Axminster Rider No 7... concave sole, customer service pants as usual

[Dave Moore]

Hi,
Another way of flattening is to get a piece of flat glass from a car or van from scrapyard. Using carborundum paste as for grinding engine valves this will flatten the sole of your plane.

 

[segovia]

I use aluminium 24"x 1" x 2" hollow form straight edges with sandpaper on the 1" side for flattening. I prep the straight edges first to remove any hollows/bows from them. Initially, I used a piece of 30" x 10" x 3/8" plate glass as my reference to flatten the 1" edge of the aluminium bar. I spent hours trying to get a flat edge on my straight edges and couldn't figure out why my marker pen wasn't getting removed in some areas. After I a couple of hours hard graft with no progress I checked the glass, it was bowed! - Moral of the story I made an assumption the glass was flat before you spend hour flattening a plane sole make sure your reference in flat

 

[D_W]

why not take it to an Engineering shop and get them to precision skim it like they do with cylinder heads ?

If they're not familiar with grinding flexible items, they may not do the work to a standard that will satisfy you. Also, there are accounts of folks in the U.S.who took planes to job shops to find a significant amount of material milled from their planes. How many of those are direct accounts, I don't know, but worth asking if you're going to pay someone to do something that may cost more than the materials would cost to do 10 planes in your shop.

There aren't many job shops left here that do more than engines and welding on a regular basis, though.

 

[rafezetter]

Hi,
Another way of flattening is to get a piece of flat glass from a car or van from scrapyard. Using carborundum paste as for grinding engine valves this will flatten the sole of your plane.

Sorry but this is bad information, if it's from a vehicle it'll be tempered, and thus not "flat" enough for lapping a plane - there's a reason why makers like Ollie Sparks (a member here) use a certified granite surface plate and elbow grease - for some things there are just no shortcuts and a plane without a dead flat sole along most of it's length* will just give continued poor service and headaches.

* ideally from the tip at the front, in front of the mouth most especially (no hollows), and the majority of the back towards the end - for those unfamilar with how a plane sole should be lapped.

Lapping a plane sole on tempered glass will result in a slightly convex sole, and a plane which is good for F ALL but as a door stop - or planing the inside circumference of REALLY REALLY REALLY big wagon wheels

 

[Roseland 2]

Can you not have the sole skimmed by an engineering workshop? Years ago a garage organised for my car's cylinder head to be skimmed, and it wasn't expensive.
Andrew

 

[Jameshow]

How about asking at your local FE college they may well have a certified flat bench and some wet and dry. For a few beer tokens they might do it.

Failing that a granite worktop off cut off ebay? Or ask at a local kitchen installers??

Just s thought.

Cheers James

 

[Ttrees]

Lapping a plane sole on tempered glass will result in a slightly convex sole, and a plane which is good for F ALL but as a door stop - or planing the inside circumference of REALLY REALLY REALLY big wagon wheels

Lapping on a larger surface abrasive than an item is will make everything convex, doesn't matter how flat your lapping plate is, if your not going to use it right.

I would argue that you can achieve a flatter plane with something pretty flat, rather than stick ones head in the sand and believe a guaranteed flat surface to whatever tolerance will automatically ensure that lapping is a mindless process with nothing but elbow grease involved.

You don't have a choice on where you want to remove material if you are using that large of a surface, doesn't matter how clean and taut the abrasive is stretched out, the plane will go convex if its lapped enough.
I messed up a few planes before doing that, thanks to being absolutely convinced that mindless lapping was the correct way to do it.
Those videos you may see of folks lapping things like that are doing a disservice, as those before them, which led to so many hand planes having most of the mass removed from the heel and toe, just look on the bay for some job lots to see.
Ask yourself why have they still full length irons?

Some historical numpty must be to blame, still not as ignorant as the advice you see in this day and age from some of the gurus, which probably have something flat in the background to check the thing...
And yet other folks and myself have to keep repeating ourselves to stop planes turning into bananas.

Tom

 

[Ttrees]

I have some granite which is very convex on the polished side, unusable.
Very evident if you butt two squares against each other and push one with the other, that might just be the best way to check if you don't have a precision straight edge handy.
More difficult than it sounds to get something flat enough, if you don't want to pay the earth for it.

 

[Phil Pascoe]

I think many people are trying to split an atom. There are many methods that might not be perfect but are good enough for 95% of the people 95% of the time. I "flattened" a Marples No.5 on an abrasive disc on my lathe (it was not only hollow, but winding. It's perfectly useable.

 

[Ttrees]

I can't speak for doing so on a lathe Phil, but I will rant on for them gluttons for punishment who are going to do it by hand.

I've made huge errors in the past lapping with a surface plate,
destroyed two no.60 1/2's, a wafer thin welded Bailey no.5, thankfully I made sure I had sense to buy a thick soled n.8 which I also made convex.
I'm not talking a sheet of paper or two hollow either!
(not to mention other things not so important as a hand plane)

This needs to be understood for the folks using a lapping plate, as there is a large amount of misinformation out there.

