Actually I was wondering about the coulters on these moldboard plows. I see some with and some without. Are coulters always a necessity or are they more useful for certain soil types rather than others?
IMHO, I wouldn't own a plow WITHOUT coulters. Others may have a different opinion. I'll go out on a limb and say MANY of those who don't like them, haven't plowed with properly adjusted coulters. They can be a source of aggravation in "trashy" (crop residue or tall weeds/grass) conditions if not set correctly.
Coulters cut crop residue so it doesn't hang up on the leading edge of the plow shin. They cut through roots when plowing sod, albeit just a few inches deep. That helps keep a clean furrow wall so the landslides have a consistant surface to work against.
It isn't a "life or death situation" if you DON'T have coulters, but they sure make for a better looking finished job if installed and set properly.
Of course, there's a lot more to making a plow work well than just the coulters, but they do a considerable bit IF....IF they're adjusted correctly. Often times, people will set them too deep, or too close to directly in line with the edge of the shin. They need to run 3/8" to 1/2" towards the land side of the plow (from inline with the shin) If the plow has coverboards, the distance needs to be increased to 3/4" to 1" and set a bit shallower when in crop residue (ie corn stalks, wheat straw, ect)
Setting coulters too deep will hurt the plows ability to "suck" into the ground in cases where soils are dry and/or hard. I've always had better performance when coulters are set to where they run 1-1/2" to 2-1/2" deep when the plow is at operating depth.
In some rare instances, you'll find "plowmen" who run coulters ALMOST as deep as they're plowing. That takes light soils, and a VERY good plow. (good sharp, unworn shares, enough built in weight to help pull the plow in the ground) You'll find this to be a more common occurance in competitive "match ploughing" rigs.
