Lapping planes correctly

[Jared Walters]

Simply put... I suck at it. I bought a piece of fairly thin glass from home depot and have adhered sandpaper to it using spray adhesive. I put so much time and sweat into trying to lap my Stanley #4 this way and I can't believe how little progress I made. I used 60 grit for 30 minutes straight and I couldn't remove a pretty shallow scratch from the sole (where someone must have run over a nail). I couldn't even tell the difference honestly.

Is this normal? When people say "this takes a while" are they talking hours per plane? Is it possibly because I am using the wrong sandpaper (or too low quality?).

I could really use some advice. I have never been more close to trying to justify purchasing a LN plane, which I can't really afford right now :p

[Sean Hughto]

My advice: Other than to make it look pretty and smooth - don't lap the sole by hand. Despite the hype, it's not necessary. Learn to really sharpen the blade; that's time much better spent.

[David Weaver]

If it's not out of flat, I agree with Sean. Leave the scratch in the bottom (and learn to use the chipbreaker) . It'll make you feel better when you hit a staple.

You need a rigid surface to do a good job, which means thicker glass and a flat hard surface below it.

[Kim Malmberg]

I agree with Sean and David. One of my favorite planes is a old and well used MF no 9 with several deep scratches on the sole. They makes no difference whatsoever. The notion that the sole has to be entirely flat is not one I would follow. And lapping the sole on a thin piece of glass might just make things worse. Make sure your iron is very sharp, tune the chip breaker and set it close enough and forget about the rest.

[Jim Koepke]

Jared,

There are a lot of opinions about lapping a plane's sole.

In my opinion:

1. If the plane is working fine, do not lap it.
2. Lapping is difficult to do without a lot of care.
3. Lapping should be done either by someone with a surface grinder or absent that, use a long flat surface like a table saw or jointer surface. My surface is a 4' piece of granite.

Sandpaper tends to load up quickly. A magnet wrapped in paper helps to clean out the wasted iron. If the iron filings are allowed to gather, it can do more to mess up the bottom than what it was in the beginning.

Some sandpaper will dull quickly. It will still cut, only slower. I am not sure if I even have 60 grit in my shop. It seems like it would leave bigger scratches than most of my planes started with in the first place. Mostly my lapping is done with 80 grit. That is also where my lapping usually ends. Some folks like to go through the grades for a mirror finish. To each their own, ymmv.

If glass isn't on a solid flat surface it can flex.

If the scratch on the bottom of your plane isn't leaving its mark on the work, as hard as it may be, it should be ignored.

jtk

[Jared Walters]

Oh man it's rare I ask for advice somewhere and get told EXACTLY what I wanted to hear. Thanks everyone :)

[Kees Heiden]

To give a bit more background information: There are a few reasons why you might want a flat sole.

When you want to use a tight mouth to limit tearout, the sole just in front of the mouth needs to press down on the wood. The rest of the sole isn't important for this reason, but it is best to have the nose, the area in front of the mouth and the heel of the sole all in one plane. In between you can have concavities or scratches (but not convexities!). On many old planes you will find a hollow just in front of the mouth, because of wear.

When you can't take a fine shaving anymore, only thick ones of nothing, a concave sole is usually the culprit. Again, it is all about the area just in front of the mouth.

A jointer with a concave sole or even a twist makes it very hard to create a straight edge.

And scratches are only a problem when they have a burr and leave marks in the wood.

So what to do? First forget about the tight mouth. Then test the plane when it is a smoother to see if it takes a fine shaving. And if it is a jointer have a look with a reliable straightedge to see if you didn't aquire a banana. Then post another question to ask for advice on how to proceed :p

[Matthew N. Masail]

I use a piece of 1 1\2 inch thick MDF that I verified for flat with a straight edge. sometimes they might have a slight bow. I use PSA back sandpaper on it, starting at 80grit, then 180 is more than enough for planes. I have been using the same MDF board for 2 years or so, unless the plane is convex, lapping it flat and smooth is easy and takes very little time. on old planes, don't worry about cosmetics, just get it flat, I feel that it does make a difference and with a simple setup very easy to do.

