# Gluing miters.



## djonesax (Mar 3, 2008)

I built my wife a picture frame this weekend. I didn't do anything fancy on the joints I just mitered and glued them. I had a heck of a time getting the frame properly clamped and I ended up with some very small gaps that I filled with wood putty. You cant even tell on the finished product but it still bugs me. What clamping tricks do you all use for gluing and clamping things like picture frames?


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## Ken Johnson (Nov 8, 2007)

I like using a self squaring picture frame clamp. If your miters are accurate and your opposing sides are the same length, this is the greatest tool.

http://www.woodcraft.com/family.aspx?familyid=3087


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## Leo G (Oct 16, 2006)

Make perfect 45º and you won't have this problem. However, perfect 45º's are difficult to make.


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## firehawkmph (Apr 26, 2008)

Djone,
I use the spring clamps made by Uhlia(spelling?) in Germany. They come as a kit and separate with a special set of pliers to expand them. They have sharp points which grip the wood on the outside of the joint and squeeze the joint together. They work very well. When I am picture-framing window casings or even the three pieces of a door casing, I use titebond III and the clamps and pre-assemble all the casings. I can cut and fit say eighteen window casings in less than an hour. By the time you have them all assembled, the first ones are set up enough to pick up and carry over to the window and install. Most of the time I will also drill and install a 2 1/2" drywall screw in each joint to strengthen the joint. I drill the holes in the top and bottom casings so the holes don't show.
Mike Hawkins:smile:


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## cabinetman (Jul 5, 2007)

All kinds of corner clamps HERE.


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## widekerf (Aug 9, 2008)

Leo G hit it with a perfect 45. Small biscuits seem to help hold hold it while the glue dries and makes the joint a little stronger too, assuming you have the width to add one. I just cut them on the router table with a slot cutter. haven't reaquired a plate joiner yet, but with the router table, I haven't missed it all that much. The biscuits give you just enough friction to hold the small frame together without a lot of clamping. First time I tried it though, I just stretched a large rubber band around the outside, laid it on the bench to dry. Went back a couple hours later to see if the glue was dry-----it was, but the little bit of squeeze-out, of course, had glued it to the bench. Chisels got it up without pulling it apart. Now I remember to put down butcher paper.


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## djonesax (Mar 3, 2008)

It did seem as though the miters were off a bit but I cut the 45's on an almost brand new dewalt miter saw so I thought that they would have been perfect. I even made sure that they were all exactly the same length.

I have a ton of those little stanley 45 degree clamps that I picked up a yard sale but they are a pain to use.
Just like this.
http://www.woodcraft.com/family.aspx?familyid=4250

I know there are a ton out there I just wanted to see what you all thought the best clamps were.

I'll follow some of these links and if my wife wants me to build many more of these I'll pick something up.

Thanks,


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## djonesax (Mar 3, 2008)

*self squaring picture frame clamp*

Ken that self squaring picture frame clamp look pretty neat.


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## Tweegs (Sep 8, 2007)

djonesax said:


> It did seem as though the miters were off a bit but I cut the 45's on an almost brand new dewalt miter saw so I thought that they would have been perfect. I even made sure that they were all exactly the same length.


Never assume that anything from the factory is perfect.
Good rule of thumb is to check all of your tools for level and square prior to each project. It will save a lot of headaches.

Voice of experience :laughing:


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## niki (Jul 16, 2007)

For a mitered picture frame to be square and the miter to be tight, you must fulfill 4 conditions;

1. The frame members must be at the same (and consistent) width.
2. The length of the members must be EXACTLY the same (I mean 2 and 2)
3. The sum of two miters at each corner - must be 90° i.e., if one member angle is 44°, the mating miter should be 46°...I'm not talking about ±1º but a fraction of a degree.
4. the miter cuts - vertically - must be at the sum of 90º, I mean - imagine that you are cutting the miter with the blade tilted to 45º, you'll get 45º cut right of the blade and 45º cut at the left of the blade. The direction of the 45º will be opposite but when you connect the two members, it will give you 90º (more correctly 180º) without any gaps. 
I'm mentioning it because, if the blade is not EXACLY at 90º to the table, you can get gaps when you'll glue the frame or, the frame will not be flat. 

