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View Full Version : Bad Day Jointing....


John Sanford
02-23-2015, 11:50 PM
I was working on fitting the endcap to my Split Top Roubo, and found that it had some rock'n'roll action going. The endcap is a sandwich of purpleheart, hard maple, and purpleheart. The purpleheart (PH) is a bear to handplane, plus there were some other issues (I'll be heading over to the Neander side with those questions) which led me to take a shot at doing it on my PM 6" jointer.

No luck. I'm still getting the rocking, from corner to corner. I don't know if it is my technique or if there's a problem with my jointer. The rocking is corner to corner. Even when I reversed my feed direction, same result.

So, jointer, technique, or both?
Jerry Miner
02-24-2015, 12:14 AM
Technique, I suspect, but you might consider checking the co-planeness (co-planarity? co-planitude?) of your jointer tables. Then examine your technique.

After the jointer begins to cut, keep downward pressure on the leading portion of the work piece. If you put pressure on the rear, the piece will rock and you won't get the twist out.
Rich Riddle
02-24-2015, 12:20 AM
Sorry to hear of your misfortune. The blades on the jointer can cause problems if not set just right. It could be operator error, but if you know how to properly use the jointer, that is doubtful. I find this video helpful:

http://www.finewoodworking.com/how-to/video/squaring-up-rough-lumber.aspx
Myk Rian
02-24-2015, 8:24 AM
What are the dimensions of the piece you are trying to joint?
Bill Orbine
02-24-2015, 10:30 AM
Small dimensions and dull knives. Waiting to here your answer to Myk's response. As for the knives in your jointer, HSS or Carbide inserts?
John Sanford
02-24-2015, 11:36 AM
What are the dimensions of the piece you are trying to joint?

@4" wide by 18" long by 3.5" thick.

Knives are HSS.
scott vroom
02-24-2015, 1:01 PM
You didn't mention how you are orienting the piece on the jointer table. For a short piece like that where neither end of the board ever leaves the table surface I always orient the board as a frown, where the ends are making contact with the table and the middle of the piece is elevated. Each subsequent pass will remove material from both ends until the frown flattens.