Everything You Ever Wanted to Know About Stanley Bed Rock Planes

317 SBR605C Type 6 Post 1

Stanley Bed Rock no. 605C, Type 6, c. 1912-1921

History

The motivation behind Stanley’s decision to develop the Bed Rock line of planes is debatable. However, given their genius at marketing and creating demand, I suspect it was driven by a couple of different factors. In 1895, Justice Traut patented what would become the basic Bed Rock design. That same year, E. A. Schade patented the frog adjustment feature that would initially be used on the Bed Rock planes, and eventually (1907) would become a mainstay feature of the Bailey line of planes.

US536746-Traut Bed Rock0

J. A. Traut Patent 536,746, Apr 2, 1895

US545732-Shade Bed Rock

E. A. Schade Patent 545,732, Sept. 3, 1895

The introduction date of Bed Rock planes is a little uncertain. They first appeared in Stanley catalogs in 1900, but there is some evidence they may have begun manufacture as early as 1898. Apparently there was a dispute over the Schade patent, because those sold for the first year or two have the Sept. 3, 1895 patent date on the bed milled out.  This was done by the factory, and after the body had been japanned, indicating there was some sort of legal dispute over the Schade patent that required a last minute intervention prior to the planes being sold to the public.  By 1900, the milled out date was gone and just the single APR 2, 95 date from the Traut patent remained stamped into plane bodies until about 1911, when Stanley introduced a major design change.

Differences between Baileys and Bed Rocks

The Bed Rock line was marketed as Stanley’s premium line of bench planes. There were two primary differences between the Bailey line and the Bed Rocks, and both were in the frog design.

1. The mating surfaces of both plane body and frog was substantially larger than on the Bailey planes, and the frog on the Bed Rock fit into a groove on the body, eliminating any slop or shifting of the frog once in place. As Stanley described it in their marketing material:

The absolute solidity and one-piece effect of the “BED ROCK” PLANE is as much a fact as if the parts were all one, for the reason that the entire under surface of the Frog is in perfect contact with the solid seat cast in the Plane Bottom. The frog and the Bottom are so perfectly fitted together, that from the Plane Iron to the Bottom, the Plane is as one solid piece of metal. This form of construction positively prevents any chance of vibration.

2. Additionally, the Bed Rocks originally featured the frog adjustment mechanism that was patented by Schade on Sep. 3, 1895.  This same feature was eventually added to the Bailey line in 1907. Again, as described in a Stanley catalog:

The width of the mouth may be regulated and made wider or narrower as coarse or fine work may require. First remove the lever and cutter and loosen the two frog screws that fast en the frog t o it s seat. With a screw driver turn the center adjusting screw to the right to close the mouth, and to the left to open it. When the frog is in the position desired, tighten the frog screws and replace the cutter and lever .

Of course, there were other less significant differences as well. Interestingly, Stanley used the same numbering system for the Bed Rocks as the Baileys for the first 2 years of manufacture. It wasn’t until 1900 that the ‘600’ series of numbers (602 through 608) were cast into the plane bodies.  Stanley also had a Bed Rock branded lever cap that was used to help distinguish the two lines. The first design of this cap was marked ‘STANLEY’ on one line, then ‘R.&L.Co.’ on a middle line, with ‘BED ROCK’ on the bottom line. In 1908 the middle line was removed and caps were marked ‘STANLEY’ over ‘BED ROCK.’

Stanley Bed Rock no. 607 Type 3 c. 1900-1908

Stanley Bed Rock no. 607 Type 3 c. 1900-1908

Major Design Changes of 1911/1912

After the frog adjustment feature was added to the Bailey line in 1907, there was little to clearly differentiate the Bed Rock planes from the Bailey planes. For example, while the frog base design was arguably superior, it was a feature that was not readily apparent unless one were to disassemble the plane. Further, up until this point, the profile of the plane base was the same on both Bailey and Bed Rock lines; with both using the same classic ‘hump’ on each cheek. For Stanley to differentiate the two and justify the premium cost of the Bed Rock, it’s pretty easy to see the reasoning behind the changes they were about to make.