For the reasons above, I prefer to make the cuts on the table saw with a "45º cutting sled" in a method of "left - right", i.e., one miter is cut on the left of the blade and the mating miter on the right of the blade and that, will automatically compensate for some small deviations horizontally (45º) and vertically (90º).

As for the "clamps", I'm using one of those "car straps" with ratchet and with special homemade clamping corners as you can see on the pic below (you can see the LL and RR marks that is Left of the blade and Right of the blade) 

niki


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## djonesax (Mar 3, 2008)

*That looks good*

Thanks for the info.

I like that idea for clamping because I have lots of those staps. Not having adequet clamping pressure could have been part of my problem too I guess.

I am yet to build a table saw sled but this sounds like a good excuse.

Thanks,


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## Rob (Oct 31, 2006)

I made Niki's miter sled and it works wonderfully. 
I agree with Leo...if perfect miters are obtained all around, they should meet without any clamping force and can be held together until the glue dries with rubber bands.
I also use the spring clamps firehawkmph mentioned but mostly in the dield for door trim, crown molding etc. They are great little clamps.
My clamp of choice in the shop for frames and boxes are simple band clamps.


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## boondocker (May 31, 2008)

To pull mitered corners together I cut a number of these pieces and glue a piece of sand paper to the bottom of the long tail.











Then I either clamp them to the workpiece opposing each other or sometimes (when I'm going to paint the piece) I just hold them in place with a small brad. When I apply the pressure with a small clamp the miter comes together neatly. I also use a glue with a long work time because sometimes getting it all to line up is wiggly.


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## allthunbs (May 14, 2008)

Rob and Niki: interesting. 

I have a nice Hitachi Sliding Compound Mitre Saw. It is as accurate as I can measure. I bought an engineering square at Lee Valley and it's supposed to be extremely accurate. I measure 90 degrees either side of the blade and it is bang on. However, 30, 45, 60 degrees seem impossible to do accurately. I have several protractors and squares and none seem accurate, even the fancy drafting versions from the 1960s.

Suggestions on how to setup a mitre saw to produce accurate 45 degree cuts? I'm close but not exactly. I always have a slight crack.

boondocker: Those "guides" seem interesting. Do you have a version that will work with straps as in Niki's?


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## Roy Harding (Jun 8, 2008)

allthunbs said:


> Rob and Niki: interesting.
> 
> I have a nice Hitachi Sliding Compound Mitre Saw. It is as accurate as I can measure. I bought an engineering square at Lee Valley and it's supposed to be extremely accurate. I measure 90 degrees either side of the blade and it is bang on. However, 30, 45, 60 degrees seem impossible to do accurately. I have several protractors and squares and none seem accurate, even the fancy drafting versions from the 1960s.
> 
> ...


Miter saws are nice and all - but they aren't (in my experience) all that accurate. The pre-set detents tend to be off by as much as .75 degrees. That may not sound like much, but as you need to make TWO cuts for any miter, that adds up to 1.5 degrees - WAY too much. I use my miter saw to make the cuts slightly longer than needed - then I use a shooting board and plane to make them perfect. If you can achieve PERFECT miters, all you need is masking tape (or a rubber band) to hold the joint together when gluing.

Best of luck to you.


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## allthunbs (May 14, 2008)

How did you design the shooting board? How do you protect the fine corner from getting mashed when you're planing? What tools do you have for measuring angles?

Niki: how do you cut one angle to 44 and the other to 46? The only way I can do this is with a "90 degree shoe" that fits the mitre saw. If I setup for one side of the blade on a tablesaw, I need two mitre jigs, one for each side of the blade and each with it's own inaccuracies. Comments?

allthunbs


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## Lucas54 (Aug 21, 2008)

Depending on the size of what you are gluing, masking tape does work just fine.


