Help me make decent miters please.

One way to eliminate some of the gap is to make your miter sled so that it can cut both “right and left” miters. That way if one angle is off, the opposite angle will compensate. If you need a picture of this type of sled, let me know and I can send you a photo.

Lew

I agree with Lew. That’s the best advice I’ve seen for low-tech great miters. I made a sled like he’s talking about, and it’s easier to get nice miters now.

-- Robb

I don’t think this is always possible, so I’d look to see why you are not getting accurate cuts. I’d check for slop in your miter gauge, or perhaps replacing it if your cuts are not repeatable. Once you have a repeatable error, you can correct it.

JC

-- Somewhere, something incredible is waiting to be known. -Carl Sagan

I think what you need is a shooting board. You can find many examples of this easy to make jig. There are two kinds of shooting boards. One is used to cut a perfect 90 degrees and the other is for a 45 degree cut. You use a block plane on its side and by shaving a little of the miter you can sneak up on a perfect fit. One of the frustrating things about miters is if the board is now too short after you corrected the miter.
Here is the fix, you can make the short board longer, that’s right longer.
Use your plane and take a few swipes off of the inside edge of the board. It will move the board closer to the mitered corner and actually make the gap come together. After glue up, just resqaure slightly and you have a perfect fit.
The other tip, and the one I use to dial in my miter gauge is to go buy yourself a large plastic drafting square from an office supply house for about $3 bucks. Raise the blade of your table saw to max height. Place the long side of the sqaure along the blade, making sure that you are not resting on a tooth but on the blade itself.
Now set your miter gauge to the 45 degree side of the drafting sqaure.
You now have a perfect miter. If you attach a long fence board to the miter gauge with a stop on it, you will cut exact lenght miters and a perfect fit, every time. If it’s off, use the above techniques to fix it.
I hope that helps you.

There is a hand tool method that works well for truing up miters. Clamp the pieces together, take a dovetail or gents saw and “kerf in” the mitre by sawing the joint. This method removes wood from both sides of the joint and is amazingly accurate.

-- Don, Pittsburgh

Frankly, not all table saws & miter gauges on the market are capable of the kind of precision to produce consistantly perfect mitered frames. The selection of a high quality crosscut blade is also desirable.

That being said, not only do the angles have to be very precise, but the opposite sides of the frame have to be exactly the same length. I made a miter gauge extension out of baltic birch and with a stop block clamped in place can cut to exact lengths. I invested in a stainless steel dial protractor that is accurate to 1/12 of a degree. (Highland Woodworking product # 168072, www.highlandwoodworking.com)

Last year I made a sled to cut bowl segments. There are four fences: four, six, eight, and ten sided angles. The angles are precise down to a “knat’s hair”.

-- "Heaven is North of the Bridge"

I pretty much always clean up my miters with a handplace and a shooting board. I don’t even bother with a 45 degree fence anymore. I just use the standard fence and hold the workpiece at the 45 +/- the fraction I need. In your example, I would hold the workpiece such that the sole of the plane isn’t quite touching the inside of the miter. After a couple of passes I would check the actual fit. Assuming that was correct, I would then make some more passes at the same orientation until the plane touches the inside edge and the gap disappears. In that sense, relative to the inside of the frame, you haven’t change the length of the workpiece. With a well tuned handplace (I use either a block plane or a jackplane), this is a really quick and accurate technique.

-- Disappointment is an empty box full of expectation.

Thanks for all the help. It seems that at least some of you seem to think I should be trying this with the miter gauge. My sled is set up to both sides. So I basically have a ”/\” with a kerf running through the center. I notice that the sled doesn’t pass through the miter slots with even force. like it gets tight in the middle.

OH!!! wait a minute. So you guys that use sleds are saying that it doesn’t mater if I’m off a little bit because they should still match up. Hmmm I guess I would still have to have my fences on the sled at a perfect 90 degrees to each other.

