Pane sole Flattening

[bugbear]

I agree with your comments about surface plates - bigger ones get expensive very quickly, and to accommodate a 24" plane sole something about 24" x 18" would be required

What's the diagonal length on a 12" x 18" surface plate?

Whilst so-called-lapping requires a surface around double the length of the plane, spot removal doesn't...

I flattened a #5 on a 8" x 12" plate.

BugBear

 

[Beachcricket]

Just flattened all my hand planes last week. Bought a piece of float glass 10mm thick, 115mm wide X 800mm long, cost me £17. Dead easy to attach and remove abrasives and gets your planes as flat as you'll need them to be.

 

[mr edd]

Hi D W,
They scorned my wallet, I don't think anything was going to get me within a hundred yards of their surface plate, thanks for your advise tho,
I did think if I undertake it myself it might be a bit of graft but that's ok.
As for doing things for reasons you can't recall I do plenty of stuff for reasons like that but I usually feel better for having done it!

Hi Bugbear
Sorry if I'm being dense but are you saying whilst lapping with abrasive stuck to a plate requires a plate longer than the sole of the plane, using spot removal with a small block to do the abrading and a smaller plate used in the diagonal to test flatness might do the trick? A bit like hand scraping and using engineer's blue? or am I barking up the wrong tree?

Your responses are appreciated,

I have successfully restored other planes which work very well on difficult woods like satinwood but they were much smaller planes, I think it is the size of the plane which is daunting and that is what prompted my initial questions.

I will check the deviation of the sole and try to come up with a meaningful figure
Also the plane's sole is corrugated which I hope will make the process easier?

Cheers Edd

 

[G S Haydon]

https://www.youtube.com/watch?v=RVy789Oxq98

I've used melamine faced MDF, it can be shimmed flat easily enough and it's cheap. On D_W tips on adhesive backed abrasive, I've found it almost impossible to find. There I would revert to Jacob's tip on paper choice.

The advise from everyone else was sound too. Better still, sell it and buy a wooden version. Nice and easy to true up

 

[matthewwh]

Good news,
1) It's concave so you don't need to go past flat change technique and come back.
2) If you overshoot and end up marginally convex it will still work beautifully.
3) Since it's unusable concave it hasn't seen significant use since it became that way.

Bad news,
1) It wasn't made concave and castings that have moved before have the potential to do so again.
2) It's a No.8

Suggest you investigate getting it machined, then measure it six weeks later, still flat - crack on, not flat - lose it.

It might cost you a few quid but if it works you've got a super plane, if it doesn't you haven't invested too much time in it.

 

[Jacob]

...... On D_W tips on adhesive backed abrasive, I've found it almost impossible to find. There I would revert to Jacob's tip on paper choice......

The wet method is easiest, cheapest, quickest, - you don't need adhesives but you do need wet for faster cutting and floating away the swarf.
If the sole is convex you just use one A4 piece and work the middle. If concave you use two pieces and work each end.
I know I'm repeating myself somewhat, but I sense a general level of scepticism about a method which I've used and I know works well.
You don't even need straightedges, feeler gauge or Rizlas - you can see where the high points have been touching, and the remaining hollows, from the abrasive scratches.

 

[bugbear]

Hi Bugbear
Sorry if I'm being dense but are you saying whilst lapping with abrasive stuck to a plate requires a plate longer than the sole of the plane, using spot removal with a small block to do the abrading and a smaller plate used in the diagonal to test flatness might do the trick? A bit like hand scraping and using engineer's blue? or am I barking up the wrong tree?

Your responses are appreciated,

Lapping (or what woodworkers have come to call lapping) can be made to work, but has a number of issues:

• the lapping surface needs to flat, at least as flat as you want to make your sole
• the lapping surface needs to be rigid enough to stay flat, since you'll be putting considerable pressure on it (especially when your arms start to ache, and your patience starts to ebb )
• the abrasive needs to be much longer and wider than the plane; otherwise, as the abrasive is used up, the sharper abrasive at the perimeter cuts more than the worn abrasive in the centre, leading to convexity
• swarf tends to build up in the middle of the abrasive, again leading to convexity
• any tendency not to hold the tool carefully seated on the abrasive (and this is a long, very physical process) leads to (you've guessed it) convexity.
• as the sole becomes flat, the surface area in contact with the abrasive becomes larger, and hence the pressure on the abrasive reduces, so the cutting rate reduces. this is going to affect larger planes even worse. As a corollary to this, the process starts off removing localised high spots very quickly.

