Flattening plane soles

[Marcus Ward]

I've been bitten by the neanderthal bug. I've accidentally (yeah right) acquired a few (9) planes and was wondering about flattening the soles. I purchased a VERY clean 3-date stanley #4C off ebay and while it is gorgeous, the area of the sole in front of the mouth is not in plane with the sole behind the mouth. It looks like it's 2 or 3 thousandths higher (off the workpeice) when the aft area of the plane is resting on it. It seems to cut fine, but being a newly minted neanderthal, I don't know fine from shoe-shine so I can't say if it's really okay this way or not. Do you guys think that flattening the sole (and removing .003 of material from the aft sole) is a good idea? There seems to be adequate thickness at the mouth to support some stock removal without making it too thin but again, I'm no expert.
Thanks.

Marcus

[David Weaver]

You can flatten that out without issue if you have a good reference surface. Flattening a nice small smoother is definitely a good starting point as your first one to do. Don't start with a #8!

[Pam Niedermayer]

Marcus, if it ain't broke....

Pam

[James Davis]

If you start with a #8 the rest seem like a piece of cake.


James Davis

[Marcus Ward]

Marcus, if it ain't broke....

Pam

That's a sentiment I normally embrace, as it makes things easier (less work), however, I'm afraid I may be too ignorant to know if it's working properly! Of course, the corollary is true, I may be too ignorant to know not to mess with it. I have 3 #4s so I may try to lap it and see if it actually performs better. I can get some pretty whispy shavings with it now but all I've got to test it on is white oak. I will measure it tonight and see how much it is actually off, to see if it'd be worthwhile to lap it or if it'll take off too much material and ruin it. I appreciate all the input!

[David Weaver]

I have one that was probably off by a similar amount to the smoother above and I have run it on a 42" piece of plate glass for about 2 hours now, and all I can do is keep wearing out wet and dry paper impregnated with silicon carbide grit. Soon I'm going to have a workout party where everyone comes over and pushes the plane back and forth on the glass! Trouble is, the only remaining spot is at the front of the mouth. It could be used as-is, but I like those jointed edges that you can't get a sheet of paper through when you back two boards together, and I'm trying to get this thing to the level of a poor-man's LN #8, though I don't think results of the "by hand" method of flattening the sole are ever going to be as good as an LN bottom - it's not practical with larger planes, unless there's something I don't know. At any rate, the mouth has to be at least in plane all the way around before it's done.

I have changed the paper 3 times now, and I'm soon going to get formica to top off the glass instead of going through the paper. I hold the paper on with 3M spray adheisive, which works very well.

I think it took about 20 minutes to do an out-of-flat #4 that I got somewhere. If I would've started with the #8, I probably wouldn't have ever done another one out of fear.

Yuck!

[Marcus Ward]

Supposedly (according to 'they') the Alumina Zirconia paper works a lot better for flattening soles. Norton 'Select', 3m File Sheet Dry, Gator Grit Power Plus are all brands that use this abrasive. I got some 80 and 120 grit 20" belts to cut open and lay on my table saw table to try tonight on this #4, I'll let you know how it goes. I know how fast regular sandpaper cuts - not fast at all!

[David Weaver]

I'm willing to give it a try. My instructional video recommends silicon carbide loose grit, but I can tell you that I've gone through a lot of it and it's still not flat on the bottom.

The silicon carbide paper wears smooth faster, and from what I understand about the alumina zirconia paper, it breaks off in sharp shards - so it may be a lot better. Is the paper you mentioned wet and dry paper?

[David DeCristoforo]

Silicon carbide powder/water slurry on a flat, hard steel plate. You can get the stuff here:

http://www.japanwoodworker.com/dept.asp?dept_id=13100

The steel plate (Kanaban) is intended for flattening plane irons but I do the soles of my metal planes on it too. It's really hard steel!

[James Davis]

It seems t work better than any thing else. I but the rolls for the wide belt sanders that they ssell and cut it apart

[Marcus Ward]

Is the paper you mentioned wet and dry paper?

I assume it's dry paper since it's a belt sander belt, although a little wd40 probably wouldn't hurt. I'll try it dry first. From what I've read, most people use it dry and vacuum it frequently to remove debris.

