# Gaps in the final glue up for endgrain cutting boards



## BrendanC (Jun 3, 2012)

Hello everyone. I apologize in advance, am new to relatively new to woodworking, and don't know all the correct terminology. Here is my problem, I like to make endgrain cutting boards. I start with the lumber glue up the strips and use the drum sander to get them even. when I crosscut the sections to do the final glue up, i've been getting gaps between the pieces that require more clamping force to get them to connect, which distorts the patterns I was going for. The gaps are always in the middle of the pieces ( like they are bowed slightly) I've checked my drum sander and it is level. So it should be sanding them square, I think. Is there something else I should check or something else I should be doing? Any advice would be greatly appreciated.


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## PurpLev (May 30, 2008)

a drum sander - like a planer will only plane/sand a surface PARALLEL to the opposing surface - it will not make a surface FLAT!

IF the referenced surface is FLAT, then the parallel surface that the sander/planer will make will be FLAT as well, not because the sander/planer makes it flat - but because the referenced surface was flat to begin with.

to put it in other words - if you have a bowed/cupped board (rough cut, or a panel, or a glued up board) then the sander/planer will not flatten it - you need a jointer, or some other means (router sled) to make it flat before you use the sander.

the sander will only smoothen it out to give you a nice finish - but will not flatten it.


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## a1Jim (Aug 9, 2008)

You might think about doing you glues from the middle out and using lots of clamps.


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## Cory (Jan 14, 2009)

I've had that problem before and it was caused by one of two things:

1) my stock wasn't flat at the time of the first glue up. Either my milling was bad or the pieces twisted or bowed after milling.

2) too much clamping pressure. Using pipe clamps you can really crunch a board, causing it to warp under the pressure. I use parallel clamps now and only tighten enough to see a little glue squeeze out.

After I corrected those two issues, I haven't had any problems with gaps.


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## jgreiner (Oct 23, 2010)

@PurpLev
That's a general misconception .. with careful setup and work a planer, and drum sander can flatten a surface, the hardest to remove is a twist .. but a general bow or cup especially across the width and not the length is pretty easy to remove via planer or drum sander.

When glueing up your panels if you get some bowing, you'll have to flatten it. You need to make sure that the inside thickness is the same as the outside thickness.

It could be possible that your drum sander isn't perfectly level and is also causing a divot in your boards.

-jeremy


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## lumberjoe (Mar 30, 2012)

Jeremy, I am new to woodworking so there are a lot of things I don't fully understand. I have experienced first hand that a planer will not flatten a board, bit will simply transfer whatever defect is present on the "bottom" to the top. I know there are sleds that can be used in a planer, but I don't see how it's possible to remove a bow simply by passing it through the planer. 
Could you elaborate?


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## gscott40 (Jan 8, 2008)

I realize this is a really old post but….in case anyone looks at it here is my answer. I do lots of these board and in the early days did the same thing, had the same problems. Still do once in awhile. Solution…joint each piece before gluing them. Glue up your master strips, surface plane the resulting piece, cut it into strips, joint them both sides, and glue them into two halves. Finally glue the final end grain board.
Yeah I know ….. but it works fine. When doing your final glue up glue only half of the board and use metal channel on each end to keep the pressure more evenly distributed. Then glue the two half pieces together and you are done. 
I also glue a scrap piece on the outside ends of the final board and run it through the surface planer to get it flat…well smooth. This save time in my sander. cut them off after you are done.
You can buy 36" metal channel at Home Depot…cut it in half and put a 3/4" piece of white oak in between. It doesn't flex much and great for gluing end grain boards. That means one 36" channel for one 18" clamping caul.

George


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## AandCstyle (Mar 21, 2012)

Okay, George, for the slower learners (me) on the forum, would you be good enough to provide a little more explanation/detail? I thought that running an end grain board through the planer was a definite "No-no". Perhaps a slow speed tutorial of your entire process would be beneficial for everyone new to the cutting board making process.


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## lumberjoe (Mar 30, 2012)

What a timely post! I would never consider sending end grain through a planer, however my dad spent some time over my place today and wanted to help. While I was feeding the baby, he decided to send my first end grain board that I glued last night through my planer. It's in 11 pieces right now and judging by the 1/2" deep gouges (my planer does not have a cutter head lock), at a minimum I need new blades, I may need a new planer. Luckily no one was hurt.

I made a jig but never got a chance to use it. The basic concept can be seen here:

http://www.thewoodwhisperer.com/videos/flattening-workbenches-and-wide-boards-with-a-router/

This was on the top of a workbench, but you'll get the basic idea. I have a brand new 3/4" bit still in the whiteside package what that impossible to remove plastic on the end of it.


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## jgreiner (Oct 23, 2010)

Hey this is an old thread, and I forgot to answer the question asked of me ..

If a board is bowed/cupped across the width, all you have to do is make sure that the board will rest against the reference surface without rocking, some quick sanding of the corners can ensure that. With that you can slide it through the drum sander like the picture below taking light passes, and it will slowly shave off the top until it is flat as the reference surface.










