# Mitered table joints do not fit



## Henry82 (May 22, 2018)

Good day everyone!

I am creating a small TV table with mitered corners. The material is purchased Oak glued panels. 
After cutting at 45 degrees, it turns out the corners do not want to fit. The saw i used was electronically controlled and is used in furniture factory. I am suspecting that the panels are warped or something. Any advise is welcome.

Thank you for the time.
Henry


----------



## MarioF (Feb 6, 2009)

The saw is not cutting at exactly 45 degrees….......and make sure you have a square assembly when gluing


----------



## fivecodys (Dec 2, 2013)

My guess is warped panels. Is it a panel saw you are using?


----------



## sras (Oct 31, 2009)

One or more of:

Incorrect angles (saw set slightly off, piece was positioned slightly off during cut)
Warped wood
Inconsistent length of pieces
Misaligned at assembly

It seems to me that if it was just warped wood, the joint should be tight in at least one spot along the joint. I guess that would depend on how it warped. A straightedge might help show any warp.


----------



## Loren (May 30, 2008)

Case miters can be tricky to get right if the
panels are warped at all, which is likely. 
The warping results in curved miters, miters
which are off 45 by a little, or a combination.
The 45 degree stop on the saw could have 
been off but if the panel isn't dead flat when
sawed (can be clamped flat sometimes) the
miter will not be perfect.

It takes some discernment and patience, but
the miters can be fitted by attaching a piece
of coarse sandpaper (a cut piece of sanding
belt is ideal) to a flat surface like melamine
or mdf and rubbing the parts back and forth
apply pressure to remove material where you
want.

This sort of device can be used to flatten boards
for mitering. (image from Home Depot)


----------



## Unknowncraftsman (Jun 23, 2013)

Here's my diagnosis from a thousand miles away.
If they were cut 1 hour ago then the saw was off.
If they were cut 1 week ago you waited too long and the wood warped.
Miters are very tricky


----------



## wormil (Nov 19, 2011)

Get a protractor and measure the angles.


----------



## Chashint (Aug 14, 2016)

I think mitered joints this long are very hard to cut even with careful setup.
The slightest wiggle during the cut and it's hosed.

If you did not machine the panels to all be flat, square, and the same thickness it turns a difficult build into an impossible build.

I don't know what kind of furniture factory saw you have access to, but the store bought furniture I have taken apart and examined / repaired has not had precision cut joints.


----------



## recon49 (May 21, 2018)

It looks like not perfect 45-degree angles to me.


----------



## enazle (May 18, 2018)

You need to make yourself some miter joint assembly jigs out of 3/4 shop plywood. Use C-clamps or wood clamps to draw your miters up tight. Let me know if it isn't clear what to do?


----------



## Henry82 (May 22, 2018)

Thank you all for your quick response.

The workshop i used had computer controlled saws therefore i assumed everything is accurate and square. I try to get myself a protractor and measure the angles. 
Unfortunately i did not indeed machine the panels flat, before cutting. Does that mean i should discard the plan of TV table and make some floating shelves from the material (another project i want to make and seems more easier)?
I forgot to mention, the panel width is 40 cm (15 3/4 inch)
Enazle, i will try out your jig. and see, if i can press them together. 
What kind of glue you guys recommend? I read from other topic that 2 compound epoxy is most suitable (strongest) for mitered joints like this, or can is stick to regular PVA?

Regards Henry


----------



## Loren (May 30, 2008)

PVA fills gaps adequately but isn't very strong
when it's tasked to do that. Polyurethane
glue foams up and expands, filling gaps very
well and with good strength, but it's messy
and spoils in the bottle.

Epoxy would probably work well because it
can fill gaps with integrity.

As I mentioned above, the joints can be sanded
with some elbow grease.


----------



## Henry82 (May 22, 2018)

Thank you Loren for the encouragement, I sill try to sand the angles right and see what happens.


