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Forum topic by Jackietreehorn posted 07-19-2015 04:21 PM 939 views 0 times favorited 23 replies Add to Favorites Watch
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Jackietreehorn

150 posts in 1405 days


07-19-2015 04:21 PM

Topic tags/keywords: jointer

Hi guys, I wanted to this whole jointer thing without having to ask for help, but I’m a bit confused now. I’ve been reading up all I can in the past few weeks and I have an issue I’m trying to figure out. I have powermatic 6” jointer and it’s hard to explain in writing but when I’ve searched the topic I’ve come up with jointers cut tapers. I get that, but on this last board I cut it seemed to be going fine and then went astray. I’ll use the word braap to describe the cutting sound.
So I took my wood, put it with frown upside down and it went like so;
Braap silence braap so I figured hey, cutting the ends out. I did it again
Braap braap silence braap braap ok, getting closer.
Next go around braap braap braap silence.
Hmmm that’s not right,
I go and check my board with straight edge and it’s flat across most of it and then tapers away from the straight edge towards the end. I’m thinking/hoping it’s something in my technique since I’ve jointed a few boards already today without issue. Any thoughts?
Note, it’s a 64” long 4/4 board about 5.5” wide. Jointer beds are 32”
Thanks in advance!

Oh, another question, I’ve left the boards at 5”+ wide to joint before cutting down closer to desired finished dimension, is it smarter this way or should I rip them and then joint them. I figured joint at 5.5, rip to ~2.75, then let sit for a few days, rejoint the edge if need and then dimension final width. Then plane down to final thickness. Sound about right? Does the same apply for length too? For example I have two 20” pieces I need so I left my stick around 44 to account for snipe and figured cut down to 20” after milling, or is it easier to joint two 20” pieces (assuming leftovers for snipe)?

-- www.nobleprojects.blogspot.com


23 replies so far

View mahdee's profile

mahdee

3555 posts in 1235 days


#1 posted 07-19-2015 05:42 PM

You are better off to cut them at 22” before joining. As far as the curve toward the end; it is because you are pushing down at the adjustable plate. You should let the board ride on the fixed plate.

-- earthartandfoods.com

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joey502

487 posts in 985 days


#2 posted 07-19-2015 05:54 PM

I cut my lumber to rough sizes before jointing, both in length and width.

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joey502

487 posts in 985 days


#3 posted 07-19-2015 05:55 PM

What do you mean frown upside down? Over the length or width?

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Jackietreehorn

150 posts in 1405 days


#4 posted 07-19-2015 06:46 PM

Over the length for the frown. Such fun learning this is (sarcasm)

-- www.nobleprojects.blogspot.com

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Jackietreehorn

150 posts in 1405 days


#5 posted 07-19-2015 06:50 PM

I went through and measured the parallelness of the tables.
If looking down at table with cutter head on left I have
.026. .026
.025. .023-.024
That should be considered pretty dialed as far as I’ve read. Going to check knives and then assume I need to practice technique more.

-- www.nobleprojects.blogspot.com

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rwe2156

2198 posts in 948 days


#6 posted 07-19-2015 07:49 PM

Is it tearing out? The only sound I’ve heard romtoely like that is going uphill against the grain in hardwood.

Whatever that’s from, cut your tapers with taper jig on your TS.
Clean them up with a hand plane forget the jointer except for the non tapered sides.

-- Everything is a prototype thats why its one of a kind!!

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Jackietreehorn

150 posts in 1405 days


#7 posted 07-19-2015 08:29 PM

No it’s not tearing out, I was just referring to listening to the machine as it makes its cuts. Braap means material being removed. So basically it was removing material at both ends as as it got closer to getting flat it would stop removing any material towards the end. As Joey said above, I bet I pushed down on indeed and then the next cut didn’t so it stayed off the table too much. I’m learning. Slowly.

