# Planning for saw kerf?



## rhybeka (Nov 8, 2009)

I'm sure this is a newbie question but I'm attempting to design my project in a way that maximizes the needed plywood (going for a red oak ply). One piece in particular, I'm cutting two 44×32 pieces (a bottom and a platform). I was hoping to get at least two 16×32 in pieces and some of my smaller pieces with what was left, but with saw kerf I think it will end up more like 15 7/8×32. So do you just make sure you subtract an 1/8 or whatever your saw kerf is going to be from your measurements so that you can make sure you order enough wood? Thanks for all of the input!!

Becky


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## knotscott (Feb 27, 2009)

You definitely have to figure on loss due to kerf width….that can vary depending on your blade width and runout. You can always measure a test cut to get an idea of your exact kerf loss.


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## jmos (Nov 30, 2011)

I would be hesitant to plan my cuts so precise that the saw kerf will make or break how much I need. I'd plan on leaving yourself some slop to allow for a slightly off square cut, or cutting off a scraped up edge, or some defect in the board, or some other irregularity. I've gotten bit too many times, but you mileage may vary.


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## JAGWAH (Dec 15, 2009)

Always plan on an issue.Ditti jmos.
The issue of a kerf should never come into play. The only exception for me has come when I have a special piece of wood and want to maximize it's use. The size of kerf may determine a change in my design.


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## huff (May 28, 2009)

Becky, Here's a little tip to remember when working with sheet goods; like the others said, you shouldn't plan your cuts so close as to whether a saw kerf makes or breaks the project. I like to rip my sheet goods (plywood) a little oversize on my first rip. Two reasons: If I don't get a perfect rip the first time (primarly because of working with a full 4×8ft sheet), I can always trim a little off on a second rip. The second reason I oversize my first rip is I never like to use the factory edge on any plywood. I want to rip a wisker off that side also. Usually plywood will get dinged up a little in handling and I like to work with a fresh edge. I've seen where I've had to buy another sheet of plywood to have enough and have quite a bit left over, but I always find something to build with the leftovers. lol.
Good luck and let us know how it turns out.


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## rhybeka (Nov 8, 2009)

Thanks guys, all good points! I should know by now what Jag said - to plan on an issue. And to John's point -being a fair beginner and going to cut these pieces on my own (circular saw with good blade and a straight edge) cutting them a hair large would probably be in my best interest. At $60 a sheet, I don't really want to be buying much more than I need (yeah, I know that I can always use it for another project but my projects are far between as it is. It looks like I may need to see if I can downsize my cubbies slightly to give myself some wiggle room, or just be able to afford an extra piece of plywood


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## huff (May 28, 2009)

Becky, sounds like a little downsize is going to solve the problem. Good luck on your project and hope we get to see the end results!


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## oldnovice (Mar 7, 2009)

There is software available for maximizing the plywood but it do not know if it considers grain direction.

*Cut optimization software:*
#1
#2
#3

Some of these are FREE!


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## rhybeka (Nov 8, 2009)

thanks oldnovice! I'll have check them out when I have a few - too bad they're all Windows based!


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## oldnovice (Mar 7, 2009)

rhybeka,

I suppose you wanted Linux … or maybe that one named after a fruit ….... !

Sorry, I didn't search for Apple versions but I am almost willing to bet there are iPad version out there.

I am writing this on an Acer tablet so a search on this wouldn't do you either!


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## MrRon (Jul 9, 2009)

I have the luxury of a good CAD program (Autocad©). I lay out all my projects. I can position and reposition all my pieces before making my first cut. I generally leave 1/4" between pieces to allow for final trimming.


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## rhybeka (Nov 8, 2009)

heya Oldovice  I'm a PC and Mac lover - not a hater  unfortunately my PC gave up the ghost last year and I haven't taken the time to rebuild the drive since I've been using my mac for school. I can run windows on my mac it's just cumbersome to load up. @MrRon that would be nice! I think the Cutlist plugin for Sketchup might help? I haven't really played with it more than once. I was going to try to get all my boards the right size and such in my second design. Hopefully I can stay within two pieces of ply! from the looks of it I need to first find a good plywood blade and make sure to leave 1/4 or more for final trimming.


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## oldnovice (Mar 7, 2009)

*rhybeka,*

You took my attempt at humor way too serious! I love Apple in my opinion they were the real first personal computer because they were the first with a friendly UI. The Pet and Comodore were meager attempts compared to that first Apple. I am less than 8 miles from Apple HQ and some of my former colleagues were once Apple employees.

Where I worked (a company named for two well known men and is commonly known by two letters, as little test for jest) had both in the workplace and we had to use both to be proficient in our jobs!


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## Dusty56 (Apr 20, 2008)

Don't forget to cut with the plywood best face down if you're using a circsaw : )
You can also use tape on your cut line to help minimize tear out.


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## Surfside (Jun 13, 2012)

What's the deal with placing the plywood's best face down when using a circular saw?


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## Doss (Mar 14, 2012)

What's the deal with placing the plywood's best face down when using a circular saw? - *Surfside*

Face down with a circular saw it due to that particular saw's characteristic of tearing out or splintering the side that is face up. A tablesaw requires the opposite approach (good side face up).

Tape helps as well. So does avoiding cross cutting. Having a special blade only for finish quality plywood wouldn't be a bad idea either.

Be careful though when putting the plywood face down. Make sure the surface (probably saw horses) you're putting it one is clean and smooth (won't mar the surface).

And, as the others have said, never plan your cuts such that something like a saw kerf calculation can make or break you. That's just setting up for disaster IMO.


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## Dusty56 (Apr 20, 2008)

*Surfside , Doss* explained the reason very well for you : ) 
The circsaw blade spins and cuts from the bottom up versus the tablesaw blade rotation cuts from the top down. 
Which ever side the teeth exit from gets the most tearout : )


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## pintodeluxe (Sep 12, 2010)

Just buy extra stock. After selecting best grain pattern, and cutting away any rough factory edges, yield will not be as high as you might like. I just buy a ton of plywood and hardwood because- heck I will use it on the next project. Plus it relieves the stress of possibly miscutting a piece.


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## rhybeka (Nov 8, 2009)

lol - sorry OldNovice - I'm used to getting picked on for being a dual user  I like my Macs but I know they have their issues as well.

Thanks guys! I've been perusing the reviews of circurlar saws and saving my pennies for an entry level Milwaukee and a good plywood blade. The plan is to use a guide,tape, and a lot of prayer and make sure I buy enough stock just in case. I'll at least have two sheets of the red oak. I think I'm going to start by building an assembly/outfeed/extra flat surface work table first to help with this piece of furniture


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