# I cant make a miter fit to save my life



## afx (Feb 5, 2010)

Pardon the long windedness I'm going to try an put my skills into perspective.

I've been wood working for about 5 years and I think I've gotten pretty efficient around my shop, I am by no means a professional and I lack some of the intuitiveness that you see the really advance workers have, my wife says its my creative mind clouding my logical one.

I'm about to start a really large project that will require ripping long lengths of plywood at a 45 to create an inner box.

My only problem is I cant seem to ever cut miters that fit properly! I have absolutely OBSESSED about this on prior projects. I've spent entire days tuning my table saw, miter saw and radial arm to cut better miters but they never seem to be as tight as they should. It almost always comes down to me finding another form of joinery or some kind of workaround to get it done. So far the radial arm is the closest fit for me but it still seems to be a degree or so off when you try to make a small box.

My question(s) is(are), what is your process to ensure you have tight miters? Do you use a table sled? A digital angle gauge? When you measure the angle, do you measure from the tooth or from the body of the blade?

I'm open to all suggestions and/or criticism's. 

These are the tools I've been using just in case that has anything to do with it.

Table saw is a Rigid TS2424 with a Diablo 60 tooth fine blade

Miter saw is a Delta Shopmaster something or other, I cant remember the model #

Radial arm saw is an old craftsman I restored which oddly enough gets me the closest 
http://vintagemachinery.org/photoindex/detail.aspx?id=12551


Thanks a ton!


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## Chris Curl (Jan 1, 2013)

i have not yet had a need to make miter joints, so i don't have any personal insights to share, sorry. but maybe these might help? 

http://theapprenticeandthejourneyman.com/2010/12/11/how-to-make-perfect-miter-joints/

http://americanwoodworker.com/blogs/techniques/archive/2008/09/02/Perfect-Miter-Joints.aspx


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## Dave Paine (May 30, 2012)

I understand the frustration. I had also had problems.

What is the dimension of the box?

If the cut width is less than the max height of the blade, you can use a mitre gauge. If wider, then you need to tilt the blade.

I get better accuracy if I am able to use the mitre gauge.

I would start with eliminating variables. I have learned to regret when I say that some setting is correct, unless I have rechecked. Too easy for something to have moved.

You should have a dial caliper to be able measure the settings accurately.

I would start with double checking the blade being exactly parallel to the mitre slot. Any deviation here will impact all cuts. If you need help with how to do this, let us know.

I would then check the fence to be parallel to the mitre slot. Some folks like the far end of the fence can be e.g. 1/64th to the right so the wood is not pressed against the back edge of the blade.

I have a DIN standard 90deg and 45deg set of squares. It is important to have accurate squares. If you do not have metal ones, get the plastic drafting squares.

Next step would be to check the blade is 90deg to the table top. Raise the blade to the max height and check against the steel BETWEEN two teeth.

If you are using the mitre gauge next step is to use the 90deg square flat on the table between the blade and mitre gauge to confirm the 0 deg setting for the mitre gauge is 90deg to the blade.

if you are tilting the blade 45deg you will need to tilt and check with the 45deg square. Do not assume your stops are good.

Take a piece of plywood and cut the 45deg angles. Place the pieces together and use the 90deg square to confirm you have a good cut. You want the wood used for the test to have parallel faces and consistent thickness or you will go crazy chasing your tail.

If the tilted blade was checked and was good but does not cut correctly it is possible the saw may have a problem. Remote, but it can happen.

Good luck. Post your findings.


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## bradnailer (Nov 11, 2008)

I build stave drums and the angles have to be exact. I use a digital angle gauge and my miters fit perfectly. I also use a fine tooth blade on my table saw or miter saw to cut them.


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## woodnthings (Jan 24, 2009)

*bevels/miters using the fence*

These are one of the hardest joints to make. Everything must be spot on. To test your angle setting, as described above, cut the 2 pieces and stand one up tight to the other and see if you get a 90 degree angle. If it's more than 90, your angle is too great, less it's not enough.

A digital angle gauge will help for precise angles. like this:
http://www.woodcraft.com/product/2005894/18124/wixey-digital-angle-gauge.aspx

A corner clamp has the 90 degree built in, but they may not be perfectly accurate. 

A different approach may give the same result. A half lap rabbet on both pieces will give a strong joint, but expose some end grain on one edge. This can be minimized if you make a very thin lap on the exposed piece.

A splined miter is a way to hold the piece in registration during a glue up. After cutting the bevels set the blade to vertical and make a kerf into the bevel. Then make some spines the same width as the kerf and insert them, a slip fit is best since the glue will expand them. Practice first! :yes:

A search on this forum for "splined miter" gives lots of threads including this:
http://www.woodworkingtalk.com/f2/joining-two-panels-best-joint-24093/


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## mengtian (Nov 8, 2012)

woodnthings said:


> These are one of the hardest joints to make. Everything must be spot on. To test your angle setting, as described above, cut the 2 pieces and stand one up tight to the other and see if you get a 90 degree angle. If it's more than 90, your angle is too great, less it's not enough.
> 
> A digital angle gauge will help for precise angles. like this:
> http://www.woodcraft.com/product/2005894/18124/wixey-digital-angle-gauge.aspx
> ...