[James Mittlefehldt]

That's a sentiment I normally embrace, as it makes things easier (less work), however, I'm afraid I may be too ignorant to know if it's working properly! Of course, the corollary is true, I may be too ignorant to know not to mess with it. I have 3 #4s so I may try to lap it and see if it actually performs better. I can get some pretty whispy shavings with it now but all I've got to test it on is white oak. I will measure it tonight and see how much it is actually off, to see if it'd be worthwhile to lap it or if it'll take off too much material and ruin it. I appreciate all the input!


What Pam said.

If you are now getting wispy shavings off white oak then concentrate on keeping the blade sharp, the sole is probably flat enough.

Otherwise you are merely flagellating the deceased equine

[Fred Washam]

Marcus, It has been my experience that the key areas to worry about are the toe,the heel and the area directly in front of the planes mouth. If you have those three sections of the sole flat and in the same plane,(sorry couldn't resist), your plane will work fine. Trying to flatten the rest of the sole behind the mouth might help a bit, but I doubt it. If it is only 3 thou off, (low), then I wouldn't bother going any further. In fact I am of the opinion that a little relief in that area might be beneficial. Less drag and so on.

[Marcus Ward]

Fred - well, that's the thing. In front of the mouth is not in the same plane as behind the mouth. It's like the entire sole in front of the mouth all the way to the toe is a bit higher than the rest of the plane so the whole back of the plane needs to be ground down a bit. I think it's only .003, but I was eyeballing it. I'll do some more measuring when I get home.

[David Weaver]

Marcus, that's identical to how my #8 is. Makes you wonder if someone was using it to joint abrasive boards. Wouldn't know how that would happen on a smoother, though - unless people were jointing really short boards.

Do you have any feeler gauges? A straight edge and a set of feeler gauges would probably give you a good idea of what you're dealing with. A lot of times those hollows look deeper than they are because they take on more patina or something.

[Marcus Ward]

Okay, I tried that Alumina-Zirconium sandpaper. I'm sold!! That's all I'll ever buy from now on. It stayed sharp (and is still sharp) after 2 planes, a 4 and a 9 1/2. It took about 300 strokes to bring the plane down to flatness. It wasn't really far out, about .003 at the toe but enough to make me want to try lapping it. It seems to be cutting more smoothly now. I'll have to give the blade a once-over to make sure.

[Barry Vabeach]

Marcus, one way to test the sole is to withdraw the blade slightly, then lay a straightedge against the sole and hole it up to a light. You may have the rock the sole - straight edge assembly, but eventually you should see exactly where the straight edge is touching ( you will want to check from side to side to see if it is the same across the width) A smoother will work fine if the highest point on the plane is immediately in front of the mouth - even if the toe and heel are below that point ( this is all from the perspective of the plane upside down ) It will function as if it were a shorter plane. The opposite condition is if the straight edge (S E) is touching the heel and the toe, but the front of the mouth is below the S E - and it won't work properly. If that is the condition, or more likely the S E rests on the toe and a point right behind the mouth - and the area ahead of the mouth is below the S E, it won't work well. You need to remove some metal immediately behind the mouth till the area in front of the mouth just kisses the S E. I have never been able to do that with the sandpaper on a flat surface - instead I have had more luck using local abrasives - either sandpaper, files, or scraping the area in question. As others have pointed out, the plane will work just fine if the SE touches just the heel, toe, and right in front of the mouth and IMHO, it doesn't matter whether the other areas are all in that plane of a few thous lower - so I shoot for a few thous lower. In use, you will notice that with a plane with a flat or convex sole, you will be able to shave the full length of a board and get a fine shaving. If the plane has a concave sole, either the shavings will stop and start, or you will have to extend the iron out to get a full length shaving. Good luck.

[Jim Nardi]

Keep your eye's out for one of those tacky glass table tops. Reuse centers or Recycle centers or the dump.

[David Weaver]

Or call a glass shop and ask if they have plate glass for cabinet shelves. I got a 10mil piece of plate glass that's about 8x42 for $20 with a finished rounded edge.

