Replies

1. 
   YesMaam27577 | Nov 17, 2009 05:10pm | #1

   IMO, adding clamping pressure is not the answer. That much stress on a glue joint will eventually cause it to fail.

   You need to mill those built-up planks such that the glue joint has no gap -- even gaps as small as 1/32" will stress the glue and open up in a decade or so.

   I won't be laughing at the lies when I'm gone,
   And I can't question how or when or why when I'm gone;
   I can't live proud enough to die when I'm gone,
   So I guess I'll have to do it while I'm here. (Phil Ochs)

2. 
   ak | Nov 18, 2009 01:07am | #2

   I've got to agree. You're closing too large of a gap. The best solution is to unfortunately disassemble it all and replace the warped pieces with new.

   hard now, but best in the long run.

   Inspiring Your Passionate Pursuit of the Craft

1. 
   BrentD | Nov 18, 2009 06:55am | #4

   I think you have to fix this before you can rely on a glue joint. In my opinion, having just built a maple bench of similar sized stock, I would glue one board at a time or maybe a couple at a time to the main group, building the bench a few boards a day. For exactly the problems you are experiencing, I do not recommend making multiple segments of the top and then gluing them together.Brent

1. 
   stewie | Nov 18, 2009 03:59pm | #5

   If there is a next time , I'll take your advice and do it one bd. at a time. My process was 6 sections of 5 boards each. Then I glued up 3 and 3 sections, run the 12" widths thru the planner to smooth the top. I had used the same process on my butcher block kitchen counter top of beech and maple ( but only 2" thick) and no problems..
   All went well till the last glue up. I'm leaving it in the clamps for 3 days. I'll fill the gap with sawdust for the first 10 years , and chisels after that , when I'm too old to reach all the way across .Stewie
   Woodworking is like golf : Always a new way to screw up :) .

1. 
   BrentD | Nov 18, 2009 04:45pm | #6

   I almost went the route you did. Almost. Had the same plan to use the planer. But when I thought about the straightness factor, I changed my mind. Instead, I leveled the whole unit with a router. That took some careful planning and a good bit of muscle but it worked perfectly. I think you can straighten your sections on a table saw if you build a jig that will effectively lengthen your fence. It is doable. Brent

1. 
   stewie | Nov 19, 2009 03:30am | #7

   Thanks, Brent.  Table saw easier to manage 90 lb. sections than  my 6" jointer.

    

   So , if it splits when I take the clamps off , and the chisels fall thru. , I'll use the table saw to re-do it.

    

   Stewie

2. 
   kre8ted | Nov 19, 2009 05:25am | #8

   Brent, interesting solution. Can you describe the process you used when leveling with a router?

3. 
   BrentD | Nov 19, 2009 05:55am | #9

   Yes, However, I did not invent this idea. I just modified it to meet my needs. First, I built a pair of rails that were longer than the bench (~70"). I had a lay out table that wider than the bench I was making so is wide (32" IIRC). The rails were connected by a pair of cross pieces that laid on top of the lay out table. Every effort was then made to make the rails perfectly parallel and equal height above the layout table. The bench top was laid on top of this jig and shimmed to be as close as possible to parallel with the plane of rails but below the rails so the router has room to work and chips can escape. Think of the rails as something like railroad tracks and the cross pieces as the ties. The bench top was then laid on the ties between and below the rails. Next a very rigid jig was built out of plywood to span the rails. It was slotted and had sides that the router would run against while the router was slid from one rail to the next cutting about 1/8" on average off of the bench top. Some places it was a little more, some a little less, but you have to be sure when you start that you are cutting enough to skim the spot that is the lowest point below the rails. I used a 1" end cutting straight router bit. Standing on one side of the bench top, I would run the router across to the other side while holding it against the left side of the cross jig. I then moved the router to the right side of the jig and pulled the router back to me. At that point, I had to slide the cross jig down the rails about 1.5" and repeat. Once this is done I have one true and flat side. I then flipped the bench top (about 300# I think it was) and repeated the process on the other side. If you have made the rails carefully and if the rails are truly parallel on the layout table, then you will not have to shim to do the second side. The first side of the bench top that I did was the underside, so if there were errors, they would not matter. This was all pretty easy, skill wise, but took some heavy lifting to flip the bench top. And it took a fair bit of time too. When done, there were small ridges from the passes with the router, but a very little sanding and that was gone. Winding stick checks for flatness showed it was about as close to perfect as I could see. There are variations on this method that attach the rails to the sides of the top being planed. This can be done to reflatten old benches too. Of course real men and women would use a hand plane, but frankly, I ain't that good. I do love my bench though. It is the pride of my shop and made with sugar maple from my own woods. I think there is something about this method on this website somewhere in the various blog and project pages, but damned if I could find it again. This place is seriously confusing in that way. Does that help?Brent

4. 
   kre8ted | Nov 19, 2009 06:15am | #10

   Thanks Brent.  It sounds very doable.  What was the advantage of doing this versus using a planer and sander.  We have a fairly large millworks shop near here that can handle slabs that size.  Would you use that approach or are there special reasons why you used the router method?

   Edited 11/20/2009 11:44 am ET by kre8ted

5. 
   BrentD | Nov 19, 2009 06:58am | #11

   The planer I have is only 12.5" wide. So, I would have to do it in sections. If those sections have any twist, I'd never get it out. And sooner or later, in building the sections I'd get a bow and once 3 or so boards are glued up, I'm not going to be able to bend them enough to mate with the other sections.Then, once I have the sections, then I have to glue them up perfectly and that's not going to happen in my experience. So, I'd still have to flatten. Give me a belt sander, and I'll turn my nice flat bench into something that looks like the Sand Dunes of the Sahara on a bad day. I used it only to very very lightly take out the small ridges left from the router. Then I used a light touch with the palm sander and I was done. The way I did it was not the only way, but for me, my skill set, time and tools on hand, it was the best way, and I could not be happier with the results. Maybe next time I'll be courageous and buy a big hand plane and do it the old fashioned way. But I'm happy with this one. BrentPS, When building up the top, I would glue up about 3 boards in the morning, clamp with pipe clamps and then do another 3 in the evening after work. The whole thing has about 27 or 28 boards total I think. So, it took a few days.

6. 
   kre8ted | Nov 19, 2009 02:13pm | #12

   I wondered about the glue up - it seemed like gluing sections together then gluing them together was full of risk.  I think I like your idea of gluing onto the same section each day until wide enough.

   Thanks for the insights.

7. 
   DonStephan | Nov 20, 2009 04:42pm | #13

   On occasion I've had to glue up a top "in sections" but I was afraid of getting bowing, as described by original poster.  My solution was to put all the pieces in the clamps each time, even though only a few at a time were glued together.  The thought was that the individual pieces, and the glued sections, would always mate without bows that way.  Has anyone else ever tried this approach? 

8. 
   Eef | Nov 23, 2009 09:53pm | #14

   don, yes, i've done that also. one advantage to this method is that i can, sort of, preview the "coming attractions", i.e. one can see how each board relates to it's mate and correct, re-arrange as needed.
   eef

3. 
   roc | Nov 18, 2009 05:20am | #3

   I was holding back to see if that was a serious question. My first thought was through bolt the ends and store chisels in the gap down the middle.

   : )

   roc

   Give me six hours to chop down a tree and I will spend the first four sharpening the axe. Abraham Lincoln ( 54° shaves )