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I am looking for advice about the tiny, thin lines that appear on the surface of wood after running them through a power planer. I assume that my questions apply to most power planers. I have a used DeWalt DW735, which I bought several years ago. I recently flipped the blades over for the first time. The blades for a DW735 are two-sided, so flipping the blades is like installing new blades on other planers.

I ran softwoods (basically SPF construction lumber) through it after flipping the blades, and what came out initially was as smooth as glass. It did not take long before there were quite a few thin lines appearing on the boards, presumably from nicks in the blades.

I can sand them off quickly and easily with a random orbital sander, even from hardwoods like maple and walnut.

Here are my questions:

* Why did the thin lines appear so quickly in the softwoods? I would have expected the output to stay smooth for a long time, especially with softwoods.

* What causes the thin lines? Can I assume that it is nicks in the blades? Am I failing to do something to prevent them?

* Are the thin lines normal for everyone? Do people live with them and sand them off, or do they adjust the blades when they appear?

* How long do you expect blades to last before you need to change them or flip them? (The right answer is, "it depends", but I am looking for a rough sense of what others get from their blades.)

I know that I can shift alternate blades slightly left to right to hide the lines and extend the useful life of the blades, but want a better understanding of their root cause and what people do about them.

I know that I can buy a sharpening jig, but I wonder whether I can do a perfect matching job on three blades, whether those sharpening jigs can take out the nicks, and whether the high cost of those wood/brass jigs is worth it.

-> What do you do about those thin planer lines?
 

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I have 735 too, and currently i'm running some car paneling for my sunroom. I get the 1X4s and plane them down to half inch before i run T&G and V. LOL! So far ran something like 130 12 footers and 80 8 footers. All spruce.
The nives are done on both sides after all that, well i did run some hardwood, but not much. The nicks happen very quickly and i think it's because the steel is not that hard for these nives.
If i need a super smooth surface i put in new set just for the last pass and than switch back to old set. It's time consuming but it works for me.
If i don't have a lot of material to run, i just finish it with my hand plane which gives me better surface than sanding.

Hope this helps
 

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I have the DW734 and can't say that I've noticed the thin lines. I'm starting to notice more chipping if I take thicker passes, but that's after probably close to 500bf of mixed hard and soft wood.

I was thinking the last time I used it that I needed to order new blades to have on hand.
 

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The lines are caused by nicks in the blade.

Especially with construction lumber, or rough lumber debris can be jammed into the ends of the boards, as well as trapped in knots, so carefully check these areas as well as knots for foreign debris.

How long blade will last can't really be answered. It all depends on the quality of the steel, what material you're planing (hard vs soft wood) and the number of knots you're running through.

A helical head is really the way to go. When I changed over it seems like they out last knives by 10:1.
 

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I was very frustrated the first time I rotated the blades in my 735 to get rid of the lines, and quickly had them back again. They are indeed small chips in the blades. I put another set it and had the same issue, I put a helical head in and I did not have the issue. I've run a ton of lumber through mine and I have yet to rotate the cutters. I know they are expensive, and I was reluctant to spend the money, but after I did I kicked myself for wasting money on replacement blades for the stock head.
 

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where's my table saw?
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I question your wood source .....

.......

I ran softwoods (basically SPF construction lumber) through it after flipping the blades, and what came out initially was as smooth as glass. It did not take long before there were quite a few thin lines appearing on the boards, presumably from nicks in the blades.

Here are my questions:
* What causes the thin lines? Can I assume that it is nicks in the blades? Am I failing to do something to prevent them?

* How long do you expect blades to last before you need to change them or flip them?

-> What do you do about those thin planer lines?

If the nicks appeared very quickly, I'd be looking for small stones or hard particles in the boards. Normally, Pine or Spruce will plane very smoothly, no lines from nicks. I would look at getting some different boards, maybe from a different source. There is no there explanation for those nicks other than something embedded in the wood. The OEM knives are HSS whereas the Shelix cutters are Carbide, a much harder material. In the video, the guy says the OEM blades are erratic and some nick on the very first pass of clear wood, at 4:37 in.

