Planing a board flat - Is there literally no light when testing with a straight edge?

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Arthur Dent

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County Fermanagh
Hey all,

I'm a newbie and I'm sure like many, struggle with flattening stock. I've rewatched a few of the classic recommendations on YouTube a few times.. but I always find myself bewildered when I go to put it into action.

When you hold a steel ruler to a piece across the width, if it's truly flat is there actually no light, even when holding up to a LED roof batten etc?

I know it takes time lol.. but it's proving difficult to get the boards even close to being "lights out".

My method currently roughly entails the following:

1.) Pick a side to work on
2.) If convex in middle, scrub plane across the board to remove a lot of high spots.
3.) Quick check, then look for twist
4.) Try diagonal plane high spots from each end
5.) Check again, repeat as required.
6.) Try finish with No4/5 up and down, targeting areas that look high when glancing ruler at light

I feel like my boards are just getting thinner and thinner as it's a never ending cycle lol especially when I get to point 6 above..

Any tips greatly appreciated! I've watched Paul Seller's, Rex Kruger, Matt Estlea, Chris Schwartz and probably more in attempts to get me head around it lol..

I'll try post an example picture of my latest board to get some clarity a bit later

Cheers
 
It should certainly be possible to get no light across the board. Could be you are taking too big shavings or have your plane blade canted over.
Sounds like you are doing the right thing in principle, just need a bit more finesse as you get close to the end. Of course if you leave the board for a few hours it’s likely to move a bit anyway, especially if you put one side down on a surface.
 
I'd recommend buying the book by wearing 'the essential woodworker', his method is the best I have found yet, basically you need winding sticks, and remove all twist but it also must be flat length ways and across before marking it with a face symbol, then you can do the edge and from there all the other marking out, if you're doing something like dovetails it is really important to get the boards flat where two boards meet and also edges dead square with a shooting board or you'll never get perfect joinery, it's even more important with mitred dovetails.
 
Hey all,

I'm a newbie and I'm sure like many, struggle with flattening stock. I've rewatched a few of the classic recommendations on YouTube a few times.. but I always find myself bewildered when I go to put it into action.

When you hold a steel ruler to a piece across the width, if it's truly flat is there actually no light, even when holding up to a LED roof batten etc?

I know it takes time lol.. but it's proving difficult to get the boards even close to being "lights out".

My method currently roughly entails the following:

1.) Pick a side to work on
2.) If convex in middle, scrub plane across the board to remove a lot of high spots.
3.) Quick check, then look for twist
4.) Try diagonal plane high spots from each end
5.) Check again, repeat as required.
6.) Try finish with No4/5 up and down, targeting areas that look high when glancing ruler at light

I feel like my boards are just getting thinner and thinner as it's a never ending cycle lol especially when I get to point 6 above..

Any tips greatly appreciated! I've watched Paul Seller's, Rex Kruger, Matt Estlea, Chris Schwartz and probably more in attempts to get me head around it lol..

I'll try post an example picture of my latest board to get some clarity a bit later

Cheers
You don't need a scrub plane for normal sawn timber. It's a specialist plane for rough work such as riven green timber or for cleaning up reclaimed timber, not for normal bench work. You are probably overdoing it.
I presume you are cutting to length first, according to your cutting list, and not just planing up stock? Seems to be a common mistake; the shorter it is, the easier to plane flat. Never plane anything until it has been reduced close to finished size for the untended use. And when you do, just plane it flat enough.
It's handy to mark the surface - rub a pencil on the edge of your steel ruler and then rub the ruler across the width - it'll show up the high points. Then you just plane them off.
Check for twist with two winding sticks - just lengths of straight lath of equal width, no need to buy anything.
Check for straightness by squinting down the length. If it looks straight it's straight enough for most purposes.
It's usual to start on the best face first and when flat mark it with an F. Then square an edge and mark that. Then gauge mark the width and thickness and plane to the lines.
 
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A couple of observations I might make would be:
1. Is your straight edge to be trusted?
2. If you see a slither of light underneath a true straight edge, this could be 0.001" ( a thou...)

When you say "...truly flat..." how accurate do you really need it to be?

And I ask these questions as someone who is pretty fussy about accuracy.
 
Hi Geoff,

Good question on 1, I am not sure on that one, it's a steel ruler from an adjustment square.

For number 2, I really don't know how flat I need things, still learning on that one! Attached a picture of a board I just ripped in half to glue together on the edge I am showing in the pic. The purpose of this piece will be to form the jaw of a vice.for my work bench.

To my uneducated eye, it looks kind of not very flat, but I've spent a few evenings on it lol what are your thoughts?

I kind of gave up going over it again and again, as I felt I wasn't making much progress.

Thanks!
 

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Hi Geoff,

Good question on 1, I am not sure on that one, it's a steel ruler from an adjustment square.

For number 2, I really don't know how flat I need things, still learning on that one! Attached a picture of a board I just ripped in half to glue together on the edge I am showing in the pic. The purpose of this piece will be to form the jaw of a vice.for my work bench.

To my uneducated eye, it looks kind of not very flat, but I've spent a few evenings on it lol what are your thoughts?

I kind of gave up going over it again and again, as I felt I wasn't making much progress.

Thanks!
You need to use the ruler at 90º, not tilting it. It might be slightly bent, they often are, but with the edge still OK.
You need to cut it to size for the vice before you plane it, just a bit over to allow for fine adjustment of the size.
 
Charlesworth's videos are the only ones worth a damn, and everyone else has bad habits.
The next best thing you can find easily..other than Charlesworth, which is on another level, and would teach you what you need overnight, without even needing practice I might add.
I cannot describe how much thought must have went into those videos,
a language onto it's own, specifically for accurately describing everything in detail,
in such a manner as to convey knowledge of whats really happening.

