Plane Sole Flattening

[Jeff Gorman]

Being a bod who with scraper and surface plate has hand scraped his smoothing plane as flat as he can get it, I've been very interested in the expert discussions about achieving the ultimate in flatness.

However, I wonder whether we should consider this in the context of an experiment of mine that demonstrated that a cast iron jack plane can deflect. Please see http://tinyurl.com/l58267

Possibly, mild steel plane will differ, of course but I'd be surprised if they were completely rigid under the conditions applied by normal use.

Jeff Gorman
www.amgron.clara.net

 

[xy mosian]

Fascinating, fascinating.

xy

 

[bugbear]

Being a bod who with scraper and surface plate has hand scraped his smoothing plane as flat as he can get it, I've been very interested in the expert discussions about achieving the ultimate in flatness.

However, I wonder whether we should consider this in the context of an experiment of mine that demonstrated that a cast iron jack plane can deflect. Please see http://tinyurl.com/l58267

Possibly, mild steel plane will differ, of course but I'd be surprised if they were completely rigid under the conditions applied by normal use.

Jeff Gorman
www.amgron.clara.net

Good to see that page back!

BugBear

 

[Philly]

Very interesting - I know Richard Jones says he applies pressure to his #7 to remove wind when edge jointing.
The flat sole subject is an interesting subject - I'm of the opinion that as long as three points of the sole (toe, front of mouth, rear of mouth) are co-planer a good result is achievable (when talking about extremely thin shavings). For heavy stock removal all that's necessary is that the plane HAS a sole.... :lol:
Cheers
Philly

 

[TrimTheKing]

For heavy stock removal all that's necessary is that the plane HAS a sole.... :lol:
Cheers
Philly

Like James Brown?

 

[Philly]

For heavy stock removal all that's necessary is that the plane HAS a sole.... :lol:
Cheers
Philly

Like James Brown?

Kinda - take it to the bridge :wink:
Philly

 

[TrimTheKing]

For heavy stock removal all that's necessary is that the plane HAS a sole.... :lol:
Cheers
Philly

Like James Brown?

Kinda - take it to the bridge :wink:
Philly

Whoa, I feel good (nana, nana, nana, na) I YEW that I WOOD

 

[paulm]

:lol: :lol: :lol:

 

[bugbear]

Very interesting - I know Richard Jones says he applies pressure to his #7 to remove wind when edge jointing.
The flat sole subject is an interesting subject - I'm of the opinion that as long as three points of the sole (toe, front of mouth, rear of mouth) are co-planer a good result is achievable (when talking about extremely thin shavings). For heavy stock removal all that's necessary is that the plane HAS a sole.... :lol:
Cheers
Philly

Here's the Great precursor of Jeff's data:

http://swingleydev.com/archive/get.php? ... =1#message

Doug Dawson did a whole series of calculations related to planing (as you may gather from the thread title)

His overall conclusion was that planes work... !

It's always nice when the results of calculations tie in neatly with empirical data, and he adds a good deal to the understanding of what's going on when planing.

BugBear

 

[Sgian Dubh]

Very interesting - I know Richard Jones says he applies pressure to his #7 to remove wind when edge jointing. Philly

Philly, I have claimed for years now that I do a bit of plane sole bending with long planes, particularly when straightening the edges of boards ready for gluing up an edge joint.

I've never quantified or tested how much bending is achievable, and I have to admit that quantifying any such numbers isn't important to me; I just know bending a plane sole in use is both possible and, used judiciously, it can help create a straight edge on a board.

I can't even properly recall how I learned the trick. I might have been shown it by a couple of old fart cabinetmakers sometime back in the 1970s or 80s, or I might have discovered it on my own. Either way, it doesn't matter, but I pass on the knowledge and demonstrate the trick to any learners I happen to be working with when a demonstration of plank edge straightening is in progress. Slainte.

 

[Jeff Gorman]

Many thanks to Paul for resurrecting one battle of the 'plane wars' in which parts of my contribution were somewhat tongue in cheek.

One thing we missed was the force applied directly at the mouth by the action of the cutter itself.

I think it was sometime after this discussion that I did the work on this topic that is still presented at:http://tinyurl.com/cj535x.