When I had a glass shop make me a piece of purpose made 1/2 inch glass before that, 12x18 - it cost $95. I won't do that again.

[Stephen Pereira]

Hello,

There is a discussion on the practical machinist forum about flattening woodworking plane soles. The concensus is using glass as a flat surface is worthless. Forrest Addy, moderator, woodworker and machinist tells a story where he tested the "flatness" of glass with a DI and granite surface plate.

I haven't performed Mr Addy's test with my surface plate.. I'll take his word on it. You can buy a small granite surface plate from Enco or Grizzly for cheap.. much flatter and unyielding than glass. Smear some Prussian blue on surface plate and spot your plane.. it will show you where the high and low spots are.

Warning.. the subject of hand scraping and generating flat surfaces by hand can be addicting and expensive..

I'd post the link but not sure if that is allowed.

Steve

[Marcus Ward]

Because glass has a refractive index different than that of air you can tell when it's not 'flat' because objects viewed through it will look distorted. I use glass to adhere sandpaper to to level the frets on guitars and if it weren't flat, it'd be obvious as it would result in fret buzz at the low action levels I use. I'm not saying Mr. Addy is wrong, there is just a point where you reach diminishing returns. Once the object you're sticking sandpaper on is smoother than the variation in thickness of the sandpaper the point is moot. As long as it's in plane over its length it should yield acceptable results.

I used my table saw table to level the plane sole. It's flat, and smoother than the grits of sandpaper I was using.

Holding a straightedge up to the sole and then in front of a light was how I was checking it. It's important that you grab a straightedge that is actually straight!! :) The sole is acceptably flat now, and the front and back of the mouth are in the same plane. My problem now isn't getting a full length shaving, it's getting a full width one. I think I've got to revisit sharpening this iron. I just did a cursory job on it when it was first acquired.

[David Weaver]

Hello,

There is a discussion on the practical machinist forum about flattening woodworking plane soles. The concensus is using glass as a flat surface is worthless. Forrest Addy, moderator, woodworker and machinist tells a story where he tested the "flatness" of glass with a DI and granite surface plate.

I haven't performed Mr Addy's test with my surface plate.. I'll take his word on it. You can buy a small granite surface plate from Enco or Grizzly for cheap.. much flatter and unyielding than glass. Smear some Prussian blue on surface plate and spot your plane.. it will show you where the high and low spots are.

Warning.. the subject of hand scraping and generating flat surfaces by hand can be addicting and expensive..

I'd post the link but not sure if that is allowed.

Steve

Granite reference surfaces are probably flatter, even those that are coming from china. I have one that's flat within 2 ten thousandths of an inch, it was a little over $20 bucks.

That said, there is a level of practical flatness, and one of the things you need to have with glass is a flat workbench to put it on. I can't put a 0.001" feeler under a starrett straight edge when I put it on the glass I have. If you're working with a surface that has no hollows of even as large as 0.001", you're well beyond what you need to flatten a plane practically. Technique is going to yield a bigger error than that around the nose or sides of the plane.

You can't use thin glass, and you can't use the glass without support, but if you have a flat bench and feelers to check, there's nothing wrong with using glass. It's a whole lot flatter than my jointer and table saw tables, and it doesn't get hollowed like a granite plate would. I doubt there's much float glass that has an error in flatness of 0.001" - I would question the use of the indicator in this case.

All in all, granite may be better for flatness, but from a practical standpoint, you can't get a reference surface to flatten a #8 (figure 24" plus enough room to move around - 42 inches is a nice length) for anywhere close to $20. Even if you could, how could you move it in a limited space workshop?

The one thing that I have found that you have to be sure of with glass is that the surface under the glass is clean. You have to brush off the table top and feel it to make sure there's no grit on it before you lay the glass down. Even some silicon carbide grit under one end - a few granules - will affect flatness.

[Alex Carrera]

With over 15 planes now, I have to say that I think the obsession with flattening is BS. One of my favorite planes is a #4 that had to be coated over the entire sole with JB weld to fill in the pitting - even near the mouth. I got it as a parts plane and thought I'd expiriment. It works fantastically well. I just use a belt sander (the rubbery cleaning sticks do wonders on keeping the belt cutting) to get them flat. I do focus on filing the mouth perfectly straight, as that seems to have the most impact.

