CT-8 20-Degree Plane

Any cutting edge is the intersection of two planes. These two surfaces in a plane iron are the back of the iron and the bevel. The five factors impacting sharpness are: the material to be cut, the metallurgy of the plane iron, the temper of the tool steel, the surface quality of the intersecting planes and the intelligence of the user. Four of these five criteria have been addressed with this plane iron....

The precision ground, A-2 tool steel plane iron of the CT-8 20° Precision Block Plane is cryogenically tempered and will keep a razor edge much longer than traditional tool steels. (Cryogenic tempering is a supplemental process to heat/quench tempering where tool steel is cooled below -300 degrees Fahrenheit in liquid nitrogen for several hours, which completely and thoroughly alters the molecular structure of the steel. The results are dramatic! The fine grain structure of the metal allows for extremely sharp edges that stay sharp much longer than traditional processes.) After tempering, the back is lapped. This mirror surface will never need to be visited for sharpening! The primary bevel is ground to 25 degrees and a final 30-degree micro-bevel is achieved with an 8000-grit water stone. 

Beginning with a solid blank of stainless steel, the interior bosses of the tool are precisely CNC milled. The throat is completely adjustable allowing you to tailor the tool to your needs. The last machining step is grinding. The CT-8 20° Precision Block Plane will need no assistance from you to be true. We believe the CT-7 and CT-8 are the only planes with stainless steel soles for a very good reason, this material is very difficult to work, the results however are well worth the effort.

The solid brass sides of the CT-8 20° Precision Block Plane are joined to the sole with an interlocking double dovetail joint. This joint is difficult and time consuming and equally difficult to figure out. Most of you will wonder how we got this tool together—both exposed surfaces of the joint are dovetailed! After assembly, the sides are ground square to the sole, so the CT-8 20° Precision Block Plane can be used on it’s side to shoot an edge.

The iron of the CT-8 20° Precision Block Plane is adjusted by a stainless steel, 40 threads per inch lead screw (identical to a micrometer) mechanism. One full revolution moves the blade forward .025", however because of the 20 degree blade pitch, actual edge advancement is .009" per revolution. With one-quarter turn of the adjustment knob, you advance the cutting edge 0.00225" which is less than the thickness of a human hair! Finally, the blade adjustment shaft exits through a brass-bushing inset into a wooden infill.

Lateral adjustments are done manually by canting the undersized blade either left or right. (It is important when honing to keep your fresh edge square to the sides. This is a precision tool and will not cut square if you are not reasonably close in your sharpening techniques.)

Investment cast from silicon brass, this gorgeous study of motion and functionality is the key visual element of the tool. The radial knurls of the locking wheel create a contrasting visual feast and a functional mechanism for securing the blade to the body of the tool. The portion of the cap in contact with the blade is milled, insuring a light-tight seam that eliminates chatter and keeps the razor edge rigid to withstand the forces of cutting.

Functionality was the driving criteria for this plane design. The front knob is smooth to the touch and can be used as a finger rest for one-handed use or as a knob for two-handed applications. It also serves as the lock for the adjustable throat. The curvature of the handle allows hands of all sizes to comfortably use this tool without compromises. The sides are free of intersecting protrusions allowing either to be a reference for side cutting applications. The rosewood or ebony infills are a unique final touch.

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This item is no longer in production and is not available for purchase. It is listed here for reference purposes only.

Regular price $39.00

Any cutting edge is the intersection of two planes. These two surfaces in a plane iron are the back of the iron and the bevel. The five factors impacting sharpness are: the material to be cut, the metallurgy of the plane iron, the temper of the tool steel, the surface quality of the intersecting planes and the intelligence of the user. Four of these five criteria have been addressed with this plane iron....

The precision ground, A-2 tool steel plane iron of the CT-8 20° Precision Block Plane is cryogenically tempered and will keep a razor edge much longer than traditional tool steels. (Cryogenic tempering is a supplemental process to heat/quench tempering where tool steel is cooled below -300 degrees Fahrenheit in liquid nitrogen for several hours, which completely and thoroughly alters the molecular structure of the steel. The results are dramatic! The fine grain structure of the metal allows for extremely sharp edges that stay sharp much longer than traditional processes.) After tempering, the back is lapped. This mirror surface will never need to be visited for sharpening! The primary bevel is ground to 25 degrees and a final 30-degree micro-bevel is achieved with an 8000-grit water stone. 

Beginning with a solid blank of stainless steel, the interior bosses of the tool are precisely CNC milled. The throat is completely adjustable allowing you to tailor the tool to your needs. The last machining step is grinding. The CT-8 20° Precision Block Plane will need no assistance from you to be true. We believe the CT-7 and CT-8 are the only planes with stainless steel soles for a very good reason, this material is very difficult to work, the results however are well worth the effort.

The solid brass sides of the CT-8 20° Precision Block Plane are joined to the sole with an interlocking double dovetail joint. This joint is difficult and time consuming and equally difficult to figure out. Most of you will wonder how we got this tool together—both exposed surfaces of the joint are dovetailed! After assembly, the sides are ground square to the sole, so the CT-8 20° Precision Block Plane can be used on it’s side to shoot an edge.

The iron of the CT-8 20° Precision Block Plane is adjusted by a stainless steel, 40 threads per inch lead screw (identical to a micrometer) mechanism. One full revolution moves the blade forward .025", however because of the 20 degree blade pitch, actual edge advancement is .009" per revolution. With one-quarter turn of the adjustment knob, you advance the cutting edge 0.00225" which is less than the thickness of a human hair! Finally, the blade adjustment shaft exits through a brass-bushing inset into a wooden infill.

Lateral adjustments are done manually by canting the undersized blade either left or right. (It is important when honing to keep your fresh edge square to the sides. This is a precision tool and will not cut square if you are not reasonably close in your sharpening techniques.)

Investment cast from silicon brass, this gorgeous study of motion and functionality is the key visual element of the tool. The radial knurls of the locking wheel create a contrasting visual feast and a functional mechanism for securing the blade to the body of the tool. The portion of the cap in contact with the blade is milled, insuring a light-tight seam that eliminates chatter and keeps the razor edge rigid to withstand the forces of cutting.

Functionality was the driving criteria for this plane design. The front knob is smooth to the touch and can be used as a finger rest for one-handed use or as a knob for two-handed applications. It also serves as the lock for the adjustable throat. The curvature of the handle allows hands of all sizes to comfortably use this tool without compromises. The sides are free of intersecting protrusions allowing either to be a reference for side cutting applications. The rosewood or ebony infills are a unique final touch.

Customer Reviews

Read Reviews | Write a review