I wonder if my angles were good but maybe one side was a hair short? Could that cause it to open up a fuzz on the inside corner?

-- Wipe the blood stains from your blade before coming in.

If you are using a sled, instead of the miter gauge try this. Get a drafting square. I cannot tell you how much I use it. They are very accurate and cheap.
First, check to be sure that your sled is cutting 90 degrees to the sawblade. Once again, rasie the blade, put the square against the back fence of the sled and run it up the blade the blade ( POWER OFF!!!!!)
Is it square? does it lay flat against the saw blade and flat against the rear fence?
If not, adjust the rear fence until it is.
Once you are sure that the sled is tracking square to the blade, put the drafting square against the blade, NOW install your triangle shaped piece right up to the 45 degrees on the drafting square and fasten it to the sled.
Also, check to be sure that your blade is sharp. If it’s dull, it will slighlty flex under load ,and cause the cut to be off by a hair.

BLADE FLEX?! Crap! That’s a brand new thing for me to worry about.

-- Wipe the blood stains from your blade before coming in.

One thing to check is your saw. some saws just don’t produce the accuracy needed for true miters. If the saw is junk and the blade is dull it just won’t work. I do miters on the chop saw and a miter box works well. I think Blake wound up with a guillotine miter trimer which is the way to go on moldings and small picture frame stock. cheapest fix is the shooting board and a SHARP miter plane. Maybe some filler as well.

-- Thos. Angle

Lots of good info in this thread. It can be very discouraging trying to get a perfect joint. The blade has to be at a 45 to the miter gauge… and of course, the blade has to be 90 degrees to the table too. I found that’s where some of my problems were coming from. Good luck.
-JJ

-- JJ...... I guess you could say I'm a 54 year old "juniorjock". — Make things with wood.

Hi Spaids

For a mitered picture frame to come-out square and tight joints, 4 conditions must be fulfilled…

1. The 2 opposite frame member must be at the same length

2. All the frame members should be at the same width

3. The sum of the two corner miters must be exactly 90°

4. The sum of the two corner miters – vertically – should be 180° (I mean that the blade must be exactly 90° to the table).

Those 4 conditions are very easy to achieve in a perfect world or when you are drawing it with CAD…but, when we have to make actual cuts….well, yes, its’ not a “perfect world” :-)

For the reasons above, I prefer to cut the miters on a sled.
Cutting at the method of “Left” and “Right” will compensate for any very small deviations from 45° and for the blade not exactly at 90° to the table.

You will notice, that I’m first, cutting the members to “Final Dimensions” but because of my method (I put the stop at the front of the board and not 10 feet behind…), the blade removes half kerf thickness at every cut and, because we are cutting every member from both sides, the member will be shortened by one kerf width…

In simple words: If you want the frame to be 20” x 20”, cut your members to “Final dimension” of 20-1/8”....the 1/8” will be removed during the cutting of the miters and you’ll get 20” as you planned.

I went through my posts here but many pics are missing (from the time that I lost the Photobucket account) so I’m sending you to other forum…just across the pond….

First, how to make the sled…most of the pics are not for your TS but the on the last pictures, you’ll see how I’m setting the fence to be square to the blade (or more correctly – to the miter slot)
http://www.ukworkshop.co.uk/forums/viewtopic.php?t=18879&highlight=

Another post that you can see how I made the sled and set the fence.
http://www.ukworkshop.co.uk/forums/viewtopic.php?t=23367&highlight=

On this post, you’ll see my method of cutting the miters
http://www.ukworkshop.co.uk/forums/viewtopic.php?t=10072&highlight=

On this post an actual cutting of a frame
http://www.ukworkshop.co.uk/forums/viewtopic.php?t=22924&highlight=

And here another mitered frame for glass coffee table
http://www.ukworkshop.co.uk/forums/viewtopic.php?t=15648&highlight=

I would like to note that I didn’t need or make any “fine tune” – - from the table saw, directly to the gluing table (well, passing through the router table to make the “biscuits” and rabbet for the glass)...

