how to make 45 degree angles?

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Forum topic by WWilder posted 10-13-2008 04:17 AM 32370 views 0 times favorited 13 replies Add to Favorites Watch
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31 posts in 4869 days

10-13-2008 04:17 AM

Topic tags/keywords: joining

I am just starting out and i am having issues making 45 degree angles. I know how to adjust the saw blade on my table saw but how do i make sure to cut the angle to match the dimension i want? Example: i am trying my luck at building a small box using 1/4” poplar. How do i cut the 45 on the side pieces to match? And the sides? I know this is a stupid question and i am probably gonna be embarrassed about how easy it is and how i should have known but….. i ask anyways. Thanks in advance

-- my mind is constantly racing..... but it hasnt came in 1st place yet

13 replies so far

View Betsy's profile


3394 posts in 5237 days

#1 posted 10-13-2008 04:33 AM

Not stupid by any means. Everyone who starts making miters has the same question. First off – to make sure your sides are the same—- use a stop block. I like to cut my miters lying flat on the table as opposed to having the material standing on edge. Doing it this way means that my “inside” of the box is lying on the table and very little of the blade is exposed over the table. I also use a sled, but a well adjuster miter gauge works well also.

I’m sure you can find a pictorial on the net about this. If not, you’ve picqued my interest in showing you how I do it and I’ll try to do a quick tutorial for you tomorrow.

As for the dimension. – Make a straight line down the surface of your wood where you want to miter to stop. For example – you are starting with a 6” board, but you want it to be 4.5”. Cut the first end – the first miter cut is always the easiest. then measure from the edge of the miter cut to the other end – make a mark at 4.5 and – then flip the board around (keeping the face down) and line the blade up to cut just barley outside of the line. You should now have a board with two mitered ends that is 4.5” long.

that’s probably not the best explanation. I really will try to do a photo tutorial tomorrow. I’m kind of limited on what I can do, but I should be able to do this much.

-- "Our past judges our present." JFK - 1962; American Heritage Magazine

View WWilder's profile


31 posts in 4869 days

#2 posted 10-13-2008 05:02 AM

very cool. Thanks for the help and the pending tutorial. I am very “lamans terms” type of person. I do better with pictures and drawings as opposed to descriptions. You a Florida woodworker?

-- my mind is constantly racing..... but it hasnt came in 1st place yet

View Betsy's profile


3394 posts in 5237 days

#3 posted 10-14-2008 02:44 AM

I’ve tried to answer your question in my blog. Check this out.

Hope it helps.

-- "Our past judges our present." JFK - 1962; American Heritage Magazine

View 8iowa's profile


1591 posts in 5102 days

#4 posted 10-14-2008 08:38 PM

With the exception of Betsy’s “Go Bucks” (I’m a Gator fan) I agree with everything he has said.

I made a simple miter gauge extension out of baltic birch that attaches to the miter gauge with screws and wing nuts. A small block of wood clamped further out controls the length. A 45 degree drafting triangle can be used to set your miter angle. A 60 to 80 tooth crosscut blade usually gives a smooth enough cut for joining pieces together. I love my “safety grip” miter gauge as it keeps my fingers away from the blade on shorter length cuts.

By-the-way. There is no such thing as a stupid question when you are using power tools.

-- "Heaven is North of the Bridge"

View WWilder's profile


31 posts in 4869 days

#5 posted 10-15-2008 12:35 AM

You are the best Betsy, it is very much appreciated.

-- my mind is constantly racing..... but it hasnt came in 1st place yet

View WWilder's profile


31 posts in 4869 days

#6 posted 10-15-2008 12:37 AM

Oh and thanks also 8iowa. Appreciate your take on power tool questions not being stupid.

-- my mind is constantly racing..... but it hasnt came in 1st place yet

View Betsy's profile


3394 posts in 5237 days

#7 posted 10-15-2008 04:50 AM

how did Martin let a Gator fan on this site! Gone to the dogs now!

Glad I add a little to your woodworking experience aspirations.

-- "Our past judges our present." JFK - 1962; American Heritage Magazine

View Joel's profile


1 post in 3572 days

#8 posted 04-17-2012 01:54 PM

I got a question for you, or your fans that know about 45 degree angle cutting…...I cannot get the corners to fit correctly, why is this?...I’ve measured from outside & inside of the corners.
For instance, I installed an access door for a cousin it all worked out good for the shorter ends of the access door, than came time to put the sides, longer pieces yet my corners didnt match up & I spent all kinds of time trimming the angles down… thier a better way to do this faster?....I use a dewalt ‘chop saw’, I thought it would be easier than this!! lol

-- DONE!

View Joe Lyddon's profile

Joe Lyddon

10963 posts in 5393 days

#9 posted 04-17-2012 10:32 PM

I’m not sure what you’re trying to cut & how…

Here is a very good Video on making Perfect miter corners.

Now, if you’re trying to put miter cut molding around a door, maybe the frame is not square… You cannot put squared molding around a NONsquare door. LOL
If that is the case, your angle cutting, you might say, has to be Custom Cut to fit the frame’s angles…

Hope this helps…

-- Have Fun! Joe Lyddon - Alta Loma, CA USA - Home: ... My Small Gallery:

View Sawkerf's profile


1730 posts in 4410 days

#10 posted 04-17-2012 10:51 PM

One of the most common questions – and one of the most difficult things to do with precision.

When I’m tipping my blade to any angle (including 90), I use a gauge of some sort between the table and the blade. I position the gauge between two teeth (I’m setting the blade body here), and move the tilt wheel until I can’t see ANY light between the gauge and blade when the gauge is sitting on the table.

For most common angles (30, 45, 60 & 90), I use one of my old drafting triangles (I’ve had them for almost 50 years and do all of my drafting with this ‘puter these days. – lol)

Now for a dirty little secret to get 90’s every time. This only works with flat (no profile) stock.

Tilt your blade to something close to 45 and make your cut
Flip one of the pieces over and match up the angles. It will be 90 every time because they’re complimentary angles. (i.e. no matter what each angle actually is, their sum is 90.)

Don’t try this on your box, however. You’ll get three 90’s and who-knows-what for the fourth.

One other thing necessary to get perfect rectangles is to make the opposite sides EXACTLY the same length. Even a slight difference will cause one of your joints to be off.

-- Adversity doesn't build reveals it.

View Tom148's profile


39 posts in 3605 days

#11 posted 04-18-2012 12:37 AM

I would recommend

Doug Stowe has a video series on box making that pretty much walks you trough the process step by step. He is very good about showing fixtures and jigs that make life a lot easier. Also. the skill necessary for building the jigs and fixtures are pretty similar to what you need to build the boxes.

It costs to join and I don’t remember how much but you get a discount if you subscribe to FWW. I have found it to be a very useful site and worth the subscription fee, at least for me.

Have fun!

-- Tom

View Al Killian's profile

Al Killian

85 posts in 3967 days

#12 posted 04-18-2012 12:40 AM

I always cut it on the miter saw then trim it to final length on the router table with a 45 degree bit.

-- Owner of custom millwork shop

View Grandpa's profile


3264 posts in 4017 days

#13 posted 04-18-2012 01:07 AM

I have found that the “right” blade makes the saw more accurate too. Thin blades flex. Get a good blade with lots of teeth and a negative hook angle then make sure your miter saw stops are set. Stops make it happen too.

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