[David Weaver]

I agree. I do it because fettling is what I like to do. If I didn't, I would try the plane first and fix problems that presented themselves when actually using the plane. Most of the planes, even the ones that look a little screwed up on the bottom - probably wouldn't need much or any fettling with the bottom. It's more of an issue that if I get an old plane and strip the japanning off of it, paint it with industrial paint, clean the rust off of everything and shine up the brass - I'm going to shine up the bottom and flatten it. It's the "pretty tool" obsession, I guess.

My WW buddy, who is also a mechanical engineer and sometimes machinist - always teases me about that. "Are you a tool builder or are you a woodworker?".

[Mike K Wenzloff]

A few thoughts before heading into the shop...

BugBear's (Paul Womack) website has a great tutorial for flattening via files/scraping.

http://www.geocities.com/plybench/flatten.html

Personally except in extreme cases, getting a plane to such tolerances if it is already capable of doing the work required is pointless--but then again my standards aren't others'.

For the few metal planes I have flattened, I'll use a coarse belt on a 6" x 48" belt sander for initial removal. Then onto 6" x 48" belts that are cut open and afixed to a table saw or jointer.

I suspect the reason the plane works now is that the sole, from the description, is slightly convex--much preferable to concave. Any plane with a slightly convexed sole shape will typically work fine. The longer the plane, there is also a degree of flex in use.

Take care, Mike

[Marcus Ward]

Obviously there is a fine line between making the tools work well and just spending time getting them to fantastical levels of accuracy. I just wanted the sole of that one flatter than it was, I'm not obsessed with it. At some point the hobby becomes about the tools rather than what you do with them. That's not really where I want to go. I love gear, I'm a gearhead through and through, and I appreciate that quality in others, but in the end I'm trying to create something with my tools instead of just messing with tools so I try to split the difference and just go for it. I appreciate all the opinions and input on this subject, it's really helped quite a bit.

[Marcus Ward]

As an aside, here are my most recent acquisitions. I ended up with more than I need because people kept selling them to me at ridiculous prices and I can't say no when someone is trying to sell me 2 #5s for less than a replacement tote costs me. :)

http://www.f-64.org/planes.jpg

[Hank Knight]

That's a nice looking stable. Enjoy 'em.

[Bill Brehme]

I agree that flatness is only relative to how flat your sandpaper is. On that note, I also have the problem of the bottom of my #4 Stanley store bought plane becoming convex as I approach flat. And it seems that the closer to flat I get, the less metal is being removed between sandpaper changes. I have only been guaging metal removal by drawing lines w/ a sharpie. Before frustration set in I had the entire sole in plane w/ itself except a few small milling marks in front of the mouth. I've spent about 4 hours only trying to remove these miniscule scratches. If they werent directly in front of the mouth I wouldnt even be worried. This leads me to believe that the large surface area created by having the (almost) entire sole flat is forcing me to remove metal from the entire sole just to get to the bottom of the score of the scratches. This was whooping my a$$!

[David Weaver]

I agree with the last part. In the planes that I have that have a few pits or a deep scratch that won't affect functionality, I don't do anything past flatness. You have to remove a lot of metal just to get those scratches, and I wouldn't touch them if they run in the same direction as you're planing, and they're wider than any other scratch.

It sounds like your technique is probably rounding the outside edges of the plane. I can't say I have too much advice other than to hold the center of the plane when you lap it. It's not comfortable, but it will minimize it some. That happens to me more with larger planes, and some that I've bought off of ebay have been hand lapped and when I put them on the straight edge, they have that going in a severe way because someone really went after them and was pushing them all over the place without checking what they were doing.

[Bill Brehme]

Well thanks for the advise. And thanks for this thread... I was really getting disgusted w/ the whole flattening process, thinking I was the only one getting this convexity problem. I am really intrigued w/ this concept of filing/scraping a .001 hollow between the toe/front of mouth and rear of mouth/heel. I would have to believe that it would be alot easier to then lap the toe, front/rear mouth, heal and sides to be "in plane" with each other.