The helical cutter heads are expensive, but may pay off in the long
term.


https://www.amazon.com/Byrd-Tool-woodworking-Shelix-cutterhead/dp/B0756QS699

https://www.grizzly.com/products/Gr...pZpzVo8YtIiOiLcw11hFCqWAzyEBNK80aAosEEALw_wcB


 
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Carbide blades last longer and can cut different materials than hss. Carbide is also more brittle and susceptible to chipping. I still use hss blades in my planer, as well as my jointer. I have become more careful about running glued up boards where the glue line will be cut. That, in my experience, is the biggest culprit for those little groove causing nicks. All is not lost though. If you do get one of those nicks just choose a cutter knife and ever so slightly shift it over. In order to have those lines all three knives have to be nicked in the same spot. Move 1 knife over a fraction and the line should disappear.
 

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I have 735 too, and currently i'm running some car paneling for my sunroom. I get the 1X4s and plane them down to half inch before i run T&G and V. LOL! So far ran something like 130 12 footers and 80 8 footers. All spruce.
The nives are done on both sides after all that, well i did run some hardwood, but not much. The nicks happen very quickly and i think it's because the steel is not that hard for these nives.
If i need a super smooth surface i put in new set just for the last pass and than switch back to old set. It's time consuming but it works for me.
If i don't have a lot of material to run, i just finish it with my hand plane which gives me better surface than sanding.

Hope this helps
I do something similar; however, I only flip one blade to do that final pass. Generally, I remove those lines with a card scraper. Wood loves to be worked with a card scraper.
 

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My solution. I set the blades into this jig, then stroke a diamond plate from end to end until the nicks disappear.

If the wood grew in an area that was particularly dusty, some of that grit ends up in the trunk of the tree and can't be avoided. The tree captures some of it while growing, And is particularly prevalent in the crotch areas of a tree where animals may build nests.
 

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CharleyL
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You can shift one blade at a time slightly one way to the other in a 735 planer so that the line left by one blade will be cut flat by the next blade. This works well, until there are so many chips out that there are no good edges left. If the lines can be sanded off easily, I don't do anything. Planers are for thinning boards, not for making them perfectly flat and smooth. Wide belt sanders are for flat and perfectly smooth. I don't have one, but my ROS does a great job.

Charley
 

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I've had a 735 since they first came out. The little lines are no big deal, they'd sand right out. As long as the wood is feeding through on its own I don't change the blades. I'm mainly concerned about thickness when I'm planing, not a finish that doesn't require sanding.
Mike Hawkins
 

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Discussion Starter · #13 ·
Thanks for the input. I hope people keep posting their ideas! I am learning a lot here.

The nicks must be coming from mineral grit on the wood. It is my own @#$% fault. The softwood was leftover construction lumber from years ago, stored outside under a tarp. The wind blows dust and sand and grit under the tarp which gets on the wood.

Lesson learned #1: Clean the wood carefully before running it through the planer.

I appreciate everyone's ideas very much. I am looking at scrapers and burnishers to give them a try. I have wanted to try them for a while for general woodworking projects anyway. Getting out the random orbital sander and connecting the shop vac dust collection is a pain. (Yeah, putting on a dust mask and hearing protection, too.)

I also plan to make a sharpening jig, but I suspect that the nicks are too deep. If I sharpen them enough to take out the nicks, then I bet that the blade dimensions will fall out of the required precise alignment needed for useful work. I wonder whether it is worth the effort to sharpen those "disposable" blades?

I tend to make many very light passes, and probably too many in the "finishing" mode rather than the "dimensioning" mode. It had not occurred to me that more passes (or a higher ratio of finishing passes) means more chances to nick the blades. Obviously heavier cuts are hard on the wood, the blades, and the planer too, but there may be a "happy medium."

Comments about how to best use dimensioning vs. finishing modes, and the best approach for heavy vs. light cuts would be appreciated. Actually, all comments are appreciated.
 

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About the jig used in post 9... it can be used by draw filing to remove heavy nicks. Use consistent strokes end to end using a single cut file to remove the nicks, then finish using a diamond plate. It doesn't take very long to do.

To drawfile, you hold the file at 90 degrees to the knife length... and stroke down the length while maintaining the file at 90 degrees.. It will leave a very smooth finish.
 

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I have only had a 735 for a short while but saw the same fine lines the first day I owned it right after I planed one pine board that had a few knots. I thought it was crazy that a single pass of one board would do that.

But it seems to me that after a little time, these nick marks have now gone away. My guess is the blade at first is very sharp reaching too fine a point that is easily nicked. But once it wears a tiny bit it is still sharp but works well again.

This is just based on planing about a half dozen pine boards recently and not seeing any lines at all in them.
 
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