Planer Problems

[jussi]

Recently changed the knives on my DW735 planer knives and now I'm noticing little scratches on the wood. See Pic. I didn't have that problem before. It's almost like the wood chips are somehow causing them. Anyone have ideas on what's causing it and how to fix it.

Also I just added a DC to it. Previously was just using the deflector attachment. I get most of the chips but notice quite a few pieces spitting back out onto the infeed table.

[crybdr]

Are you talking about the 'snipe' lines (see attached image) or the little flecks of white marks?

If it's the 'snipe' lines - i get this whenever the planer feed stalls. Dirty rollers, debris on the table, oily wood... Any time the planer stops feeding the wood, I get a tiny little divot of material removed.

If it's the tiny flecks - it looks like tear-out, but I'm no expert (though I see it on hard maple ALOT). Your new DC should pick up chips better than what you had before so I'm not sure that's the cause.

How big of a bite were you taking? Big bites can lead to tear-out and stalls as well.

Others here will have better guidance. Good luck..

[LCHIEN]

Like Crybdr, I saw the snipe lines but i don't think someone would call snipe as scratches.

I also see some grain lines going left to right but there are some faint straight lines that don't look like grain left to right at the top of the page that might be scratches from going through a machine.

are those raised lines or scratches?

[crybdr]

LCHIEN...agreed, I also couldn't discern obvious scratches in this pic.

jussi...can you take another pic highlighting the scratches?

For lighting, I usually hold freshly planed boards under any overhead light at an angle (45 degrees, or so), which casts shadows over chip-outs and most other planer marks. This would be a helpful pic to understand what you are seeing with your planer.

We just can't see what you are experiencing from this pic.....

[jabe]

I think It's grain tear outs, not to sure as the photos aren't too clear on my computer. It can happen on one peice of lumber and not on another even though it came from the same tree. Sometimes its just on one section of the lumber not on the whole peice. The grain is stringy and tears out cause the blades of the planer can not shave it off clean. Don't know why or how it happens. I get it now & then with our local Koa wood. I found using a sander planer instead of a knife/blade planer worked much better with that problem.

[phrog]

I had a similar problem with a Delta planer. Chips were blowing back. The hose to my dust collector had gotten jammed - causing the blowback. All the chips from the blowback were causing the rollers to get "dirty" with compressed little chips. The rollers were slipping and, I don't know why but I was getting a similar result that you show. Unstopped the hose and cleaned the rollers and the problem was solved. If snipe is the problem you're talking about, sometimes the snipe problem can be ameliorated by putting support on the outfeed end of your plank.

[jussi]

I'll take another pic when I get the chance. It's the little white marks all over the board. It looks like chips being pushed down to the board. So I assume that it probably is chips being blown back and smashed by the rollers, making the indentation. I opened it up and cleaned the fan, ran it with nothing attached to the exhaust port but I still notice chips flying from the table. I can't remember if I had that same blow back before the blade change but I know the board definitely didn't look like that. Here's a short vid I took with my phone to show the chips flying out. Is that typical?

http://www.youtube.com/watch?v=C6R_JQN3E4Q

[phrog]

When I have my dust collector attached to the planer, I see no blowback at all. However, when I was having the problem described in the aforementioned post, the blowback was much greater than your video shows.

[pelligrini]

I do get chips like in your video on my 735. It seems to happen more on harder, tighter grained woods like maple; especially when using the fast speed and removing a lot of material. How much were you taking off?

I don't get as many chips or surface indentions with my DC as I did with just using the Dewalt collection bag. It's just a Jet-650 but it does work better that the trash can bag/cover I was using.

You probably ought to make sure your rollers are clean though.

[LCHIEN]

I think It's grain tear outs, not to sure as the photos aren't too clear on my computer. It can happen on one peice of lumber and not on another even though it came from the same tree. Sometimes its just on one section of the lumber not on the whole peice. The grain is stringy and tears out cause the blades of the planer can not shave it off clean. Don't know why or how it happens. I get it now & then with our local Koa wood. I found using a sander planer instead of a knife/blade planer worked much better with that problem.

I agree with Jabe, that's what the white flecks are.
Again, flecks are not what I would have termed scratches. To me, scratches are continuous lines.

Sometimes reversing the feed direction will reduce tearout. Or using a sander as described above.

problems caused by chips blowing back over the workpiece being fed, in my experience, cause tiny dents in the top surface of the wood caused by them being pressed into the wood by the roller on top. Again, dents are not what I'd term a scratch.

I'd get that snipe fixed... that looks bad.