Big Gap In Mitre Corner?

[Foresty Forest]

Why do I keep getting a big gap on one corner of my picture frames?
I'm using an electric mitre saw and a band clamp for joining.

 

[Tigercubrider]

Your saw (or you ) is not accurate

 

[JobAndKnock]

Agreed! But having said that it is pretty darned close. I think I'd consider adjusting that joint with a block plane or a sanding board

 

[^woody^]

Is this mitre saw one of the big ones meant for first fix rough cuts? There is a bit of wobble in the blade.

 

[conny]

Try a (accurate) set square on the inside and outside of the joint to see if you can determine which edge is running out. It may be that you are 1/2 to 1 degree out on the 45 degree mark of your saw, giving you the divergence. Maybe using a very thin shim to offset the wood before cutting may solve this problem.

 

[^woody^]

The whole cut line looks uneven, not a wrong angle.

 

[Notch7]

Blade is being deflected - it’s probably blunt.

 

[Foresty Forest]

Is this mitre saw one of the big ones meant for first fix rough cuts? There is a bit of wobble in the blade.

Is it possible I haven't put the blade on correctly? I'll have a closer look...

 

[JobAndKnock]

It's a lot more likely that the saw isn't set up quite right or the blade is deflecting due to bluntness or that the timber is warped or that the gence is a tad out of straight over its' length (a common defect with older Makitas used on sites - can't say for other brands). Have you actually done two mitre cuts in a piece of straight, planed timber and offered them up together (glue with mitre adhesive) then checked with a known good try square?

You might be surprised to learn that even big box name mitre saws aren't always that accurate as bought