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Getting a straight edge

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Forum topic by Sawlog posted 11-24-2016 01:24 AM 665 views 1 time favorited 7 replies Add to Favorites Watch
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Sawlog

5 posts in 425 days


11-24-2016 01:24 AM

Hello, I’m kinda new here but I have been woodworking for many years.
I make tables for extra cash on the side.
My question is… you do you all get a straight edge on 8’-9’ lumber? I glue all my table tops edge to edge. Sometimes I have fits with trying to get perfectly straight edges for the glue up.
I use my jointer, but sometime I think I have to make 20 passes before the edge is good. There has to be a better way.
If you have one, please let me know.
Thank you


7 replies so far

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Aj2

1178 posts in 1636 days


#1 posted 11-24-2016 02:34 AM

I know how you feel I also like making tables and struggled with jointing long boards.I now have a jointer with very long tables that are very Flat and Coplane.
I can put together boards for a table in minutes.
Start looking for a used machine with long tables.
I have a Oliver 166 bd.

Aj

-- Aj

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Loren

9633 posts in 3486 days


#2 posted 11-24-2016 02:54 AM

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JBrow

1274 posts in 759 days


#3 posted 11-24-2016 03:01 AM

Sawlog,

My belief is that if a joint can be brought together nicely with hand pressure, it is ready for glue. I am aware of an edge jointing technique where the center of the boards is slightly hollowed out in long tapers toward each end of each board. This is called a spring joint. A single clamp in the center draws the edges together and the glue keeps the joint together. Since it introduces stress to the joint, I not a fan of this joint. But the spring joint does illustrate that if clamping pressure is required to close the joint, the joint can remain closed. I would think that if clamping pressure is used to close the joint, plenty of glue in the joint is needed and the joint needs clamped before the glue begins to skim over. A perfectly glued joint is probably needed for this under-stress joint to stand the test of time.

A practice that I adopted a year ago has worked surprisingly well for me. Before edge jointing, I mark the face of the adjoining boards at the joint line. The marks are on opposite faces of the abutting planks. Then at the jointer, I ensure the mark is against the jointer fence when the edge is straightened. This eliminates any problems with the jointer fence being out of square.

But even with this trick, jointing long boards straight is a challenge. An out-feed roller adjusted to be perfectly level with the jointer out-feed table can help keep the edge in position, especially as end of the board is jointed. A perfectly adjusted in-feed roller stand could also help at the beginning of the jointing operation.

On these long boards, a pencil mark across the entire edge down the entire length of the board can serve as a witness mark that will reveal when the entire edge along the entire length of the board has been jointed. Also consistent but minimal downward pressure during the jointing operation could help eliminate any flex that might exist in the long board. The narrower the board, the more important this consideration becomes. Lastly I try to apply downward pressure only on the part of the board that is on the outifeed table.

I agree with AJ2 that a well-tuned jointer is critical. Longer jointer beds work best and can avoid the problems associated with setting up out-feed and in-feed roller stands.

If you are good with a hand plane, jointing both long boards with a hand plane at the same time would be another option. The edges of adjacent boards that form a joint can be planed at the same time. The faces that will form the lower surface of the top should be clamped together (bottom face clamped to bottom face). This method helps ensure that jointed surfaces are complementary on both edges, allowing for the joint to close tightly.

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Holt

167 posts in 2468 days


#4 posted 11-30-2016 08:52 PM

I would be tempted to build a long cutting table, couple together enough Festool tracks to cover the length needed, and use the Festool track saw. Festool says they are glue ready right off the saw. i’m not too sure about that, but a swipe or two with a jointer plane…

-- ...Specialization is for insects.

View Logan Windram's profile

Logan Windram

341 posts in 2300 days


#5 posted 11-30-2016 09:43 PM

A jointer will leave scallops or some residual machining marks, so in theory that edge will need to be cleaned up prior to a perfect glue-up. Now, the question is, are you doing one off’s or small production runs, ie 10 or more? If they are one offs, get a razor sharp 7, clean the edge flat and straight, then put a slight spring as suggested above. that glue up will be criminally good.

If you are doing production runs, Loren has a fairly quick solution, or you could get a better blade on the TS and try to get a glue line rip off the saw… with longer pieces this is harder, you have to keep that board moving to get it perfect, but you can glue right off the blade.

I little extra glue and clamp power never hurts. Fake it until you make it.

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Cooler

299 posts in 682 days


#6 posted 11-30-2016 09:52 PM

I rarely have to joint anything, but I did recently. I was not going to invest in a jointer for this, so I took a piece of 6” x 3/4” melamine covered particle board about 2 feet long. and I attached a second piece about 3” wide to the first using pocket hole screws on 5 or 6 inch centers alternating the side of the board I drilled on. I joined the two pieces and “fine tuned” the angle the pieces met at by tightening and loosening the pocket hole screws until it was perfectly square.

Then I attached two handles, and affixed adhesive backed sanding paper (which I buy in rolls).

I then used it like a hand plane. The right angles assured me that the edges were perfectly square and the 2 foot length assured me that the piece would be nice and flat.

My rip blade does a very good job so it only took about 5 minutes per board. It was cheap enough (I had the scrap melamine in house, and the sandpaper too). And it worked very well. It also works across grain. I used it again when I was joining two pieces of butcher block end-grain to flat grain for my kitchen counter top.

Obviously not for production, but for an occasional job, it worked fine. It is one of the few temporary fixtures that I’ve held onto.

-- This post is a hand-crafted natural product. Slight variations in spelling and grammar should not be viewed as flaws or defects, but rather as an integral characteristic of the creative process.

View DirtyMike's profile

DirtyMike

637 posts in 740 days


#7 posted 11-30-2016 10:27 PM

I have been using a large straight line jig then ripping to width with good success for longer stock.

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