Thread: Plane sole flattening, again...

The lapping materials were all sourced from eBay. The plates come around now and again, usually they're fairly expensive but the 18" one pictured cost a little over $200 with free shipping IIRC. If you're patient and persistent you can get them at a reasonable price.
I have two forms of diamond lapping compound - I started with suspensions in a gel base. About $15/grit. I then switched to the much cheaper dry diamond powders. When using the powders I sprinkle a bit on the plate and then spray on some light oil such as WD40 to make a slurry.

Here's a big one at a relatively low price. 20” Round Lapping Plate Machinist Tool X2 SIDES 20" DIA X 2" THICK USA | eBay

Originally Posted by rob streeper

Here's a big one at a relatively low price. 20” Round Lapping Plate Machinist Tool X2 SIDES 20" DIA X 2" THICK USA | eBay

An approximately only $388 Australia for shipping,
Stop teasing us Rob.

Cheers Matt.

Originally Posted by rob streeper

Here's a big one at a relatively low price. 20” Round Lapping Plate Machinist Tool X2 SIDES 20" DIA X 2" THICK USA | eBay

Hmmm. I added it to my watch list just out of curiosity. I have just been offered 20% off.

Not for me, but looking more attractive for anybody stateside.

Regards
Paul

Edit: Local pick up would be best I feel, but depends on where you live relative to Bristol, Connecticut.

Originally Posted by Bushmiller

Hmmm. I added it to my watch list just out of curiosity. I have just been offered 20% off.

Not for me, but looking more attractive for anybody stateside.

Regards
Paul

Edit: Local pick up would be best I feel, but depends on where you live relative to Bristol, Connecticut.

Maybe we could do a group buy,an hire one of those big ships that are just floating about at the moment,too bring them over ??.

Cheers Matt.

Originally Posted by Simplicity

Maybe we could do a group buy,an hire one of those big ships that are just floating about at the moment,too bring them over ??.

Cheers Matt.

Might have to get a bit more work done and invoiced for first

Originally Posted by Mountain Ash

Might have to get a bit more work done and invoiced for first

Ye maybe Just a little bit lol.

Concerning flattening and not polishing...
I would save my money and buy a decent straight edge instead of a lapping plate.
Then you can hopefully find something that will do the job.
I ended up scraping some lab countertop material as nothing I could find at hand was flat enough for the job.
I suspect you could buy some nice chunky float glass, not plate or hardened, where you guys are.

I get by flattening with some cheap abrasive rolls.
There is some awful advice out there regarding lapping and it took me some time to realise that I had been fooled.

What I learned THE HARD WAY, was the abrasive paper cannot be longer or wider than the item being worked.

If it is, then you will produce a convex profile, which becomes very apparent on anything longer than a no.4 plane, or a plane with a
movable shoe in front of the mouth, in which the moving component needs to be parallel to the sole.

No video existed on lapping a plane correctly, which I mentioned on another forum, and I was challenged to do so.
Hopefully you can see what I'm doing in the video...
I use some self adhesive paper smaller than the plane is, and place another similar sized sheet on top.

The paper cannot crinkle as it would if it were larger than the plane/item, the abrasive under the abrasive creates enough friction to stay put.
The edges or perimeter of the plane are not in contact with the abrasive, and the loose grit falls off of the edge of the paper, so not dulling what's left.
If you have a big belly then a shorter strip will be faster, followed by a slightly longer strip before the close to the length of the item strip.

Check afterwards with a full width, longer and wider than the plane is abrasive.
You should need only a few rubs, as any more than that will introduce convexity.
Or do a figure eight and work the edges that way.

The latter means that you can get away without needing a huge plate.


Here's two videos I made on the subject.
Terribly produced and not even fresh abrasives used, but hopefully you get the point.
How to flatten the sole of a hand plane correctly Part 1 - YouTube
How to flatten the sole of a hand plane correctly Part 2 - YouTube

From other forums, It seems some are in disbelief that one can end up with convex surfaces by lapping,
often questioning or speculating obvious things, like was your paper held down tight, or was the lapping plate flat, or you've must have been doing something wrong, like leaning on each end causing it to rock.
It is impossible to flatten a plane with abrasive paper on a lap like so, even if it were a Starret plate and a machine that could hold the plane.
The abrasion will always favour the edges, so you need the abrasive to be a smaller area than the item being flattened.

Not only across the length is important to have flat, but also the width if you have a double iron plane.
When the going gets tough, the cap iron needs to be closer than the most popular youtube gurus suggest.


If you have a plane that needs a lot of work and you try and flatten it with the full sheet of abrasive, then you will likely create the same effect as
what would happen if you honed a concave profile to the iron,
i.e each end of the iron would stick out but the middle of the iron would not be in contact with the wood.

All the best
Tom

in my experience, if enough material needs to be removed for convexity to be a problem, it's generally better filed/body floated off of the center of a plane and then lapped to finish. An alternative is a coarse machine paper on a hard wooden block around 2x3 inches. I have from time to time lapped a plane by going over the end of the lap, but lapping in general is not a good method for removing a lot of material (at least not if one is going to do it quickly). The speed that a 2x3 block removes cast iron using 60 or 80 grit machine paper is pretty shocking - it doesn't suffer from the bed of nails phenomenon (as in, even as the paper starts to dull, there are few enough points of contact that it continues to dig in deeply).

As far as some convexity goes - a couple of thousandths probably makes for a more useful plane than dead flatness, but dead flat is nice. Even a little bit of concavity is the sharts.

I have yet to try this David, perhaps that's why there is no videos on lapping correctly.
I was just putting it out there, as some folks might not wish to believe that convexity will happen lapping on a larger surface than
the item. (without prior selected removal)
This method still has merit as mentioned with a no.60 1/2 for example, and might not be as slow as some think.
I will probably try doing a third video using some fresh abrasive to finish that plane off, I just got it flat enough to do the job.

I've used some fancy paper before that I found in a skip, and that stuff is quick compared to the cheap sold by the meter stuff.
I reckon it would be more resourceful rather than wrapping it around a block, as it is pricey stuff.

Might try using a file if I ever stumble across another plane for peanuts.
I must have tried that before using the end a file in anger to scrape out a massive convexity I had created when I was "of that thinking"
My files might be a bit worn for that, but I have got a few more since then, including a flexible flat file to try out.

Another good excuse to pick up another plane.
All the best
Tom

Fresh files are a must. Some kind of mill file with aggressive teeth and a little bit of flexibility, and it will lose its initial snap by the time one is done (I have a lot of uses for mill files so one that's partially dull will find plenty of follow-on use, and there's a good source for simonds files here in the states for $8 each - figure the bulk removal is about $2 out of pocket plus maybe another $2 of psa paper to lap the "ring" that's created by filing the center of a plane hollow.

Flattening a well worn infill - Album on Imgur

I mention the targeted block because I once got a banana stanley 8. It was high about a hundredth toe and heel. I lapped it for 5 hours and went through about $10 of PSA paper going back and forth between being stingy and then realizing I was making no real progress. Out of frustration, I tried sanding with my fingers and realized under my thumb, the paper that I was using would still cut fast. When lapping such a large surface, it quickly was teetering between cutting and burnishing (progress is lost at that point), thus the idea to use a small wood block struck me and I was able to remove steel more or less at a filing rate with much less physical effort. Once everything is close, then marking fluid can be used to find the high spots on the plane and they can be worked very close to flat and then a "consolidation" lapping can be done to get rid of all of them.

I agree with your assessment that most people will banana a plane, but it may be possible on a segmented plate to go to great lengths and lap very flat as rob is doing here. Beyond a certain point, the only real gain is in how thin of a shaving you can get.

Once in a while, a plane will be a bear to lap just because the cast is super hard. later stanley planes are soft, millers falls are soft, early stanley planes are a little harder.....

....and for some reason, this marples plane that I got from your side of the water was intolerable to lap.

