Hand Plane Surface Grinding

[AHill]

I've heard knowledgeable metallurgy people say will re warp even if surfaced due to inherent stress in the metal.

I asked a machinist friend about this once and showed him a plane.  He said he wouldn't guarantee anything because the plane goes in tension when the lever is clamped, but mostly, there's a huge issue mounting the plane in a fixture securely without distorting the sides.

The former is bunko.  I'm also a metallurgical engineer.  Residual stresses in cast iron - especially on really old cast iron, have dissipated after aging.

The latter is true. The most challenging part of grinding a plane body is holding it and preventing induced stresses while clamped on the grinder.  If you clamp the body too tightly, the flat grind while clamped might not be flat when unclamped.  That's the skill Tom brought to the table.  Tom ground things because he had the skills and he could.  If a plane can give you consistent width 0.001" shavings, no matter what you measure on the sole, it's good enough for woodworking.

[Tony Z]

Not only clamped but supported at heel & toe.

It takes a very knowledgeable machinist/toolmaker to do this properly.

[Timberwolf]

Not only clamped but supported at heel & toe.  

It takes a very knowledgeable machinist/toolmaker to do this properly.

LIL
.................
My two cents........................somewhere around here I have an old Stanley Catalog and IIRC it is from around 1920..The main thing I remember was the photo of a Stanley employee holding what appeared to be the sole of a #7  on a very large belt sander..The machine had a belt about 12" in width and several feet long..The worker was holding it with both hands against the belt...Stanley was making tools for "carpenters" working in "softwoods"...not the hard native species or exotic imports.
   We have to remember the fine furniture that has been created for centuries by craftsmen using nothing but crude planes with hardwood soles and bodies..We all know that wood is an organic material that "moves" with changes in humidity and temperature...How "flat" can they be????

     I follow Stanley's lead and use a 6"X48" belt grinder to "true up" the soles if needed...but I actuate the belt using a foot switch..Place the sole on a stopped belt and holding it with both hands, step on the switch and I stop the belt first, before removing the plane...if you want it any better, follow that on  a surface plate and sand cloth...use a black marker to define the hollow spots and sand them away..Do this with the iron under tension...Not "perfect" but I doubt you could tell the difference between that procedure and one that has been "surface ground"....Look at the shavings that japanese craftsmen achieve with their wood-bodied planes and ask yourself if you could do any better...
 

[Strokes77]

But Mr. Timberwolf sir.  

If I can slip a Starrett feeler gauge (chinese feeler gauge's clearly won't work) underneath my Starrett steel strait edge when testing flatness of my #5 jack plane, then it would be utterly impossible to appropriately flatten my table top. 

Impossible I say.

[Admiral]

But Mr. Timberwolf sir.  

If I can slip a Starrett feeler gauge (chinese feeler gauge's clearly won't work) underneath my Starrett steel strait edge when testing flatness of my #5 jack plane, then it would be utterly impossible to appropriately flatten my table top. 

Impossible I say.

It will if the toe, heel and areas before and after the mouth are coplanar.  Nothing else matters, really.

Japanese planes actually have a purposeful and intentional convexity, and they have make things flat for centuries.  Read about the "Plane Body" here: http://www.toolsfromjapan.com/store/inde...&chapter=5

where it is said:

"The shita-ba, plane bottom, is not flat as might be found on other planes. The reasons for this is to reduce the effort required to pull the plane on the wood being planed and to allow the critical areas at the very front of the plane (in it's direction of travel) and the area just ahead of the mouth to be easily and quickly adjusted so they are 'in plane' with each other. Aside from these two critical areas, most kanna have the remaining area of their bottoms 'relieved' so they are not touching the wood being planed at all. There are exceptions to this rule of course, but the common dimensioning or smoothing plane only touches the wood being planed in these two relatively small areas." 

[Timberwolf]

It will if the toe, heel and areas before and after the mouth are coplanar.  Nothing else matters, really.

Japanese planes actually have a purposeful and intentional convexity, and they have make things flat for centuries.  Read about the "Plane Body" here: http://www.toolsfromjapan.com/store/inde...&chapter=5

where it is said:

"The shita-ba, plane bottom, is not flat as might be found on other planes. The reasons for this is to reduce the effort required to pull the plane on the wood being planed and to allow the critical areas at the very front of the plane (in it's direction of travel) and the area just ahead of the mouth to be easily and quickly adjusted so they are 'in plane' with each other. Aside from these two critical areas, most kanna have the remaining area of their bottoms 'relieved' so they are not touching the wood being planed at all. There are exceptions to this rule of course, but the common dimensioning or smoothing plane only touches the wood being planed in these two relatively small areas." 

.......................
All true!!!


"Japanese planes actually have a purposeful and intentional convexity, and they have make things flat for centuries. "..

Reminds me of a time in 1945 when our Army Air Corps made two large areas of Japan pretty "flat".........
 

[EricU]

seems to me that it really matters what your depth of cut is  before you should worry about distortion on a grinder.  They all have magnetic chucks.  Not all that much force, but it doesn't take much.  Makes grinding Ti really difficult
''

It's been a while since I have seen a pic, but it seems that Tom used a right angle plate and started on the sides.  

I have a 20 y.o. stanley that is so badly out of flat it doesn't cut.  The old ones were never that bad.  You don't need them to be ground, which is a good thing given that it's going to cost a lot to get it now.

[opticsguy]

Picked up a Stanley #6 a few years ago. Performed poorly and examination showed some warp/curvature to the body.
Held the plane body against my 6" horizontal belt sander just long enough time to flatten.  This plane is now a very excellent performer.
Nuff said........

[Admiral]

I generally don't buy planes that have warp, a keen eye at the markets takes some time to develop, and I leave them on the table and walk away unless the price justifies it as a parts plane.  

Now, the belt sander technique will surely work, but a note of caution, as one can do more damage to the plane if you aren't careful and attentive when using a belt sander, and experience is key.  So for those out there who have a plane that does good work, but maybe has some pitting in the sole and you feel somehow compelled to achieve a perfect sole, the better route is lapping on sandpaper on a flat surface, much more control and much less chance of buggering the sole up.  Yeah, it takes a lot more time and is really a PITA, but the effort is worth it.  In other words, I don't recommend belt sanding for anything other than gross imperfections (i.e., its useless otherwise due to the warp or other serious problem) unless you are skilled in doing this sort of thing.  It's also hard to keep the cheeks square to the sole, which is not all that important unless you plan to use the plane as a shooter.

Oh, and some pitting on the sole, so long as the toe, heel and mouth are coplanar, means nothing in terms of performance, its just "round corregation" really . . . . .  Of course, we all know why we lust for totally flat and perfect soles, but sometimes less is more so long as the plane does what it should.

[bandit571]

Machine grinding the soles of hand planes...ranks right up there  with hand scraping a block plane to make it "flat"   pure silliness.

Oh, and there was a video out of that hand scraping of a block plane, even......he even machined a new ( and ugly) way to adjust the opening of the mouth......

Too many think a plane's sole "warps", when all that really happens is just plain wear.    After a 100 or so years of use, cast iron will wear a bit. and, depending on how it was used, will determine  how the wear shows up.   If you run the plane at a diagonal all the time...guess where the wear shows up....

Why would I try to grind a sole flat, by taking iron off, leaving a sole even thinner than it was?     About like "mud" spelled backwards...