Regards
niki

Depending on the type (shape) of the frame members, cutting the top and bottom at the same time, as well as the sides at the same time keeps them the same length. You can tape them together to make the miter cuts. This assumes that there is a flat side to the frame pieces.

-- Rich in Richmond

A well tuned mitre saw does a pretty good job…

On the table saw I usually use the aforementioned drafting square to set my fence or sled. The only time my mitres go sloppy is if I let some crap build up between the fence and the sled. To combat this, I cut a relief kerf on the very bottom of the fence so that there is somewhere for any errant fibres to go.

If all else fails- plastic wood

-- The only easy wood project is a fire

My vote is for color putty.

-- http://www.woodsongsfurniture.com

Take a flat board and glue a pc of laminate on the edge. nail, glue or screw a 1×3 board onto your flat board at a 45 deg angle off of your laminated edge. Screw some lock down clamps to your flat board. Pre cut your sides 1/16” long. Place them on your “new” board letting them hang over 1/32” and clamp into position. Now use your router with a flush trim bit and bearing to clean up your edges. The laminate on the edge will help keep your bearing from indenting into the wood.

This sorta problem is one of the many times a horizontal sander comes in handy. Just a touch or two and you have a perfect fit.

-- miles125, Alabama.."Architecture is frozen music""

Don, that is very true and its nice to see “old school” tricks. :-)

-- Chris, South Carolina

A picture frame is really hard to make. It looks like a very easy thing to build but it is amazing how accurate you need to be to get a tight fit. The problem that you have described happens to many people so I would not feel bad. If you go to a frame shop, you will see that they often use double miter saws set at a fixed 45 degree angle and have an adjustable width.. Now to take a look at this problem and why it has to be so accurate is you have 4 joints and you have 2 45 degree peices fit into each joint. If you were putting to peices together to make a 90 degree angle no sweet. Four….........Well that is a different story.

One of the best cut that you can get is on a miter saw. You have to cut at a 45 degrees and compare it against a standard (A accurate 45 degree angle) then set your saw. You can do this with scrap wood. Use a stop for exact sizing. You just have to try test and adjust. You set your saw until it is accurate.

.........The other approach is to fit it by hand. I personally would not use a miter on a table saw but that is just me. There are too many variables and chances for the material to move etc. I like the material fixed and clamped in a mitersaw that is set for 45 degree work.

Good luck and I think you will do well. It is a little tougher than it looks and it takes practice and once you learn you will build perfect frames.

Cheers,

Ben

and…...what about using a Mitter Saw?

-- Francisco Luna, San Francisco Bay Area.

I have a story with some tips on cutting more accurate miters and bevels at the link below. Nothing beats good tools with the exception of patience….

See the story

-- Tom Hintz, www.newwoodworker.com

When checking my shop made miter sleds I cut scrap to find the error. If the sled is for 45º four short pieces are cut to the same length and mitered on both ends. Laid on the table saw top they should close up all four miters. If not the sled is tweaked to get it right. I sometimes make pinwheel designs this way for inlays.
I keep sleds for all the angles I use and I’ll make a new one if an unusual angle is required for a job.
I almost never use a miter gauge that comes with the saw.
Once adjusted the sleds give me good, repeatable miters.
I also have a sled for 90º, 12.5º and one for a very odd angle used for an unusual angle on an unusual cabinet.

db

-- If a man says something in the forest and there's no woman to hear it, is he still wrong?

Whether you do this with a tablesaw or with a handplane, you need to understand the notion of “complementary angles”. That is, two angles add up to 90 degrees. It does not matter if one side is 44 degrees and the other 46 – if they total 90 then the corner will be square.

Since I do not do this with a tablesaw, I do not have a picture of the relevant jig. Others here will have. It is simply a mitre fence that clamps a length from both the right- and the left side. Ideally both run into the saw blade at 45 degrees, but since the mitre fence end in a 90 degree, double-sided angle, it does not matter if they are slightly out or not.

