mitered corners question

  • Advertise with us

« back to Woodworking Skill Share forum

Forum topic by Kathy posted 07-12-2010 03:27 AM 1895 views 0 times favorited 24 replies Add to Favorites Watch
View Kathy's profile


210 posts in 2915 days

07-12-2010 03:27 AM

Topic tags/keywords: question

I am attempting to make boxes. I used my chop saw to cut the 45 degree angles (I don’t have a table saw).
The problem I am having is that the outside angles fit well but the inside of the corners don’t quite meet. The first box I did I fixed this with putty, but there must be a way to get these right.

Is there a better tool? Or a woodworkers trick that I don’t know????? (I find that there are a lot of those!)

Thanks you!

-- curious woodworker

24 replies so far

View hairy's profile


2701 posts in 3526 days

#1 posted 07-12-2010 03:33 AM

A belt/disc sander could square it up.

It might be too late if there is not enough left, but it should only reqire a little sanding.

Just a thought. Good luck!

-- My reality check bounced...

View a1Jim's profile


117086 posts in 3571 days

#2 posted 07-12-2010 03:35 AM

Of course your angle is off. You need to make sure the parallel sides are exactly equal and you need to make sure your angles are exactly 45 degrees because chop saws are not very accurate. You can check the angle by using the angled side of a combination square.

-- wood crafting & woodworking classes

View Ger21's profile


1074 posts in 3125 days

#3 posted 07-12-2010 03:49 AM

You need a good, sharp blade and need to have your saw adjusted perfectly. I prefer to use a table saw for miters myself.

-- Gerry,

View patron's profile


13603 posts in 3335 days

#4 posted 07-12-2010 03:53 AM

your saw should have a way to adjust ,
check your manual ,
the best way to check for 45 deg. ,
is to cut (on each side of saw) ,
and take the same cut pieces ,
and reverse one of them ,
they must come to a perfect 90 deg. .
if not adjust saw ,
then the same for other side .
some saws have the back fence ,
that slides slightly in and out each end ,
to adjust with .
the same is true for 90 deg. ,
cut straight and parallel board at 90 deg. ,
and flip one over ,
if they don’t come together perfact ,
it needs to be adjusted till they do .
there will be a slight ‘v’ front or back ,
if it is out of square .

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View GMman's profile


3902 posts in 3691 days

#5 posted 07-12-2010 03:57 AM

I am with Jim and David I had the same problem with a new saw it takes quite a while to set a chop saw to be exactly at 45 and 90.
Also if one side is only a hair longer or shorter it will not fit right.

View TopamaxSurvivor's profile


18266 posts in 3670 days

#6 posted 07-12-2010 04:42 AM

Hand cut dovetails will take care of this :-))

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View Gregn's profile


1642 posts in 2977 days

#7 posted 07-12-2010 05:11 AM

It sounds to me like you need what is called a shooting board to true up your miters. Not having a table saw maybe you can find someone with one that can cut accurate 45’s to make a shooting board for you. A shooting board can be made from scrap material so cost wouldn’t be a problem. A shooting board will allow you to fine tune your miters to fit using a hand plane to true up the miters.

-- I don't make mistakes, I have great learning lessons, Greg

View TopamaxSurvivor's profile


18266 posts in 3670 days

#8 posted 07-12-2010 05:21 AM

Might take a scrap that is tall and straight enough, make a fence to clamp on the the miter saw. Start with it square, then tap it lightly untill you get perfect 45’s. You can get a drafting 45 & square at the office supply stores that are very accurate to check with.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View supervato's profile


153 posts in 2923 days

#9 posted 07-12-2010 05:38 AM

Like a1jim said and patron said your miter saw needs to be tuned up as for the same for any saw you buy. But one thing nobody has mentioned is when you cut the board make sure you make the cut hold the arm down and let the blade come to a stop before you lift the blade. The upstroke with the blade running can and will mess up a perfect cut.

