Planer Problems

[Joe Austin]

I have a DeWalt 12-1/2 heavy duty portable thickness planer that I am having a problem with. When I pass a piece of stock thru, the feed end will come out thinner then the rest of the stock. The table extensions are all aligned properly per the instruction manual. I am a novice and weekend woodworker so I don't use this every day but I needed to know why this is happening and if it is common. It is getting frustrating. Am I supposed to waste the inch or two that is cut thinner or is something wrong with my machine? It has always done this but I just wasted the end but now I am working with short stock of ebony that I have and can't afford to waste the ends. Are there any adjustments that I should be looking at or what am I missing.

One more bit of info: The feed end that comes out thinner seems to be perhaps the length of the diameter of the cutter head and is radiused up to the proper thickness as if the cutter head raises slightly after the first rotation.

I hope this explanation makes sense. Thanks in advance

[Yves Pinet]

Sounds like snipe. This happens because the weight of the board brings the end up after it passes the front roller. Two solutions are to hold the piece up for the last little bit to prevent this, or to feed a second board right after the first. With short pieces of ebony, I would tend to use the first solution, and make your cuts very shallow.

[glenn bradley]

Yep, snipe. As Yves points out this is caused by the material meeting the cutterhead at an upward angle. When the rear roller gains control and flattens the board path out, the desired thickness is cut. Some folks pick this up on the trailing end by letting the material sag out of the planer.

My DW734 is adjusted so that the outer tips of the infeed and outfeed tables are higher than the platen by about the thickness of a dime. This cures my snipt on short pieces but I need to use roller stands at each end (or two) if the pieces are longer.

[Andy Pratt]

Joe,

The other guys have already named the problem for you, I just wanted to offer a few thoughts on reducing the snipe.

On boards that are long enough, the easiest thing to do is to make sure you're holding up the trail end of the board just slightly above the plane of the platen/feed tables when you feed the board in, and to do the same with the lead end as the board is coming out. This never seems to completely fix the problem, but it reduces it a lot.

If your boards are too short for this, and valuable enough to bother with the effort, one surefire way to eliminate the snipe on the ebony would be to glue two thin boards (any flat, square scrap would work) of equal height and 2-3" longer on each end than the ebony to the side of each piece of ebony, then run that "panel" through the planer. This makes sure the snipe (both on lead and trail ends) is only happening on your scrap boards, not the ebony. It's a major effort for a small gain, only worth it on really valuable woods like you're using. Afterward you would have to remove the strips on the table saw, so that's another step and you're losing a tiny bit of material to the glue joint there, but it would be less overall than losing a few inches on each end to snipe.

Hope this was helpful, I had a lot of problems with this in my early work and just ended up doing a lot of sanding to make up for it, hopefully you don't get stuck doing that on ebony, I'm sure it wouldn't be fun.

Andy

[Lee Schierer]

As the others have noted you are having a snipe problem. The cause is the weight of your boards resting on the infeed table is causing them to bend. If this is a protable planer you can build it into a table like the one in the back ground of this photo.
http://www.home.earthlink.net/~us71na/lsfence1.jpg

My table has about 24" of infeed and about 30" of outfeed. I get virtually no snipe on my Delta 12-1/2" when I use this table.