Question : The scraper being discussed... the Sandvik carbide scraper... Is this the paint scraper I'm seeing online? If so, would this really remove cast iron from the bottom of a plane sole?:confused:

[Phil Clark]

James you have described exactly what Garrett Hack says in his hand plane book. Here's a question - I didn't have plate glass but I did have laminated flooring left over. I glued my abrasive to it and set it on my table saw and went to work. Seemed to work well as a glass substitute. What do you think?

[Wilbur Pan]

I also have the problem of the bottom of my #4 Stanley store bought plane becoming convex as I approach flat.

I should probably wait until I get home to post this to check my book, but I recall David Charlesworth saying that a slightly convex sole is not necessarily a bad thing. The worst case scenario is that your planed surface will be slightly hollow, which can be fixed with the same plane, and judicious planing. Having a concave plane sole is much worse, as it will leave a surface with a slight hump in the middle, and that cannot be fixed with a plane with a concave sole.

He also advocates concentrating on making the front of the sole in line with the area just in front of the mouth, and absolutely making sure that the area in back of the mouth does not ride lower than the front of the mouth.

[David Weaver]

The proof of whether or not it works is pretty easy to check. Get any good quality straight edge and hold your plane up to a light (or sunlight) and see how flat it is when it's done.

If it works and you have a bottom that doesn't let light through when you use a straight edge, nobody's opinion matters.

[Bill Brehme]

Thanks again Wilbur, I will try out that approach before further lapping... In the middle of some awful finishing techniques right now. :o

[Josh LaFrance]

How big of a flat plate do you need to do a big plane like a #7 (22")? Does it really need to be longer than the plane? From Enco I can get a 12x18 granite plate for $25 but the next size up goes to $45 plus freight.

[David Weaver]

Bigger than that if you want to do a good job. Ideally you want to have a plate that is as long as the plane plus enough for the stroke.

A #7 is not going to be easy to fettle if it's far from flat.

I have a #8 that has a big hollow near the mouth, and my solution - rather than a nearly immovable granite plate - was to get a plate glass shelf from the local glass shop - $20 total. That's the best way to get it - just check and make sure it's float glass - most things are now. If you ask for a custom piece of glass, it'll cost you a whole lot more.

Do you have a relatively flat bench to fettle the thing on? If you use glass, you'll need to have that, but life will be easier.

At any rate, I've been through two alumina zircona 6x48 60 grit belts, 6 of the same in aluminum oxide (from a klingspor bargain box), and 9 sheets of silicon carbied paper in 60 grit (I adhere 3 in a row on the plate glass), and I'm still only about two thirds done. I've added silicon carbide grit on the sandpaper once it stops cutting, until it wears through the paper.

Just to check, I fettled a #5 to make sure that my paper wasn't an issue, and one with a large hollow flattened in about 10 minutes.

What I'm saying is, if the plane is more than a couple thou out of flat near the ends or near the mouth, I would resell it and find one that's flatter - it may not be worth the expense to flatten it. I wouldn't buy the #8 I got again, and it was passed off on me as a beginning by someone who rehabbed planes because "he just had too many to rehab". I think he gave it to me because he looked at it after getting it on ebay and realized that only a dummy would try to flatten it. I'm the dummy.

[Randal Stevenson]

Bigger than that if you want to do a good job. Ideally you want to have a plate that is as long as the plane plus enough for the stroke.

A #7 is not going to be easy to fettle if it's far from flat.

I have a #8 that has a big hollow near the mouth, and my solution - rather than a nearly immovable granite plate - was to get a plate glass shelf from the local glass shop - $20 total. That's the best way to get it - just check and make sure it's float glass - most things are now. If you ask for a custom piece of glass, it'll cost you a whole lot more.



What EXACTLY is float glass? What is the difference between it and other types/forms of glass?

I have a piece of glass that is 24x30" and 5/8" thick, that I picked up from the estate of a retired glass man (friend of mine). It certainly seems to be the flattest thing I have (never used feelers on it), but I think it is hardened glass (as compared to safety with its coating, etc).