1. On March 14, 1911, Schade was granted another patent for the use of pins and set screws to both attach and adjust the position of the frog. This new design was superior to the previous (and the one provided on the Bailey planes), and set the Bed Rock line apart from all of Stanley’s competitors.

E. A Shrade Patent 987,081, Mar 14, 1911

E. A. Schade Patent 987,081, Mar 14, 1911

The Two Frog Attachment and Adjustment Designs

The Two Frog Attachment and Adjustment Designs

2. In addition to the new frog attachment and adjustment design, Stanley, in a move of marketing brilliance, also changed the profile of the body casting, flattening the tops of the cheeks to give the Bed Rock planes a unique look all their own. With such a clear visual distinction, it’s not hard to imagine that this decision was intended to induce those with the financial means to spend a little more and buy the premium Bed Rock planes.

3. The third major change was the addition of a raised receiver for the front knob, and the transition from the low knob to the high knob. It’s interesting that high knobs weren’t introduced to the Bailey line for another 8 years, and the raised receiver wasn’t added to the Bailey design until 1929, some 19 years later!

Miscellaneous

The Bed Rock line included pretty much the same assortment as the Bailey line, with the omission of a number 601, which was never produced. The line included everything else from the 602 to the 608, including half sizes and corrugated versions. The only other exception is that they never made a corrugated version of the 605 1/4.

Bed Rocks were slightly heavier planes with slightly greater mass. The 1934 Stanley catalog offers a comparison, with the no. 603 weighing 1/4 lb more than the Bailey no. 3, and the no. 608 weighing 1/2 lb more than the no. 8.

Prior to the 1911/1912 changes, Stanley manufactured Bed Rock style planes for both Winchester and Keen Kutter. These planes were very similar in design, varying mainly in the lateral adjustment levers, lever caps, and numbering system.

Bed Rock Flyer Bed Rock Flyer-1923

Bed Rock Type Study

The chart below is a summary Type Study of Stanley Bed Rock Planes based on Bob Kaune’s thorough 1996 study and additional research I have conducted over the past several years.   Please note that all type studies are approximate as production variations throughout the manufacturing years were quite common.   Also keep in mind that Type Studies are present day references, time-lines that map changes in the design and features of tools manufactured in the past.  Understand that neither Stanley nor any other manufacturer followed type studies.  They didn’t exist at the time.  In fact, it is only in the last 30 years or so that type studies have been assembled through historical research and the physical inspection of hundreds or thousands of tools made over the years.

Bed Rock Distinguishing Features By Type

Dates

Low Knob – Rounded Sides

Type 1 Beds marked with Bailey model numbers (Nos.2 to 8.)
Space below “PAT’D APR. 2. 95″ was milled out at the factory
S casting mark on bed (a single raised dot on some specimens)
Frogs & Lever Caps have “B” casting marks
Lateral lever has two patent dates “10-21-84 & 7-24-88”
STANLEY R & L CO…BED ROCK on lever caps, Q trademark stamp on most irons

1898

Type 2 7-24-88 is the only patent date on the lateral adjustment lever

1898-1899

Type 2a Model No.603 and 604 beds (only these two) were marked “No.60x”

1899

Type 3 All beds now marked with “600” numbers, i.e.; No.602 – 608
No milled space below “PAT’D. APR. 2. 95.” on bed, B casting marks
Frogs of some planes are nickel-plated on the machined surfaces

1900-1908

Type 4 B casting marks eliminated. No patent dates on the lateral adjustment lever
Lever caps now marked “STANLEY….BED ROCK”
Some irons have “S” trademark stamp, later planes have “T” trademark stamp

1908-1910

High Knob – Flat Sides

Type 5 Beds now marked “BED ROCK” in addition to “600” model numbers
2 patent dates behind frog, “PAT’D. APR. 2. 95″ & APR. 19. 10″
Flat-top sides introduced for first time
Raised knob receiver (flat version), Tall knobs introduced, “T” tm on irons
Frogs are now attached to beds with adjustment pins and set screws