The longer a plane is, the more material will be removed off of the toe and heel, as it will start to pivot from the point that's getting larger somewhere in the middle,
and this will lead to it going convex across the width next.
(which means possibly hindering the use of the cap iron if its bad, as it would act like a negative camber)

Having a slightly concave plane only needs to have the edges feathered off, if its only concave across the width, then it is very likely that one would need to stop removing metal from the toe/heel on a plane this long.
That means the abrasive must be shorter than the plane is.
lapping will always favor removal of the edges

For the folks still in doubt, then I suggest getting some 4 or 5mm mild steel plate and doing some experiments with a small square, scribble marker over all of a face and try and remove metal only from the middle, or try and lap flat some intentionally filed convexity , and you will see lapping will just copy the profile and polish it.
You will learn the same thing as with wood preparation that the edges are the reference and those contact points are important for the wood to sit flat and not pivot/see saw about from the middle.
See Charlesworth's video again

Tom

 

[pe2dave]

Perhaps the caveat is that common sense needs to be applied to the lapping process.

 

[D_W]

I can't speak for doing so on a lathe Phil, but I will rant on for them gluttons for punishment who are going to do it by hand.

I've made huge errors in the past lapping with a surface plate,
destroyed two no.60 1/2's, a wafer thin welded Bailey no.5, thankfully I made sure I had sense to buy a thick soled n.8 which I also made convex.
I'm not talking a sheet of paper or two hollow either!
(not to mention other things not so important as a hand plane)

This needs to be understood for the folks using a lapping plate, as there is a large amount of misinformation out there.

The longer a plane is, the more material will be removed off of the toe and heel, as it will start to pivot from the point that's getting larger somewhere in the middle,
and this will lead to it going convex across the width next.
(which means possibly hindering the use of the cap iron if its bad, as it would act like a negative camber)

Having a slightly concave plane only needs to have the edges feathered off, if its only concave across the width, then it is very likely that one would need to stop removing metal from the toe/heel on a plane this long.
That means the abrasive must be shorter than the plane is.
lapping will always favor removal of the edges

For the folks still in doubt, then I suggest getting some 4 or 5mm mild steel plate and doing some experiments with a small square, scribble marker over all of a face and try and remove metal only from the middle, or try and lap flat some intentionally filed convexity , and you will see lapping will just copy the profile and polish it.
You will learn the same thing as with wood preparation that the edges are the reference and those contact points are important for the wood to sit flat and not pivot/see saw about from the middle.
See Charlesworth's video again

Tom

In this case, the toe and heel of the plane are low and a long flat lap is exactly what's needed for a final check. I think it's more practical to have a long reference and work convexity out if that were the problem here, and then finish on the lap.

I've used the long lap for 10 plus years now and never had a problem making bananas. A couple of thousandths of toe and heel pride on a long plane is probably a good thing.

 

[Ttrees]

Agreed David, a long lap is very very good to have around to check the state of the entire sole.
A bit of a toss up between buying a straight edge to check for a flat plate or a plate if you can't find anything.

I've not used the method you have mentioned before with a flexible file working the high areas down first, and as you say not needed if the plane is concave.

However, how much concavity there is, is unknown yet.
It could be way out for all we know...
enough to start the banana cycle off, especially for someone who might not be used to treating the edges as a reference.
Quality of abrasive could play a part, as a lesser quality would multiply the strokes more than likely highlighting the issue.

I assume many folks would be weary of using a file to sort an issue out prior to lapping, that's why continue my issues with the full lap method.
It may well be a whole lot slower
Surprised you have not had issue with this occurrence before
as I presume you have picked up some old jointers in the past prior to your plane making days..

Another issue I have with a full lap plate, even a small one, (to take questionable surface plate deflection out of the equation)
is working on cheap adjustable mouth planes, which the bed for the shoe needs to be in line with the sole, otherwise the mouth will lift the plane when adjusted.

That cost me some mula to get three 60 1/2's... two of which didn't make it from that, and I won't mention what jewelry i bought not to have to experience this issue again.

Tom

 

[D_W]

The concave removal or spot removal (either with a flexible file - especially if the plane is steel instead of cast - or with a 2x3 or so wood block with psa or some kind of coarse machine paper attached) is the way to go if a plane is convex. The long lap is used as a reference and then to consolidate once all convexity is gone. It's much faster.

I did experiment with shorter glass, but it's less accurate and slower and doesn't solve the issue of it being slow to remove much convexity with a lap in the first place. A smaller contact area is much more efficient.

The long lap is very useful for other things (that you can live without, but once it's available, you won't). I can't think of an easy way around a good 24" straight edge, though (the very cheap could make one using high carbon bar stock if a friend has a reference square. I don't have a true reference square, but a friend does, and it's a nice thing to have available without paying to keep or chasing rust from).

