79 - Slant Front Tool Cart, страница 50




79 - Slant Front Tool Cart, страница 50

Snipe is a result of a deeper cut at the beginning and end of a board —

Whenever I use my thickness planer it appears to make a deeper cut at the ends of the board than in the center part. What causes this and how can I stop it?

Tom Holsinger Awn, Minnesota

snipe SIPEV1EW -vj*_

WORKPIECE

When a planer cuts a little deeper at the beginning or end of a board, it is commonly referred to as "snipe." The problem is usually due to the relationship between the feed rollers and the short bed of the planer.

If you look closely at your thickness planer, you will note that there are feed rollers on both sides of the cutter head. These rollers hold the workpiece flat against the bed as it passes through the planer.

scrap stock for other end

At the beginning and end of a planer cut, only one roller is holding the workpiece flat against the bed. Tliis can allow the end of the board to tip up into the knives of the cutter head, resulting in snipe.

Locking heads on newer planers have reduced some of this problem. But if your thickness planer doesn't have a locking head, here a few solutions to consider.

Bed Extension. An easy solution is to extend the support of the workpiece as it passes through the planer. You'll find that using a roller stand on either side the planer may help minimize snipe. This will keep the workpiece flat to the planer bed as it passes all the way through the planer.

Raise the End. Lifting the back end of the workpiece up slightly as it begins to pass into the cutter can also make a difference. A small amount of lift at the right time can help reduce snipe. Repeat the process as it leaves the planer.

planer snipe is a common problem and can appear at both ends of a workpiece

Use a Scrap Board. Another technique that can help is to butt a scrap board of the same thickness to each end of the workpiece as it's fed through the planer (drawing bottom left). This holds the rollers in position as the workpiece enters and exits the thickness planer.

Plan Ahead. When any significant thickness must be planed off in my shop, I always plan the passes so that the final passes will only remove a small amount of material. Since the last passes only remove a bit at a time, any snipe made will be small and end up being barely noticeable.

Cut it Off. If all else fails, you can always leave the board a few extra inches long when you plane it. Then after you've planed the board to thickness, you can simply trim off the snipe when you cut the

board to it's final size

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50 ShopNotes No. 79

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