1911

Type 6 Lever caps now marked “BED ROCK”
Irons stamped with “V” trademark or “X” trademark stamps

1912-1921

Type 6a 1-1/4″ diameter frog adjustment wheel
Iron stamped with “Y” Trademark (1922-1923)

1922

Type 7 One patent date behind the frog – “U.S. PAT. APR. 19. 10.”
Lever caps marked “STANLEY” only in the notched rectangular logo
Irons stamped with “AA” Trademark (1923-1935)

1923-1926

Type 8 Bed now stamped “MADE IN USA” in addition to the one patent date
Knob receiver boss now cupped for fitting knob

1927-1930

Type 9 Beds no longer have a patent date; stamped “MADE IN U.S.A.” only
Some lever caps nickel-plated with orange paint behind STANLEY logo

1931-1932

Type 10 Beds of No.603, 604 & 605-1/4 planes have raised handle receivers
Some frogs have orange paint on sides like Bailey planes
Lever caps now have kidney-shaped bolt holes
Irons stamped with BB tm starting in 1936

1933-1941

Type 11 Castings are heavier and thicker during war production years
Finishes left rough; lever caps not plated or polished

1942

Type 12 Frog adjustment nut either hard rubber or small diameter steel
Knob and handle are hardwood (maple) with dark varnish stain
All brass parts eliminated during war-time production
END OF PRODUCTION FOR BED ROCK PLANES

1943

The chart below lists specifications for Stanley’s line of Bed Rock planes.

Plane No. Dates Made Iron Width Length Weight
No. 602 1898-1942 1 5/8 7 2 lb 4 oz
No. 602C 1898-1923 1 5/8 7 2 lb 4 oz
No. 603 1898-1943 1 3/4 8 3 lb 4 oz
No. 603C 1898-1935 1 3/4 8 3 lb 4 oz
No. 604 1898-1943 2 9 3 lb 12 oz
No. 604C 1898-1935 2 9 3 lb 12 oz
No. 604 1/2 1898-1935 2 3/8 10 4 lb 12 oz
No. 604 1/2C 1898-1935 2 3/8 10 4 lb 12 oz
No. 605 1898-1942 2 14 4 lb 8 oz
No. 605C 1898-1935 2 14 4 lb 8 oz
No. 605 1/4 1925-1943 1 3/4 11 1/2 4 lb
No. 605 1/2 1898-1935 2 1/4 15 6 lb 8 oz
No. 605 1/2C 1898-1937 2 1/4 15 6 lb 8 oz
No. 606 1898-1941 2 3/8 18 7 lb 6 oz
No. 606C 1898-1934 2 3/8 18 7 lb 6 oz
No. 607 1898-1943 2 3/8 22 8 lb 12 oz
No. 607C 1898-1935 2 3/8 22 8 lb 12 oz
No. 608 1898-1940 2 5/8 24 9 lb 12 oz
No. 608C 1898-1935 2 5/8 24 9 lb 12 oz

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References

Kaune, Bob, Bed Rock Type Study, 1996

Sellens, Alvin, The Stanley Plane, 1975

Smith, Roger, Patented Transitional & Metallic Planes In America, Vols. I & II, 1992

Walter, John, Stanley Tools – A Guide to Identity & Value, 1996

Various Stanley catalogs, flyers, pamphlets

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The 5 Hand Planes Everyone Should Own

Unless you live in a city apartment, or happen to be wealthy, disinterested, or lazy enough to pay someone to do all of your home maintenance projects, chances are now and then you have need of a hand plane.  Even the most ardent power tool minded woodworker can’t escape the reality that some jobs are just easier solved by a couple of passes with a hand plane than with anything you plug into an electrical outlet.   Whether you’re an active hand tool user, a neophyte learning to work wood by hand, a weekend woodworker or a casual homeowner, a basic set of good hand planes is essential.

