct. The longer the plan, the further from the front the mouth and blade are positioned.

In my understanding of using a jointer, it is more the technique of the user that causes the finished surface to be flat than it is the length of the plane. Give me a 5' plane with a 4' board and I can make it produce snipe, rounded ends and even a valley in the middle if you like. Yesterday I was working 10' boards with an 18" #6 and getting it straight. My #7 & #8 were also called on during the day.

On long boards, a #6 can be the smoother.

As I recall, one time Harry showed us his long grain shooting board with a block plane.

It is amazing how many boards I have made straight by just doing instead of theorizing while this thread has been active.

jtk

[Pam Niedermayer]

Actually, this does not sound correct. The longer the plan, the further from the front the mouth and blade are positioned.

In my understanding of using a jointer, it is more the technique of the user that causes the finished surface to be flat than it is the length of the plane. Give me a 5' plane with a 4' board and I can make it produce snipe, rounded ends and even a valley in the middle if you like. Yesterday I was working 10' boards with an 18" #6 and getting it straight. My #7 & #8 were also called on during the day....

I agree. What's key is how the blade treats the board, and that's pretty much up to the user. Although, I do notice a difference in the handling of my 30" and 22" jointers, both of which are western woodies. Not sure at the moment on how to talk about this, since I haven't used either plane for quite a while, been working mostly with a 16" Japanese jointer, shorter boards and all that.

Pam

[Will Blick]

> The longer the plan, the further from the front the mouth and blade are positioned.

Well, agreed, but from what I have seen through the years, it's not distance, its % of total plane size. Just guessing, it seems most jointer planes have the blade about 25 - 35% from the front. Except the ones Pam mentioned...



> it is more the technique of the user that causes the finished surface to be flat than it is the length of the plane.


Just to be clear, are you referring to edge jointing, or face (surface) jointing? Face jointing is an entirely different animal vs. the discussion above.



Pam, any chance of getting pix of this 30" jointer plane? :-) Sounds impressive...

[Pam Niedermayer]

>...Pam, any chance of getting pix of this 30" jointer plane? :-) Sounds impressive...

Sure, go here and scroll down to Jointer (http://www.planemaker.com/products.html). :)

Pam

PS I bought the last of a previous set, much cheaper, which is not meant as a comment on the price, more about how much I have to spend

[Will Blick]

Wow, great site Pam, never saw this maker before.... its nice to see these new vintage tools still being made in good ol usa...

I notice their jointer plane is 28", which is 4" longer than LN Jointer plane, which is claimed to be the longest of the commercially available metal planes.

For boards 6 - 8ft, I have surrendered the task of edge jointing to my Festool 118" rail... its fast, nearly perfect straight, and cut is so clean, it rarely needs clean-up with a hand plane. As we discussed, the length of the "reference" vs. the work piece length is a critical factor for ending up with a straight edge (yes, I know, you still need a brain).... and even my relatively large 12" power jointer struggles with 8ft boards...although I can achieve very close to straight. But, nothing can be more beat a precise full length straight edge. (which you don't need much of a brain to use) But the Festool Rail technique is not Neander so......

BTW, when I refer to straight, my goal is, long edge jointed boards to mate with no visible gaps b4 clamping.... this level of perfection is NOT mandatory, but I guess its one of those accomplishments I get pleasure from :-)

[Pam Niedermayer]

Yeah, C&W (now Old St. Tools) is a great vendor. My jointer (about 5 years old) is actually 30" long, just measured it, don't know whether the newer ones are 28" or thereabouts, probably depends on the stock they can get.

Festool rail? Used with a circular saw? I think the only potential problems are blade wandering (not saying yours does) and the ability to cut thick stock in one pass. My LV dozuki for plywood did a lot better than a similar rail with my crummy circular saw.

I haven't found that a longer plane is as necessary for jointing long boards as one might think. It's one of those solutions needing a problem issues; but using a tall wooden plane makes it easier to make good joints. Also, match planing helps from time to time.

Pam

[Will Blick]

> Festool rail? Used with a circular saw? I think the only potential problems are blade wandering (not saying yours does) and the ability to cut thick stock in one pass.


Yes, its an entire system made primarily for cutting down sheet goods. It's of very high German quality, the price reflects the quality. The saw, rails and accessories can cost as much as some cabinet saws. But it performs a very unique function, closer to a sliding table saw. But since it's a rail, you can place it wherever you desire a long straight cut. No blade wander on these saws, they even come with a splinter guard, sort of a zero clearance insert for circular saw. One of the reasons the Festool saw system has become so successful is due to it's glue-ready cuts. Once I experienced this, I gave up on edge jointing long boards the more traditional ways. I had to experience it, to digest it myself. sometimes I take a single pass with a block plane just to make sure the edge is not burnished b4 glue.

Since its a circular saw, there is limit to stock thickness, IIRC about 2.5"... similar to a hand-plane when used for edge jointing.

You mentioned match planing.... I think you refer to planning two matting edges at once.... while this is ideal for width error correction, the problem with straight errors on the length, would be they oppose each other during glue up, i.e a center concave will create a 2x gap when joined. Or were you referring to something different?

[Pam Niedermayer]

>...You mentioned match planing.... I think you refer to planning two matting edges at once.... while this is ideal for width error correction, the problem with straight errors on the length, would be they oppose each other during glue up, i.e a center concave will create a 2x gap when joined. Or were you referring to something different?

I intended to mention placing two boards together for simultaneous jointing.

Pam