LumberJocks

Oak boards and warping

  • Advertise with us

« back to Wood & Lumber forum

Forum topic by Bcemail posted 05-30-2017 09:58 PM 1430 views 0 times favorited 10 replies Add to Favorites Watch
View Bcemail's profile

Bcemail

16 posts in 342 days


05-30-2017 09:58 PM

Hi all, always enjoy reading through the forums and getting inspiration from the projects!

I’m knocking together a guide for my circular saw as I don’t have a table saw and I’m getting tired of the wavy line look on my projects. It’s a basic straight edge/poor man’s track saw that lots of people make.

I see a lot of people use plywood (I’m guessing due to stability) for this type of thing, but I don’t have any on hand which means extra $$. I do have an 8’ oak board that’s left over from some shelves I added to a closet. They are basic 1×6s (or maybe 1×8s) from HD, so nothing too fancy but it’s nice and straight at this point.

I know wood moves and it can always warp and twist. Most of what I use around the house is pine and so I know what can happen there. Can I expect an oak board to stay mostly straight at this point? Do I need to determine the moisture content to tell? I don’t want a straight edge that ain’t straight down the line. If plywood makes more sense, I’ll try and get some, but always like the stuff that’s already paid for.

Thanks for the help!


10 replies so far

View AlaskaGuy's profile

AlaskaGuy

3637 posts in 2143 days


#1 posted 05-30-2017 10:17 PM

I think you answered your own question. Find some plywood.

-- Alaskan's for Global warming!

View gargey's profile

gargey

862 posts in 610 days


#2 posted 05-30-2017 10:18 PM

For this application, it makes sense to use plywood (or MDF or whatever), rather than real wood. You want your reference lines to be dead straight.

Also, it makes sense to use 1/4” ply, which will save you some money.

I used 1/4” ply as the base for the “track,” with a 1×2 board as the reference (the piece that the sole of the circular saw slides against). Glued together.

Its worth noting that this system does totally suck ass compared to a table saw or a band saw, but I do not have space for a table saw or a band saw.

View Kazooman's profile

Kazooman

867 posts in 1787 days


#3 posted 05-30-2017 10:34 PM

As the others have said, ditch the oak board idea. I know that you have an idea to save money since you already have the oak board, but think about the long term performance. The oak board WILL move over time with changes in humidity. You do not want to have that in a guide for your saw.

This should be a “one time do it right” project. A good base made from some very good quality plywood (real Baltic birch comes to mind) and a good guide fence from the same material. The 1/4” ply that was mentioned would probably suffice, but the minor difference in cost to go a bit thicker would seem well worth it to me. You can make it cheap now, and wish you had done it better and make another in the future. I have never cursed a jig I have made saying that it was “over engineered”. I have lamented not making the jig properly in the first place on several occasions. A guide for your circular saw is something that you will use over and over again. Make it right and you wil never regret it.

View gargey's profile

gargey

862 posts in 610 days


#4 posted 05-30-2017 10:42 PM

Thinner ply for the base results in less distance from the sole of the saw to the material you are cutting, and therefore less room for error as well as less loss in total depth of cut. Thus the 1/4” recommendation.

The reference material piece can be any thickness.

View Bcemail's profile

Bcemail

16 posts in 342 days


#5 posted 05-30-2017 11:29 PM

Thanks for the help! I’ll get some plywood. Wasn’t sure if at some point will dried wood stayed true but guess it always varies. Glad to hear it doesn’t have to be the nicest stuff which I’ve been surprised how pricey it gets.
And yes, I know it doesn’t compare to a table saw. I’ve told my wife that but she’s not yet convinced…

View Kazooman's profile

Kazooman

867 posts in 1787 days


#6 posted 05-30-2017 11:43 PM



Thinner ply for the base results in less distance from the sole of the saw to the material you are cutting, and therefore less room for error as well as less loss in total depth of cut. Thus the 1/4” recommendation.

The reference material piece can be any thickness.

- gargey


View Kazooman's profile

Kazooman

867 posts in 1787 days


#7 posted 05-30-2017 11:57 PM

When was the last time you were starved for depth of cut using a circular saw guide? Probably never. 1/2” ply or at least 3/8” ply is more stable. You will never miss the difference in the depth of cut, but you will feel the difference in the heft of your saw guide when you go to use it. Why on earth would you choose to skimp on a jog that will probably last you a lifetime? I can assure you that I can intentionally clamp any 1/4” ply saw guide out of square if I try to. A full half inch base? Not so likely. Just my opinion, and I actually have a old circular saw guide in my shop with a 1/4” base. I would never do that again.

View Madmark2's profile

Madmark2

371 posts in 422 days


#8 posted 05-31-2017 01:27 AM

Oak is a large pore grain wood that can rapidly change humidity & can have 5% of width change from fresh cut to overdried.

You want less warpage, try something with a tighter grain.

M

View ArtMann's profile

ArtMann

683 posts in 650 days


#9 posted 05-31-2017 01:53 AM

1/4” hardboard (Masonite) also works well for a surface that the circular slides on. I tried it one time. I think this saw guide you are making will make a huge improvement in both accuracy and ease of cutting. You might want to make a long one for rip cuts and a short one for cross cuts.

View pintodeluxe's profile

pintodeluxe

5459 posts in 2648 days


#10 posted 05-31-2017 02:14 AM

I used MDF trim that is painted white. Easy to find in ten foot lengths to guide the saw before and after the cut. Really inexpensive at the local home center.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com