I recently acquired a General Intl 15" planer with the motor mounted under the base. This model is similar to the Jet, Grizzly, Powermatic, and Bridgewood 15" planers except for the paint. My problem is snipe. I got the planer and can't get rid of the snipe no matter what I try.
I adjusted the infeed, outfeed and chipbreaker to .020 as per manufacturer recommendation. I also adjusted the bed rollers to .005 and tried rollers beneath the table and still had snipe. I did some research online with the other similar planers and some say to adjust the infeed, outfeed and chipbreaker at .020 and others say .040 below the knives. So what gives? I guess I could live with the snipe with some planning, but if there is a way to eliminate it I am all ears. The snipe is on both ends of the board.
(Solid Wood Machining Forum)
From contributor S:
I have occasional success with minimizing snipe by elevating the far ends of my infeed and outfeed conveyors to be slightly higher than the planer table, and minimize the setting on the bed rollers. As an example, I have a 6' long infeed conveyor. The end of the conveyer at the planer is set at the same height as the planer table, and the opposite end is set 1" to 2" higher.
I have not done this yet, but when I am doing small amounts of wood I just lift the end of the board up some and it will usually eliminate the snipe. Feeding end to end with multiple boards will usually yield a snipe on the first infeed board and the last outfeed board with no snipe for the boards in the middle.
That said, I have a 15.625" Makita planer and I have almost totally eliminated end snipe (what little snipe I do get is probably .010- .015" (very slight). From what I know, the big culprit in snipe is the bed rollers. Think about it in exaggerated terms. The bed rollers are set, lets say 1/4" above the table height, you feed in a board, it hits the infeed bed roller which pushes it up, which causes the end of the board to get cut deeper than the rest of the board. The same happens when it hits the outfeed bed roller.
Take your bed rollers way down or all the way to exactly flush with the table and you should see results. Another fact that others mentioned is that the thinner the board, the greater the potential for end snipe. When I plane any thinner than .625", I put an auxiliary table (3/4" melamine with a cleat on the front edge to holt it in place) down on my planer bed. The auxiliary almost totally eliminates snipe in thin stock.
A word of caution - you must keep your planner bed or your auxiliary bed if you are using one waxed at all times and not run with very dull knives. Some planers will break if you fail to wax , run dull knives, or take too big a cut when you donít have much bed roller in play.
I broke my planer a couple of times before I finally wised up and decided it wasnít worth it to be cheap about sharpening and the time spent changing knives. Listen to your planer, the sound will tell you if you are pushing it.
When you first infeed a board it is pushed down by the overhead infeed roller. Then it passes under the cutter head and finally encounters the overhead outfeed roller. The second roller increases the downward pressure on the board pressing it flat against the table. The board continues through with both overhead feed rollers pressing down until the tail end passes beyond the infeed roller. Subsequently you only have one roller pressing down from that point to the end of the board.
My take on this is that end snipe occurs at both ends in that area where the wood has not yet engaged the outfeed roller (infeed end snipe) and has left the infeed roller (outfeed end snipe). If you measure the distance between the center of the cutter head and the center of the feed rollers, and then measure the length of your end snipe on the board ends you can confirm whether or not this is the case.
As other people have suggested, the cure is to support the end of the board slightly higher then the planer bed during that point in the cut where the board is only held down by one feed roller.
You did not mention what you have for infeed and/or outfeed support. You can't expect a plank that is cantilevered out typically 8' to 12' from the center of the planer to be held solidly on the planer table by only one spring loaded feed roller. End snipe is almost a certainty.
Also, thinner boards can have more end snipe then thicker boards because they are more flexible and will bend up into the cutter head more easily then a thicker board. Also, I think we tend to hold onto heavier boards more solidly and subsequently help them remain in the same plane as the planer table. Again though, all this applies to a properly adjusted planer. Improperly adjusted bed rollers can certainly also cause significant end snipe.
For my purposes, I am rough cutting solid wood furniture parts about 1" longer than net size. I then run the wide face on the jointer until itís flat. When I plane the parts I have to squint to see the snipe. After I dress out the edges of the part I cut about 1/2" off each end and itís finished.