Flatten a twisted smoother - Album on Imgur

(I like the sectional and filing thing because it's quick and the involved effort is relatively low. You can get absurdly accurate by creating a very shallow ring around the outside of the plane sole and then lapping that off. Like more accurate than LN ships plans accurate, and within an hour or most planes).

My reference surface is checked by a starrett edge - it's just inexpensive glass, but the bench it sits on is flat and so is the glass. Cheap and practical

Looks like I removed a picture from the second album in error - between the two shavings was a picture of an iron and cap iron, and flipping through just now, I thought it was included in error - so I deleted it. Now, I realize that it was in the album on purpose, so the captions in the last two pictures don't make sense together.

There we was, happy to possess a 3-foot long, 5" wide by 3/8' thick glass plate to flatten the sole of my planes, when someone comes to say that my planes will go bananas if I lap them on a piece of sandpaper longer & wider than the size of their sole...I give up !!!

Despite the fact that Tom trees may be quite correct, who am I to argue, I will continue to use my glass plate: 1) because I have it & 2) because a few thou of convexity here and there will not make one iota of difference to the overall accuracy of what I try to make, as most of my woodwork still consists of lots of wood dust.

BTW, thank you for a most interesting thread!

Cheers Yvan

more or less the size of glass that I use. I gave up using loose paper years ago, though, and use the PSA (sticky) roll intended for certain drum sanders. It's a lot more durable than hand-used paper, anyway.

It's not so much the issue of making a plane a banana, but dealing with one that's already a banana. the only real option with a lap is to start fore or aft on long paper and work until the flat spot you make goes end to end when it would be a lot more desirable just to cut the middle out.

Paper shorter than the plane will be a severe impediment if the plane is already concave, though.

Hello again
David,
Maybe its my computer, but your links don't seem to be working for me.
I have seen one or two of the pictures that you posted before though, so I was waiting to see if anyone else has the same problem, not seeing them.

Yvan
It would be lovely to own a nice hunk of glass, I tried getting some locally to no avail.
It's how you use it that counts!
If you spend a long time lapping, (with larger lap abrasive) this will happen.
If the plane needs a lot of work, and you choose to lap in that fashion, then that could mean a heck of a lot more than a few thou, maybe 1/32" for a long plane
rendering that extra length as baggage.


My post or videos was intended to be more of a warning than a tutorial.
I have made super embarrassing errors in the past, embarrassing that I didn't figure out what was happening before it got too late.
I was just convinced or under hypnosis that lapping was a task as straight forward as the "gurus" made it out to be.

I am not saying my way is the best, just one method that follows the rules of physics, i.e the abrasive must be smaller than the work.
I cannot comment on that lapping plate and loose grit method referred to earlier,


I am not so good at describing things that well, so probably coming across rather sharply for some, but feel strongly about one not wrecking their plane, which may be their pride and joy.
The evidence is there on the bay, if one wants to see many many planes which got lapped incorrectly and very thin on the ends, but with full length irons
This is just speculation on my part though, as those irons could be replacements..
Maybe the keener more knowledgable eye could detect how much wear the tote and knob has, and make a more informed guess.


David
First thing to do is check before you start, like what I was intending to get across with the shoulder plane photo.
Might not have explained this well enough,

It's debatable on what one could call a concave profile, I suppose.
What if a plane has a hollow across the width, but that hollow is convex across the length?

Higgledy piggledy is what I call it, but I still would treat the plane as convex, because I would intend to flatten it.

In working yes, it would be more problematic "as is" having a hollow across the width where the mouth is,
but lapping that plane to get that hollow out would likely end up with a convex banana,
so that's where some misinterpretation might happen.

I like your wording on the matter David,
a consolidation lapping... makes me think of David Charlesworth being so descriptive!
This brings up a point I wasn't getting across,
I'm not declaring all planes should be dead flat to a sub thou tolerances,

I feel strongly about being able to have a choice how flat one wants to get their plane.
Any of the "guru's" I have watched, those methods don't provide one with that choice.


All the best
Tom