[nbo10]

Hi All,
I have a question on the flatness of #7 planes. I have two #7's and both have a very concave sole. It will take a lot of sanding to make either of the flat. I googled this question and come up with different answers. Some say it doesn't matter, some say it does. The overall answer seems to be, do what works for you? :blink: So what works for you? Does your jointer have a dead flat sole? Does your jointer work with a curved sole? Let me hear you opinions.

 

[BWSmith]

I guess it would depend on what one consider'd "very".And not being cheeky.

Here,we have a beautiful 1947 Norton surface grinder.It has a Pope spindle.The factory ran your plane across a similar grinder.We also do an occasional "scraping" job where parts are mated.Nether of these procedures are used on our planes however.And it's mainly out of laziness and lack of time/desire.

Our few handplanes(cpl dz)get used in a working environment just like they've been for the last hundred or so years in our family.I simply don't want to spend the time re-working them....it takes too long for the minimal effect it would have on the actual workpiece.BUT,ours are pretty dang straight.....hence the comment above on,"very".

Not going to preach on the subject.I truly believe that handplaning is one of those subjects which is so personal,that you're going to have to figure it out for yourself.One thing you can try is a comparo.Go find a true'd up,dead flat jointer...and then use it side X side with yours.Try to do it as "blind" as possible.There are so many "little" things that one can change on a plane that effects it's behavior......most of which are going to be more noticable than a few "tenths"(.0001) twist/straightness issues.

And don't get me started on that age old wood vs metal arguement.There are a lot of instances where we can grind wood WAY more accurately than metal....which in cast form,can move around just having it pass or walking by the grinder,haha.

Have a look at a nice Granite surface plate.Keep an eye out for used,in your area(shipping is a deal breaker).And an imported one is also an OK option.

 

[Gilgaron]

Do your edge joints line up if you gang plane two boards at once? That's your test to see if it is a problem.

 

[railaw]

Do your edge joints line up if you gang plane two boards at once? That's your test to see if it is a problem.

Do you mean because the edge of the board will end up convex? I have been wondering the same for my no 8.

 

[Turner1944]

Flattening a plane sole

I think flattening a plane sole will allow taking a much thinner shaving from the board. If perfectly flat, a smoothing plane can take say 0.0010" thick shaving. With a jointer or fore plane you are looking to remove thicker shaving in order to get to a straight surface(s). If the #7 sole is out of flat by say 0.0015", then it can still remove a shaving near 0.0030" which in my opinion is just fine.

David Turner
Plymouth, MI.

 

[Gilgaron]

Do you mean because the edge of the board will end up convex? I have been wondering the same for my no 8.

As long as the blade is straight it shouldn't be able to cut a curved profile... by trying planing them ganged up side by side you can see if the potential skew is a problem or if they match up anyhow. That's my thinking anyway. I never bothered checking if my no 8 was perfectly flat, as it works just fine. I think nbo should try his planes out before worrying about flattening them.

 

[railaw]

As long as the blade is straight it shouldn't be able to cut a curved profile... by trying planing them ganged up side by side you can see if the potential skew is a problem or if they match up anyhow. That's my thinking anyway. I never bothered checking if my no 8 was perfectly flat, as it works just fine. I think nbo should try his planes out before worrying about flattening them.

I meant if you plane an edge of the board then look at it from the side. In other words, the start and end of the planed edge being lower than the center. Some may call it a crown.

 

[Dave Paine]

I meant if you plane an edge of the board then look at it from the side. In other words, the start and end of the planed edge being lower than the center. Some may call it a crown.

In my hand plane restorations I do not recall any soles which were initially flat. In some cases worn in the middle more than the sides, so making a slight curved shaving. In other cases relatively flat side to side, but not flat front to back.

If the sole is slightly concave from e.g., wear over the decades, I would expect the plane may not produce a perfectly flat side-to-side edge on a board. How much of a convex shape is difficult to predict. The plane is not likely to be passed along the board's edge exactly the same position and alignment with each stroke.

I normally sand the soles on my restorations to have the area in front of the mouth flat, and ideally the entire area between toe and front of the mouth.