As mentioned before, I prefer to fine tune with a hand plane. That means a shooting board. In this regard, the shooting board of choice is this one …

If you are interested in shooting boards, then here are a couple of articles I have on my website:

Setting Up and Using a Shooting Board

Shooting for Perfection

Regards from Perth

Derek

-- Building and Reviewing Tools at http://www.inthewoodshop.com

Wow this thread has turned out AWESOME! Its like an online college course in miters.

Thanks

-- Wipe the blood stains from your blade before coming in.

Great work guys you’ve cover multiple ways of tuning up miter…I like the shooting jig the best for fine tuning any slop in the joint. The jig take off .005 in that neighbor hood for super fine tuning. One of the best store buys is the Dubby Jig by in-line Industry, next time your at the thewoodworkershow check this guy out. His jig has been a staple of the show for over 20 years, he also has a web site(inlineindustry). Great thread spaids …Blkcherry

My accuracy improved with the compound angle sled and I’m working on shooting board fixtures for both frame and case miters. The frame miter has consistently eluded me until the sled due to minor blade to miter slot issues with my saw. I’ve installed a PALS and done some fiddling, but the sled has done the most good thus far. The shooting board should yield perfection.

That said, if you want an easier out and can stomach a complete re-do, you might contemplate a half-lap or a bridle joint, both of which can be artfully effective with the right wood choices, and both in evidence authentically in Arts and Crafts pieces. Incidentally the current Fine Woodworking found those two joints to be number one and two, respectively in destructive testing versus the entire range of joints used to form a face frame. My first project of the new era (resuming the hobby after a 25 year hiatus since junior high school shop) of woodworking was a bridle joint frame for a heavy mirror. Even a blind pig finds the occasional acorn…

-- "Bordnerizing" perfectly good lumber for over a decade.

I have gotten the best results on case work by kerfing in. I saw it on the Wood Wright cut both miters a tad long clamp them together then take a thin kerf hand saw and just cut the center. the saw will follow the miters and usually cut half kerf on both sides if it bobbles that’s fine because the opposite piece will be the exact opposite.

The wood wright show was the one about the toolbox great show and some very neat joinery combinations a must see

-- jay Rambling on and on again

I made a 45 angle cutting sled for the toy workshop and it cuts perfect 90 degree angles. (both 45’s together) It’s set up to cut one board on the left of the blade and then other end of the same board on the right of the blade. That way all 4 corners are a right/left matching pair. The inside of the frame is always touching the fence.

-- What happens in the workshop stays in the workshop. No wait that doesn't sound right. Karson Southern Delaware karson_morrison@bigfoot.com †

I’m with the miter saw crowd here, but I could see how a V sled on a table saw would work good too.

At my shop we also have a custom frame shop, we use a Morso guitine chopper to cut our miters. Now I understand that that’s a tool that not everyone’s going to rush out and buy, however when we have small gaps in our frames (which happens at all frame shops from time to time) we use framers wax that’s been colored to match the color or the frame to fill in those gaps. A 64th is a very small gap that most people wouldn’t notice, we’ve used the wax to fill gaps close to a 32nd of an inch. Also, if you make the frame an eighth of an inch longer and wider (called a framers allowance), depending on the dimentions and the width of the frame, you should be able to get it to flex enough to close that gap. Hope this helps.

-- "At its best, life is completely unpredictable." - Christopher Walken

Stick with your miter sled. I just started making boxes and built a miter sled out of MDF that works perfectly.

Here’s how to make sure it’s dialed in to 45 degrees. Go to your art supply store and get a plastic 45 drafting square. Use it to adjust your blade to table at exactly 45, then cut the slot in your miter sled.

I also recommend building the shooting board suggested just in case you need to fine tune. However, if you use the drafting 45, you’ll probably not have any issues.

-- Gerry