# Minimum Thickness for End Grain



## dustbunny (May 18, 2009)

I have a customer who is asking me to make butcher block for her bar island.
She thinks it is 4' x 6'. My plan is to make this in four sections 
then glue up those for sections for the complete top.
Purpleheart and hard maple, end grain.
It is going to sit on a 3/4" ply base, and be edge trimmed.
There are cabinets under the base.

I made a couple sketch up patterns to give her ideas on a creating her own pattern-





My question is- What is the minimum thickness I can make this in end grain ?
We want to keep the weight down as much as possible.
What obstacles am I facing making this GIANT cutting board ?
Does anyone know how to estimate the weight of the finished top ?

Any ideas would be appreciated,

Lisa


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## patron (Apr 2, 2009)

beats me , lisa ,
but with good glue ,
and tight clamps ,

' how low can you go " ?


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## Karson (May 9, 2006)

As to weight. Find the weight of the wood species that you are going to use. I used to use 4lbs per sq. ft as a rough estimate. so for your 4 X 6 at 24 sq ft id guess 100 lbs. as a beginning estimate. That's for a top that is 1" thick.

From the web Weight: Hard maple:42-45 lbs./cuft. Soft: 35 lbs/cuft.

A cubc foot is 12 sq. Ft at 1" thick

You would need to estimate the ply also. It's usually made with a wood species that is not as heavy say popular.

Here is a website that has many species and their weight.


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## vegeta (Mar 10, 2009)

Lisa, i have made end grain boards as thin as 1/2 inch with out any issues. seeings how this is going to be glues to ply i would shoot for this thickness. i think any thinner and you would have glue up issues or possibly warping with the wood getting wet form the glue up


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## teenagewoodworker (Jan 31, 2008)

I would stray away from this. remember the wood needs to expand and contract. You're looking at a big 4×6 board here. If you glue it to plywood it will blow up. The same goes for if you trim it. That's why if you see the old french butcher blocks and things they have big metal brackets attaching everything. to hold it all together but it all cracks eventually. most companies won't deal in blocks this big for the same reason. you can't attach it and it will probably still warp and crack.


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## sras (Oct 31, 2009)

This is going to be so cool!

How do you think your customer will treat this top? If they are going to be using it as a cutting board, you should allow for several refinish processes - including sanding down. This could also apply if you are expecting this to be around for a long time.

A large end grain piece will definitely move a lot with expansion/contraction. I would consider mounting methods that allow for the top to move on its plywood support. You really do not want to create something this fantastic and then have cracks show up. Maybe screws with oversized holes and large washers. You could lock it down in the center - maybe a 8 to 12 inch zone that is screwed directly to the plywood support.

If the end grain top needs to float on the plywood base, then the top needs to be structural do a large degree.

Given these three observations, I would go no thinner than 1 1/2 inches and would not think 3 or 4 inches to be overkill. Professional butcher blocks tables can be much thicker - but they get beat on!

A final thought is that as the top gets thicker, the counter will get taller. Depending on your customer, this could be a good thing. If the structure under the counter is also new, its height can be adjsuted as you determine the final thickness of the top.

I am looking forward to seeing what you create!


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## sras (Oct 31, 2009)

Teenagewoodworker brings up a good point (we were typing at the same time). It could crack on its own. Here is another thought. You could make 4 2'x3' boards and lock them down in the center of the 4×6 assembly. This would create slip joints. You could even use a sliding dado style feature along the slip joint. Slotted holes along the slip line should ensure a tight fit.

There are several examples of 2×3 cutting boards. That should be a safe size.


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## JAGWAH (Dec 15, 2009)

A client I did work for had a large bureau with top made of 4"x 4" ingrain material with a lovely marquitry border. The pieces were 1/4" thick and every square had checked and curled up ever so slightly at their edges. The top looked like an old abused piece.

He said it was brand new he bought it made that way, called it a NewTique instead of antique.

Your patterns look cool. This should be a fun and unique looking top. But I might try to stay 1/2" plus in the thickness. At worst if it curls or checks you can call it a newtique maybe thry'll like it.

Just a side note be very careful the substrate. If the plywood is of poor manufacture the upper veneer could delaminate due to the glues curing that are used to adhere them together.


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## teenagewoodworker (Jan 31, 2008)

JAGWAH brings up a good point on the plywood. be carefull with that too as most of it is not made to be used in an environment were it will be wet. if there is water on the board and it is not sealed it could go right down through. Also do to one side what you do to the other. In this case if you attach it you are locking off one side of the ply and not the other. which could cause the ply to warp due to moisture imbalance and it will crack the board.


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## LateNightOwl (Aug 13, 2009)

I don't know nuttin' about how to handle it structurally, but I have no doubt it will be the centerpiece of the kitchen and a source of joy for its owner. You can get really creative with the design.


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## a1Jim (Aug 9, 2008)

A cool design sounds like the rest have the weight issue handled


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## sras (Oct 31, 2009)

Hope you don't mind another thought from me - I find myself puzzling over this one. Another possibility might be to seal the wood with something like a bar top epoxy . Might have to seal both sides …


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## TopamaxSurvivor (May 2, 2008)

Here's another that will give weight per cu ft instead of by the cord http://www.ces.purdue.edu/extmedia/FNR/FNR-109.html

Make sure both sides get the same finish!


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## TopamaxSurvivor (May 2, 2008)

I just calculated the weight of a maple slab I cut for making my lathe mount. It was about all I wanted to lift and handle, so I guessed the weight at a bit over 100 pounds. That web sites figures make it 120.5. I can't weight until it drys, it will be down to 70.75 )

It doesn't give a weight for purple heart, but using the maple figure, the cutting board top would be 110 pounds at 1 1/2 thick.

I agree that gluing the whole thing down would be a disaster. Maybe secure it from the bottom in the middle.


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## dustbunny (May 18, 2009)

Wow, so many things to consider.
Dennis- You are right about not gluing to a border or to the ply.
My plan is to use the ply just for support, no adhesive.
Border it with purpleheart flat grain using silicone between 
the board and the frame to allow for expansion and contraction.
The frame will be glued to itself on the miters. Or no frame.
This should prevent any liquid spill issues. I will seal the ply. I think this would work ?
Karson- Thank you for the weights and measures. That helps give me a better idea.
JAGWAH- Sorry, I don't think she would appreciate NewTique….LOL
Steve- You are really excited about this ! No way on the bar top coat.
I don't think I could pull that off in one pour, 
and I am sure she doesn't want to pay all that money. It's expensive.
Planning on the usual Howard's Butcher Block Conditioner 
and a buffed out coat of beeswax with carnuba wax for hardness.

I am thinking no less than an inch in thickness, no more than 1 1/2". Based on the feedback.
I guess that means 1 1/4" thick ? Eddy I am leery about going 1/2" thin. 
I have made small pieces in endgrain thinner than 1/2", 
but it just doesn't seem warp proof on a piece this size.
With 30 bf of lumber I don't want to take a chance.
I think this will be more of a countertop than a cutting station.
With the build not glued to the bottom it can also be removed to be worked on if needed.
Just cut the silicone.

Thanks for all the great input, I am open to more if you have it. 
I hope she decides to go forward with this project,

Lisa


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## TopamaxSurvivor (May 2, 2008)

Going 1 1/4 thick would cut the weight to 92 pounds.


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## Dennisgrosen (Nov 14, 2009)

that was one I don´t wuold consider 
think of you have different kind of wood 
with different movement , it cuold very esay 
crack and woble all over in a short time
I know you are a woodworker , but if it was me
I realy wuold consider to make it out of tiles instead
sorry I can´t help you othervice

but I will look forward to see and hear if you come up with a solution for this

Dennis


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## degoose (Mar 20, 2009)

Hi Lisa… I have made large boards in edgrain but they have been 3 inches thick.. I have one that is unfinished and it has not moved at all in nearly 12 months.. I did make on just ove 1 inch and it warped chronicly.. admittedly that was in my earlier period..
Love the designs and as for being able to surface the whole board… wait for your Torque to arrive…


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## dustbunny (May 18, 2009)

Okay Larry, that's 72 board feet, and approx 285 lbs or 130 kg.
Would you think 2" thick would keep it from warping?
I was thinking if I did it in four parts I could run it through
my drum sander…..forgot the Torque is on it's way !! : )
I shall buy a surfacing bit…

Lisa


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## childress (Sep 14, 2008)

Nothing under 2" on this size….


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## Porosky (Mar 10, 2009)

Lisa, I agree with teenagewoodworker, about this thing blowing up. 
I also just had a guy approach me about a similar project and I had similar concerns. 
My answer: I'll be making end grain boards and fitting them together on top of some laminate with a small lip around the edge. (A Floating end grain counter top). Two sides of the "edge lip" will be adjustable to keep boards tight during expansion and contraction. The owner will be able to loosen or tighten the moving edges and the "Floating Boards" simply by loosening up a concealed threaded knob under the lip of the counter top. The boards will be different length and width and fit like a simple puzzle with in the working area using four standard sizes so you can swap the same size board in or out with another from a different location on the counter top, to get a different look when ever you feel like it. 
I will also be placing some finger grabs so this guy can pull a board up flip it over and cut on it, basically he will be able to cut on one side of the counter top and display the other. Since size and weight are not going to be a issue because of the individual pieces, I'm making them about 7/8" thick so they will be plenty rugged. My customer would also like me to be as creative as possible in making each piece unique with the end result being a end grain quilt effect. Fun. Fun. Hope this helped. Good luck.