[David Weaver]

Simply put... I suck at it. I bought a piece of fairly thin glass from home depot and have adhered sandpaper to it using spray adhesive. I put so much time and sweat into trying to lap my Stanley #4 this way and I can't believe how little progress I made. I used 60 grit for 30 minutes straight and I couldn't remove a pretty shallow scratch from the sole (where someone must have run over a nail). I couldn't even tell the difference honestly.

Is this normal? When people say "this takes a while" are they talking hours per plane? Is it possibly because I am using the wrong sandpaper (or too low quality?).

I could really use some advice. I have never been more close to trying to justify purchasing a LN plane, which I can't really afford right now :p

Time wise, by the way, I've never spent more than about 20 minutes on any 4 or 5, no matter how bad they were to start.

[Derek Cohen]

Hi Jared

I glue 100 grit (sometimes 80 grit) sander belts to a 1" thick section of flat granite, and this is used on a flat tablesaw top ...

http://i13.photobucket.com/albums/a262/Derek50/Restoration/lapping1_zpsb971aa60.jpg

http://i13.photobucket.com/albums/a262/Derek50/Restoration/lapping2_zpsa34dedaa.jpg

As Kees notes, it is the section in front of the mouth that is relevant. Make this, along with the toe and heel, with a blue sharpie, and work until these are removed.

I remove the handle and knob, but the frog stays with the blade tensioned (and retracted).

The aim is to push the sole down onto the surface (80%) and forward (20%). It must stay flat. Do not attempt to sand as if you are planing - that will cause the sole to rock on the sanding surface.

Before starting on this, check where the high spots are. There can be scraped away first - and this is particularly important to do if they lie around the mouth/centre of the plane. Failure to get this area flat before starting on the rest of the sole will create a curved sole.

Keep in mind that the more you do, the slower the progress - because you have moved past the high spots. Use coarse paper to start but not so coarse that it requires extra effort to remove the scratches. I do not go below 80 grit, generally stay with 100, then 180, and finally 240. Keep applying the blue to the sole to check that you are staying flat.

Regards from Perth

Derek

[Prashun Patel]

I think it's worth it to test your soles by beginning the lapping process. If it looks pretty good at the critical areas, then I have just left it; I don't have the patience for it.

The better I get at sharpening (and whenever I use a blade someone more skilled than I has prepared for me) I realize that proper sharpening is SO much more important than any of the other variables.

So, I'm in Sean's camp. Focus on your blades if your soles are good enough.

[John Coloccia]

FWIW, once you're flat, getting rid of that last scratch will take FOREVER. Think about how long it takes to get rid of that last little bit when you're flattening the back of a cutting edge, and now apply that to an entire plane! There's a lot of metal that needs to come off to get those last couple of scratches :)

[Daniel Rode]

As the other's have suggested, once it reasonably flat you're done lapping. That scratch will not affect the use of the plane. Removing will thin the metal unnecessarily. FWIW - I have planes with corrugated soles that work just fine, so a scratch is nothing.

[Jim Koepke]

This thread has me wondering if some of our problems with vintage planes might have been caused by someone who felt their plane needed a thorough lapping decades ago.

Just a thought...

jtk

[Jonas Baker]

This thread has me wondering if some of our problems with vintage planes might have been caused by someone who felt their plane needed a thorough lapping decades ago.

Just a thought...

jtk

I don't think the issues of vintage planes being concave or convex has to do with them being lapped in the past. Even the ones I have found that are nearly unused with the original machining marks from the factory are not flat.

Of the 20 or so I've found and measured for flatness, I've never found one old stanley plane that was actually flat, or within an acceptable level of flatness for fine work, and the same goes for the sides being square to the sole. Mind you, I'm a big proponent of the importance of having at least one flat plane, so take this with a grain of salt if you don't think flatness is important. Of course a plane for thick shavings doesn't need to be flat, but if you're trying to do fine jointing, or getting stock well squared up, a flat plane helps immensly, in my experience. With my old stanley planes that I haven't flattened, I have a much harder and more frustrating time jointing a long board edge flat so I can prepare it for gluing, for example. Then I take out my flat Lie Nielsen low angle jack plane out, and I can quickly make a piece of wood squared and flat. That's my experience, so I think it can be very nice to have at least one flat and properly machined hand plane.

