Almost every hand plane has a chip breaker which at first glance is easy to dismiss!. But the chip breaker is essential on all bevel down hand planes such as a Stanley Bailey no 4.
Where is the chip breaker
The chipbreaker on a hand plane attaches to the plane iron or blade with a Flathead screw. This screw has a knurled texture so it can be hand tightened while you align the chip breaker and then locked in place with the screwdriver. The chip breaker is clamped against the back face of the plane iron on a smoothing plane. It should be placed as close to the edge of the blade as possible usually about 1/64 of an inch back. For thicker shavings reveal more of the blade tip.
Hone your chipbreaker
The chip breaker is honed at an angle so it makes solid contact with the blade. Any gap between these two parts will result in the hand plane getting clogged with shavings you may need to rehone the chip breaker on a Whetstone.
What could happen without a chip breaker?
The tip of the plane iron acts like a wedge which splits the grain ahead of the blade this can cause tear out resulting in an uneven wood surface.
For example, if you split a log with an axe the split will be ahead of the axe head Following the grain.
This image is of the edge of my victor plane iron and chip breaker assembly. The chip breaker is the curved metal part. This prevents the shaving from following its own path. The breaker fractures the shaving while it passes over the chip breaker weakening the shaving.
As the wood is split by the plane iron the shaving hits the chip breaker crumpling the grain this prevents it from splitting in front of the blade minimising chip out and resulting in a smoother surface.
The blade depth should be adjusted so the edge of the blade sticks out through the sole of the plane while keeping the chip breaker above the sole of the plane
This can be set by using the depth adjustment at which is usually a wheel made out of brass. Cheaper hand planes have plated or plastic adjustment knobs.
The adjustment wheel rotates on a reverse threaded screw and engages the yoke by moving forward and backwards
The top of the yoke engages a square hole in the chip breaker thus moving the blade assembly changing the depth of the cut. You’ll also want to make the mouth of the hand plane small by moving the Frog forward or backwards using the Frog adjustment screw.
This is the set-up you want for a smoothing plane when you’re making fine shavings. For a rough plane to remove a lot of stock like a jack plane or a scrub plane you want the blade to lower the chip breaker hire and a wider mouth opening