Can a jointer or planer blade be to sharp?

Alan Bienlein

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As you know I've been building my kitchen out of pecan. Well I never knew how tough this wood is on jointer and planer knives. My last set of doors it only took one pass thru the planer and it looked like I had serrated knives in the planer or jointer.

The reason I ask is because I took my planer knives and ran them across some 320 wet and dry sandpaper on a sheet of glass to get rid of the burr and now they are lasting longer than when they were brand new. Same with the knives for my ridgid planer.

Any one have any thoughts on this? Is there an optimum angle for the knives to be sharpened at depending on the type of wood your planing?:dunno:
 
well funny you would ask that,, i got a set of planer knives that i had sharpened by a reputable company and they are now showing lines in the finish after around 700 bf.. 350 on oak and 350 on walnut.. to me they should have lasted longer i havent check for a burr but i am guessing its there alan,, so how did you run yours on the sand paper??? maybe a differnt angle would be better when they were new i had a very smooth finish but it didnt last.
 
I'm thinking that the angle they are sharpened at is to small ???? They might be sharpened at 25 degrees when maybe 30 or 35 would be more durable. It's almost like the edge is too thin and being rolled over. Yea it gives a glass smooth finish but it doesn't last very long.

I didn't do anything very systematically Larry. I should have made up a jig but was in a hurry to just try it out. I used wd-40 and did the back of the blade first to get rid of the burr and turned it around and adjust the angle till it felt like it wanted to grab when pushing it accross the wet and dry and held it at that angle. I then laid it flat one more time to remove the burr and put it back in the machine. They last much longer now.
 
I learned the hard way dirt and grit on the wood can destroy a planer blade in a single pass.
Now, any wood that is even questionable I give a good wire brushing before putting through the planer.
I bought a little planer/jointer sharpening stone that (supposedly) puts the proper angles on the blades. So far, so good.
 
Thats what I was thinking Frank. So on this last batch of pecan I wire brush off the wood and used a airhose to make sure it was as clean as possible. I got the same results as if I never cleaned it and the same thing happens if I resaw it and joint and plane the newly exposed surfaces.:huh::dunno:
 
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