That is how I did my first picture frame. Also, as mentioned before, use a plastic drafting square to check, they are more accurate.


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## afx (Feb 5, 2010)

Thanks for all the replies folks. The wood I'm cutting is 42x15, the miter will be on the 15" side (its a buffet) and I haven't yet started testing cuts, I wanted to get some pointers before I go out there and drive myself bonkers. 

Thanks for those links BTW! I just bought one of the exact same digital gauges from Rockler (luckily I live next to both a Rockler and Woodcraft) I also have a few drafters squares.

Quick question though, does the kerf of the blade affect the angle?

I'm going to read over your tips and get back with you.


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## woodnthings (Jan 24, 2009)

afx said:


> Thanks for all the replies folks. The wood I'm cutting is 42x15, the miter will be on the 15" side (its a buffet) and I haven't yet started testing cuts, I wanted to get some pointers before I go out there and drive myself bonkers.
> 
> Thanks for those links BTW! I just bought one of the exact same digital gauges from Rockler (luckily I live next to both a Rockler and Woodcraft) I also have a few drafters squares.
> 
> ...



No. The kerf is parallel in it's entirety, or should be without operator input. That's the hard part, keeping a constant pressure along the fence. Then when you've got one angle cut and you need to ride a sharp edge along the fence, there is less area on the work piece to bear against, so it's more critical.


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## firehawkmph (Apr 26, 2008)

One other thing Afx, besides all the tuning of the saws and checking your angles is to make sure your pairs of wood for each side are exactly the same length. If one is just slightly longer, it will throw off all the joints. I usually set up a stop block when cutting multiples to insure they are the same. 
Mike Hawkins


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## woodnthings (Jan 24, 2009)

afx said:


> *
> I'm about to start a really large project that will require ripping long lengths of plywood at a 45 to create an inner box.*
> 
> ..... *as posted 15"* ......
> ...


I'm gonna call that a bevel at 45 degrees. These are not face frame miters, but 15" long bevels..... just sayin' :yes:


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## tcleve4911 (Dec 16, 2006)

One thing not mentioned.....
You have to make sure that the stock stays absolutely tight to the table saw top by using a featherboard.
If the stock raises at all, it will throw off the line of the bevel.

Just a thought .......


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## afx (Feb 5, 2010)

woodnthings said:


> I'm gonna call that a bevel at 45 degrees. These are not face frame miters, but 15" long bevels..... just sayin' :yes:


Are you sure? :icon_smile:

I was taught to bevel is a verb and to make a miter is a noun :blink: I can bevel the hell out of anything, I just cant make it fit together properly to make a miter.:laughing:


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## afx (Feb 5, 2010)

tcleve4911 said:


> One thing not mentioned.....
> You have to make sure that the stock stays absolutely tight to the table saw top by using a featherboard.
> If the stock raises at all, it will throw off the line of the bevel.
> 
> Just a thought .......


That could be one of my problems, I've never been big on featherboarding but I've been thinking of buying a set or making one.


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## woodnthings (Jan 24, 2009)

*bevel vs miter definitions*



afx said:


> Are you sure? :icon_smile:
> 
> I was taught to bevel is a verb and to make a miter is a noun :blink: I can bevel the hell out of anything, I just cant make it fit together properly to make a miter.:laughing:



The discussion rises again.:blink:
BEVELS
You bevel the long *edge *of a board or other material by setting the blade over at an angle:
http://en.wikipedia.org/wiki/Bevel









The edge of a plane blade or chisel is referred to as the bevel.

MITERS:
You miter the *face* of a board using a miter saw or miter gauge:  

A power miter saw, also known as a _chop saw_ or _drop saw_, is a power tool used to make a quick, accurate crosscut in a workpiece, at 45 degrees precisely is mostly used for softwoods. Common uses include framing operations and the cutting of molding. Most miter saws are relatively small and portable, with common blade sizes ranging from eight to twelve inches.
A primary distinguishing feature of the miter saw is the* miter index that allows the angle of the blade to be changed relative to the fence*. While most miter saws enable precise one-degree incremental changes to the miter index, many also provide "stops" that allow the miter index to be quickly set to common angles (such as 15°, 22.5°, 30°, and 45°).

Boards that are narrow in width can be beveled or mitered within the capacity of the saw. A table saw can bevel an edge of greater length because you can use the fence and run it parallel to it. A miter saw can bevel the edge of a board by holding it vertically against the fence rather than laying it face down, which would be a miter..... 
It only matters what you call it when asking a question here, because the answer may depend which process and machine 
is applicable.


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## bradnailer (Nov 11, 2008)

afx said:


> (luckily I live next to both a Rockler and Woodcraft)


Man, that would be deadly for me!