I remember at an Axminster show I attended the local training college had a nice rig set up with abrasives, and the students were running a #7 backwards and forwards. I attended the show for two days, they worked continuously (AFAIK) and they didn't finish.

Here's a blog showing lapping being done successfully.

I believe the approach that I've developed with help from others, and adopted for my own use, addresses all these points.

my original page, evolved over time
page on the principles
page on the practise, including a montage of progress shots

BugBear

 

[Jacob]

I think all the points above are answered by the thin paper / wet process, assuming a good base to start with.
BB carefully and correctly describes all the difficulties of using dry paper but stops short of the next logical step;
basically it's a mistake to use wet n dry paper dry, when you can use it wet.

PS by "wet" I mean very wet, not just damp, moist, sprayed on, etc. You flood the surface and work in a pool of liquid.

 

[Cheshirechappie]

I think all the points above are answered by the thin paper / wet process, assuming a good base to start with.
BB carefully and correctly describes all the difficulties of using dry paper but stops short of the next logical step;
basically it's a mistake to use wet n dry paper dry, when you can use it wet.

PS by "wet" I mean very wet, not just damp, moist, sprayed on, etc. You flood the surface and work in a pool of liquid.

Might be worth a quick Elf-n-Safety assessment here - depending on the flat surface selected. Sloshing large quantities of water or white spirit around electrically-driven machines (even when they're isolated) might have potentially undesirable conequences later....

 

[Bedrock]

As far as self adhesive abrasive is concerned, Axminster sell a 4" roll in various grades, at a price which I think is reasonably under a fiver. Can't remember the name, but it is pale blue so is easy to spot.

Not tried Jacob's method, but BB has commented elsewhere on the need to avoid convexity across the sole. If the plane is already this shape, ploughing up and down, as I have found, only increases the curvature, and I think it is nigh on impossible to hold such a plane flat so that you only remove the linear high spot.
If the sole is convex across, I found it better to abrade the centre line area with a block to a very slight concavity, so that it will sit flat on the glass/MDF/whatever, then finish so that the raised edges are removed. Some large granite/marble flooring tiles are 10-12mm thick, ground to an acceptable flatness, and are sensibly affordable.

 

[Racers]

I stretch the abrasive tight by clamping a block to each then use two clamps to pull it apart.

Pete

 

[D_W]

I used to stretch belts, but I always got dubbing.

I didn't have as much luck with the wet paper method jacob's talking about, inevitably the paper would come apart and it would take a while fiddling with it. I still like the dry PSA better, you can either brush the swarf off or vacuum it, but the glass run has to be long enough to make it worthwhile (3 1/2 feet is what I have, but at a cost of $20)

Bugbear - as far as lapping a 7, there's probably an issue with technique. I've lapped 6 #7 planes, and they are fine as long as the PSA roll is fresh, I've never had to use more than two runs of paper (which is about $4 worth) and never spent more than an hour. For some reason, a #8 is just beyond what my weight can force cast iron to be cut on (i'm sure there's a tipping point for everyone).

Since spot - reducing a few #8s, I haven't had to do another #7 since then, but if I had one that needed more than heel or toe, I'd probably spot reduce it, too, and then consolidate the results by finishing on the lap - it's just less physical work to use a block than to lap the whole plane.

Paper that will no longer allow lapping with a 7 can still finish several 4s and 5s.

I'd like to say I never got caught up in buying and refurbishing a bunch of old planes, but I did that for a while. It's an even money game, and thus a waste of time, unless someone is finding 4s and 5s at a public sale. But I learned a lot of subtle physical things that were then helpful to make three steel infill planes that need the lap after draw filing off the tails.