Then you can flip and remove the cup.

There are exceptions to this, if the item is too thin, and pressure is applied it will be pushed down before the sanding or cutter head can shave off the top. This is more noticeable on planers because they have the rollers that apply a good amount of downward force on a board. Taking very very light passes can help with this.

This doesn't help with twists, or bows/cups that are across the length of a board (unless the board is short enough to fully fit on the planer/drum sander bed).

Depending on the bow, this can cause the edge to no longer be square to the top/bottom (quick pass through the table saw can fix that, which usually happens anyways to remove glue squeeze out).

As added, I would never ever put an end grain cutting board through a planer. The woodwhisperer posted a blog from a user a while back:
http://www.thewoodwhisperer.com/articles/end-grain-through-the-planer/

But simply put, the planer knives can grab onto the end grain and cause chip out, to the extreme and split the board which can cause all sorts of chaos to happen inside the planer.

I haven't tried, but I also don't see why a traditional planer sled that is used for jointing long boards can't be used for panel glue ups through the drum sander if you have a crazy twist.

If you don't have a drum sander, building a router planer jig is an excellent and cheap alternative assuming you have a router. It's messy (unless you have really good dust collection on your router) .. but very effective.

-jeremy


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## lumberjoe (Mar 30, 2012)

It's messy even with really good dust collection. You have a board between your vac port and most of the chips.


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## Dusty56 (Apr 20, 2008)

The OP never replied if any of the comments helped him with his problem. Hopefully he's alright : )

*Jeremy* , if the board in your sample picture was 3/4" to start with , it will end up at about 1/4" when finished , with no guaranty that it won't cup all over again. Best thing to do would be to rip it down the middle and joint one face and then plane or sand the other side parallel. Glue the two together and you've just saved yourself a lot of time and materials. 
*Purplev* is correct and I have also had the same experiences through the years.


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## derosa (Aug 21, 2010)

I've actually not had any problems doing exactly what Jeremy is talking about on the planer and have never had a board re-warp. I send it through twice on each height adjustment and move in smaller increments, once one side is finished I send the other side through. I assume it tends not to re-warp because an equal amount tends to come off each side. I prefer doing it this way due to a lack of clamps and time, if I had to do this with every board that was cupped I'd have to do every board I'm currently working with and that would either add to the aggravation of trying to glue up 4 boards over 12 inches with me hand jointing each glue line; or gluing the two boards back together, waiting a day for them to dry and then gluing up my panel and still having to hand joint extra. And no matter what I still never seem to get my panel glue ups perfectly flat which requires still more work. Extra time at the planer means less time elsewhere and a lot less work. All the wood I'm using was free seconds from the mill but nice and thick so my boards are still over 3/4" thick when done and flat.

As to cutting boards in the planer, I don't have drum sander either and have sent boards through the planer. If you must do it make sure the board doesn't rock in any way by shimming under the corners and take very shallow cuts, I take 16 adjustments to turn the knob one time which is only a 1/16 of an inch total. Don't stand in the way of planer, stand completely to the side. I've done this with about 5 boards so far and though I've never had a hitch in doing it I still don't fully trust the process.

Although this is way to late for the OP, if I have a glue line that looks really bad with a gap I run the band saw blade right through the middle of it, doesn't remove a lot from either side and basically joints the edge if you have a good sharp and wide blade that doesn't wander or flutter.


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## jgreiner (Oct 23, 2010)

@Dusty
The board in the picture above was an over exaggeration so you could clearly see the method used. This is also meant as more of a cup or bow introduced into glued up panels or cutting boards where cutting down the middle isn't an option.

The reason your board re-bows is because the board was flattened by the pressure of the rollers on the planer. The planer rollers push the board flat against the bed while making the cut. This is all dependent on the wood used and the thickness of the wood and how deep of a cut you take.

I've flattened many end grain cutting boards this way with the drum sander. The drum sander is ideal for this method because there are no rollers and you are already generally taking a very light pass. And secondly a cutting board is generally so thick, with so much glue strength that it's very easy to get a stable hold on the bed even if there is a small gap at the bottom.

@derosa
I've heard a lot of people using their planer with success, especially with a helical head instead of the straight knife heads. I think it depends on the planer, and how sharp your blades are and how crazy you are willing to be  I'm glad it's working for you.


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## Dusty56 (Apr 20, 2008)

*Hi Jeremy *,
I realize the sample picture was just that….my statement was if it was 3/4" to start with , you can pretty much eyeball the "sample" board and see that you would lose 2/3 of it to planing or sanding, and I offered a process that has worked for me on numerous occasions : ) 
If you take a look at your drum sander , you will find that there are rollers in it as well….well , at least there are in my Delta and Ryobi models as well as my Performax brand.
They push down on the boards and apply pressure to keep the board against the feed belt so your boards don't shoot back out at you from the rotation of the drum : ) I have plenty of experience with drum sanders , and have saved more than a few cupped boards , it's just that they ended up much thinner in the end despite taking off very little at a time to flatten them : )


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## gscott40 (Jan 8, 2008)

