Blog: Conquering Planer Snipe! By: John Heisz
I’m currently building a new pair of speakers for my office and in a departure from my usual more practical approach, I’m using solid wood for much of the box. Solid wood should be avoided for speaker boxes because it expands and contracts with seasonal moisture changes.
There is a way to minimize or completely neutralize the effects of this problem, and that’s to use a mix of solid wood and plywood, using the solid wood for the sides, top and bottom only. Plywood is then used for the front and back. With the box built like this, it’s free to expand and contract from front to back, while the plywood front and back stay dimensionally stable.
Another drawback of using solid wood is the processing time, if you are starting with rough stock. I’m making mine from cherry that I bought more than a year ago, so it’s had time to settle down and release some of the drying stress from kiln drying. Even so, it still needs to be handled in such a way to keep it flat after it’s been milled down to the final thickness. That’s something that you don’t need to worry about when using plywood.
Anyway, the title of this blog is how to defeat planer snipe, so let’s get on with that. Snipe happens at the leading and trailing ends of a board as it passes through a surface planer. The reason why this happens is that at the beginning of the cut, the outfeed side feed roller is free hanging – it’s not pushing down on the stock yet. Same on the trailing end when the board runs through, the infeed feed roller drops off the end of the board before the cutting is complete.
In a perfectly rigid machine, this wouldn’t make a difference. but here in the real world, there are no perfect machines – parts flex – things move – and snipe is the result.
The solution is to always have stock of the same thickness and width under the both feed rollers at all times during the cut. Continuously feeding the stock through end to end, without breaks, is also critical. I use a scrap of the same size stock to run through at the beginning and end of the cut, and that provides that continuous support all the way through.
The result is snipe free ends on the stock that can save a lot of expensive material:
I made a video showing this procedure a few years ago, but did a shorter updated version:
Here’s the original that has a bit more explanation: