Ever gone on a snipe hunt? You just go into the woods on a moonless night with a burlap bag and then the fun begins… at your expense. A ‘Snipe Hunt’ is a practical joke where inexperienced campers hear about the fun of hunting snipe and are sent out to bag the quarry, often while banging rocks together and yelling into the night. It’s great fun for the pranksters but not so much for the one being fooled.
Woodworkers are more concerned with planer ‘snipe’. It’s not a bird; it’s a machining problem. Figuring out why your thickness planer cuts too deeply at the beginning or end of a board isn’t much fun either, but it will make your projects go better.
Snipe occurs when the planer takes a deeper cut for the first or last 2-3 inches at the ends of the board. It may be subtle but you will definitely feel it. And it will be very obvious once finish is applied.
Here are two common causes of snipe:
- Planers have pressure rollers on either side of the cutter head that hold the board down as it passes under the cutter head. But at the beginning and the end of the pass, the board is being held down by only one roller. The rollers apply downward pressure to the board but there’s nothing under the second roller, so the whole cutter head assembly moves down and cuts too deeply into the board. When the second roller is engaged, the pressure equalizes and the cut depth is corrected.
- If long boards are fed into the planer without being held perfectly level, the board will push the engaged roller up slightly and cause the end of the board to tilt up into the cutter head.
Reducing snipe isn’t complicated. You just need to keep the stock level on the planer bed at the beginning and end of the cut.
- Check your setup – Check that infeed/outfeed tables are perfectly level with the lower table and are solid.
- Support your work –If the infeed/outfeed tables flex or are too short, you may need to add additional support with tables or roller stands. Slightly lifting the end of the board at the start and end of the cut will keep the leading/trailing edge flat on the table.
- Constant feed – Run boards one behind another to even out the pressure from the rollers, resulting in a level cut on each. Or you run scrap pieces ahead of and behind your good work piece.
- Add rails – if practical, glue wood strips that are a few inches longer than your workpiece to either side. During planing, the strips reach the cutter head first, sustaining any snipe, and are held flat under the outfeed roller by the time the workpiece reaches the knives
- Go long – If all else fails, size your workpieces long and then cut off the snipe.
If you’re having trouble with your planer maybe it’s time to organize your own ‘snipe hunt.’