Well Art I see Joe had some problems. I have had no problems running my end grain boards thru my surface planer….now with that said not everyone has a large planer. Mine is a Powermatic 15", 3 HP model. Not hugh but it handles the end grain fine. I am not sure what one of the 12" bench top type would do.. It is true that it is not recommended to run end grain through a planer but that's because it's going to probably tear up both the leading edge and trailing edge. That's why during the final glue up of a board I glue a scrap piece of 3/4 inch wood on each end.
I also try to sneak up on it….I scape the board with a paint scraper to get is as smooth as possible (do that while the glue is a bit green) and take light cuts. I have had no problems.
I sometimes make 10 or 12 in a batch and in the past I have run my boards through my sander…a small 1632 Powermatic ( a 5hp small wide belt, not a drum sander)...and it takes forever doing that. I can only imagine what a drum sander would be like. I was tired to spending time standing there feeding board after board and one day tried the planer and it worked. I now only have to make a pass or two through the sander to flatten it out. Less sanding marks too.

Now as for the cracks in gluing the strips. I used to glue up 11" X 36" boards consisting of various width boards to get the pattern I was after. Once glued I would run them through my planer to get them somewhat flat and then take them to my sander and sand them. After that cut them into strips about 1 1/4" wide and the glue them up. Always had problems with cracks. Not every board but enough to make it very frustrating. I got the thinking why not joint each strip? I tried it and it worked fine….no tear out. Just take a very thin cut..1/16" or less. This, plus gluing up half of the board at a time seemed to help tremendously. Distributing equal pressure over the whole board is tough…especially out to the center. I used three clamps on the bottom and two on top but those strips are far from ridged and don't transmit the pressure well. They tend to flex. So I had some 2" wide channel I had bought for other purposes. I cut two in half (they were 36" long) and put a piece of 3/4" white oak between them. They then sandwich the strips I am gluing and now I only need three clamps and have little problem with gaps. When the two halves are glued I joint the ends and glue them together for the final board plus scrap on each end for the surface planer.

This season (I sell boards at our local farmers market) I decided to make larger boards 12"X18" and started by gluing up 48" master boards. I run the that 12" wide 48" long master board through the planer and then cut it into strips. I, of course get more strips than I need. I use the extra strips to replace bad ones and often have enough to glue up what I call mini-boards or half-boards. They are popular as they are small and easy to carry around the kitchen. My wife loves hers.

Understand please that I am producing 10+ of these boards a week plus other "stuff" and don't have time to use a router sled or a drum sander so I look for things that are expedient and work for me. Gluing takes forever and I sometimes have four boards (8 halves) in the clamps at a time. I suggest for those of you who feel this is dangerous….Don't Do It. I am just sharing some thing I found that function for me

A long post and probably has typos, misspellings and other errors. Forgive me it is 7:45 PM and I have to be up at 4 AM to meet my partner at the market to set up. It opens a 6:30. Just spent 9 hours making turn tables, pizza peels, chess boards (oops game boards), and some side grain cutting boards And why do I do this? Certainly not making any money. Have a good week end everyone


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## AandCstyle (Mar 21, 2012)

George, thank you for the great response. I think that I mostly understand it now. I will try it out and see how I do with it.


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## laanguiano (Jun 15, 2010)

Ive had my fair share of small gaps. The key is 1) not creating them… duh, 2) finding them before you glueup.

One thing that is simplistic to decrease the amount of gaps is to use thicker pieces of wood. That way you dont need to glue up as many strips.. the more strips, the more compounded your error will become. I use 6/4 wood now to make cutting boards.

2nd thing is before i do my final glueup, i will clamp all the strips like i would with glue, then turn off all the lights, and shine a flashlight behind the board, looking all over the other side of the board to see if there is any hint of light.

my 3rd tip is to not glue up the final board in one section. if its a 12×18 cutting board. glue two 12×9 sections seperately. Then pull them out of the clamps when dry and join the pieces. if its not perfectly tight then you can use a crosscut sled on each piece so they fit perfect.

PS: I had problems using the drum sander after the first glueup to flatten perfectly straight so i switched to the planer.

those are my processing tips to prevent failure


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## arkahoot (Sep 12, 2012)

I've been making end grain cutting boards in the style of the Wood Whisperer recently and had the same issue. After doing my first glue-up, I ran the whole thing through the planer to smooth up the surfaces. Looked good, so I made my second round of cuts. During my mock up, when I flipped all my pieces end grain up, there was a noticeable gap at the center of each board. Turns out, there was a buildup of wood chips in one of my planer blades which was essentially gouging out the center of the glued up board. I cleaned it up and ran some test pieces and the build up occurred again right off the bat. Turns out, the metal bar that holds the planer knife down had a slight gap, which was allowing the wood chips to build up. I got a new bar and it seems to have fixed the problem. I should mention that I bought the planer on Craigslist, and before using it, took the knives apart for inspection. I noticed the build up under one of the knives, but just assumed the previous owner had not cleaned it well. It wasn't until I had the gouging issue that I discovered what was really going on.


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