And I still use the lap to finish the soles on new beech planes - it's easy and convenient (a 5 minute process to have a finished sole that is just biased a tiny bit with the mouth low) and a pass with the smoother after lapping leaves a clean surface that isn't hairy from sandpaper.

The only issue that I've ever encountered with a long lap is stray grit getting under the sandpaper, but it's easy to take a junk chisel and run it bevel down over the whole lap -takes only a minute - between sandpaper applications. It doesn't damage the chisel, and the glass is always very clean and ready for the next bit of paper.

 

[bugbear]

I used to stretch belts, but I always got dubbing.

I didn't have as much luck with the wet paper method jacob's talking about, inevitably the paper would come apart and it would take a while fiddling with it. I still like the dry PSA better, you can either brush the swarf off or vacuum it, but the glass run has to be long enough to make it worthwhile (3 1/2 feet is what I have, but at a cost of $20)

Stauer and Steiner (in the link I gave earlier) use a magnet for this.

I do this (some pieces of rare-earth magnet got from old computer hard drives, in an old spray can lid to keep it clean) when using scary sharp.

Very effective.

BugBear

 

[Jacob]

As far as self adhesive abrasive is concerned, Axminster sell a 4" roll in various grades, at a price which I think is reasonably under a fiver. Can't remember the name, but it is pale blue so is easy to spot.

Not tried Jacob's method, but BB has commented elsewhere on the need to avoid convexity across the sole. If the plane is already this shape, ploughing up and down, as I have found, only increases the curvature, and I think it is nigh on impossible to hold such a plane flat so that you only remove the linear high spot.
If the sole is convex across, I found it better to abrade the centre line area with a block to a very slight concavity, so that it will sit flat on the glass/MDF/whatever, then finish so that the raised edges are removed. Some large granite/marble flooring tiles are 10-12mm thick, ground to an acceptable flatness, and are sensibly affordable.

Can't say I've ever encountered convexity across the sole and it certainly isn't a feature of the thin-paper / wet process.

PS it may come about with stuck-down cloth-backed paper as this makes for a slightly springy surface which will depress like a very thin mattress. Thin wet paper doesn't do this.

 

[Jacob]

....
I didn't have as much luck with the wet paper method jacob's talking about, inevitably the paper would come apart and it would take a while fiddling with it. ....

Er you must be doing something different.
My method involves no fiddling about - you just lay down the paper on a pool of white spirit (or water etc). pour some more on top and you are off! It never comes apart either. it wears out eventually but I usually swap it for fresh one well before this so that it carries on cutting fast.
If the paper is a bit curly it may take a minute or so to get it flat and held down by capillary action or whatever it is, but if you store it flat even this isn't necessary.
This is thin paper wet n dry - it won't work with cloth backed, you don't get the stiction.

PS pleased to see that my suggestion of a magnet has caught on so widely! But it won't remove the non-magnetic component i.e. the worn out detached grit, which is why the wet process is so much better - it floats it loose and it can be washed/wiped off

 

[D_W]

I got all of those details, Jacob, except I used water because the paper was on a waxed bench. I may use more pressure when lapping (fastest is best). The method you describe is what I started with.

Generally, it takes me about 5 minutes total to lap a #4 and a bad #5 takes 10 with the dry paper, and it doesn't require a work surface that can tolerate water or mineral spirits, etc.

 

[Jacob]

I'd guess not enough "stiction" with water on a wooden bench. I've always used a machine bed but I imagine glass, granite, even MFC, would do just as well as long as they are impermeable and very smooth.

 

[D_W]

I'd guess not enough "stiction" with water on a wooden bench. I've always used a machine bed but I imagine glass, granite, even MFC, would do just as well as long as they are impermeable and very smooth.

I wasn't clear about that. The glass lap was on a wooden bench. I used water on the glass lap because I didn't want swarf to run over the sides and strip the wax and oil off of the wooden bench.

I had a table saw at the time, but it was very poor flatness front to back (about a hundredth hollow) and the glass would easily flex in that. On the bench, I couldn't get a .015 feeler under a starrett edge regardless of the pressure I placed on the glass. that kind of accuracy isn't really necessary, but it doesn't hurt to have.

For what it's worth, if grit particles or chip got under the glass on one end (from lifting the lap up for any reason and replacing it on the bench without sweeping any foreign particles off), I could put a feeler under the straight edge. I only checked the first couple of times I used the lap, but I was surprised by just how much the glass flexes.

I don't have a power jointer, so the TS at the time was my only truly flat other surface that I could've put a significant amount of pressure on.

 

[Jacob]

I'd guess not enough "stiction" with water on a wooden bench. I've always used a machine bed but I imagine glass, granite, even MFC, would do just as well as long as they are impermeable and very smooth.

I wasn't clear about that. The glass lap was on a wooden bench. I used water on the glass lap because I didn't want swarf to run over the sides and strip the wax and oil off of the wooden bench.

I had a table saw at the time, but it was very poor flatness front to back (about a hundredth hollow) and the glass would easily flex in that. On the bench, I couldn't get a .015 feeler under a starrett edge regardless of the pressure I placed on the glass. that kind of accuracy isn't really necessary, but it doesn't hurt to have.

For what it's worth, if grit particles or chip got under the glass on one end (from lifting the lap up for any reason and replacing it on the bench without sweeping any foreign particles off), I could put a feeler under the straight edge. I only checked the first couple of times I used the lap, but I was surprised by just how much the glass flexes.

I don't have a power jointer, so the TS at the time was my only truly flat other surface that I could've put a significant amount of pressure on.

I think you need a more rigid base (thicker glass?) and more space. It's a wet process and if you don't want it spreading you need a wide and level surface so that you are working in a puddle which doesn't reach the edge. Maybe some sort of tray?

 

[D_W]

I'd guess not enough "stiction" with water on a wooden bench. I've always used a machine bed but I imagine glass, granite, even MFC, would do just as well as long as they are impermeable and very smooth.

I wasn't clear about that. The glass lap was on a wooden bench. I used water on the glass lap because I didn't want swarf to run over the sides and strip the wax and oil off of the wooden bench.

I had a table saw at the time, but it was very poor flatness front to back (about a hundredth hollow) and the glass would easily flex in that. On the bench, I couldn't get a .015 feeler under a starrett edge regardless of the pressure I placed on the glass. that kind of accuracy isn't really necessary, but it doesn't hurt to have.

For what it's worth, if grit particles or chip got under the glass on one end (from lifting the lap up for any reason and replacing it on the bench without sweeping any foreign particles off), I could put a feeler under the straight edge. I only checked the first couple of times I used the lap, but I was surprised by just how much the glass flexes.

I don't have a power jointer, so the TS at the time was my only truly flat other surface that I could've put a significant amount of pressure on.

I think you need a more rigid base (thicker glass?) and more space. It's a wet process and if you don't want it spreading you need a wide and level surface so that you are working in a puddle which doesn't reach the edge. Maybe some sort of tray?

Well, I'm pretty happy with the dry method. It's quick and I've got my variables. I'm in agreement with absolutely everything else you've said (coarse and then knock off the burrs with a fine abrasive - no need to go nutty going through a progression of grits), but my experience with speed and results has just been different wet vs. dry.

My setup is very rigid. The glass is 10mm between two dogs, and I check the flex in the middle both with the setup at rest, and also holding near full bodyweight on the center of the glass and then checking again to see if I can slip a feeler under a starrett edge. I cannot in either case.

I may be a bit cheap (selectively, I guess), but in this case, it hasn't affected speed or results. The whole process ends up costing about $1 a plane, and certainly as time has gone on, the amount of lapping that I do takes less time because there's less actual lapping (I go for flat instead of cosmetically perfect).

What I've found so far, is that the most pressure and the least strokes yields the flattest bottom of a plane (another reason not to go for cosmetic perfection).

Any amount of dirt that ends up off the glass and on the bench top (and it can make the top black) is easily removable with a card scraper, but I usually don't have to do that.

As I mentioned above, I'd estimate 4s probably take 5 minutes maximum, 5s 10. A 7 may take 45 minutes, though, but there will be no fast method for that if any appreciable amount of work needs to be done.

A mild steel panel plane took MUCH longer and was much harder on sandpaper than any cast plane that I've done, but I won't be doing another one of those.