There’s a great deal of generalization that goes into compiling a list like this.  Because hand planes tend to be used for specific applications, some woodworkers my find greater utility in some planes than others.  Someone who makes musical instruments would obviously need different tools than a furniture maker.  But speaking in the broadest sense, these are the 5 essential hand planes that virtually everyone should own.  Certainly for anyone interested in acquiring a first set of planes to use around the shop, farm, or house in the suburbs, these tools offer the greatest utility and versatility.

1. Fore Plane – The Stanley No. 5

Stanley Bailey No. 5, Type 11 (c. 1910-18)

Stanley Bailey No. 5, Type 11 (c. 1910-18)

Fore planes are those ranging from approximately 14 inches to 18 inches in length. In the Stanley bench plane assortment, these include the nos. 5, 5-1/4, 5-1/2, and 6. The term ‘Fore’ dates back several hundred years and is generally assumed to be a contraction of ‘Before’ and interpreted as the plane used first in flattening a surface. “It is called the Fore Plane because it is used before you come to work either with the Smooth Plane, or with the Joynter.” [1]

As the first plane one would use in preparing a surface, the Fore plane takes the most aggressive cut, removing rough saw marks and leveling out low and high spots, etc. The iron is sharpened with a significant camber, or curvature to the cutting edge, with as much as 1/16″ to 1/8″ difference between the center and the edges. This removes the most waste, but subsequently leaves the surface of the wood with a scalloped finish.

While either the Stanley no. 5 or no. 6 will do, the no. 5 is the better choice in our 5 plane roundup. Rough planing is a very physical activity, and the lighter weight of the no. 5 makes it less fatiguing to use. It’s smaller size also makes it more appropriate for the wide variety of other day to day planing jobs that most people likely face. The no. 5 is, in my opinion, the most versatile of all the bench planes and the plane I use most often.

2. Try (or Jointer) Plane – The Stanley No. 7

Stanley Bailey No. 7, Type 10 (c. 1907-09)

Stanley Bailey No. 7, Type 10 (c. 1907-09)

Try planes, more commonly known as Jointer planes, are those over 18 inches, and are most commonly 22 to 28 inches. Stanley’s offering of Jointer planes are the no. 7 and no. 8, measuring 22 inches and 24 inches respectively.As the name implies, a Jointer plane excels at truing the edges of long boards that will be glued together to make table tops, shelves, and carcasses. But its value and place on the workbench isn’t limited to edge work. The Try, or Jointer, plane is used to flatten and refine the surface left by the Fore plane. Its extra length allows it to true large flat surfaces without riding up over the peaks or dipping down into the valleys created (or left uncorrected) during the initial surface preparation.

Despite its heft, the Jointer should be considered a precision tool. The iron should be sharpened with a slight camber (or perhaps none at all if used exclusively for edge work), and the frog typically adjusted with a fine set for thinner shavings than the Fore plane. Working both across the grain and in all directions, the Try plane leaves a perfectly flat surface that requires only final touch up with the Smoothing plane.

Your choices between the two standards, nos. 7 and 8, are really a matter of personal preference. In this case, Newton’s laws of motion lend a helping hand.  The greater heft is actually a benefit, in that once you get it moving the additional mass helps keep it going with less effort. That said, the no. 8 is quite a beast, and my personal preference is for the lighter and shorter no. 7, which I find easier to manage.

3. Smoothing Plane – The Stanley No. 4

Stanley Bailey No. 4C, Type 10 (c. 1907-09)

Stanley Bailey No. 4C, Type 10 (c. 1907-09)

Smoothing planes include the shorter planes in the lineup, those 10 inches or less. Stanley made a number of planes in this range, from the tiny no. 1 to the most popular no. 4 and its wider sibling, the 4-1/2.The Smoothing plane is the final plane used prior to applying the finish. Executed properly, there should be no need for sandpaper. Used primarily with the grain, the Smoothing plane is normally sharpened with just the slightest camber or left straight with its corners eased to prevent them from digging in or leaving tell tale ‘lines’ along the edge of the cut. The frog is adjusted with a closed mouth for the finest of cuts, and the shavings produced are tissue thin, ideally produced from long strokes covering the full length of the wood. Aside from perhaps a little hand scraping here and there, the surface left by the Smoothing plane should require no further treatment. In fact done correctly, sanding would actually diminish the quality of the surface left by the Smoother.