View rance's profile


4258 posts in 3154 days

#10 posted 07-12-2010 07:12 AM


First, make sure your saw is adjusted and accurate. I use a chop saw in a box class I teach for building mitered boxes. They CAN be accurate. In fact, I believe most can be accurate. To answer your questions… 1) Using a CS is fine, so is a table saw, 2) Yes, there’s a secret. If you knew the secret handshake, then I could tell it to you. Sorry. Uh… OK, well, the secret is to make for darned sure your opposing sides are EXACTLY the same length after cutting the miters. The real secret to this is by using stop blocks rather than eyeballing a line to cut to.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View Rick's profile


9591 posts in 3027 days

#11 posted 07-12-2010 10:22 AM


Simple as this sounds… said in your Posting “Chop Saw”. Is it in fact a Chop Saw or a “Mitre Saw”? Some of the Posters above have used both terms. There is a Difference. There was a Post on here a day or two ago about that. So before somebody jumps all over me and says there ISN’T a difference. ....LOL… Oh! Hang on I think I have 2 Pictures still in Photo Bucket…if I didn’t delete them.

New Hitachi Chop Saw

New Hitachi Mitre Saw
Hitachi Dual 288x288 C10FSB $800


-- LIFE is what happens when you're planning on doing Other Things!

View Kathy's profile


210 posts in 2915 days

#12 posted 07-12-2010 12:31 PM

Thank you for all the replies and a couple of questions again. From the pictures I do have a chop saw.

1. Gregn -What is a “shooting board”?

2. rance – What do you mean by a “stop block” and where do I learn the secret handshake:).

3. I will look in manual to see how to adjust but I do have one of those boxes with a hand saw that are used for miters. Would it be more or less accurate?

Thank you again and I really really really enjoy this forum and all of the projects that I see.

-- curious woodworker

View BobG's profile


172 posts in 2955 days

#13 posted 07-12-2010 02:53 PM

You can also use a rough form of adjustment. Take a piece of masking tape and put it on the guide fence of your miter saw. If as you say you have a gap on the inside of the joint, your angle is not 45 degrees.

Now do this with scrap wood until you get the angle right.

Place the tape vertically on the guide fence of your miter saw close to the saw. Use a piece of scrape cut two pieces, put them together, and see how square the joint is on the outside. If the the gap is still at the inside of the miter, you need more tape. Place another strip of tape on top of the one already on the fence. Trial and error will get you a good fitting joint.

If the gap were on the outside of the joint, you would put the tape at the furthest point from the saw blade.

Or, you could just go to the beer joint and after 4 beers everything looks pretty good!

Good luck with the miter joint!

Bob G.

-- BobG, Lowell, Arkansas--------My goal in life is to be the kind of person my dog thinks I am! Make more saw dust!!

View Gene Howe's profile

Gene Howe

10476 posts in 3422 days

#14 posted 07-12-2010 02:59 PM

While not rance, I do know the secret handshake. But, If I told you, it wouldn’t be secret anymore.
A stop block is simply a block clamped to the saw fence to limit, and insure the consistency, of the length or your cuts.
For 45 cuts, your block would be cut at a 45 and the work piece would nestle into the block for the opposite end, or second cut.
You’d cut all four boards on one end, set up the block and cut the longest sides, move the block and cut the other two sides.
Another trick you might try: For any cut, cut the work a “smidge” long and “sneak up” on the final length, with the final cut being less than a saw blade width. In this case, your 45 stop block would be positioned just for the final cut.
I use two blocks. One is flat and square, the other is cut at a 45. I figure where the 45 is to be placed and clamp it. Then I clamp the square block behind it and tight against the back side of the 45 block. That gives me a positive stop for the 45 stop. Remove the 45, make the “smidge” cuts, replace the 45 and make the final cut.

I’ve never been successful with a miter box, as you describe.
One more suggestion…..get a MITER saw and outfit it with a GOOD miter saw blade. Chop saws are a little too gross for the type of cuts you are attempting.
Like others have stated, the table saw method is better (IMO), too. But, if ya ain’t got none…...

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View SnowyRiver's profile


51457 posts in 3474 days

#15 posted 07-12-2010 03:10 PM

I agree that the angle of the blade is off. Wonder if you are using the scale on the saw? Try taking an angle gauge and check to see that 45 degree angle is correct and matches the scale.

-- Wayne - Plymouth MN

showing 1 through 15 of 24 replies

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