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## Roy Harding (Jun 8, 2008)

allthunbs said:


> How did you design the shooting board? How do you protect the fine corner from getting mashed when you're planing? What tools do you have for measuring angles?
> 
> Niki: how do you cut one angle to 44 and the other to 46? The only way I can do this is with a "90 degree shoe" that fits the mitre saw. If I setup for one side of the blade on a tablesaw, I need two mitre jigs, one for each side of the blade and each with it's own inaccuracies. Comments?
> 
> allthunbs


The shooting board is nothing more than a slab of wood with a rabbet that I can clamp to my bench. The fence is set at exactly 45 degrees to the rabbet. I use a drafting triangle (plastic - which can be had at any Office Depot/Staples for a buck or two) as my reference.

The fine corner doesn't get "mashed" because it's backed up by the fence - and my plane is sharp.

I'll leave your question for Niki to Niki.


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## GeorgeC (Jul 30, 2008)

Tweegs said:


> Never assume that anything from the factory is perfect.
> Good rule of thumb is to check all of your tools for level and square prior to each project. It will save a lot of headaches.
> 
> Voice of experience :laughing:


ditto. Very seldom will any "new" tool be perfectly set up, regardless of brand.

G


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## allthunbs (May 14, 2008)

Roy Harding said:


> The shooting board is nothing more than a slab of wood with a rabbet that I can clamp to my bench. The fence is set at exactly 45 degrees to the rabbet. I use a drafting triangle (plastic - which can be had at any Office Depot/Staples for a buck or two) as my reference.
> 
> The fine corner doesn't get "mashed" because it's backed up by the fence - and my plane is sharp.
> 
> I'll leave your question for Niki to Niki.


I made one for general smoothing with a hand plane. It is set roughly at 90 degrees. It never occurred to me to try to create a 45 degree one. How high is your fence? 

I have a collection of drafting squares and not one agrees with each other and I don't know how to test them individually. i.e. with a square, you mark a line with a good baseline, flip the square and compare the line. How does one do it with a 45 degree angle, or 30/60 for that matter. BTW, my protractors suffer the same problem. None give the same result when compared with each other.

Hey, I'm learning. This is a long and sometimes painful process.:wallbash:

Allthunbs


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## boondocker (May 31, 2008)

> I have a collection of drafting squares and not one agrees with each other and I don't know how to test them individually. i.e. with a square, you mark a line with a good baseline, flip the square and compare the line. How does one do it with a 45 degree angle, or 30/60 for that matter


.

If you have a Starrett combination square you can check out your plastic ones. Starrett is almost absolute in being square.



> boondocker: Those "guides" seem interesting. Do you have a version that will work with straps as in Niki's?


The object of the design is to allow you to clamp the joint perpendicular (sp) to the mitered 45 corners. I don't see how a strap would accomplish that. I've used these blocks for years - they last practicallly forever. The sand paper on the tail prevents the bolck from skidding out of alignment when the clamp is applied and you don't have to apply a lot of pressure when using a small clamp to hold the blocks in place.


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## boondocker (May 31, 2008)

Sometimes a lot of clamps are a good thing


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## allthunbs (May 14, 2008)

Holy S---! I have a clamp tree with a few clamps and a lot of wishful thinking. You got a lot of clamps dere! Can I borrow sum? I got lotsa room for dem.

No wonder you use the table saw as a glue-up station. It's the only thing in the shop strong enough to support all of the iron and the bit of wood. Is the floor 6" slab or 12"?

Is jealousy showing through? ;.-)

Allthunbs


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## allthunbs (May 14, 2008)

Niki: which way is the grain running in your corner blocks? I have 2x4s and I'm wondering if I can lay them out on that or is there a glue-up method?

boondocker:

In your picture you have clamps on the tails of your corner blocks. I had visions of straps holding the tails in place but I couldn't figure out how. How critical are the clamps on the tails or are the clamps intended to hold the sides in place or both? Would you clamp just the tails and corners or would you prefer the sides and corners?

Allthunbs


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## niki (Jul 16, 2007)

allthunbs said:


> Niki: which way is the grain running in your corner blocks? I have 2x4s and I'm wondering if I can lay them out on that or is there a glue-up method?