Jonas

[Stanley Covington]

If you use a plane hard for enough years, especially on tropical hardwoods or dusty roughsawn lumber, the sole will wear and get out of wack. And of course, even the best planes, including Lie-Nielson products, can be out-of-wack when brand new. I know from experience. So it is worth knowing how to flatten a sole.

How flat does the sole need to be? It depends entirely on how precisely you need to work. If you are dimensioning boards to remove lots of material quickly, then flat doesn't matter much. If you need to take gossamer thin shavings to create a perfect surface, then it matters a lot.

Does the entire sole really need to be perfectly flat to function well? No. But you need precise, coplanar contact at three critical locations: immediately in front of the mouth (the most critical), at the toe, and the heel. Any metal that projects beyond the plane formed by these three areas must be cut down. On the other hand, any metal below the plane formed by these three critical areas is fine, and can remain depressed.

To check for flatness, you need a precise straightedge. To check for wind (twist) a flat plate, such a float glass, will work. Use machinists dye or a marking pen to mark high spots and areas. You also want to have at least one side perpendicular to the sole, so a precision square is needed to check. I prefer a diemaker's square for checking for square and for checking across the sole because the blades are easier to read precisely.

Begin by checking in front of the mouth, and marking the high spots. You need a rectangular area in front of the mouth at least .25" wide. File this area flat, checking frequently with your square or straightedge.

Layout a similar area at the toe and another at the heel. Mark and then file (crosswise and diagonal) the longer expanses between these critical areas if they are higher. If lower, leave them alone. The goal is to shape the sole so the three critical areas at mouth, toe and heel are less than .001" higher than the rest of the sole.

A superior method to files is a metal scraper. These can be made from wood chisels, or old files. Work the chisel's blade, or end of the file, so it is flat and square and forms a sharp 75 to 90 degree angle. Be careful not to soften the blade by getting it too hot on a grinder. Used in a pulling motion, this tool is very effective at scraping metal away cleaner and quicker and with more control than a file. This is an ancient method that works very well and is satisfying to do.

Rough shaping of the sole using sandpaper and glass can take a long time, and using the very rough sandpaper in an attempt to accelerate the process can make things worse, at least that was my experience using a 10X floor sander belt one time.

When the three critical areas are standing proud, use the glass or precision plate to check for twist. To do this, set the toe and mouth on the plate with the heel hanging off. Does it rock? If it does, locate the gap (or high spot) at the toe with a feeler gage or Mark-1 Eyeball and mark it (leave the mouth alone). Scrape or file the high area so the rocking stops. Repeat for the mouth and heel, with the toe hanging off. Note that the area behind the mouth opening should be low, leaving only the three critical areas in contact with the glass. Finally, check the full length of the sole on the glass. If it rocks, use feeler gages or Mark-1 Eyeball to locate high spots (preferably at the heel if you have a choice), mark and file or scrape.

Attach quality wet or dry paper (320 grit?) to your very flat and well-supported float glass plate or precision granite plate, lube the paper well with water or WD-40 or your preferred non-toxic cutting fluid, mark the entire sole with machinists's dye or a marking pen, and work the entire sole back and forth on the paper. Don't let it travel off the paper. Don't let slurry build up. Don't put much pressure on the plane because pressure will often tend to make contact uneven. After a couple of passes, check the sole. The high areas will be shiny and the low areas will remain colored. If areas other than the three critical areas are shiny, use your file or scraper to cut these high areas down a few passes at a time. Mark and repeat.

Gradually, the sandpaper will abrade the three critical areas at mouth, toe and heel so they are in the same plane, and you will have a very flat sole.

Now, you are thinking that, with perhaps only three areas in contact with the wood being planed (that is not the goal, but it works fine), the sole will wear quickly and get out of wack easily. This is true to some extent, but the reality is that as the three critical contact points wear with use, more of the sole comes into contact with the wood, slowing wear. And as you will see, it is much easier to keep three critical areas coplanar than an entire sole.

It is a mistake to assume that, just because your plane's sole is steel, and it it is used to work relatively softer wood, that it will stay flat forever. Unless it is just a tool cabinet queen, that is.

Two Cents (money back guarantee).

Stan

[Kees Heiden]

Well said Stanley. Just one comment. Test the plane first. If it can take gossamer shavings allready, then you're ready.

