Does a double-sided planer replace a jointer and a planer?

Question

I want to buy a brand new jointer and planer for my workshop. But recently I learned about double-sided planers that provide better flexibility and allow you to program the sides that need to be planned in the machine's PLC.

The only downside of double-sided planers is the high price. Does a double-sided planer replace the functionality of a planer and a jointer? Can it make the edges of the timber perfectly straight and parallel? What are the pros and cons of using them?

Currently, I am using an inexpensive jointer and planer. But I am starting to go over capacity with them. Now that I need to upgrade, I am thinking of future-proofing my workshop. I've never used a double-sided planer by itself. So I am not sure if a double-sided planer would do the same job that planer + jointer does.

Answer 1

No, a double-sided planer does not do the job of both a planer and jointer. A jointer is used to flatten surfaces, and to create a square edge on board with one flat surface. A planer makes boards a uniform thickness (they are in fact referred to as thicknessers in many English speaking countries other than the US). Planers require one side of a board to be flat, relative to the table surface of the planer, in order to produce a second flat surface. Without special jigs (which would not work in a double surface machine) a planer cannot produce an initial flat surface. So, all a double-sided planer does is make the process of getting both sides of a board flat, and the thickness down to what you want, quicker.

As to pros and cons, unless you are in a production setting, I see no advantage to a double surface planer. The extra money you put into one in a non-production shop will do you a lot more good going into getting more width and mass into either your jointer or planer, or maybe some really nice wood to work with. You can't possibly amortize the extra cost in terms of speed and convenience in a setting where the machine is not used at a high duty cycle.

Answer 2

No, a double-sided planer does not appear to do the jobs of a planer and a thicknesser/jointer. If you have a twisted or bowed piece of wood, passing it through a double-sided planer may not be sufficient to remove the bow or twist.

However, combined "planer/thicknesser"s do exist, which seem to be what you're looking for. For example the DeWalt D27300:

https://www.tooled-up.com/dewalt-d27300-planer-thicknesser/prod/266850/

Many other brands also manufacture them. If you do a google search for "combo planer/thicknesser" or "jointer/planer combo" without the quotation marks then you'll find plenty of info.

Note that with a combo machine like this you would still need to plane the board on the top table first to establish a straight & flat face and/or edge before then passing the piece through the thicknesser/jointer part beneath.

There's a good article about them here:

Popular Woodworking Jointer/Planer Article

Answer 3

It might, but would still require multiple operations as well as a fence (which is a feature I've never seen on any thickness planer). It likely would need to be reviewed on a per-model basis and only attempted if the manufacturer designed it for jointing.

Where it might come close is if the feed rollers were only on the top cutter. You may be able to raise the top cutter well above the workpiece, exposing the lower cutter in a manner that is quite similar to a jointer. However--having the upper cutter fully exposed would be quite dangerous! Also, without a fence you might be able to remove some twist, cupping, or bends--but you would not be able to produce a precise 90-degree corner, which is a key ability of a jointer. Since you would need to raise the cutter to flatten a side, then lower the cutter to bring the opposing edge in parallel, you'd be doing multiple operations with a changeover time in between.

All in all--it doesn't sound like what you want, or a good idea. Using a combination planer/jointer (which also requires separate operations and reconfiguration) is likely as close as you'll get, and far safer.