 

[railaw]

In my hand plane restorations I do not recall any soles which were initially flat. In some cases worn in the middle more than the sides, so making a slight curved shaving. In other cases relatively flat side to side, but not flat front to back. If the sole is slightly concave from e.g., wear over the decades, I would expect the plane may not produce a perfectly flat side-to-side edge on a board. How much of a convex shape is difficult to predict. The plane is not likely to be passed along the board's edge exactly the same position and alignment with each stroke. I normally sand the soles on my restorations to have the area in front of the mouth flat, and ideally the entire area between toe and front of the mouth.

My idea of concave was from toe to heel, not across the plane. Makes sense what yore saying in that respect. Im more worried about having too muck taken off at the start and finish of the stroke, when the toe or heel is off the board.

 

[Gilgaron]

Ah, I was thinking the plane was being described as 'cupped' from perhaps planing the edge of one too many boards.

Dave, I'm not disagreeing with you, I've only been hand planing for a little over a year now, but if the blade is straight how can it cut a curved shaving even if the base is curved? Unless the board was narrower than the plane base I'm not picturing how it will create a defective cut. Sort of how a pit not near the mouth won't really hurt anything...

 

[nbo10]

I'm talking about concave from toe to heal. I tried truing up an edge on a 20ish" board and it didn't work out too well. I ended up using a #4 to finish the edge.

 

[Dave Paine]

Ah, I was thinking the plane was being described as 'cupped' from perhaps planing the edge of one too many boards.

Dave, I'm not disagreeing with you, I've only been hand planing for a little over a year now, but if the blade is straight how can it cut a curved shaving even if the base is curved? Unless the board was narrower than the plane base I'm not picturing how it will create a defective cut. Sort of how a pit not near the mouth won't really hurt anything...

The blade edge is straight, but the depth of protrusion of the blade below the sole also affects the shaving.

I use a piece of clear straight grain scrap 2x4 on the edge for testing my planes after sharpening the blade. Should be easy to plane and provide consistent shaving.

I set the blade to give thin shavings for testing purposes. In one of my worst cases of sole wear I had not flattened the sole enough. As I sighted down the sole I could see more of the blade exposed in the middle and zero on the edges. Drat, I needed to go back and do more flattening.

The plane was in my hand, the board was in the vise. so I did some test cuts anyway. Not a surprise, the shaving was not the full 1 1/2in width. Slightly thicker in the middle and thinner on the outside tapering off to nothing so not consistent side to side or along the length of the shaving.

I stopped after a few shavings. The blade was cutting, but the sole needed to be flattened more. If I had continued I expect the edge of the test board would not have been flat side-to-side. The lack of cutting on the outer edges would eventually limit the plane from cutting in the middle of the board - unless I moved the plane so that the edge was cut by the part of the blade which protruded from the sole. Hence I could have moved the plane position to work around the issue in a real world situation if I was merely roughing down the edge of a board.

After flattening the sole so that it was at least flat around the front of the mouth, I was then able to get a consistent blade depth when sighting down the sole. The next set of test cuts gave me the desired full shaving side-to-side with consistent thickness.

 

[amckenzie4]

If the sole is concave toe to heel, I'd try to flatten it a little, but it needn't be perfect. How much are we talking about, here? If you set it on a flat surface (plate glass, or a marble slab, or something like that), how much of a gap is there at the center? I would suggest that at around 1/32", you should be able to work with it. More than that, but less than 1/16", you should probably work on flattening it. More than 1/16, and I probably would work on either getting a new plane or finding someone with a machine shop who can flatten it for you; that's a LOT of metal to remove.

As for how, I'd get a piece of glass longer than the sole, stick some sandpaper on it (I've started with 60 grit in the past with good results, though that was on a #5), put some oil on the paper, and start sanding. I've gone down to 800 grit on a couple of planes, and I quite like the finish it leaves.

 

[Gilgaron]

I appreciate the science experiment, Dave... there must be some more flex in the system as it works than I'd have thought.

 

[Billy De]

Interesting thread this,my own personal experience has shown me that the toe the area in front of the mouth and the heel should be co planing for best results.

But just think about something for a moment if I use a machine jointer I set the in-feed table say 1/8" low so as the stock passes over the blades they remove 1/8" and the stock then sits flush on the out feed table,so half way through the operation the two tables are at different hights but the stock registers on both.

Now if I use the hand jointer planer, the sole is one level all the way through and yet it works, it will joint the stock.Yea that's what its soposed to do,but how?