Q.
I need to plane glued up panels. I have seen planer/sanders with a helical carbide cutting head. Do stand-alone planers come with this type of head, and what are the benefits and performance in relation to straight blade planing?
Forum Responses
Newman Whitney makes a spiral carbide head. I put them in every planer I rebuild. You will find planing panels to be much more economical than sanding panels.
You do not rotate the knife on the Newman-Whitney head. The knife is replaced with a new one.
I have customers who run their finish planers all day long--8 hours minus breaks and lunch. Many of these customers get 2 to 3 years out of a set of knives. But they are highly skilled in grinding and jointing.
On small planers, the use of insert cutters may be a better choice. Each application should be looked at before a decision is made.
Provide info on what wood species you are using and what the expected feed rates and moisture content are.
Dave Rankin, forum technical advisor
a) True helical insert head (Newman type) has considerable advantages in cutting geometry because of the extreme shear in cutting action, which tends to reduce tear-out, especially on difficult species. It is also re-grindable and can be jointed. Disadvantages include higher initial cost and the need for specialized grinding/jointing attachments on the planer.
b) Replaceable straight insert heads, or standard planer heads, are much lower cost, but need to be used sharp to minimize tear-out when cutting against the grain direction, or working with difficult species, and therefore need to be changed more frequently.
c) The new segmented insert heads (Drake type) have small inserts that are mounted in a spiral pattern flat to the tool surface. Since each insert cuts parallel to the axis of rotation, it does not have a true shearing action in cut. Advantages are lower initial costs and replacement costs for inserts. Typically these inserts have finer grain carbide with sharper cutting edge, because inserts are not brazed onto a holder as they are with the spiral head. Also, each insert can be rotated/replaced independently, which has considerable advantage when your wood has problems with surface grit or nails/staples. Disadvantages include the fact that they do not cut perfectly flat (each insert has a minute curve to overlap the next insert) and they cannot be reground or jointed.
I strongly recommend the true spiral head if your planer is equipped with grinding/jointing attachments; otherwise, the Drake type.