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## dustbunny (May 18, 2009)

Hey Scott thanks !
This gives me some additional ideas.
Still pondering the build.
Customer wants me to see the room first, then do design patterns.
It is a country motif with overhead beam work in a pattern.
She is thinking to create a board pattern to tie the beams into the whole room motif.
If that makes any sense.
She wants to discuss it over a few drinks.
This should be fun !!

Lisa


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## NathanAllen (Oct 16, 2009)

I still think that our concept of wood movement is tinted by the fact that most woodworking techniques were developed in a period before climate controlled environment.

Most explosions are caused by the crafter locking down cross grains with zero tolerance for movement. In this case the border would need to be beaded since it is the only secion that is running cross-grain, otherwise the wood will move with itself.

However, the nightmare in this project is the time required to make the cuts, glue-ups and sanding the surface flat.

Likewise, purpleheart isn't the best material for a butcher block, you have some mild irritation risk and without a heavy duty UV/water blocking finish to prevent it from darkening to brown the customer won't necessarily be pleased with the result in a year.

Also, whats the number one thing you can't do with a food safe surface? Make it unsafe for food.

Personally I'd do the design in long-grain, beadlock it and let her know that there are better woods that will create a contrast with Maple under mineral oil.


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## sras (Oct 31, 2009)

You probably seen this project already. If not, take a look. Looks like he is close to the size you are considering - might be worth a PM…


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## Knothead62 (Apr 17, 2010)

Lisa, good luck on this project. So many things to consider. Keep us informed as I'm real curious as to what the final product will be. I'm sweating just thinking about building a 2X4 bench for my planer!


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## JonathanG (Jan 18, 2010)

If I read Karson's post correctly, there is an error in the math.

Karson, you're saying that a cubic-foot is 12"x12"x1". That is actually a board-foot, not a cubic foot. A cubic foot is 12"x12"x12".

So if something that is 12"x12"x1" is equal to 4-pounds, then a cubic foot of the same wood is equal to 48-pounds, as you're changing the 1" to 12". Hope that makes sense.

Another way to look at it may be easier. There was a recommendation above to go 2"-minimum for something of this size. So then you would replace the 1" with 2", so now a square foot of the above wood is equal to 8-pounds.

Sorry if this confused anybody.

Also sorry I can't offer any advice to your questions Lisa. I just wanted to clear up the math.


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## Karson (May 9, 2006)

You are right I meant to say 12" X 12" by 1 ft equal a cu ft. The charts usually specify the weight per a cu ft. I put the wrong measurement on the foot.

So a 48 lb per cu ft would be 4 lbs per square ft.

Good catch Johathan.


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## JonathanG (Jan 18, 2010)

I debated on whether I should mention/correct it or not, then I decided I probably should, just so there was no confusion or accidental misinformation.


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## renners (Apr 9, 2010)

Don't mean to be a stick in the mud, but:- 
the best thing you can do with this is find out how much your client is willing to pay for this piece and then work out how to do it… Unlimited budget? do it properly, with heavy timbers, 3×3 x4-6' long, bolted lengthways and across with threaded rod, - just get help moving it or use sack trolley/hoist to manouvre it. if budget is an issue, do what you were going to do - use thin pieces, glue it to a 3/4" bit of ply, but explain to client that gaps may appear after few months/years. I wouldn't even contemplate making this in four sections to glue together. You won't get a seamless joint unless you sand it thoroughly when its assembled, and then I would imagine the joints will be weak. 
4'x6' is MASSIVE for this kind of thing, I'd give serious consideration to tiling it as a mosaic as suggested by Dennis.


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## childress (Sep 14, 2008)

The threaded rod thing is what used to be done in the past to keep blocks together…..but with today's glues, you don't really need to go that route. And yes, you can assemble in pieces and then combine and the joints will not be weak, that is, if you properly mill the wood before glue up. It will be hard, but it can be done… Just did it.

I just read your original post again, and I would not put a trim piece round it that is not end grain too. Your just asking for problems if you do that.


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## dustbunny (May 18, 2009)

Thanks childress,
I am going to skip the trim on this one. Too likely to split.
How big was the one you made ?

Lisa


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