More so than with the Fore and Try planes, the choice of which size Smoother is really a matter of and comfort and the scale of your work. All of them will do a comparable job, although the nos. 1 and 2 are really only suited for very small surfaces (and very small hands). The no. 4 is considered the most versatile size, and the one I use most often. However, I do have a smaller no. 3 and a wider no. 4-1/2 that I reach for, depending on the size of the project. But since the point of this article is to identify the three core bench planes you’ll need for woodworking, the no. 4 is probably the best overall size choice for a single Smoothing plane for most people.

4. Standard Angle Block Plane – The Stanley No. 18 

Stanley Bailey No. 18, Type 17 (c. 1947-50)

Stanley Bailey No. 18, Type 17 (c. 1947-50)

This is my go-to block plane for everyday use, the one I always seem to grab first.  Mine is a very pristine WWI era model that I’m pretty sure I’ve used more than anyone else in its history.  Although it’s almost 100 years old, it looks like it could have been manufactured last year.  Both the japanning and nickel plating are pushing 100%, and so I baby it.

The Stanley no. 18 is a standard angle plane, meaning the iron is seated on a 20 degree bed.  With a bevel angle sharpened at the standard 25 degrees, you have a cutting angle of 45 degrees, same as a bench plane.  It also has an adjustable throat plate, an essential feature in a block plane.  The no. 18 is 6 inches long and fits my hand better than its longer, otherwise identical 7 inch brother, the no. 19.  And unlike the more popular Stanley no. 9-1/2, it feels more like an extension of my hand.

The no. 9-1/2 plane predates the no. 18 by about 15 years, was in production longer, and was the best selling block plane Stanley ever made.  It’s still made today, in fact, although the current design features a completely different mechanism from the original.  Admittedly, the no. 9-1/2 was the more popular of the two.  I truly don’t know why, though, since the design of the no. 18′s knuckle cap was far superior to the hooded lever cap on the no. 9-1/2, and it’s also more comfortable to hold in the hand.  I also find that the hooded cap on the no. 9-1/2 is more prone to slip around a little in use.  Not so with the no. 18.

Ironically they are both basically the same plane with two different styles of lever caps.  Other than the lever cap and its mounting bolt, all the other parts are interchangeable. Stanley charged a little more for the no. 18 and marketed it as virtually indestructible.  This of course was not true, for while the steel cap is arguably more durable, the bodies of both were cast iron and therefore susceptible to breaking if dropped.

I have several vintages of both models in my collection, but find the no. 18 with the knuckle cap superior in both function and comfort.  I use this more often than any other block plane I own.

5. Low Angle Block Plane –  The Stanley No. 60 

Stanley Bailey no. 60 Type 2 (c. 1901-04)

Stanley Bailey no. 60 Type 2 (c. 1901-04)

The Stanley no. 60 (and the identical japanned version 60-1/2) is a low angle plane, meaning the iron is seated on a 12 degree bed.  Sharpened at 25 degrees, you have a cutting angle of 37 degrees.  The primary advantage of the lower angle of attack is that it excels at shaving end grain.

Like the no. 18, the 60 series of planes are approximately 6 inches long.  However, the 60 series are narrower with an iron width of 1-3/8 inches, vs the 1-5/8 inch irons on the standard angle planes, and the 60 series feature a narrower version of the hooded lever cap used on the no. 9-1/2.  The 60 series planes also have adjustable throat plates.

Low angle planes are typically used for cutting end grain, i.e., across the end of a cut, verses cutting along the grain, down the side of the wood.  The lower angle is perfect for the shearing action needed to cut those end fibers.  On cuts that will be visible and finished, this produces a very clean and smooth surface, whereas if left as cut from the saw, the grain tends to be very rough and porous.

