Jointing thick boards
#11
I'm building a bench and using Douglas Fir construction lumber. For the top, I'm using 4x8 (3.5 x 7.5) lumber that I bought months ago and have let dry and acclimate in my shop. I'm using 4 of these boards joined together to make the top that I'll cut down to 24" wide. The top will be 6 feet long. I am having a really hard time getting these thick boards ready for gluing. I have a power jointer but it's just a little 6" tabletop model that is useless for this task so I've been focusing on using my hand planes. I'm getting close but not perfect. I managed to glue up two boards together with a small gap of about 1/6" at one end. My clamps did a fine job of closing the gap. My method is basically using my jack plane to get things fairly straight then switching to my jointer to finish things off. I'm having a really hard time ensuing a straight edge and removing twist. Like I said, I'm getting close but not perfect.

Does anyone know any tricks or good methods for jointing boards that are thicker than 3 inches with hand planes?
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#12
Planing to a straight line I'll assume is not the problem. Then the challenge is to keep the two sides in register for squareness and to avoid twist. One approach is to start with winding sticks, and to plane a rabbet on each end to hold winding sticks you can see are not twisted. Then plane each edge to connect the rabbets at the ends with straight lines. Then take out the middle, making sure to not mess with the edges. This approach lets you focus on one problem at a time.
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#13
Woah, that actually isn't a bad idea. That will definitely help control or correct twist. I'm not sure it will help ensure a straight surface along the whole six-foot edge. Twist has been my bigger problem through. I've been trying to shoot for either a straight edge or one that is slightly shallow in the middle. My No7 gets me close but not perfect. I'll try the rabbets tonight. Thank you.
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#14
Not sure exactly what the issue is, but what works for me is to arrange the boards in the way you want them to sit when glued up, then put a traingle mark on the assembly, then place 2 the boards  face to face  ( or back to back ) and clamp them so the tops are even, then plane both at the same time.  When you use your jack plane,  if your blade or the plane is tilted to one side of the other, they will still mate perfectly.  That is ,  if for some reason, the plane cuts at 88 degrees not 90, once you put them back in the orientation of the glue up, the mating board is at 92, so when put together, they will equal 180 degrees.  I just have to keep track of which board is adjacent to which board, and make sure that they are clamped face to face or back to back.

As to a little gap on the ends, we generally want a little gap in the middle, and that is the opposite of what the jack plane wants to do.  So either take your last full length cut from one end to the other, then follow by taking a shorter plane ,  set for a very tiny cut, and plane a small section in the middle,  or use a cabinet scraper in the same area.  The flip the boards into the correct orientation, and see if there is a gap at the ends, if so,  extend the area that you scraped in the middle and recheck.
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#15
This is what I do for narrower stock, say 3/4” or 1”. Two board together face to face leaves a 1.5”-2” surface to joint. The issue is that I’m working with 3.5” boards so putting them face to face leaves a 7” surface to plane. Much wider than my plane blade so there’s more room for misalignment in glue up.
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#16
Just get one edge straight.  Don't worry if it's 90 degrees.  Then run the other edge through the table saw, flip it over and repeat on the edge you hand jointed.  Now you will have parallel edges at 90 degrees and ready for glue up.  If you don't have a table saw then use a circular saw against a guide.  If you don't have a circular saw then use a router against a guide.  If you have none of those you need to buy some tools.  

John
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#17
John, that works great for normal thickness boards, but his are 3.5" thick. Far fewer people have a 12"+ table saw or circular saw. This seems like a good project for practicing hand plane use, as he's doing.

Tyler
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#18
(06-09-2022, 03:10 PM)OneStaple Wrote: John, that works great for normal thickness boards, but his are 3.5" thick. Far fewer people have a 12"+ table saw or circular saw. This seems like a good project for practicing hand plane use, as he's doing.

Tyler

That is true for regular circular saws, but my 10" TS blades cut to 3.5".  

John
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#19
jteneyck Wrote:That is true for regular circular saws, but my 10" TS blades cut to 3.5".
Hmmm, my Unisaw only cuts about 3" deep. I'm sure there's variation between brands, but I'm surprised you get an extra half inch. What saw are you using?

If a saw doesn't go ask the way through, it might be able to use a technique of cutting part way through and flipping the board end-for-end to cut the rest, if the blade is very carefully set to 90 degrees to the table. But I don't love that approach. I'd pick hand planes instead, probably. Or a bigger powered jointer (I know the OP said his isn't up to the task)

Tyler
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#20
(06-09-2022, 08:18 PM)OneStaple Wrote: Hmmm, my Unisaw only cuts about 3" deep. I'm sure there's variation between brands, but I'm surprised you get an extra half inch. What saw are you using?

If a saw doesn't go ask the way through, it might be able to use a technique of cutting part way through and flipping the board end-for-end to cut the rest, if the blade is very carefully set to 90 degrees to the table. But I don't love that approach. I'd pick hand planes instead, probably. Or a bigger powered jointer (I know the OP said his isn't up to the task)

Tyler

My Unisaw cuts to 3-1/4".  My old Sears cuts just a whisker shy of 3-1/2".  I'd rather use my bandsaw when cutting something that thick, but it is possible.  

My real point was to think of alternatives rather than trying to joint something wider than the blade of your hand plane.  That's just an exercise in frustration or at least it would be for me.  

John
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