I have a glued up guitar neck I need to joint and theres quite a bit of spill out. Is it safe to run all that glue over the jointer blades with out "gumming" them up?
Also, I don't understand how a jointer cannot create two parallel face. If you joint a face and then place that reference against a fence to create a perfect 90 degree angle, then why can't you use the newly jointed edge against the fence to make another 90 degree angle. Is this just one of those "in theory" things?
Mark,
it isn't "theory". You cannot joint two opposing FACES as there is no way to reference the other side. A thickness planer does that trick. But yes, you can get the other edge jointed just fine, but it is typically done on the TS with a really good blade.
dave
Mark Chandler wrote:
You may be able to get close by putting a known parallel board on each side of the stock. Align the top with the flat top edge face of the stock and let the stock ride on those runners through the joiner until you have taken any humps off the stock. This would be the hard way to do it.
-Jack
Bubba there is absolutely no reason why you can't get that second 90 degree face by referencing the opposing face or edge against the fence, but THINK, what does that have to do with getting the two opposing faces, or edges for that matter, parallel?
No a glue line will not gum up blades BUT, despite advertising to the contrary, they are a bitch on the cutting edge.
Marc,
To simplify why you can't joint two parallel faces with the method you describe, picture a tapered table leg. While each of the 4 sides is in fact
90 degrees to its adjacent sides, they aren't parallel to their opposing sides.
It won't gum them, but it might nick them. Use a scraper first to remove excess glue. If your jointer is wide enough, make your passes over different parts of the cutter head. Make your passes at an angle, if possible.
Imagine a length of board that is 3 inches wide. It is 2 inches thick at one end, and 4 inches thick at the other. The faces are relatively straight, but could use some touching up. Joint one face to make it flat, then place the jointed face against the fence and joint the edge.
Turn it 90 degrees again, and joint the second face, using the jointed edge against the fence. The first face is now facing up. When you've made the second face straight, continue on to the other edge, just for grins. Now stop and look at your board.
Assuming you took 1/8 inch from each surface, you now have a board that is 2-3/4 inches wide. It will be 1-3/4 inches thick on one end, and
3-3/4 inches thick on the other. What you've wound up with is a long, skinny truncated pyramid.Although your faces aren't parallel, each edge will be 90 degrees from the other. Go ahead, put a square to it. Assuming the fence produces true right angles, you'll have four faces that are each at right angles to both adjoining faces.
That angle isn't what determines parallelism, though. Your board will be rectangular in cross-section, but not through its length.
Hope that helps,
Kevin
I think he means to Attach the boards with parallel edges to the work and then joint the whole shebang. Keep the reference boards as narrow as possible, because you will lose wood and parallelism with each cut.
Of course, if you cna rip the reference boards you should be able to rip the rough piece, as someone suggested. Wilson
HA! Now I get it.
Thanks
Good for you Mark. You can't square a circle with a straight edge.
"B a r r y B u r k e J r ."
There are those that never figured that out and presently work at the local tooth pick factory.
Even though the first face and third face are at 90 degrees to the second face they do not necessarily have to be parallel to each other.
The sec>
What is clear, Dave, is that you have never thought about the jointer as a powered plane. You _can_ join to a scribed parallel line with a jointer just as you can with a hand plane. Neat thing is, you don't have to scribe and fudge both sides, because the jointer fence is referencing the 90 degrees. Requires skill, though luck is certainly easier....
Sorry, Dave. The jointer _IS_ a motorized plane. That a subsequent machine design has taken over one of its former functions in no way negates that. You really want to see something challenging, look at how the old apprentices had to work to drag a board over a (skewed, to give 'em a chance) 16" wide stationary blade.
Oh yes, if you stop and think, there are really very few reasons why a board needs perfectly parallel faces. Never really is after being treated with one of a group of tools like planes, scrapers, sandpaper ....
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