Origin of the Skil 100 Planer

April 17 2019 – Florian Saylor

Skil 100 Patent
by Florian Saylor

The Skil 100 Planer was invented by Henry Spitzley in the late 1940's. The 7th born of 14 children, Henry grew up on a farm near Portland, Michigan during early 1900's. Henry became a machinist by trade, and was described by his family members an exceptionally innovative 'tinkerer' but also a life-long bachelor. 

His idea for the planer invention was to create a portable power-driven planer with speed and efficiency to keep up with the current building construction boom. Portable electric planers of the time were so large, that they often required two workers. He also wanted to improve the planer depth regulating devices of the time to create a depth control that allowed for close tolerance cuts. 

In his patent, he explains "the adjusting mechanism of the planer may slantingly be moved forwardly or backwardly, which moves the said mechanism downwardly and upwardly, respectively. I wish particularly to point out that the depth regulating device of my invention used in combination with the planer, can be readily adjusted to cut at substantially any desired depth and the said adjustment can be of extremely close tolerance."

Henry Spitzley, not knowing how to market the product, went to Schaberg Dietrich Hardware a wholesale hardware company in Lansing, Michigan. "SD Hardware" approached Skil Corp. with the invention, and Skil bought the rights and paid Henry $1 and SD Hardware $1 for every planer sold. Henry eventually received $125,000 over the life of the patent, which would translate to approximately $1.1 million in today's dollars. Henry never spent any of the money, he lived a frugal life and eventually died in 1974.

The Skil 100 wasn't the only invention for Henry. He had a family member in the meat packing business who complained that they destroyed several guns a day killing cattle. Henry went on to design the Cattle Stunner tool to solve this problem. The Humane Society awarded him $1,000 for developing a more humane way to slaughter at the time. You may recall the cattle stunner being used in the movie 'No Country for Old Men' to destroy door locks and other graphic uses. 

Henry’s remaining family finds it interesting that his tool invention is used widely by surfboard shapers to this day, as its intended use was so different in the eyes of the old-style bachelor. He was able to make an impact on many different subcultures through his innovations and problem-solving skills.

Skil 100 Inventor


  • David Huhn: April 25, 2019
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    I am not aware of any worm drives. I have my uncle Henry’s original first run plane and it is a 676 type 1. Skil used the lever to adjust depth.

  • Jonathan Anastas: April 21, 2019
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    In the diagrams above his original design was worm drive were any of those made

  • Kiki O'Brien: April 21, 2019
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    I’ve owned three and like Doug also love the history lesson. The ergonomics and depth adjuster makes it a superb plane. I’ve only owned two other planes, both cheapos so cannot draw any comparisons with other quality planes.

  • Doug Maupin: April 17, 2019
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    Fascinating History lesson I love the skill 100 and have a few. The skill saw invention is similar. When it was first in use it was so ureliable it had to be fixed every night for use the next day. But it was so useful they did fixed them every night until they made improvements to reliability !

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