rookie mistake with jointer

[rdewinter]

I know I made a mistake.....I face glued six 12" 2x4's to form a block that measured 12x9x3 1/2. Because the ends were not even, I passed the end grain through my Shopsmith jointer. OOPS, big mistake. That jointer bit that end grain and my accessory coupler blew into four pieces. Luckily no injuries.
Lesson learned...don't joint end grain!!!!! Square end grain with the table saw and sand smooth.
Anyone have similiar experience?

[rolands]

I'm glad there weren't any injuries. We all have learned something the hard way. Your post may save someone an injury in the future. Thanks for posting.

[Bruce]

While it's true you probably shouldn't joint end grain, I think the reason for your accident was the length (or lack of it) of the piece. At 3 1/2 inches, you can't keep the board flat on the infeed table. The board tipped into the blade opening and WHAM!

[jhanby]

Guilty. I just did the same thing after the first glue up making a chess board. What made it worse, I already knew not to run end grain over a jointer! Oh well, I think the second attempt on the chessboard is looking much better

[Nick]

Actually, folks, you can safely joint end grain.

1. Make sure your jointer knives are sharp and set to the proper height, about .002" above the outfeed table. When you put a small block of wood on the outfeed table with one end protruding over the knives, each knife should catch it and drag it 1/16" to 1/8" toward the infeed table.
2. Adjust the depth of cut to no more than 1/32".
3. Joint the end of the board 1" in from one edge and stop.
4. Turn the board edge for edge and complete the cut. Because the end near the trailing edge has already been jointed, the knives will not catch the wood at the end of the cut. There should be no tear-out.

This, of course, presumes that the stock is wide enough and short enough to hold the board stable as you joint the end. I would not preform this procedure on a board less than 10" wide or over 36" long. Nonetheless, it is possible.

With all good wishes,

[Ed in Tampa]

Actually, folks, you can safely joint end grain.

1. Make sure your jointer knives are sharp and set to the proper height, about .002" above the outfeed table. When you put a small block of wood on the outfeed table with one end protruding over the knives, each knife should catch it and drag it 1/16" to 1/8" toward the infeed table.
2. Adjust the depth of cut to no more than 1/32".
3. Joint the end of the board 1" in from one edge and stop.
4. Turn the board edge for edge and complete the cut. Because the end near the trailing edge has already been jointed, the knives will not catch the wood at the end of the cut. There should be no tear-out.

This, of course, presumes that the stock is wide enough and short enough to hold the board stable as you joint the end. I would not preform this procedure on a board less than 10" wide or over 36" long. Nonetheless, it is possible.

With all good wishes,

Nick
Again I bow to your expertise and I'm not challenging you, I just want to understand. I thought for a jointer to work properly the knives had to be adjusted exactly even with the outfeed table.

If the knives were .002 high would they not cut a .002 snipe at the end of the board?

Here is my thinking please tell me where I'm wrong. As you feed the wood is flat on the infeed and the board would be cut .002 higher than the outfeed table. Now as you come to the end of the cut you begin using the outfeed table which would cause the board to drop that .002. As the end of the board approaches the knives since the blades are actually .002 higher than the plane of the out feed table the instant the board cleared the infeed table the board would drop the .002 and this would cause the knives which are higher to cut a snipe. Small agreed but snipe none the less.

If the blades would be set exactly equal to the outfeed height as you passed this transistion there would be no difference and thus no snipe.

Help me understand this. Thanks
Ed

[Greenvilleguy]

Ed,

I've always set my jointer knifes a smidegon (probably .002) high of the outfeed table. Assuming I can't get them perfect (and I can't), I want them slightly proud of the outfeed rather than low. Low would cause the board to catch.

A smidegon (probably .002) is an acceptable amount to me.

I haven't tried the process Nick describes above for jointing end grain. Just because you can doesn't mean you should.

[reible]

Nick is not making this up... I've used this method for more years then I want to count. Besides if you have been doing your reading in the PTWFE you would have seen this in the jointer section. In the 4th edition it is on page 76.

As far as setting the cutters higher then the outfeed table that has been done for years as well. I don't own the shopsmith jointer but I had it's twin brother to grow up with. I hated the knife setting part of it because it was almost an art rather then a mechanical operation. In those days we called it "tick" setting. You would get then blades set and locked in then rotate the head backwards and listen for the "tick" the blades would make on the straight edge.

As was mentioned it is necessary to have the blade "high" so the board doesn't catch on the outfeed table. Remember .002 is like half the thickness of 20# computer paper... not much and "hand-off" happens inches before the end of the board so you don't get the drop off anyway. I don't know if any jointer is set at dead level to the outfeed table... I know the old one from my growing up years and the two I have now while not labled .002 still have the same effect in their setup. Having said that I also know that a router table with jointer fence can be set dead on.

Also remember you are trying to get the edge straight AND square so the pressure is directed to the fence as well as down.

Ed

[Ed in Tampa]

Nick is not making this up...

I never thought Nick was making this up or that it was wrong I'm simply trying to understand. I have never had to install new blades in my Shopsmith jointer. However I have in jointers with adjustable outfeed tables and on them I was trained to make the blade even with the outfeed table.

I agree if the blade is too low it will cause a problem but I also thought too high was just as bad. Perhaps .002 is nothing to worry about, I really don't know as I usually don't work to that accuracy. However I have read enough planner reviews where they cite such and such plane as producing .002 snipe. So I would think .002 is evidently unacceptable or at least undesirable.

It seems to me if the blade is .002 high somewhere on the board you would have to have a .002 snipe. When I got my Shopsmith Jointer I was also sold a jig that had magnets that held the blades so you could correctly tighten them. Like I said I have never used it but I assumed it would hold the blade level with the outfeed table. Perhaps it has a .002 offset built in I don't know.

I would like to understand the dynamics of what happens here. As I said in my thinking the board going past the blades would be .002 higher than the out feed table. Eventually the board is going to come to rest on the outfeed table doesn't this make the blade cut .002 deeper into the board from there on out? I don't know I'm just trying to understand.

[reible]

I guess it is hard to get a grip on how small of an amount we are talking here. As an example take a router bit, you get one and it says it is 1/4". For general bits that means it is about 1/4", +.005, -.005. A better bit might be +.003 to -.003. So when you route a 1/4" slot it will be about a 1/4" by what ever the bit is off plus a bunch of other factors like compression of the wood etc. Now how much off is .002", it doesn't sound like much now.

When people start claiming they have too much snipe at .002" I have no idea how they are even measuring that... If you make the cut and measure right then I can say for sure the measurement will be different a 1/2 hour later. Wood moves for many reasons and getting a reading that close would take a trained specialists and hundreds of tests... You can change .002 by changing the downward pressure of your hands.

To be honest I don't measure to see if I have .002" it could be .0015 or .001 or .0007 I just know that it is a very small amount. I also know this is typical of a lot of planners. Both of mine have adjustable outfeeds too and if you don't have that offset right they will catch.

Fine woodworking had a feature on tuning up jointers... I may have that copied in one of my binders... and the same is true of one of the other wood mags but I don't recall which one... nor do I remember when. Perhaps someone here remembers???

Ed