Jointing bowed 12' material

[Jonathan Jung]

I'm trying to straighten 12' cherry, it's at about 10/4 right now. If I feed by hand, I can more easily control where the pressure is, but the feeder can push a bow right into the table, which will spring up afterwards. Any advice? I have this stack to do...so would like to use the feeder as much as possible.

Example
Placing the bow down (concave down) I can start by feeding by hand the first bit of the board and the last bit of the board, placing no pressure in the middle.
Placing the bow up (concave up) I can start by feeding by hand only in the middle, with placing no pressure on the ends.

But what about when running a feeder? It places pressure all the way along.

These are going to be 45mm thick valences for LED tracks. I have a lot of further processing to do on them with the tablesaw and WBS, so being quite straight helps a lot.

500100
500101
500102
500103

[Mel Fulks]

I never used a feeder for that. I run the bow over the feeder taking off at least 3/16 , then go again ,a little farther out. Convex side
facing the gluttonous machine ! Then feed again a little farther out. CONVEX side down and on the bed.

Many times that actually helps to straighten the OTHER side …with no wood removed there.

[Jonathan Jung]

I never used a feeder for that. I run the bow over the feeder taking off at least 3/16 , then go again ,a little farther out. Convex side
facing the gluttonous machine ! Then feed again a little farther out. CONVEX side down and on the bed.

Many times that actually helps to straighten the OTHER side …with no wood removed there.

What do you mean, run the bow over the feeder?

[Mel Fulks]

The convex side down on the machine bed.

[Mel Fulks]

I’m sorry . That should have been over the cutter. I will be more careful about double checking before hitting the button.

[Tom M King]

I wouldn't use the feeder. Take the highest part of the hump off first, and make it bigger until you have a straight side.

[Andrew Hughes]

I’ve faced 12 ft boards flat on my 166 using hand pressure. I start a flat area in the middle of the convex side of the board.
Using this technique will sometimes release tension in the board in our favor.
Start with freshly sharpened knives helps become its a lot like using a big upside down hand plane. Same concept
Good Luck

[John TenEyck]

Might be easier to snap a chalk line on it and cut just shy of the line on the bandsaw. Then one pass over the jointer should do it.

That is one sweet jointer you have there.

John

[Jonathan Jung]

Thanks everyone. I just processed it all, 372'. One issue with long boards is that they can sag under their own weight, and also at even 101" of jointer bed with infeed/outfeed, they could go into it with a bow or twist and come out with the same bow or twist. So after talking to JR (who's on here), I determined I was expecting too much. I was aiming for 1/32" or less bow over 12' but now I'm ok with 1/8" or so. My method was, I hit the worst of the spots by hand and then made a final pass through the feeder at 1/8" cut. JR had the point that if they bow is gentle enough for the power feeder to push out, then I'll likely be ok running the sticks through the other machines.

It's a 16" jointer, which meant I could have the feeder where it's at in the pictures, and still run pcs through by hand next to it.

[Joe Calhoon]

Jonathan,
I position the feeder as you suggested to one side of the bed for facing so I can still do a pass by hand if needed. Feeder on a jointer is the same as a straightening moulder or S4S. It works well but will not work miracles. Especially if the material has any twist. I only use the feeder when faced with larger quantities and it is helpful for thick and long material. I never have any problem getting 45mm out of 8/4. Using 10/4 I would not do it in one setting as you are removing a lot of material.
500166

[Jonathan Jung]

Jonathan,
I position the feeder as you suggested to one side of the bed for facing so I can still do a pass by hand if needed. Feeder on a jointer is the same as a straightening moulder or S4S. It works well but will not work miracles. Especially if the material has any twist. I only use the feeder when faced with larger quantities and it is helpful for thick and long material. I never have any problem getting 45mm out of 8/4. Using 10/4 I would not do it in one setting as you are removing a lot of material.
500166

Thanks Joe, that's very helpful. How long is the infeed on your Martin? My Oliver has 49.25" so I am curious if I add 3' of infeed extension, that would bring it to over half the length of the material. Would that help?

If you were to run a board like the one in your picture, but longer and with a good bow, how straight could you get it? 1/8" over 12'?

I actually had to start with 12/4 because my supplier was out of 10/4 and I didn't want to risk it with 8/4 due to the length. Perhaps I should have.

[Warren Lake]

its not your table length its technique, understanding material and support. Ive heard people say its this table length and that material length. Have proper support and your material wont bend when its off the table. More important you dont want to have to be pushing down hard on material to stop it from tilting. Did facias for two homes in 14 -16 foot material on the combo 69" total table length and it worked fine because there was support on infeed and outfeed.

[Steve Jenkins]

it’s not your table length its technique, understanding material and support. Ive heard people say its this table length and that material length. Have proper support and your material wont bend when its off the table. More important you dont want to have to be pushing down hard on material to stop it from tilting. Did facias for two homes in 14 -16 foot material on the combo 69" total table length and it worked fine because there was support on infeed and outfeed.
Whenever I hear talk about table length vs material length I wonder how it’s possible to straighten a board with a hand plane. I look at the jointer as an inverted hand plane and work the high spots first.

[Jonathan Jung]

If table length didn't matter at all to get good results, why isn't everyone ok with a 10" long bed, like on a jointing hand plane? I suppose I agree with you in principle, but in practicality, jointer bed length does help.

[Warren Lake]

I didnt say it didnt matter at all, it makes it easier easier up to some length of board. if I had 105" or more jointer and did the 14-16 foot id still need support. Support is way more important and understanding the material. I never knew the number rules board length to bed length and glad I didnt. The rule is wrong. I get the hand plane analogy its good and its also a bit different.

I have a customer I have to get a job done with what machines I have at the time. All that was needed was infeed and outfeed support for that combo machine.

[Joe Calhoon]

Thanks Joe, that's very helpful. How long is the infeed on your Martin? My Oliver has 49.25" so I am curious if I add 3' of infeed extension, that would bring it to over half the length of the material. Would that help?

If you were to run a board like the one in your picture, but longer and with a good bow, how straight could you get it? 1/8" over 12'?

I actually had to start with 12/4 because my supplier was out of 10/4 and I didn't want to risk it with 8/4 due to the length. Perhaps I should have.

Jonathan, the infeed on the Martin is about 80” outfeed about 46”. Most of my work is doors and windows so lengths in the 7 to 10’. Sometimes solid wood sometimes laminated material. I always shoot for 1/16” bow or less on these. Everything is crowned and at the outside can make 1/8” work but usually get better than that depending on material. 12’ and longer for millwork I always expect a little bow but usually that can be dealt with.
The long tables help but I did this type work on a shorter 16” JP for many years.
here is a picture of rough milling 16/4 mahogany to be made into porch railings using extension table on the outfeed.
500260