[David Weaver]

Float has to do with its manufacture. The glass is floated out onto a hot molten liquid - not sure, but maybe tin? Because the molten tin and the glass don't mix, you get a very flat surface - as flat as the surface of the float liquid, I guess. I think it's rolled and stress relieved as it's cooling, too - though I don't know how that doesn't affect flatness while it's happening.

If you can check that yours is flat and confirm it is, it sounds like a really nice piece.

[Graham Wilson]

Can anyone advise what type/grade of sand-paper I should be using to flatten the sole of a plane... after reading this entire thread, I cannot find a number. What coarse grid should I start with and what grit should I end with? Should I use wet/dry paper or just regular dry paper?

Thanks!

[Jim Koepke]

Can anyone advise what type/grade of sand-paper I should be using to flatten the sole of a plane... after reading this entire thread, I cannot find a number. What coarse grid should I start with and what grit should I end with? Should I use wet/dry paper or just regular dry paper?

Thanks!

Most of this all depends on personal preference and how much needs to be done to the plane's sole.

If you go the dry route, my preference, have a brush or vacuum handy to keep the sand paper cleaned.

If the plane sole has a lot of pits and is definitely not a good flat surface, I will start with some 80 grit in my belt sander. I have heard many recommendations against using an orbital sander.

One has to be careful as the machine will take it off fast.

If it only has light pitting or staining then I would use something like a 100- 200 grit.

What ever needs to be done, 400 grit is about the finest that should be used. A mirror polish may look nice, but it will have more friction and and will not look good for long.

Again, just because so many speak of lapping the sole, it does not mean it is mandatory. I have only a few planes that actually had problems due to the sole needing attention.

One of my recent plane acquisitions seems to have the center of the sole lower than the sides. This causes a thin cut at the center of the blade and thicker cuts at the sides. It will get some attention as time allows.

jim

[Graham Wilson]

Thanks Jim. I have a couple of flea market specials that have some slight surface rust and one with a slight ding. I think I'll start with dry 120-220 see how it goes. I don't actually own any power sanders :o

[Danny Thompson]

With no beltsander, or even if your beltsander's flat section is shorter than the sole of your plane (as mine is), try this. I tried a wide variety and found dry automotive sandpaper (Purple, 120 grit from Autozone or other auto supply store), taped to a flat surface did the best job of getting to flat.

[Jim Koepke]

Thanks Jim. I have a couple of flea market specials that have some slight surface rust and one with a slight ding. I think I'll start with dry 120-220 see how it goes. I don't actually own any power sanders :o

Slight surfaced rust I might just knock off with 400 paper and a sanding block. Maybe even steel wool and oil, save the patina.

If the ding wasn't marking wood, I would leave it alone. It takes a lot of work to just remove a little pitting. If top side has a ding, a file works well.

jim

[Joel Goodman]

There is some thing that I'm not getting - what is everyone using as a straight edge? All the discussions that I've read indicate that a few thousandths out in the wrong place can be an issue but the LV steel straight edge -- their best one is rated as accurate to one thousandth over each foot or 2 thousandths over a #7. How can I measure errors of one thousandth if my tool is not more accurate? Can anyone weigh in on this? What are folks using to check flatness?

PS The Starrett is rated 4 ten thousandths per foot. Is that what's needed?

[Jim Koepke]

There is some thing that I'm not getting - what is everyone using as a straight edge? All the discussions that I've read indicate that a few thousandths out in the wrong place can be an issue but the LV steel straight edge -- their best one is rated as accurate to one thousandth over each foot or 2 thousandths over a #7. How can I measure errors of one thousandth if my tool is not more accurate? Can anyone weigh in on this? What are folks using to check flatness?

PS The Starrett is rated 4 ten thousandths per foot. Is that what's needed?

I am not sure I would get upset about .001" on the sole of a smoother, let alone a joiner. One is likely to do OK with a flaw of that miniscuality. (sure, it is not a word, but it sounds neat anyway.)

In the use of a straight edge though, it should be turned end for end and moved along the surface being checked.

Never make a decision based on a single piece of data. Measure twice, or even three times, before cutting once, they say.

jim