[Kees Heiden]

Well said Stanley. Just one comment. Test the plane first. If it can take gossamer shavings allready, then you're ready.

[Jim Koepke]

Thanks for a great write up on the sole of the matter.

One thing to add or clarify on your comment about the toe and the heel. My thought is for an area near the toe and heel needs to be coplanar. To many planes have their toe worn heavily. This might be due to being dragged along the workpiece on the back stroke with the rest of the plane off the work.

+1 on Kees comment to try the plane with a well sharpened blade first.

jtk

[Stanley Covington]

Thanks for a great write up on the sole of the matter.

One thing to add or clarify on your comment about the toe and the heel. My thought is for an area near the toe and heel needs to be coplanar. To many planes have their toe worn heavily. This might be due to being dragged along the workpiece on the back stroke with the rest of the plane off the work.

+1 on Kees comment to try the plane with a well sharpened blade first.

jtk

Jim:

Thanks for the comment. I know what you mean about the heel getting run down.

I don't quite follow the meaning of your suggestion. Do you mean there should be a another area between the mouth and heel that is coplanar? This would make a total of four, I guess. This would not hurt, but it is a lot more difficult to get four or more areas coplanar than three. Two is easy, three requires some patience and care. I once saw a guy who liked to scallop his sole with 8 or so coplanar areas using a die grinder. It looked like a snake that had eaten a bag-o-glass, but it probably worked.

The method I have described is borrowed from the Japanese plane of course. The ideal is for the final work on the wet or dry paper to remove all the low spots creating a perfectly smooth and flat sole. But if there are some low spots, well that is fine too, and makes it easier to flatten the sole next time.

I can only agree with your and Kee's comment about checking how the plane cuts first. I did not mention that essential step because the original question was how to lap a plane correctly, so I went straight to lapping. I assumed that a fellow is lapping his plane's sole because it is misbehaving and needs to be lapped.

I should add one thing while I am at it, however. The scraping and filing process, depending on how skillfull one is, can leave a scratched up mess. To clean this up, if so desired, a block of hardwood like oak, perhaps .375" thick and bit wider than the sole's width, with a rounded bullnose, and wrapped with more wet or dry paper, can be used to polish the depressed areas. If one is careful with the files and scrapers and does not cut these areas too deep or too aggressively, not much work should be required to clean them up.

Stan

[Jim Koepke]

Thanks for the comment. I know what you mean about the heel getting run down.

I don't quite follow the meaning of your suggestion. Do you mean there should be a another area between the mouth and heel that is coplanar?
Stan

No, just that the coplanar area does not have to be all the way to the toe or heel if those areas are worn from past use.

Many planes I have seen might require removing 0.020 to 0.030" just to get the rest of the sole to the same level. Usually this wear is over a small area so it is just moving the coplanar area maybe 3/8 to 1/2".

jtk

[Warren Mickley]

If you use a plane hard for enough years, especially on tropical hardwoods or dusty roughsawn lumber, the sole will wear and get out of wack. And of course, even the best planes, including Lie-Nielson products, can be out-of-wack when brand new. I know from experience. So it is worth knowing how to flatten a sole.

Stan

Stanley, are you saying that you know from experience that a plane's sole will wear and get out of whack from years of hard use? Or are you just saying you know from experience that a new LieNielsen plane can be out of whack?

[Edward Moore]

For anything larger than a jack plane I really think that stoning and scraping is a better method than lapping.

Lapping can work well on small planes. Konrad Sauer does this. However, it can also work badly. Really badly. And trying to flatten a large plane like a jointer - aside from being an enormous amount of work - would be an exercise in frustration.

Scraping isn't terribly expensive. You can buy a little granite surface plate or probably use a jointer table too if you are confident it's flat enough.The granite plate can be smaller than your plane, you just need to be careful to ensure your prints overlap and check with a straightedge occasionally. Some people use benchtop offcuts - although again, you'd need a straight edge to test.

You put blue marking paint on the granite, sit the assembled plane on it, then remove the blue spots. I have used my diamond plate to get off the worst of it and usually left it at that.

For more accuracy you can use a scraper (a $20 job from eBay or an old file). The constant sharpening is annoying but the work is otherwise pretty easy. Much, much easier than lapping.