There's no make believe to his methods, and at a standard beyond most.
It's all very easy if you play by the rules.
That's all I can say about Charlesworth's videos.

If you wish to watch youtubes, then this particular video might help,
bearing in mind you'll have to discount the bad habits of planing crossgrain which
is silly practice used by folks who won't use their cap iron.



But remember this is for thicker stock, thinner stock will deflect if not sitting on a flat bench/surface.
 
Hi Geoff,

Good question on 1, I am not sure on that one, it's a steel ruler from an adjustment square.

For number 2, I really don't know how flat I need things, still learning on that one! Attached a picture of a board I just ripped in half to glue together on the edge I am showing in the pic. The purpose of this piece will be to form the jaw of a vice.for my work bench.

To my uneducated eye, it looks kind of not very flat, but I've spent a few evenings on it lol what are your thoughts?

I kind of gave up going over it again and again, as I felt I wasn't making much progress.

Thanks!
Jacob has summed it up well
"...Check for straightness by squinting down the length. If it looks straight it's straight enough for most purposes..."
 
Charlesworth's videos are the only ones worth a damn, and everyone else has bad habits.
The next best thing you can find easily..other than Charlesworth, which is on another level, and would teach you what you need overnight, without even needing practice I might add.
I cannot describe how much thought must have went into those videos,
a language onto it's own, specifically for accurately describing everything in detail,
in such a manner as to convey knowledge of whats really happening.

There's no make believe to his methods, and at a standard beyond most.
It's all very easy if you play by the rules.
That's all I can say about Charlesworth's videos.

If you wish to watch youtubes, then this particular video might help,
bearing in mind you'll have to discount the bad habits of planing crossgrain which
is silly practice used by folks who won't use their cap iron.



But remember this is for thicker stock, thinner stock will deflect if not sitting on a flat bench/surface.

Ignore Charlesworth and Cosman whatever you do! That Way Madness Lies! They are showmen and make everything difficult and mysterious, on purpose!
Bob Wearing is good as @thetyreman says. I expect Sellers would be OK but can't say I've seen a vid of his on basic planing
 
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You don't need a scrub plane for normal sawn timber. It's a specialist plane for rough work such as hewn timber or for cleaning up reclaimed timber, not for normal bench work. You are probably overdoing it.
I presume you are cutting to length first, according to your cutting list, and not just planing up stock. Seems to be a common mistake.
The shorter it is, the easier to plane flat. Never plane anything until it has been reduced close to finished size for the untended use. And when you do, just plane it flat enough.
It's handy to mark the surface - rub a pencil on the edge of your steel ruler and then rub the ruler across the width - it'll show up the high points. Then you just plane them off.
Check for twist with two winding sticks - just lengths of straight lath of equal width, no need to buy anything.
Check for straightness by squinting down the length. If it looks straight it's straight enough for most purposes.
It's usual to start on the best face first and when flat mark it with an F. Then square an edge and mark that. Then gauge mark the width and thickness and plane to the lines.
Thanks, good tips there. I planed in this instance to get a face kind of flat as I then cut the board in half then glued it together. But should I cut first then plane, the glue? I actually have that wearing book, must look at it again. Nice tip for ruler and pencil, cheers
 
Ignore Charlesworth

David Charlesworths videos are totally comprehensive.
The problem is that he is so thorough precise and somewhat pedantic that a process that only takes a relatively short time seems complex because of how long he takes to explain every every minute detail
As a beginner I would agree with taking a more basic approach .
 
Appreciate all the responses. Sitting down with a coffee and having a read over the planing section of wearings book again.

When I looked at the board again with the ruler sitting on its edge at 90degree it was vastly improved, so I was quite happy with it.

I'm sure like most things, with practice and patience it will get better :)

Not going to lie, looking forward to installing a metal planing stop and this
vice which will help with the planing also.

many thanks!
 
Ignore Charlesworth and Cosman whatever you do! That Way Madness Lies! They are showmen and make everything difficult and mysterious, on purpose!
Bob Wearing is good as @thetyreman says. I expect Sellers would be OK but can't say I've seen a vid of his on basic planing
yeah robert wearing is good, I go back to that book quite regularly, I think mr sellers stole a few tricks from it as well and claimed it as his own, mainly the knifewall, nothing against sellers though but it's obviously a very old technique.
 
Appreciate all the responses. Sitting down with a coffee and having a read over the planing section of wearings book again.

When I looked at the board again with the ruler sitting on its edge at 90degree it was vastly improved, so I was quite happy with it.
I've seen people tilting their straight edges before. It'll give inaccurate readings, the they're designed to be used at 90 degrees as Jacob pointed out.
Not going to lie, looking forward to installing a metal planing stop and this
vice which will help with the planing also.
Take a piece of 1/2" thick plywood and screw it to your bench. Quick and easy.
 
yeah robert wearing is good, I go back to that book quite regularly, I think mr sellers stole a few tricks from it as well and claimed it as his own, mainly the knifewall, nothing against sellers though but it's obviously a very old technique.
It's a very ancient technique. What is new is calling one side the "knife wall", which I suppose is a useful idea!
 
Thanks, good tips there. I planed in this instance to get a face kind of flat as I then cut the board in half then glued it together. But should I cut first then plane, the glue? I actually have that wearing book, must look at it again. Nice tip for ruler and pencil, cheers
Cut first, then plane, then edge join. This is not easy for a beginner as ideally you have to have a very good flat and square face and edge, and gluing/clamping technique, or it wont't be flat after the glue up and you have to plane a bit more.
Practice practice!
 

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