Sole flatness with new planes

[Trevor Goodwin]

Something I've always been a bit skeptical about is how people say you need to mount the frog and blade when lapping a plane sole. Does it really make much difference to the shape of the sole when you fasten the blade? I mean, the torque is all taken up in the frog, which is fastened to the bed at a point (for bevel-down), so why should the sole flex noticeably, if at all?

This has got me thinking about modern manufacturers. Surely they don't have someone on the production line lapping the soles on a surface plate? No, I'm pretty sure they come milled and/or surface ground because you can see the marks. Based on reviews, it seems the modern planes all come flat (except for a few duds that slip through). Does anyone know if Veritas or Lie Nielson mounts the handles, frog and blade when they machine the soles flat? My gut says no but I may be wrong.

Anyway, hopefully I haven't started another flame war, just interested in what others think of this, possibly debunk a myth.

[Robert Engel]

The experts will surely chime in, IMO its probably splitting hairs but I always do it when flattening a sole.

If the frog base is precisely machined then tightening the frog shouldn't warp the sole, but in the light steel/stamped steel/cheaper planes this is probably more apt to occur. I don't know about installing the blade/cap iron, but back when I was rehabbing old Stanley planes, looking at the way the frog base was machined, I figured better to put the plane under any nominal stress when in use?

There is a video on the LN manufacturing process. Maybe that will show it.

[Patrick Chase]

Something I've always been a bit skeptical about is how people say you need to mount the frog and blade when lapping a plane sole. Does it really make much difference to the shape of the sole when you fasten the blade? I mean, the torque is all taken up in the frog, which is fastened to the bed at a point (for bevel-down), so why should the sole flex noticeably, if at all?

This has got me thinking about modern manufacturers. Surely they don't have someone on the production line lapping the soles on a surface plate? No, I'm pretty sure they come milled and/or surface ground because you can see the marks. Based on reviews, it seems the modern planes all come flat (except for a few duds that slip through). Does anyone know if Veritas or Lie Nielson mounts the handles, frog and blade when they machine the soles flat? My gut says no but I may be wrong.

Anyway, hopefully I haven't started another flame war, just interested in what others think of this, possibly debunk a myth.

This topic is an "everlasting flame" in the sense that there are a lot of incompatible and deeply-held opinions.

FWIW Tablesaw Tom agrees with you (http://www.tablesawtom.com/plane.htm), and he's successfully flattened a bunch of plane soles for people in this forum. So do I.

Unless you're severely overtightening the lever cap the forces involved are both localized to the frog area and negligibly small relative to the stiffness of the plane body. Let the flames begin!

[Mike Brady]

This topic is an "everlasting flame" in the sense that there are a lot of incompatible and deeply-held opinions.

FWIW Tablesaw Tom agrees with you (http://www.tablesawtom.com/plane.htm), and he's successfully flattened a bunch of plane soles for people in this forum. So do I.

Unless you're severely overtightening the lever cap the forces involved are both localized to the frog area and negligibly small relative to the stiffness of the plane body. Let the flames begin!

When you think about it, the machining of a plane sole further weakens the rigidity of the tool at its most vulnerable and critical point. To further fuel that argument, the machining is most likely done without the blade and lever cap in place, so if the first proposition is correct, the machining might prove to be doubly counterproductive. I have examined corrugated plane soles that have been machined, and it was surprising how little of the corrugation remains afterward.

[James Pallas]

I have no claim about being an expert on this issue. Here is my spare change. I am one of those that releases the tension on the lever cap if I put my planes away if not needed for a while, days. I have seen planes that have been left with the cap screws so tight that you couldn't release the lever cap. I have personally wrestled with a transitional plane that had a problem. Never had a metal plane that had a problem. I have seen frog screws too long or wound down on trash that did some real damage. In any case it's easy enough to check if you want to. Set the plane up like you are going to use it, let it stay that way for a day and put a straight edge on it. I'm also one who unstrings a bow when I'm finished hunting. Just general tool care to me.
Jim

[Pat Barry]

Is sole flattening commonly done for a brand new LN or LV plane? It seems that I should expect it to work well right out of the box. I certainly shouldn't have to do much with one, right?

[Patrick Chase]

I have no claim about being an expert on this issue. Here is my spare change. I am one of those that releases the tension on the lever cap if I put my planes away if not needed for a while, days. I have seen planes that have been left with the cap screws so tight that you couldn't release the lever cap. I have personally wrestled with a transitional plane that had a problem. Never had a metal plane that had a problem. I have seen frog screws too long or wound down on trash that did some real damage. In any case it's easy enough to check if you want to. Set the plane up like you are going to use it, let it stay that way for a day and put a straight edge on it. I'm also one who unstrings a bow when I'm finished hunting. Just general tool care to me.
Jim

The difference here is that the tension on a bow is significant relative to the stiffness and strength of its arms, which is why they bend.

I still think that the tension on a lever cap is insignificant relative to the stiffness/strength of the components involved. Releasing that after every session is about as helpful as loosening the lug nuts on your car every time you park...

[Trevor Goodwin]

Is sole flattening commonly done for a brand new LN or LV plane? It seems that I should expect it to work well right out of the box. I certainly shouldn't have to do much with one, right?

That was kind of my point. It isn't commonly done for brand new planes, but they are probably aren't flattening the soles under tension at the factory.

I recently received a Kunz Plus bevel-up-jack and its a ripper. The sole is dead flat, I have trouble with it sticking to the wood sometimes...

[Patrick Chase]

Is sole flattening commonly done for a brand new LN or LV plane? It seems that I should expect it to work well right out of the box. I certainly shouldn't have to do much with one, right?

Yeah, LV and LN planes come out of the box flat with few exceptions and stay that way, whether tensioned (and left tensioned) or not. Ductile iron isn't any stiffer than grey iron, and the castings aren't much heavier, so I don't see why Stanleys would be any different.

That plus back-of-the-envelope engineering math is why I think Tablesaw Tom is dead right about this.

Of course I also think that people sometimes make too big a deal of sole flatness in general. As Japanese craftsmen have long known, there are only a couple/few parts of the sole that actually matter. I love my uber-flat modern planes, but that doesn't mean they aren't overkill...