Here are the  guys who started this all in early plane history.

Does Corrugation Reduce friction on a Hand Plane  This has been debated over and over. I decided to perform an unscientific test. Equipment was not the best, but I think the results speak for themselves.

I took some planes from my type 11 set. A #5,#5C,#6,#6C and #7 and 7C. I dragged these across my wooden benchtop with the blade up.

I did each drag 3 time to ensure consistent results. Each drag went the length of my bench.

I add weight to simulate downward pressure from planing one every other pull set.

I used my old Zebco fishing scale. Not highly accurate, but accurate enough for what I was looking for.

IMG_20170202_151557725

Note it was very hard to differentiate a #5 pull when it was not weighted due to the scale I used. That is why some test only include the #5 weighted.

#5 weighted #6 weighted #7 weighted
Smooth 2.75# Smooth 3.66# Smooth 4.0#
Corrugated  2.25# Corrugated  3.0# Corrugated  3.0#
     
  #6 unweighted #7 unweighted
  Smooth 1.25# Smooth 2.0#
  Corrugated  1.33# Corrugated  1.66#

The results are in pounds pulled.

In a second round of testing, I tried to be a little more methodical. I waxed the soles of all of the planes before beginning with Johnsons Past wax. I never did 3 pulls on a plane at a time to avoid the transfer of wax to the benchtop or lumber piece to be a significant issue. I pulled a smooth sole, then a corrugated sole, then a smooth sole, then a corrugated sole and so on for 3 repetitions.

The last pull in this series is on a pieIMG_20170202_151551711ce of air dried rough sawn black birch.

Here is the benchtop pull first.

#5 weighted Pull 1 Pull 2 Pull 3
Smooth 2.33 2.33 2
Corrugated 2 2 1.0

 

#6 unweighted Pull 1 Pull 2 Pull 3
Smooth 1.33 1 1.33
Corrugated 1.33 1 1.33

 

#6 weighted Pull 1 Pull 2 Pull 3
Smooth 2.5 2.6 2.25
Corrugated 2 1.25 2.25

 

#7 unweighted Pull 1 Pull 2 Pull 3
Smooth 2 1.75 1.75
Corrugated 1.75 1.25 1.5

 

#7 weighted Pull 1 Pull 2 Pull 3
Smooth 3 2.8 3.1
Corrugated 2.75 2 2.25

___________________________

And now the results when being pulled on a rough sawn black birch piece.

 

#5 unweighted Pull 1 Pull 2 Pull 3
Smooth 1.75 1.25 1.33
Corrugated 1.6 1 1.25

 

#5 weighted Pull 1 Pull 2 Pull 3
Smooth 2.9 2.9 2.75
Corrugated 2.25 2.75 2.6

 

#6 unweighted Pull 1 Pull 2 Pull 3
Smooth 2 1.9 1.8
Corrugated 1.9 1.75 1.75

 

#6 weighted Pull 1 Pull 2 Pull 3
Smooth 3.33 3.25 3.1
Corrugated 3.1 3 3

 

#7 unweighted Pull 1 Pull 2 Pull 3
Smooth 2 2 1.9
Corrugated 1.8 1.8 1.8

 

#7 weighted Pull 1 Pull 2 Pull 3
Smooth 3.3 3.25 3.1
Corrugated 3.1 3 3

 

The weight of the planes used in this test.

#5 4.8 ozs
#5C 4.46 ozs
#6 6.8 ozs
#6C 6.68 ozs
#7 7.78 ozs
#7C 7.28 ozs

The results show a corrugated plane is going to push easier. We can still debate whether that effect actually makes a difference in real life, especially given most woodworkers today are hobbyist and will not be planing all day long. But if you do plan to plane all day long, this information may help.

A final Note – This is NOT me telling you to go out and replace all your smooth bottom planes with corrugated. I still doe not believe the difference in a corrugated bottom will make a noticeable difference in every day use. And I don’t care for corrugated planes for jointers, the grooves tend to pinch my finger when jointing. But you can be the judge. This is just stating facts. 

Here are the  guys who started this all in early plane history.

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