Of course, this is only worth the trouble if there's something wrong with the function of the plane.

[ian maybury]

+1 that sandpaper isn't very realistic if there's a significant depth of metal to be removed over a decent area - it's very slow. Either that or i'm missing something. Against that it'll bring up a beautifully uniform finish in no time if the objective is primarily just to clean up the surface.

The reference surface matters a lot. I bought a largish (roughly 32in x 18in x4in) surface plate for another job (now that they have got cheap), and while it would be total overkill it's amazing how much difference working over a totally flat, stable and immovable reference surface makes.

+1 though that removing scratches is likely to be a long job.

Scraping is an option, but needs a good reference surface (blued) as above to work from, and there's considerable potential to get it wrong. Best to prove the technique on a test piece first. A genuinely flat diamond plate (maybe 400grit) can be a good way of stoning back/smoothing/making more slick/regularising the look of a scraped surface - since after scraping it's only got to remove material from the edges of each cut/scrape mark it works surprisingly fast. (compared that is to working over solid material)

I can imagine how a fashion could develop for scraped plane soles - the look is very pretty (for some), and more to the point it's for some reason (probably reduced total contact area) very low friction. An unanticipated side benefit of scraping the tables on my planer thicknesser (below) to properly flatten them was the difference it made to how easily the wood moves over the surface - compared at least to the relatively texturedmilled original.

Grinding is the other possibility. One that probably needs lots of care in that regard is to ensure that the method of work holding/clamping does't distort the casting - especially when clamping over the sides. Not only might they be pushed in, this would also bow the sole. Heating may be a factor too...

[Stanley Covington]

Stanley, are you saying that you know from experience that a plane's sole will wear and get out of whack from years of hard use? Or are you just saying you know from experience that a new LieNielsen plane can be out of whack?

Warren:

Both.

Stan

[bridger berdel]

as said, if the plane works, don't fix it.

however, if you do want to make the sole flatter than it is for whatever reason, scraping is the better method than lapping.

start here, and read:
http://www.practicalmachinist.com/vb/woodworking-woodworking-machinery/restoring-planes-flatten-sole-269653/

[Warren Mickley]

Iron planes do not have to be resurfaced on the sole during a lifetime of use. I have used the same five planes for stock preparation for over thirty years. Of these five, three are iron. They have not needed flattening since they were first brought into service. I have worn several plane irons down to nothing. I have worn six or seven thick sharpening stones down to nothing. These things wear out. Iron plane soles wear very very slowly. Just ask Jared, who started this thread.

[ian maybury]

Hope I didn't frighten the horses Edward - not my intention. Chances are if you have successfully completed a few scraping jobs that delivered a very flat surface then you are probably reasonably well on top of it.

I'm speaking in the very general (not specific to planes) sense about hand scraping to remove metal - my experience is self taught from the various web sites and videos about, and is just a few jobs in. My main job was a biggie undertaken in desperation to flatten the tables on my planer thicknesser (see below) - i ended up with muscles on my muscles. (hard work! - each table required about 12 cuts to get to where i chose to stop) It delivered a great result (within about 0.0005in all over each table when finished), but my scraping while OK/not unattractive isn't in the 'high art' category so far as the incredibly regular patterns the experts can create is concerned.

What I meant was just that the unwary that piles in with a carbide scraper seeking to remove material on a 'seat of the pants' basis could end up removing material from the wrong place/removing too much/doing damage. Best to read up the topic, get properly equipped, and then do a few test pieces so that it becomes possible to sort out a practical game plan.

The sort of issues I had in mind were:

