Thread: Still Leaning... Snipe....

Originally Posted by lemerv

Which does raise the question. The explanation I always see for snipe is that the piece is only being help down by one roller at the start and end, causing the workpiece to tip up into the blade. But that doesn’t make any sense to me if simply placing a sacrificial piece at the start and end of the main piece prevents snipe. It’s not like they are holding the main piece down.

An alternative I read, which makes more sense, is that the work piece engages the front roller as it enters, which forces that roller upwards a bit, causing the whole blade and roller assembly to tilt. The tilt causes the blade to now be slightly lower. Once the piece reaches the back roller, it forces that one up too, eliminating the tilt. Likewise on exit but in reverse.

But I’ve seen the innards of a thicknesser so not sure if the later theory hold water. Anyone any the wiser?

The cause of snipe is very much related to the design & construction of the thicknesser, the infeed and outfeed setup, and the workflow. Industrial thicknessers are mostly a four-post design and have a very rigid chassis.

"Lunchbox" style hobby thicknessers are more susceptible to snipe issues due to the rather light construction and the two-post support of the cutter head assembly. (edit - the Sherwood is a four-post design & has the lift mechanism on both ends of the cutter head - linked under the table. - corrected) They can flex somewhat if the workflow does not fully support the board and the infeed / outfeed table setup is not spot on. The tail board supports the infeed roller whilst the board exits the machine, thus minimizing movement of the cutter head. To some extent snipe can also be minimized by a slight lift of the leading end of the board just prior to the trailing end passing the infeed roller.

Industrial thicknessers will also produce snipe if the board is not supported correctly as it passes through the machine. IF the board can drop, then there will be snipe, the longer the board, the more leverage, which equates to more force/pressure on the rollers & cutter head.

EB's sled can still produce snipe if the board to be thicknessed is at the rear of the sled and the sled is unsupported as it exits the machine. The reason snipe is eliminated is more to do with the board being in the middle of the sled, not at either end. The tail board performs the same mission. A close inspection of the sacrificial runners on EB's sled may reveal snipe on them, which is of no real concern.

Good workflow practices and setup will overcome most snipe issues even with a "lunchbox" style thicky.

ps. When thicknessing thin boards, I use an auxiliary base board which passes the full length of the standard infeed & outfeed tables plus some. Rough passes go straight thru, but for the final passes I use a tail board of scrap whatever that is the same thickness as the subject board - works well for me & I have the same machine as EB.