Along the grain in both direction...

It's just two pieces of wood that I glued together with a 1/4" plywood spline (or if want - loose tenon) and than, I rounded the corner for the strap.


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## GeorgeC (Jul 30, 2008)

If you have a table saw and a sled you might want to try that for miters. I have found that my table saw combined with my Rockler sled gives very good miters. The scale on the sled is so large that I feel that I can vary a miter within 1/4 degree accuracy.

George


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## boondocker (May 31, 2008)

> boondocker:
> 
> In your picture you have clamps on the tails of your corner blocks. I had visions of straps holding the tails in place but I couldn't figure out how. How critical are the clamps on the tails or are the clamps intended to hold the sides in place or both? Would you clamp just the tails and corners or would you prefer the sides and corners?
> 
> Allthunbs


The small clamps holding the tails are applied to hold the block in place. The corollary to never having enough clamps, is needing more than two hands to hold things aligned when applying glue and clamps. The small clamps keep things aligned and the sand paper glued to the bottom of the blocks help keep the block from sliding as you apply the diagonal clamp to draw the miter joint closed.

There does seem to be a lot of clamps used here, but there are really only four 36" Bessy's, the rest being four small clamps holding the blocks in place and four small diagonal's to pull the joint together. The Bessy's hold the whole frame plum and square on the base. I glued this up in two steps: back segment and then front.









This is the rail frame after the clamps are removed.

BTW, I realize that using the saw table as a glue-up station is anathema, but I only have one flat station in my small shop (if you don't count the Freezer chest) and I wax the heck out of the table so any glue that does drip will simply wipe off after it is dry.


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## niki (Jul 16, 2007)

Hi Boondocker

Very nice work

I made a few (4) "Elevators" that are just an "I" section that keeps the workpiece high above the table and gives a space under for clamping.

The top and bottom is held by 2 screws each so I can change the length of the upper (and/or lower) board to bigger or smaller.

I cover them with this plastic packing tape and even Polyurethane glue doesn't stick to it.















When I have really big jobs like this glass cabinet below, I use the floor but, you can clamp the "elevators" to two Workmates to have the work at "hands level".






















Regards
niki


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## allthunbs (May 14, 2008)

*love those clamps*

More information please on those homebuilt clamps. How do you keep the sides parallel? Do they bind when you are tightening them? Have you ever tried a caul?

Make sure you post a picture of the finished product please. 

Allthunbs


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## boondocker (May 31, 2008)

allthunbs said:


> More information please on those homebuilt clamps. How do you keep the sides parallel? Do they bind when you are tightening them? Have you ever tried a caul?
> 
> Make sure you post a picture of the finished product please.
> 
> Allthunbs


You can say that the 45 degree blocks I've been discussing are another form of a caul. They are secured in place by a small clamp on the tail and the sandpaper bottom. If I'm clamping a rectilinear form rather than a mitered corner I use square blocks of wood under the clamp to protect the wood. The blocks are held in place with hot glue.


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## boondocker (May 31, 2008)

Niki - I like the way you have threaded those pipe clamps through wood blocks. Protects the work piece and does a nbice job of spreading the pressure over a larger area of the work piece. Think I'll scrounge some scrap and do that to my clamps.

Y'know, as these things are scored, I really don't have *a lot* of clamps. Woodcraft is having an anniversary sale next month so I'll probably pick up a couple more, but I've seen shop where there are litteraly dozens of clamps of varous denominations.


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## allthunbs (May 14, 2008)

what is a rectilinear form?

in the picture...

http://www.woodworkingtalk.com/attachment.php?attachmentid=5070&d=1223920215

you are holding your I-beams on the table with what appears to be home made clamps. I'm looking for information that would help me make those.


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## boondocker (May 31, 2008)

allthunbs said:


> what is a rectilinear form?
> .


 
http://dictionary.reference.com/search?q=rectilinear

.....hence, a form {square or rectangle}or object consisting of straight lines rather than having curves. Clamps are rectilinear tools so special compensations must be created to glue angles or curves such as a corner blocks.


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