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Planning for saw kerf?

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Forum topic by rhybeka posted 09-03-2012 06:23 PM 1861 views 0 times favorited 18 replies Add to Favorites Watch
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rhybeka

533 posts in 1874 days


09-03-2012 06:23 PM

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

-- Beka/Becky - aspiring jill of all trades


18 replies so far

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knotscott

5608 posts in 2128 days


#1 posted 09-03-2012 06:39 PM

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.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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jmos

681 posts in 1122 days


#2 posted 09-03-2012 07:54 PM

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.

-- John

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JAGWAH

929 posts in 1837 days


#3 posted 09-03-2012 08:00 PM

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.

-- ~Just A Guy With A Hammer~

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huff

2810 posts in 2038 days


#4 posted 09-03-2012 08:14 PM

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.

-- John @ http://www.thehuffordfurnituregroup.com

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rhybeka

533 posts in 1874 days


#5 posted 09-03-2012 09:05 PM

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 :)

-- Beka/Becky - aspiring jill of all trades

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huff

2810 posts in 2038 days


#6 posted 09-03-2012 09:32 PM

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!

-- John @ http://www.thehuffordfurnituregroup.com

View oldnovice's profile

oldnovice

3870 posts in 2120 days


#7 posted 09-03-2012 10:02 PM

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!

-- "I never met a board I didn't like!"

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rhybeka

533 posts in 1874 days


#8 posted 09-03-2012 10:33 PM

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

-- Beka/Becky - aspiring jill of all trades

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oldnovice

3870 posts in 2120 days


#9 posted 09-04-2012 12:34 AM

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!

-- "I never met a board I didn't like!"

View MrRon's profile

MrRon

2991 posts in 1996 days


#10 posted 09-04-2012 07:53 PM

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.

View rhybeka's profile

rhybeka

533 posts in 1874 days


#11 posted 09-11-2012 11:21 PM

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.

-- Beka/Becky - aspiring jill of all trades

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oldnovice

3870 posts in 2120 days


#12 posted 09-12-2012 12:38 AM

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!

-- "I never met a board I didn't like!"

View Dusty56's profile

Dusty56

11688 posts in 2440 days


#13 posted 09-12-2012 12:53 AM

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.

-- I'm absolutely positive that I couldn't be more uncertain!

View Surfside's profile

Surfside

3372 posts in 926 days


#14 posted 09-12-2012 04:18 PM

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

-- "someone has to be wounded for others to be saved, someone has to sacrifice for others to feel happiness, someone has to die so others could live"

View Doss's profile

Doss

779 posts in 1017 days


#15 posted 09-12-2012 04:37 PM

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.

-- "Well, at least we can still use it as firewood... maybe." - Doss

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