-- www.nobleprojects.blogspot.com

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firefighterontheside

13522 posts in 1324 days


#8 posted 07-19-2015 08:55 PM

To be sure, you’re jointing the concave side right? Anything that has a pronounced curve I will run across the knives until I hear nothing and then turn end for end and do the same until I get to where I’m almost cutting along the whole length. Don’t push down so hard that you’re straightening the board. That will lead to inconsistent jointing. Once a good foot or so of you board is on the out feed table, that’s where most of your down pressure needs to be.

-- Bill M. "People change, walnut doesn't" by Gene.

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JeffP

573 posts in 859 days


#9 posted 07-19-2015 11:55 PM

I’m speaking here mainly from an engineering perspective, and NOT from a large amount of experience. So take the following with a grain of salt:

It is easy to look at your hunk of uneven wood and think of it as a homogenous critter that is just rough around the edges. Take a moment to imagine it as part of a huge tree trunk. Imagine heavy limbs jutting out this way and that. Imagine an open field to the west from whence a near constant breeze has tried to push the tree over to the east. Imagine a taller tree to the south that takes all the sun so your tree had to lean off to the north. All of these things cause the tree to compensate over the years.

So you have this hunk of wood that has been part of this complex and wonderful gestalt of forces that have held many tons of wood and leaves up in the air for half a century or more. Now somebody comes along and cuts it up into chunks.

All of those internal forces that used to balance each other out are now disconnected from neighboring chunks. Instead of a homogenous chunk, you’ve got a mass of “springs” that are in varying amounts of tension and compression inside your chunk…all trying to change its shape.

As you cut it up further, you continue this process, and what was perfectly straight before you ripped it…may be much less so after you rip it. Two opposing forces holding each other in check, now separated…no longer balancing each other out.

Long story short, the longer a piece is, the more variation it has inside from where branches were and where a crotch transitions into a straight area, etc. etc.

Also, as you make it thinner and less wide, you are unbalancing things that were still in balance before.

And finally, if a longer piece has significant bow to it, you will wind up having to sacrifice more wood to the pile of shavings under the jointer to get a long piece straight. If it is shorter when you start, less total wood is lost to make the set of smaller pieces straight. Similarly for jointing a narrower cupped piece rather than a wider one.

And unless you have a really big jointer, handling a 6 foot long board is more difficult.

And finally…many apparent experts on youtube recommend jointing in two stages. Joint it once, then let it “rest” for a day (while the internal forces re-equalize and the board deforms slightly as a result)...then joint it again before using it in your project.

-- Last week I finally got my $*i# together. Unfortunately, it was in my shop, so I will probably never find it again.

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Jackietreehorn

150 posts in 1405 days


#10 posted 07-20-2015 12:10 AM


To be sure, you re jointing the concave side right? Anything that has a pronounced curve I will run across the knives until I hear nothing and then turn end for end and do the same until I get to where I m almost cutting along the whole length. Don t push down so hard that you re straightening the board. That will lead to inconsistent jointing. Once a good foot or so of you board is on the out feed table, that s where most of your down pressure needs to be.

- firefighterontheside

Yes, concave side.


I m speaking here mainly from an engineering perspective, and NOT from a large amount of experience. So take the following with a grain of salt:

It is easy to look at your hunk of uneven wood and think of it as a homogenous critter that is just rough around the edges. Take a moment to imagine it as part of a huge tree trunk. Imagine heavy limbs jutting out this way and that. Imagine an open field to the west from whence a near constant breeze has tried to push the tree over to the east. Imagine a taller tree to the south that takes all the sun so your tree had to lean off to the north. All of these things cause the tree to compensate over the years.

So you have this hunk of wood that has been part of this complex and wonderful gestalt of forces that have held many tons of wood and leaves up in the air for half a century or more. Now somebody comes along and cuts it up into chunks.

All of those internal forces that used to balance each other out are now disconnected from neighboring chunks. Instead of a homogenous chunk, you ve got a mass of “springs” that are in varying amounts of tension and compression inside your chunk…all trying to change its shape.

As you cut it up further, you continue this process, and what was perfectly straight before you ripped it…may be much less so after you rip it. Two opposing forces holding each other in check, now separated…no longer balancing each other out.

Long story short, the longer a piece is, the more variation it has inside from where branches were and where a crotch transitions into a straight area, etc. etc.

