Over 25 years of home woodworking and 30 years of construction experience as a Carpenter/Joiner I have put a lot of lumber through planers, including both the lunchbox machines and larger stand-alone units.
There are issues with putting end grain boards through planers, and it can be done…..BUT… lets look at the issues and see if we can work around them. This article is aimed at the hobbyist who is making end grain cutting boards looking for a shortcut.
This is what I know about the challenges of end grain through a planer.
- The structural strength of the grain direction is aligned in its weakest direction.
- Understand that the glue joint is not the weakness.
- Grain tear-out will happen, not if but when and where.
- The potential risks vs the reward.
- Why hobby woodworkers try this technique.
- What to do to minimize the risks and damage.
- Recommended Alternatives.
The structural strength of the grain direction is aligned in its weakest direction.
We all know about chopping firewood. A sharp axe can cleave a block in two easily when the chopping force is travelling the same direction as the grain direction of the wood. The height of the block when it is waiting to be split will decide how hard the axe cut needs to be delivered.
It usually takes a full swing to split the block. Now visualize the end grain board as a slab of end grain instead of a block. The grain direction is the same, but the depth is far shallower. This lack of grain depth is the first of the issues we can discuss with putting end grain through a planer.
When a planer is in operation there are feed rollers that apply rolling forces to the wood and pull it through the blades and these feed rollers are located over the wood being processed.
So the pressure is from above and it is required to maintain the feed rate so the wood doesn’t slip.
The very idea of putting a board, any board, through a planer is to remove any high spots and to give a consistent thickness to that board.
When putting an end grain board through the planer there will be a time when the underside of the board is not smooth and/or level and this can create what is called a point load. This point is like a small see-saw and is where the board is likely to crack if the raised section (pivot) under the board is too high.
This cracking of the board can be the precursor to a series of potential events, none of which you want to be involved with.
What are the potential events?
The board might suffer a crack. It may not become known until the board is completed and then becomes two bits of board. This board may be salvaged but will never be trusted.
The board can be cracked into several pieces and no other damage is done. This board may be able to be re-glued and rescued but the board should not be trusted similar to the first outcome above.
The board could crack and separate while still under the rollers and parts of wood can become projectiles and harm the operator or surrounding equipment. The board is probably destroyed. If not destroyed, it should not be trusted.
The board could break into several pieces and get jammed within the feed rollers and cutter head zone. The potential for bending shafts is high and will be expensive to repair. The board will be destroyed.
Understand that the glue joint is not the weakness.
The lesson that is to be learned above is that it is not the glue joint that is the potential problem. It is the grain direction. It is common knowledge that many modern types of glue when used as per the directions deliver a joint that is stronger than the wood. This is true, and any cracks that do arrive will highlight this fact.
The cracks will follow the growth ring lines in the wood before following the glue joint. All of this information shows that end grain cutting boards are inherently weaker than edge grain boards because of the grain direction. Period.
The planer just exposes that weakness in certain situations that the hobby woodworker is likely not even aware of.
Grain tear-out will happen, not if but when and where.
Assuming the end grain board is level enough on the underside to not cause cracks, there will be a tendency for the last or trailing edge of the board to be machined to suffer tear-out or a peeling-off of chunks of wood.
It can be avoided by laminating a waste strip to the end of the cutting board so the planer knives don’t cause damage. This will work if the underside is level, and the wood is consistent in density.
The next challenge you will face is the mid-board tear-out that can happen with certain types of wood. The cutter type will help a little however even the spiral cutter heads will still cause tear out in some woods.
As the planer cutters become dull there will be a tendency to lay the grain over instead of cutting it and this can create problems with sanding and finishing.
The potential risks vs the reward.
The object of this article is to explain the risks vs the rewards to putting end grain through a planer. So far, we have not found any thing that resembles a reward and there is a valid reason for that. There is no reward other than it MIGHT save a little time IF everything goes according to plan. The chances of that happening are slight whereas the potential for damage to the board and harm to the operator are greater no matter which way you cut it.
Why hobby woodworkers try this technique.
There are several reasons why the novice hobby woodworker attempts things like putting end grain through a planer. The primary reason I suspect is the lack of the correct equipment and the desire to try a new project without acquiring this equipment before undertaking the job.
Another reason is the notion that the operator believes this time it’s different, and I know better. This line of thinking just happens, and one can only sit back and watch. Stupid can’t be fixed. It just needs to run its race and tire out.
The last reason I will mention is the notion that the process will save time.
It just might do that once or twice.
Then, as each time the technique is used, the day comes closer when the board decides to crack and we will never know the outcome until that happens. It could be mild or it could be ugly. Why risk it?
What to do to minimize the risks and damage.
This is an easy section to talk about.
Don’t try it is the first answer. The second is don’t try it.
It’s not fair to criticize the method without offering a viable alternative or two.
How to level the end grain if a planer is not to be used.
Are drum sanders good for end grain?
These machines are great for sanding end grain boards. The potential for the cracking is still there however the process for feeding the board into the sanding zone can be far less stressful on the board than the planer rollers. Expect the process to take longer than a planer however the likelihood of having an intact board at the end is far greater. The downside of these machines is the purchase cost.
Can overhead router skis be used to level end grain cutting boards?
Yes, this method works well however there is a chance that the router bit will leave tracks as it cuts and these can take some sanding to remove them. The bit needs to be sharp, and the speed of the bit fast. The feed rate of the machine over the wood will need watching depending on the species. The edges of the boards may need support to prevent grain blowout as well.
This is a method that is used to level slabs of wood and can also do the job of leveling an end grain board. There might be a temptation to level the one side of the board with this method and then use the planer but use discretion.
Personally, I won’t use a planer at all on end grain but you do what you think is best for your situation.
This is a dusty job, and one that will take some time but for the hobby woodworker on a budget this is the best method.
I think we can now close out this article as we have covered the reasons why folks attempt this method, we have covered the risks and the lack of viable rewards, and we have alternatives to use that are safer, proven, and readily available to most hobby wood workers.
Now, it’s up to you, the individual wood worker, to make the choice and get after it.
Good luck and best wishes.