Cap Iron for Plane Blades or Not?
The thumb planes and block planes used by violin makers do not have chip breakers. Larger planes usually do. Here is an interesting article, another one here, and finally, a great video here (if you have patience to watch it) about the effect of the cap iron. After watching the video and reading the articles, I came to the conclusion that if the plane is set to take a thin enough shaving, a cap iron is not useful.
The author of the article is Steve Elliott, who is a plane expert, and a very experience woodworker. I recommend all of the articles on his site. Clearly, he is a "nut" about how planes function. I asked him about the necessity of cap irons for wooden planes. He replied the following:
"After doing my original blade testing I got interested in whether cap
irons are useful and how to set them up.
Blades without cap irons are very useful and in most cases the added
fiddling to get the cap iron set just right isn't worth the marginal
improvement in surface quality they can provide. That's overstating it
a bit, but in hardwoods a higher cutting angle can eliminate tearout
just as well as a cap iron and it's simpler to get right."
I am in the process of making a wooden plane for use with one of my plane own blades, to test the performance. I also have a blade with a cap iron. I will report back here when the results are finished.