1. Important to stick with the technique. i.e. use a surface plate and an appropriately light film of wiped on and mostly polished off blue to mark the high spots on the plane. (not expensive to get a granite one these days for something small like a plane - but in the case of e.g. a jointer be aware that the surface should be long enough that it does not hang over the edge of the plate as this can easily cause misleading results/lead to scraping hollows in the surface. As would a less than flat reference surface. i.e. the blue can end up rubbing on in hollows)
2. Be led by the transfer of the blue - religiously cut only the high areas indicated by the transfer of blue and it will come flat. (don't sweat/try to second guess it - let the flatness materialise)
3. Obtaining a nice visual texture requires cutting over the entire surface with a fairly regular crossed cuts (that's the basic anyway) technique, and then stoning off to finish. This means that the first cut is usually a light 'all over' pass to create an all over texture.
4. Cuts using the Sandvik scraper linked below (UK sourced - local for me) vary in my case between maybe half a thou (?) if cutting heavily, or a tenth or two when lightly. Deep cuts tend to have a different look, and to be more deeply hollowed. So probably best to seek to work it up over multiple light passes.
5. It's easy to deeply gouge or badly scratch the surface if the scraper tips over so that a corner digs in. Best to practice enough so that your stroke is fairly consistent first.
6. Easy to gouge an edge, opening (around the mouth?) or a corner too - important to have a game plan for how to work them. (coming in from the right direction etc)
7. Best for visuals (and flatness) to progressively lighten cuts as the surface comes flat. (bear in mind that the method is much more precise than what we are used too or likely need - it has no problem whatsoever delivering flatness down to tiny parts of a thou, so you have to decide when to stop)
8. The final two cuts are often 'flaked' using a power scraper. These are light, all over and done to create a uniform appearance - and to retain oil on a machine slide way. It requires considerable skill (a fancy scraper movement) to do by hand and the result is probably more comestic than functional for our purposes.
9. Even carbide scrapers blunt pretty quickly and make it hard work/lead to loss of control, so it's a case of either having some spare inserts (which gets expensive), or having a means to lap them. (see linked video - i built a similar power lapper using bits I had about which worked very well)

I guess a question at the end is whether to try to lap the scraped finish smooth on sandpaper, or to just lightly stone and leave it as is. Possibly the latter - it'd look unusual, but maybe attractive. The scraping is potentially capable of delivering a flatter surface too.

A note of caution. It's perhaps because it's a bit of an arcane technique, and needs setting up for - but i've not heard of planes being scraped. Which seems a little surprising. Hopefully there's no hidden pitfalls. On the face of it it should be a very effective way of shifting significant amounts of metal to deliver a very flat and low friction running surface - one that isn't too hard work because the part is small, and that sidesteps the potential distortion issues of e.g. less than highly expert surface grinding. it'd be interesting to see what came up in a search. There's lots of scraping discussions on the machinists forums too.

Some links i found useful. The video gives a good feel for the basic technique:

http://www.youtube.com/watch?v=nOJrhrne80shttp://www.machinerepair.com/Home.html
http://www.andersonscraper.com/Anderson-Hand-Scrapers.php
http://www.greenwood-tools.co.uk/shopscr63.html
http://www.handscraping.com
http://www.machinerepair.com/size.html
http://bbs.homeshopmachinist.net/threads/31550-Shapening-carbide-scraper

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[Stanley Covington]

Iron planes do not have to be resurfaced on the sole during a lifetime of use. I have used the same five planes for stock preparation for over thirty years. Of these five, three are iron. They have not needed flattening since they were first brought into service. I have worn several plane irons down to nothing. I have worn six or seven thick sharpening stones down to nothing. These things wear out. Iron plane soles wear very very slowly. Just ask Jared, who started this thread.

Warren:

Our experiences differ, clearly. Most woods used for cabinets in North America, in my experience, are not especially hard on steel plane soles. But if you will look back on my first post to this thread, you will notice that I mentioned tropical hardwoods and dusty rough lumber.

Perhaps you have not had the joy of planing wood containing large silica crystals and noxious, gummy resin. Try Keruing some time. These crystals eat carbide planer blades over time, and are much harder than the steel blade in a normal handplane. Of course, they are much harder than the sole, and wear it down with enough heavy use. A simple fact that you can verify in technical book on hardwoods, which always list the working characteristics of each wood.

Dirty roughsawn lumber has its own problems. Most dirt found in nature contains grit that is harder than steel. When planning such surfaces, the sole of the plane is being rubbed over this hard grit until it is all cut away down to clean material. If you doubt this will wear out a steel sole, notice the scratches that develop on your plane's sole after even a few passes. These scratches, of course, are the marks left from mineral particles tearing steel out of the sole.

I am glad you have been blessed with clean, well-behaved wood to work on, and that your plane's soles have not experienced uneven wear in thirty years of hard daily use. But for some of us, our planes occasionally need to be tuned. Not frequently, but occasionally.

Stan