Also, as you make it thinner and less wide, you are unbalancing things that were still in balance before.

And finally, if a longer piece has significant bow to it, you will wind up having to sacrifice more wood to the pile of shavings under the jointer to get a long piece straight. If it is shorter when you start, less total wood is lost to make the set of smaller pieces straight. Similarly for jointing a narrower cupped piece rather than a wider one.

And unless you have a really big jointer, handling a 6 foot long board is more difficult.

And finally…many apparent experts on youtube recommend jointing in two stages. Joint it once, then let it “rest” for a day (while the internal forces re-equalize and the board deforms slightly as a result)...then joint it again before using it in your project.

- JeffP


Yeah, I figured that stuff was going to move, and since I’m a newbie at jointing, I’ve set the jointer ~ 1/32”. I figured I joint a face, then rip the pieces on the saw to an oversized piece (from 6” down to 3”, final size to be ~2&3/8”) and let them sit for a week or so. After todays escapade is where I’ve come to question my technique.

Here’s a picture obviously over exaggerated, but this is what I ran into twice today on two boards not from the same stack. On the lower piece you can see a taper not along the whole cut, that’s whats confusing me. would flipping the cut end to end solve this? Basically I put cupped side down, ran it through and would hear the wood being cut on both ends and not in the center. Then right when it pretty much would be cutting along the whole length is when I noticed it wasn’t cutting on the tail end after flipping directions as firefighterontheside had mentioned. If it’s technique then obviously I have to work on it, and since it doesn’t do it everytime, I’m assuming its technique or the wood, but not the machine (I hope)

 photo 29_zps9kmplguh.jpg

-- www.nobleprojects.blogspot.com

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firefighterontheside

13522 posts in 1324 days


#11 posted 07-20-2015 12:15 AM

I think you mentioned checking your cutter head. Is your cutter head even with the out feed table?

-- Bill M. "People change, walnut doesn't" by Gene.

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Jackietreehorn

150 posts in 1405 days


#12 posted 07-20-2015 12:26 AM



I think you mentioned checking your cutter head. Is your cutter head even with the out feed table?

- firefighterontheside

I know the knives are, I decided to flip the knives cause I had a groove in the current ones. (the quick set knives thing seems like a huge marketing scheme that doesn’t work well, granted I’ve never set knives other than this jointer).
Before I changed knives I checked the head relative to the infeed and not outfeed, but given that they’re pretty coplanar I guess that means the head is too? After changing knives it seemed to work better probably cause it being sharper, I ran through a couple 25” boards and was happy with the flatness, then I ran into my second half taper of the day and had to leave shop so I couldn’t test anymore pieces.

-- www.nobleprojects.blogspot.com

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Aj2

692 posts in 1265 days


#13 posted 07-20-2015 01:06 AM

It’s not always a simple task jointing 4/4 stock ,because just your feed pressure can change the cut.And if the knives are not killer sharp it takes even more pressure to keep the wood in the cut.When my jointer starts cutting funny it’s always the knives.
The best test is to edge joint two boards that are tall and not affected by the hand feed pressure.Then look at the joint it makes.Should be no light between the boards.Or at the ends.

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firefighterontheside

13522 posts in 1324 days


#14 posted 07-20-2015 01:34 AM

I’m sorry I should have said the knives and not the cutter head. It’s the knives that matter. When I got my jointer I checked that the tables were coplanar by raising them to the same level and placing a straight edge across and could see no light underneath. Then I set the knives to the height of the out feed table. I just use a speed square set on the outfeed table to set the knife height. With the jointer unplugged I set the knife such that when manually turned it drags the square about 1/8”. Set each knife like this then raise the outfeed up so that the knives just kiss the square, but don’t move it. Then never move the outfeed again until you have to change the knives. I almost never change the height of the infeed.

-- Bill M. "People change, walnut doesn't" by Gene.

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Jim B

57 posts in 697 days


#15 posted 07-20-2015 03:56 AM

I recently had a very similar problem. I found out my knives were just a bit higher than my outfit table, and i raised my indeed table to make a shallower cut.

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