Jointer blade marks- how to elimante?


When I joint boards on my 6" jointer the boards are showing the jointer blade marks across the jointed face of the board. The result is a evenly spaced pattern of rounded valleys and pointer peaks. I don't get the same marks on my planner which is performing the same technical operation (rotating blades, etc).
My question is how (if possible) do I eliminate these? Is the cause my blades, feed-rate, in feed/out feed table heights? Is there a technique I am not doing?
The machine and blades are both quite new. I would suspect I have only jointed 30-50 individual pieces of stock so far (not total number of passes across the blades) I most recently used Mahogany, but I also experienced this with some oak and even MDF.
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Somebody wrote: When I joint boards on my 6" jointer the boards are showing the jointer blade marks across the jointed face of the board. The result is a evenly spaced pattern of rounded valleys and pointer peaks.
Hard to eliminate, but can be reduced if you feed your stock slower. You'll get more cuts per inch, lessening the ripple effect. Tom
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snipped-for-privacy@gmail.com wrote:

yes nyou do. the reason you haven't noticed them is that they are closer together, ie more cuts per inch. to do the same thing on your jointer, use a slower feed rate.

keep using your jointer on mdf and you'll be adding burning to the list of bad things your jointer does.
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Could be blades. One high blade can do it. Two high blades will leave the third clean, and should be obvious.
Feed rate counts, as others have mentioned. Slower for more cuts/in. may even mask bad blade sets.
Could also be the MDF dulling the sh*t out of them. Dull makes bad marks too.
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Thanks for the adivce so far. I will check the blades and play around with feedrate. Does downward pressure have any affect, or does that mostly come into play on the ends with respect to snipe.
Before the MDF notion goes to far, I only used MDF one time so lets not get off topic on that.
Thanks
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This can also happen from too thin of a cut too. I've seen this mostly with planers but suppose it can happen with a jointer.
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snipped-for-privacy@gmail.com wrote:

Feed slower.
Be sure all blades are set at precisely the same height.
Make sure blades are sharp.
don't take too aggressive a cut.
Dave
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snipped-for-privacy@gmail.com wrote:

Actually, you do, but because the planer head rotates much faster, they're much closer together and therefore much harder to see.

Slower feed rate, lighter cut, sharper blades. Also verify that all blades are at the same height.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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Several items can cause the results you are describing. I presume you have several blades in the jointer rotating head.. Great care must be exercised when installing the blades to get them at the same height, as nearly perfect as possible.. Also a fast feed rate will cause the ripple you describe. Also taking too deep of a cut at one time can be a problem.
Don Dando

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This evening I did a few things based on the feedback from everyone and was able to eliminate the problem.
For Starters I re-checked my outfeed table height and noticed that the table was slightly lower than the blades. I adjusted that to a even height.
Following that I used a much slower feed rate than I am normaly do.
These 2 things resulted in a much cleaner cut with no noticable blade marks.
Also, during the corse of insepecting the blades, I noticed that one was un-evenly worn, with the worn side closer to the fence. This makes some sense becasue the majority of my jointing is closer to the fence, but the other blades did not display this wear. So I probably need to re-sharpen and align this blade down the road.
Thanks for the advice everyone.
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