# End grain cutting board length calculation



## regornedlog (Oct 15, 2017)

How do you calculate the starting length of a board to achieve a desired length of an end grain cutting board? Believe you would need to know thickness of board, saw blade kerf, and thickness of finished board desired.


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## Jim Frye (Aug 24, 2016)

I've looked at this post three times now and I'm still not sure how to answer your question. I'm guessing your asking how much stock to have on hand when you begin cutting off pieces to assemble into a cutting board. So, yes, you need to list the thickness of each piece, how many pieces you need, and the material loss from the blade kerf. I always add 10% for miscalculations, mistakes, bad material, or errors in judgement. I think the worst thing in woodworking is not having enough stock for a project and having to fudge or make do with an inferior piece when you are cutting parts for a project. Better to have some left over from a project. Wood has an EXTREMELY long shelf life, so you'll find a use for it later on. On a recent piece, I ended up short due to some bad wood and a couple of measuring mistakes and had to go back for more stock. I recently used some red oak from the wood rack as secondary wood in a maple piece. I once made a cherry table and used maple as the secondary wood.


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## regornedlog (Oct 15, 2017)

Thanks for your input. What I'm looking for is a formula (equation) to calculate the length of the stock needed to achieve a certain length for an end grain cutting board, Example: after my first glue up, cutting board is 1 1/4 inches thick (thickness of stock bought). I want to cut into 1 1/2 inch strips so that when flipped 90 degrees I'll have a 1 1/2 thick end grain board. Taking into consideration the Kerf of my saw blade and the other dimensions given, and I want end result of board to be 18 inches long ad 1 1/2 thick, how long does the board have to be to get this length after the cuts. I can't figure out a formula to do this. Appreciate any help!! Sorry I'm not more succinct!


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## WeebyWoodWorker (Jun 11, 2017)

Okay so the thickness of stock you bought was 1 1/4. I'm going to assume you haven't glued it up yet and since you will lose material planing it flat after gluing it up Lets say you only lose and 1/8 and now your piece is 1 1/8th. Since you want your final piece to be 1 1/2 thick and 18 long you have all the information you need to figure this out on your own but I felt like doing math. 
18 (Length in inches) divided by 1.125 (Thickness of pieces in inches) equals 14.4 (Total number of pieces needed). Assuming you don't want to be all fancy I suggest you round up to 15 and call it good. So you need 15 pieces total to get to 18". As for these pieces you wanted your board to be 1 1/5 (1.5) thick I suggest making it 1 5/8ths or 1 3/4 (1.75) as again you will lose material flatting it out after the glue up. Lets go with 1 5/8th. 1 5/8ths (1.675) (Length of piece) times 15 (Number of pieces needed) equals 24.375 (24 3/8ths). If your table saw blade is 1/8th thick and you need 15 pieces then times 1/8th(Thickness of blade) by 15 (Number of pieces and as of such number of cuts). This makes 1.875 (1 7/8ths) added to the last answer we got (24 3/8ths plus 1 7/8ths) equals 26.250 (26 1/4). 

Simplified without my babbling: 18"/1.125 = 14.4. Round up to 15. 1.675 X 15 =24.375. 0.125 X 15 =1.875. 1.875 + 24.375 =26.250. 

You need a 26 1/4 inch blank to make your cutting board if everything goes absolutely perfect. Seeing as nothing goes perfect however... Go with a 30" one just to be on the safe side. 

Someone check my work as well. I'm not perfect.


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## GeorgeC (Jul 30, 2008)

I guess I do not understand the problem. It all depends upon how thick I want the final board.

If I want the final thickness to be 1 3/8" I cut the pieces longer than that so that there is spare stock to sand/place to the final thickness. How much longer depends upon how accurate I think my glueup will be and how much sanding/planing I want to do.

Personally I would cut the individual pieces about 1/8" longer than I want the final thickness.

George


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## nxtgeneration (Feb 22, 2016)

google CBDesigner. There is another forum that the program was posted on. You are able to lay out your cutting board and it will give you the material cut list.


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## regornedlog (Oct 15, 2017)

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Thanks, been a real head scratcher for me.* However did come up with pretty much the same formula as you, with a couple of exceptions. Believe you would multiple the kerf x 14 (number of cuts).* I also added the kerf and width together and multiplied times 15.* I'll try to attach a "Calculator" I made on Excel.* Enter your figures in the highlighted boxes and the "Calculator" will/should do the rest** Haven't made my final cuts yet....will let you know if we got it right! Appreciate you input and help.


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## TTOKC (Nov 10, 2016)

I second CBDesigner. It is free and very easy to use. Even if I don't use the pattern I lay out it will still give me my initial cut list and material needs.


Some people have trouble downloading it so I put a copy in my Google Drive https://drive.google.com/open?id=0B-DP9IT5CwywT2FFcGx6M0p3R28


TT


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## regornedlog (Oct 15, 2017)

Thanks all for your input and help. I've downloaded the CBdesigner program and it looks great. That program was also recommended to me by Wood World in Dallas. I did also come up with a formula which after making an end grain board, proved to be accurate. FORMUA: desired length / thickness of board using x desired finished width + kerf = length of board needed to cut to get desired finished length (end grain on top)


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## GraceAndDrewWoodwork (Oct 20, 2017)

I use CBDesigner as well and it works great. To be on the safe side, I set the crosscut width to 1.75. That makes the board 1 3/4 thick but then I plane and sand down to 1 1/2 thick which, IMO, is plenty thick. And yes, an extra 1/4" is overkill...if I am adventurous I crosscut at 1 5/8".

Anyway, I am almost always starting with 10' boards from my supplier. I cut them to 3 40" lengths. Most of my cutting boards are 18" final length and starting with 40" stock works perfect. You get one or two additional crosscuts which comes in handy if you have knots or other major flaws. Once you have a pile of the leftovers it's time to make a chaotic pattern board.


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## coalcreekwoodworks (Dec 7, 2018)

I developed a formula a couple of years to answer this question.

y = board length
a = board thickness
b = finished thickness of cutting board
c = finished length of cutting board
d = number of cuts needed for first series of cuts
e = kerf width (waste)

d = c/a
e = d(.125)
y = (b)(d)+e


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