The only thing I could think of with wood is to bookmatch two sticks from a single board and then plane the meeting edges separately until they meet perfectly, and then plane a third to check. After that, if the two matched edges meet each other, they should still be dead straight and better than a lot of low cost metal straight edges. splitting a quartered board into a bookmatch would be a good way to avoid the boards moving in complementary ways - the bookmatched edge board will generally do the same thing, exacerbating any change away from flatness.

I guess all of it doesn't matter if one only does a couple of planes. I flatten every plane that I get (and all new wooden ones, of course) just as a matter of courtesy for the coarse planes when I turn them over due to excess. A 5 may not need flattening, but I'd imagine 95% of purchasers are going to buy a plane to use as a long smoother and it's a nice gesture. I want fast and accurate. For infills, it's a matter of pride. If I can't beat LN's spec, then why build a plane. I can beat their spec (but 8 of 10 planes that I've gotten from them were dead on, way within their plus or minus 1.5 thousandths. Two have been concave exactly at it, so I can beat their spec, but maybe only match their average plane.

The sectional edge is a good thing to learn for squareness, too, as few will create a 90 degree wall and lap that into a plane (the plane will end up at something different than the reference). It's very easy to square one side of a plane using a sectional approach and then consolidating for cosmetics.

 

[TheTiddles]

Toughened glass won’t be flat (compared to non-toughened) but also remember it’s not magic, if you put a 6mm piece of glass on an uneven surface and push on it, the glass will deform.

Aidan

 

[D_W]

Toughened glass won’t be flat (compared to non-toughened) but also remember it’s not magic, if you put a 6mm piece of glass on an uneven surface and push on it, the glass will deform.

Aidan

If you shop around for a "replacement shelf", it should just be non toughened float glass. I wouldn't get it thinner than about 9 or ten mm, but a longer shelf should be that thick, anyway, and inexpensive.

 

[johnny]

If they're not familiar with grinding flexible items, they may not do the work to a standard that will satisfy you. Also, there are accounts of folks in the U.S.who took planes to job shops to find a significant amount of material milled from their planes.

I cannot speak for US engineering standards but here in the UK Engineers are qualified to a high standard with a BSc Degree qualification and are registered with the Chartered Institute of Engineering CEng in order to practice as an Engineer and be entitled to use the title Engineer.

There is not much more precise than a CNC Milling machine, they work to +/-0.1mm geometric tolerance and a surface finish of 1.6µm (micrometer) tolerances tighter than 0.01µm can be achieved where the design requires it. ( General Tolerances to DIN ISO 2768. )

I' wasn't referring to back street mechanics and 'machine shops'

 

[D_W]

I cannot speak for US engineering standards but here in the UK Engineers are qualified to a high standard with a BSc Degree qualification and are registered with the Chartered Institute of Engineering CEng in order to practice as an Engineer and be entitled to use the title Engineer.

There is not much more precise than a CNC Milling machine, they work to +/-0.1mm geometric tolerance and a surface finish of 1.6µm (micrometer) tolerances tighter than 0.01µm can be achieved where the design requires it. ( General Tolerances to DIN ISO 2768. )

I' wasn't referring to back street mechanics and 'machine shops'

Different terminology here, yes. An engineer wouldn't run a machine like you're talking about here, they would determine spec and a trade-trained (associates degree, or 2 year college type) would operate the machine.

Not necessary for flattening planes, though. Each time this comes up, it's made really difficult because everyone has a lot of ideas and not much experience. I have a lot of experience doing this and not many remaining ideas because most of them are not functionally more accurate than doing this work manually (it is really easy as long as you only do things you're supposed to and not things you're not) and it would take me longer to get to and from somewhere to do it than it would just to do the work in house.

The "back street" old school machinists here could work to a couple of ten thousandths of an inch, but they are mostly gone. They'd be a better choice for something like this, but only if they cared about the results - but even a regular machine shop is a strange choice for something like this unless there will be only one and a machine shop owes you a favor (since it's about 100 pounds to get a good surface to use and most of that 100 pounds would be eaten by a good quality 24" straight edge with a tolerance of less than a thousandth of an inch over its length).

 

[pe2dave]

Quite a few insults in your post @D_W

Surely cost reduction means 'cheaper' labour to run machines.
We all have ideas and no experience? Doubtful if we're on this group.
My father (an old school machinist) would have been sacked for working to 10 'thou.

 

[memzey]

There's nothing insulting in Dave's post that I can see, nothing at all. He's giving the benefit of his own experience of actually flattening a bunch of planes and it all rings true to me (another one who has flattened the sole on lots of planes - including getting one precision ground by an engineering firm that specialises in the field). His point about "more ideas than experience" is, I think, particularly well articulated as this topic comes up frequently but the few people that have actually done this a number of times, always revert to the same small subset of methods.

And, with the greatest of respect, what your father would or would not have received his P45 for is of little relevance here, as is almost anything that talks to 10 thou' (0.0001”) tolerances in woodworking.