On both standard and low angle block planes, the iron is seated bevel up, whereas on bench planes the bevel is usually down. There is a tremendous advantage with bevel up irons in that the angle of the bevel can be changed to affect a change in the angle of cut.  While there is more to consider in edge geometry than just the angle of cut (durability), you could reasonably sharpen the bevel on a low angle plane iron to 33 degrees and end up with an angle of cut of 45 degrees (12+33=45), the same as on a standard angle plane.  However, to accomplish a low angle of cut using a standard angle plane, you’d have to sharpen the bevel at a very shallow 17 degrees (20+17=37).  Durability of such a thin cutting edge would be problematic with most woods.

For this reason, along with a few others, many people consider the low angle plane to be the more versatile of the two. I tend to agree.  While I use my standard angle plane more often, if I could only have one block plane, it would have to be a low angle.

***

For more detailed information on the three step process using hand planes, I highly recommend you check out Christopher Schwarz’s outstanding Course, Medium, and Fine, available on DVD.

Tools shown in the photos were returned to functional condition by Virginia Toolworks using museum quality archival preservation techniques.  Sharpened and tuned for use, every tool is fully tested and adjusted until perfect.

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1. Moxon, Joseph. Mechanick Exercises. London, 1703.

Understanding Type Studies

Catalog Image of Stanley Bailey Smoothing Plane, c. 1880sLet’s be honest, Type Studies are confusing to a lot of people, especially those new to tool collecting. One reason for this is that by their very nature, Type Studies attempt to identify very specific points in time that correspond with transitions in the design and manufacturing process of tools made in the past. There are many problems with this.  First and foremost, manufacturers never imagined that anyone in the future might care about tracking changes in the evolution of their designs.  Subsequently, even veterans who know better sometimes lose sight of just how blurry those lines of delineation are along the historical manufacturing timeline.

The first thing to clearly understand is that Type Studies are a present day construct. They were not a production guide used by manufacturers to identify, notate, or track changes in design.  Stanley and their competitors didn’t follow Type Studies.  Why, you ask?  Because Type Studies didn’t exist at the time the tools were made.  Did you get that?  Type Studies are a present day guide.

It was not until the 1970s and ’80s that people really started thinking about collecting vintage hand tools. And it’s only in the last 10 or 15 years, when woodworking with hand powered tools has enjoyed a resurgence, that vintage tool collecting has started to explode in popularity.  The big name hand tool aficionados (Roger Smith, Alvin Sellens, Clarence Blanchard, and others) conducted extensive research, pouring over company records and old catalogs and detailing the physical variations of thousands of tools in order to begin piecing together timelines for various models.

These timelines, delineated by significant and important changes in the design and manufacture of a tool are referred to as Type Studies.  Different ‘Types’ within a Type Study refer to a defined period of manufacture in which a particular set of features was unique.  That said, the change from one Type to another doesn’t mean the entire tool was redesigned.  In fact, virtually all feature changes overlapped others, and a given feature or set of features might extend over several Types.  A good example can be illustrated with the lever caps used on Stanley’s Type 13-15 bench planes made between 1925 and 1932.  While the same design cap was used on all three types, there were other feature changes that delineate the three different date ranges on the Type Study time-line.

Summing it all up, here are five important confusion-busting facts about Type Studies that should provide clarity:

    1. Type Studies are modern-day timelines used to identify the age of a tool by referencing important changes in its design, manufacture, and physical characteristics.  Different ‘Types’ within a Type Study refers to a particular period of manufacture in which a particular feature or set of features was unique.
    2. Manufacturers didn’t adhere to Type Studies because Type Studies did not exist at the time.  They simply manufactured tools and made periodic changes to design and manufacturing processes, just like manufacturers today.  We identify those periodic changes in the Type Study, and subsequently assign ‘Types’ based on the time period in which they were made.
    3. Type Studies are not interchangeable.   They only apply to a specific model or series of tools.  Different tools and different lines will have different Type Studies.  For example, Stanley’s Bailey line of bench planes have a completely different Type Study from the Bed Rock series.   Some tools, like the no. 71 router plane, have their own individual Type Study.  Many tools have never been studied in depth and don’t have a Type Study at all.
    4. Type Studies are approximations.  The manufacturing timeline was constantly evolving.  Even when design changes were made, existing (old) stock parts were used until their supply was depleted before moving to new parts.  Therefore, the changeover of features sometimes took months or even years, resulting in multiple variations of the same product being released at the same time.  While Type Studies imply that these changes were aligned with a specific date or year, collectors need to understand that the transitions were more evolutionary than revolutionary.
    5. Type Studies are not all-inclusive.  With some manufacturers and some tools, and some tools made during certain periods, features and materials varied quite a bit.  A good example of this is Stanley’s offering of Bailey bench planes made during World War II.  Brass was in short supply, and subsequently, the so-called Type 17 planes made during the war years have a variety of inconsistencies.  Some had brass hardware, where others have steel.  Some have rosewood knobs and totes, while others have painted hardwood.  Some have frog adjustment mechanisms while others don’t.   All made during this period, however, are considered Type 17, regardless of features.

***

Corrugated Planes are Groovy, Baby!

Stanley Bedrock no. 607C, c. 1911

Let me just put it out there right up front – I like corrugated planes.  Sure, their practical value is questionable.  I don’t care.  I like them, and all of the bench planes I use, as well as most of those in my humble collection, have corrugated soles.

Corrugations are a series of grooves milled into the sole of the plane.  Running front to back and spaced about 1/8″ apart, they stop short of the mouth at both the front and rear sections.  Introduced to the Stanley line of bench planes in 1898, corrugations were available on all sizes from the no. 2 through the no. 8, as well as the comparable sizes in the Bedrock series.  The no. 1 was never offered with a corrugated sole, and the no. 5-1/4 wasn’t introduced until 1921.  All the others, however, were available with corrugations and were distinguished from the plain versions by the suffix ‘C’ appended to the model number – nos. 2C, 3C, 4C, etc.  All the corrugated models were sporadically discontinued between the mid 1940s and mid 1960s.

While some argue that the feature was more a competitive marketing vehicle than a functional improvement, Stanley offered no explanation in its 1898 brochure, only stating “corrugated bottoms furnished without additional expense if so ordered.”  The reasoning most frequently accepted has to do with the vacuum created between two flat surfaces in contact with each other.  I’m no physicist, but I do know a little about science.  While this phenomenon is easily demonstrated with two sheets of glass, I have a hard time believing that wood is capable of creating much of a vacuum when in contact with something as small as the sole of a plane, even the large ones.

In my opinion, the reason why corrugations might work in theory is a simple matter of reduced friction.  Friction is defined as the resistance an object encounters in moving against another object.   Imagine that you are trying to push a plane across a board. If you apply a very small force, the plane will not move.  The frictional force between the two surfaces is greater than the force with which you are pushing the plane.  If the frictional force was less than the force you exert, the plane would slide forward.   So, in order to move the plane, you can do one of two things – reduce the frictional force of the plane against the board on which it sits, or push harder.

By milling grooves into the sole of the plane, Stanley reduced the amount of surface area that contacts the wood, the effect of which was to reduce the coefficient of friction between the two surfaces.  In theory, this should make a corrugated plane easier to push forward than one with a smooth sole.  This makes more sense to me than the theory of a vacuum created between the two surfaces, but I’m sure some will disagree.

Whether or not using a plane with a corrugated bottom provides a noticeably different experience to the average woodworker is debatable, but the idea clearly gained traction (no pun intended).  While less common than their flat soled brethren, corrugated versions were successfully sold for well over a half a century, and are still offered by some modern manufacturers today.

So here’s to corrugated planes… Easier to push or not, they’re groovy, baby!  Yeah!

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