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## LearnByDoing (Jan 18, 2012)

afx said:


> That could be one of my problems, I've never been big on featherboarding but I've been thinking of buying a set or making one.


 
Reading through this thread I was wondering when someone was going to mention featherboards. If you are going to rip a bevel along long piece of stock, I think the hardest part is keeping the board tight to the table AND the fence. Any warp, twist, or bow is going to ruin you cut. Featherboards are manadatory for this in my opinion.


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## against_the_grain (Aug 15, 2010)

I believe the spline suggestion a good one. Have seen this method recommended before by professionals.

Getting tight fitting miters without splines or other joining techniques is
pretty difficult to do (Not a fact, just my opinion).

So you aren't alone.


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## cabinetman (Jul 5, 2007)

There's many reasons why 45° angles cut on two pieces don't fit together creating a 90° corner. Reasons vary from the stock not being held to the table, guided straight on the fence, the angle cut is not a 45°, or the two pieces not fitting tightly.

My take on the alignment issue is that the miter slot is just a point of reference used because it's part of the table and doesn't change unless the table gets off kilter to the relationship to the arbor. The blade can be checked for parallel to the slot (I use the left slot). Then the fence can be squared to the blade and in essence should be parallel to the slot (but can be checked just to satisfy our curiosity).

Now comes the situation of having the blade parallel to the miter slot or the fence when it's tilted. The difficulty with that is getting an accurate distance measurement because the blade is tilted, and the front/rear distances point of measure may not be the exact same place on the blade.

If out, and shims are used to change the table, that could change other things like depth of cut. A suggestion; if the blade measures good @90 degrees, and it cuts well, evaluate the cut at a tilted position. It may also be within specs even if the measurement may be off. IOW, the measurement for parallel (if done with a digital gauge may show some differential three places to the right of the decimal), but that actual differential may be due to the method in attaining the measurements.

It can be checked by fitting two parts cut with 45° angle on each piece and see what kind of corner is created. 








 







.


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## RogerInColorado (Jan 16, 2013)

I may have missed these points, but if I did I submit to you that they are worth mentioning again.

Use some sticky back sandpaper on your miter gauge to make sure your stock doesn't slip.

First, deal with one variable at a time and don't cut your work stock until your sample stock proves your accuracy.

Second, make sure your stock is dead flat. If your blade is square to the table but your stock is not flat, you are going to have something other than 90 degrees between your "flat" surface and the edge of your mitered edge and that will look like a bad miter, even if the miter is perfect.

Third, make sure your reference edge is dead straight. Your miter gauge can be set to a perfect angle, but if the work is bowed slightly convex or concave, your miter will be off and it won't be your saw's fault.

Test your miter with a valid square. If you have a machinist square, use the 45 angle function to test the miter making sure that you are using the same reference edge your miter gauge used. If you don't have a machinist square, cut two samples and test how they mate with an engineers square or a carpenter square. 

Patience will get you better results than speed.

My miter saw cuts reliable miters for crown molding, etc., but for real precision like picture frames there is nothing like a tuned table saw.


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## afx (Feb 5, 2010)

RogerInColorado said:


> I may have missed these points, but if I did I submit to you that they are worth mentioning again.
> 
> Use some sticky back sandpaper on your miter gauge to make sure your stock doesn't slip.
> 
> ...


Thank you for the tips!

Actually, thank you ALL for the tips! I will be diving into the project next weekend, Ill be sure to let you guys know how it all went.

Thanks again! I have a lot of tips to try out!


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## johnmark (Jul 21, 2012)

i hand cut and plane ala:

http://video.pbs.org/video/1771726651


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## afx (Feb 5, 2010)

Well guys I think I might have gotten it!

After a LOT of tuning, calibrating etc etc. I think I have my tools and saw running true.

I was able to make this 12 section piece for a segmented bowl I'm going to make. This was just a test piece and I ran through it a little quick but it still turned out well!

Thanks again guys!


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## Snaglpuss (Nov 28, 2012)

Is what you want to do is miter the edge of two pieces of plywood and glue them up so the plys don't show as in a furniture carcase?

If you are just ripping a piece of ply on the fence you are almost never going to get a perfect result.
When we do something like this at work we usually cut up the pieces square and to the correct size on the cnc or saw (no miters on edges).

After we cut the blanks we run the edges against the sacrificial fence on a table saw with the blade being on a 45' and buried in the fence.
This can also be done on a shaper or router table with a 45 bit or knives. This alows you to have either a feather board to keep the ply dead flat against the table of the machine. If I was on a saw I would set the angle just a HAIR heavy. We would also at work try to use veneered MDF as opposed to ply if possible (more consistant thickness).
If you use a saw the blade has to be sharp, and you may get better or worse results depending on the number of teeth on the blade and the tooth style. If I remember right we get the best results from an ATB blade (alternating top bevel).
Glueing up a mitered carcase is another art unto itself


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