----------



## bonesbr549 (Jan 1, 2010)

I think all gave some guidance, but I'd also check to make sure your sides/ends are all the exact same length. I don't mean you had a pencil mark to cut your pieces, but a stop of some kind. I had that problem and it masked itself as a miter issue. I'd also ask when you cut that 45 is that final cut just shaving off a hair. Depending on blade, you could be having some deflection there. I cut them close then the final pass is a shaving and that will fix it some times.

Finally, get a precision angle 45, and check it. Run several through it and are there any differences. If so, your arbor lock could be slipping a hair.

Good luck !


----------



## tomsteve (Jan 23, 2015)

there are corners open on the inside and corners open on the outside- are the lengths of opposite sides equal? is the box square?


----------



## RichT (Oct 14, 2016)

It's unfortunate to see so many inaccuracies being promulgated regarding the characteristics and performance of various glues. Fine Woodworking did thorough testing for their July/August 2007 issue that should clear the air. Patrick, of Old Brown Glue, has a PDF of it on his web site:

http://www.oldbrownglue.com/images/articles/HowStrongisYourGlue_FWW.pdf


----------



## enazle (May 18, 2018)

Henry, do your joints have a spine to lock the corners into place?

About the jig, you can glue up your corners 1 at a time if you clamp the jig plate to each part your trying to join. It doesn't require you make 4 jigs plates, just make 2 if you only have a few C-clamps. What I didn't show was a "L" brace that you clamp in the corner to keep it square. Oh use Titebond wood glue or even plain old Elmers if that is all you can get?


----------



## enazle (May 18, 2018)

Here is what I mean by a spline:


----------



## Loren (May 30, 2008)

I should add perhaps that my glue recommendations
are based on personal use in trying to close
and fill crappy beveled joints, which I did a lot
of when I was starting out.

The ideal approach is well fitted joints, always.
End grain miters are about the weakest joints
there are so no matter what glue one uses it
will be a dubious bond imo. The PL glue will 
foam up and fill that weak joint while the pva
may run out, depending on its viscosity, and 
won't take a stain at all. I suppose the PL glue
won't take a stain either but as I recall the stuff
I used dried to a sort of amber color that wasn't
so distracting and in the case of an open miter 
the top portion of the foamed glue could be
scraped out and replaced with a colored wood
filler without much trouble. In the case of
epoxy it can be colored after mixing it up. I've
used powdered pigments and I think I tried
acrylic art paints successfully with it.

To a minor extent depending on the wood type
a miter which is open on the outside can be 
"fudged" by burnishing it with a round 
screwdriver shank.


----------



## RichT (Oct 14, 2016)

> The PL glue will
> foam up and fill that weak joint while the pva
> may run out, depending on its viscosity, and
> won t take a stain at all.
> ...


That's just it - the polyurethane glue will fill it with foam. That's fine for eliminating a rattle, but very weak from a joint strength standpoint. Take a look at the FWW article I linked to. The polyurethane glue had 58% of the strength of PVA. They said its weakness was the big surprise of their tests.

I'm with you though, that cutting the joint right in the first place is the way to go. Trying to fudge it with glue is a losing proposition. You'll have failure down the line.


----------



## Lazyman (Aug 8, 2014)

It sounds like you may not have many tools as your disposal? If not, to fix this your best option may be to recut the ends at 90 degrees and make butt joints. You will lose a little in the width but you can keep the height the same if the sides are resting on the bottom and the top is resting on the sides (assuming that the opening will facing the front?). Just use standard wood glue and you may want to reinforce the butt joints with some screws. Finish nails would work too. You will want to close the back opening with plywood screwed to the back to add a little strength and prevent racking. Not the most elegant solution but simple and with the plywood back, it should be strong enough.


----------



## enazle (May 18, 2018)

Wouldn't re-cut from what I see. Using those jigs I posted will put as much as 2000 pounds of pressure on the joint. I guarantee it will pull-tight the joints you have pictured. If you do not have access to a table saw, private message me and I will make you some jigs out of scrap laying around my shop. You will need 6 or 7 clamps. Dont cut or sand anything until you try using these jigs, if you do, you will only screw your project up.


----------



## TheFridge (May 1, 2014)

When he goes to glue the last joint I bet it explodes.


----------

