Introduction: Make Straight Cuts Every Time With a Door Board

When dealing with large project parts or plywood it can be tough to get good results cutting them down to size. This jig allows you to get accurate & straight cuts every time using a circular saw. I have always referred to it as a Door Board and it is super cheap and easy to make. Additional info as well as tons of other builds shop stuff can be found here

Step 1: Material Selection & Cuts

I used 1/4" MDF (medium density fiberboard) for the project. I tend to make a lot of my shop jigs & fixtures from MDF. It is a very stable material and it cuts nicely. The only drawback is the dust isn't very good for you so I would recommend some sort of dust mask or to make your cuts outdoors. Plywood or harboard would also work well for this. 1/4" thick material is plenty adequate as the material to be cut supports the jig from bowing.

Cutting your material can be done numerous ways. I used a bandsaw as that was quick & readily available to me. A jigsaw or circular saw would also work. The great thing about this jig is that the cuts DO NOT need to be super accurate at this point. DO however use a factory edge for the top piece. This will ensure when you finish the door board it makes straight as an arrow cuts.

Step 2: Sizing & Tips

The exact size of your pieces will depend on what circular saw you will be using for your jig. In my case my boards were approx. 6" wide & 10" wide. DO NOTE: the wider bottom piece should extend just past the blade and also past the motor housing a few inches. The narrower top piece should have that factory edge to have the saw ride against. Keeping all this in mind will allow for you to clamp the door board to your work piece without the saw getting in the way. Length will be however long you want to make the jig. I have made one that is 8' long for plywood rip cuts & one 4' long for plywood crosscuts. 2' long boards come in pretty handy as well.

Step 3: Glue Up

To make it easy to know where to apply the glue I like to put the top piece in place & mark it with a pencil. Then just add some wood glue & clamp the 2 pieces together. Any glue that squeezes out of that factory edge should be cleaned up at this point so as to not interfere with the saw later.

Step 4: Final Cutting to Size

First things first, run your saw in the channel created in the glue-up. This will make the bottom part to the size of your saw. NOTE: This jig will only be good for that model saw now. You may want to mark the jig to indicate that saw if you have multiple saws. Purely for aesthetic reasons I also trimmed the back edge & ends flush on my table saw.

Step 5: Get Cutting!

At this point your new door board is ready for use. Mark a line on your workpiece where you need it cut. Then position the jig edge up against your cut line, clamp the jig in place & make your cut. I also added a handle to make it a bit easier to carry. I show how to make those in this instructable. I highly suggest making one of these as it really improves the accuracy of cuts and makes breaking down plywood & sheet goods a breeze. Thanks for checking it out. Let me know what you guys think in the comments section.

Comments

author
arawn (author)2017-07-20

I'd say it works for jigsaw as well... very good.

author
MegK8 (author)2017-03-03

Nice video, with a great set of information - Just what I needed! Thanks!!!

author
reversed strength (author)2015-12-11

Smart idea, great video. Make me what to make a door board immediately.

author

awesome!

author
allani (author)2015-12-04

So simple yet so good !...Thank you :)

author
nick ferry (author)allani2015-12-04

no problem - thanks for checking it out!

author
SLF (author)2015-11-28

very good idea. I'm going to make a couple

author
nick ferry (author)SLF2015-11-28

very cool, thanks

author
rod yates (author)2015-11-28

Brill will be making one off these, cheers :)

author
nick ferry (author)rod yates2015-11-28

awesome!

author
wood doctor (author)2015-11-27

You come up with good ideas,i like your ideas,keep them coming.

author
nick ferry (author)wood doctor2015-11-27

thank you kindly, will do!

author
Holje (author)2015-11-25

Very nice! ;)

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nick ferry (author)Holje2015-11-25

thanks!

author
MartinD30 (author)2015-11-22

This is a very handy jig to have. I have one for my router as well. I like to use 1/8th ply for the bottom piece and 1/2 inch to the the top piece but you can really use anything you have available.

author
nick ferry (author)MartinD302015-11-22

1/8" for the bottom is a good idea to keep a max depth of cut - very cool

author
rdiesel1 (author)2015-11-22

Thanks for this tid-bit. My grandfather did all kinds of woodworking and he fabricated a lot of useful things just like this and they are always worth their weight in gold. Glad to see there are people out there still using the same tricks they used years ago.

author
nick ferry (author)rdiesel12015-11-22

very cool!

author
Mike Degrazia (author)2015-11-22

Awesome! Thanks!

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nick ferry (author)Mike Degrazia2015-11-22

no problem - thanks for checking it out!

author
Rock8 (author)2015-11-21

I like it! A nice, simple, useful tool guide.

I also think the finishing pass on your bench saw is very important for setting up square cuts, not just for aesthetic reasons.

author
nick ferry (author)Rock82015-11-21

thanks - that is a good point

author
GregM17 (author)2015-11-21

I use a similar jig for years. Mine is double sided - circular saw on one side and jig saw on the other. It is about the same width as yours but with the top board narrower. I really enjoy your instructables and videos - thanks.

author
nick ferry (author)GregM172015-11-21

that is an awesome design! thanks

author
FlorinJ (author)2015-11-20

:-D What do you do when the pieces you need to cut lengthwise are mich narrower, say 4 to 4.5 inch?

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nick ferry (author)FlorinJ2015-11-20

it's do-able but not all that practical - either cut it off from a bigger piece or improvise w/ some clever clamping

author
FlorinJ (author)nick ferry2015-11-21

What I typically do is clamp several boards placed one near the other beneath the jig. Their length helps keeping them in place. The low pressure applied by the rig over the whole length of the narrow board plus some used sandpaper padding is effective at keeping the board fixed while cutting, even if it's not clamped rigidly to the guide rail.

author
nick ferry (author)FlorinJ2015-11-21

awesome!

author
ZSchrink (author)2015-11-20

This is absolutly brilliant!

Thanks to you I have yet another weekend project!

author
nick ferry (author)ZSchrink2015-11-21

the list never ends, lol

author
manderson7 (author)2015-11-20

This is good jig, I took it one step further with this. http://youtu.be/x8mTqlW3LPw

author
nick ferry (author)manderson72015-11-20

very cool - I dig it

author
DK19 (author)2015-11-17

So simple. I wish I had thought of it first.

author
nick ferry (author)DK192015-11-17

almost too simple - I have been using this method for 10+ years - shop teacher showed me this and it truly works great

author
kaddigart (author)nick ferry2015-11-19

This was one of the first tricks of the trade my father passed on to me 20+ years ago, and to this day, one of the most useful. It's so simple I forget it's not really common knowledge. We'd use them on sight during cabinet installs and would always have people ask us about them, usually with the same type of reaction: "why didn't I think of that?"

Nicely instructed, and thanks for the nostalgic trip.

author
nick ferry (author)kaddigart2015-11-20

cool cool - thanks for checking it out - I am quite nostalgic myself

author
SRQ Sid (author)2015-11-19

If you glued two factory edges overlapping each other you could use the door board for two saws that had different base plate/blade dimensions by turning it over, as long as the "tops" were plainly marked for each saw.

author
nick ferry (author)SRQ Sid2015-11-19

that's not a bad idea and I have seen that done before but it make the jig a bit wider than I prefer

author
daveleb55 (author)2015-11-19

Where are you finding 1/4" mdf? neither Lowe's nor Home Depot have it

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nick ferry (author)daveleb552015-11-19

I have a building supply company near me where I get most of my sheet goods - tempered hardboard would also work well - or I think my HD has 1/4" HDF

author
amm4467 (author)2015-11-19

Cool!!!!!

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nick ferry (author)amm44672015-11-19

Thanks!!

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Michael_oz (author)2015-11-19

Nice & clear 'ible, thanks.

I always get into trouble measuring the blade <-> edge-of-saw-plate, then adding that as an offset to a guide strip clamped down. Your way is so much simpler...

Had you thought of putting a right-angle cleat on the bottom of one end, then you can get a good square edge easily.

author
nick ferry (author)Michael_oz2015-11-19

never tried the cleat thing but I LOVE that idea!

author
MotherDaughterProjects (author)2015-11-19

This is great! Thanks. It is exactly what I need to make.

author

very cool - glad you liked it!

author
sshah13 (author)2015-11-19

I made one a while ago, it's very useful indeed! The guide I followed (Izzy Swan, YouTube I think) also said to put sandpaper strip or pieces on the underside as a non slip aid. Obviously depends what you're cutting as glossy surfaces can be scratched but really helps and means you can do smaller cuts without clamping!!

author
nick ferry (author)sshah132015-11-19

I've seen some guys use anti-skid drawer liner but I never liked having the edge raised off the work even slightly because then you get more tear-out

author
rikkiesix (author)2015-11-19

Great instructable my friend.
Greetings from Belgium.
Erik

author
nick ferry (author)rikkiesix2015-11-19

thank you Erik!

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Bio: I like to build and make things with my hands. Think it, Build it, and repeat.
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