I know from direct experience gained when making some close-up photos for Good Woodworking (GWs 183 & 184) that involved a plane clamped to a test piece while making fairly thick shavings. After releasing the clamp, I had to actually wrench the test piece away from the jig (and this was on a narrow strip of wood).

Jeff
www.amgron.clara.net

 

[Anonymous]

As an engineer of nearly 30 years, I think I shoudl point out that this is woodworking and we are not working to femto metres (pretty small)!!

I have always found LV, Clifton and LN smoothers to be perfectly flat enough out of the box and off the surface grinder! Buy a decent plane and simply use it............

 

[Pekka Huhta]

Very interesting - I know Richard Jones says he applies pressure to his #7 to remove wind when edge jointing.
The flat sole subject is an interesting subject - I'm of the opinion that as long as three points of the sole (toe, front of mouth, rear of mouth) are co-planer a good result is achievable (when talking about extremely thin shavings). For heavy stock removal all that's necessary is that the plane HAS a sole.... :lol:
Cheers
Philly

To be precise, the japanese smoothing planes don't have even the three spots, but the area rear of mouth is 0,05 mm up from the co-planar surface, so that the mouth area is in fact a part of a compass plane with the radius about hundred meters :wink: . And they generally produce a brilliant surface...

Pekka

 

[Dave S]

As an engineer of nearly 30 years, I think I shoudl point out that this is woodworking and we are not working to femto metres (pretty small)!!

I have always found LV, Clifton and LN smoothers to be perfectly flat enough out of the box and off the surface grinder! Buy a decent plane and simply use it............

Yeah, like everyone has the means to spend £200+ on a plane. :roll:

Agree on your first point, though.

Dave

 

[bugbear]

As an engineer of nearly 30 years, I think I shoudl point out that this is woodworking and we are not working to femto metres (pretty small)!!

Absolutely - one of the most difficult question to get an answer to is HOW flat a plane sole needs to be.

I think everyone agrees (*) that there is a degree of curvature (or ripple) that will render a plane unusable, and that planes flat to a 1/10000" (a tenth) are overkill.

But I've never seen a convincing analysis of where the boundary falls.

If one happens to have the patience or equipment to make a plane TOO flat (i.e. flatter than strictly neccessary) you can at least be sure you're the right side of the boundary.

Further, given the tendancy of cast iron to drift a little, if one made a plane "only just" good enough, even a little movement would take you into "not good enough". Again, erring on the side of "too good" does no harm, except the resource (time and/or money) taken to achieve it.

BugBear

 

[Digit]

I thought it was just me so I'm glad to see that Philly also thinks that the three point contact is all that is necessary.

Roy.

 

[bugbear]

Very interesting - I know Richard Jones says he applies pressure to his #7 to remove wind when edge jointing.
The flat sole subject is an interesting subject - I'm of the opinion that as long as three points of the sole (toe, front of mouth, rear of mouth) are co-planer a good result is achievable (when talking about extremely thin shavings).

Heh. When talking about smoothing planes, a two point contact (toe, front of mouth) would be enough.

Three? Indulgent Luxury!

BugBear

 

[Philly]

Three? Indulgent Luxury!

Well, you know me........ :lol:
Philly

 

[xy mosian]

Very interesting - I know Richard Jones says he applies pressure to his #7 to remove wind when edge jointing.
The flat sole subject is an interesting subject - I'm of the opinion that as long as three points of the sole (toe, front of mouth, rear of mouth) are co-planer a good result is achievable (when talking about extremely thin shavings).

Heh. When talking about smoothing planes, a two point contact (toe, front of mouth) would be enough.

Three? Indulgent Luxury!

BugBear

I take both those comments on board. But what happens towards the end of the cut when the contact between the toe and the stock is rapidly reducing?

xy

 

[Philly]

XY
As long as the front of mouth area and area directly behind the mouth are co-planer as the plane reached the end of the board the cut is still supported by the area behind the mouth.
Japanese smoothers can have their soles relieved behind the mouth - the plane is used with a very quick stroke, whipping the plane off the workpiece at the end.


As an afterthought - this talk of having only certain areas in contact. This is a minimum, no a goal to achieve. Ideally, the complete sole would be flat and all areas co-planer - but this is difficult to achieve and retain. So when maintaining your plane, this three point approach is the minimum to aim for.
Hope this helps
Philly