When purchasing a thickness planer, what are some features that are
essential? Some nice-to-haves? Anything that is just fluff, especially
for a beginner woodworker?
- type of cutterhead
- knives: straight, spiral, or segmented; disposable vs. able to be sharpened
- segmented cutterhead: spiral/v configuration, helical configuration; typically reduces tearout vs. straight knives
- number of cutters - usually more cutters provide a smoother finish, given the same style of cutterhead and feed speed
- speed of cutterhead - faster speed allows faster feed rate
- number of speeds - refers to the feed rate; faster for initial dimensioning, slower for smoother finish
- width - determines widest board you can plane
- maximum height - determines thickest board or widest ganged-up boards
- infeed/outfeed tables
- preferred, but on some lunchbox planers they are an add-on option
- some have rollers instead of smooth tables--rollers potentially allow you to be pinched if you are careless
- exhaust blower - some lunchbox planers have a blower to help prevent clogging
- electrical requirements (e.g., 240V vs 120V)
- price
- size
- cut quality (see magazine reviews for head-to-head comparisons--but keep in mind you should not expect a finish-ready surface; better cut quality just means less scraping or sanding before finishing)
I see specs indicating the number of cutting heads / knives, the
rotational speed, one- or two-speed, width, material thickness, and a
whole lot more that's a bit overwhelming. Which of these are
important?
All aspects are noteworthy in different ways, but at the end of the day, just a few features (as marked in bold above) will narrow your options dramatically.
Many models with straight knives can be upgraded with a spiral or helical cutterhead. Typically knives are HSS (high speed steel) and require periodic sharpening. Segmented cutter inserts are usually carbide, last longer, and are either 2- or 4-sided, allowing you to rotate individual cutters as they become nicked or dull.
Is there a big difference between the "portable" or "benchtop"
planers as compared to the big floor-standing models (I now know there
is with table saws!)?
The main difference is that stationary planers are more heavy-duty, often run quieter, and can remove more material in one pass (1/8", vs. 1/16" for a lunchbox planer).
Segmented cutterheads are not as common on lunchbox planers, and installing an aftermarket segmented cutterhead on a lunchbox planer is not necessarily advisable since the segmented cutterhead forces the motor to work harder (because the cutters are constantly in contact with the material). Also a lunchbox planer's cutterhead has a smaller diameter so the cutters perform a more severe scooping motion against the material, as opposed to a stationary machine with a larger-diameter cutterhead.
I don't have a jointer, so the ability to use a planer sled to flatten
faces of boards would be nice - is that just a function of the size of
the opening?
Yes, you can use a planer to do face jointing, but a table saw would be better for edge jointing unless ganging up many pieces. Jointing on a planer requires some extra setup and typically involves attaching your workpiece to a sled or rails.
