Mitered Corners

What’s the best tool for making a box with accurate 45 degree mitered edges for joining? Box would be about 2’ cubed. Do we have a good sled for this purpose on the table saw?

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A sled would be nice but you’d probably want one dedicated for doing miters and that’s a real niche thing at this size workpiece.
Other options include just ripping it using the fence (gotta keep things tightly in place, but would need to do the same with a sled), the router with large miter bit or even a lock miter bit (many people hate the set-up on these lock miter bits, and I bet they’re reading this even now!), the jointer could do it in theory, but not advisable…
What are you making? Sure miters are the best joinery technique for your purpose?

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Speaker enclosures. I definitely like the look of neatly mitered edges with plywood.

The issue I have with using the saw stop to cut mitered edges is that the throat plate moves which causes the location of the mitered edge to change so you end up with an edge that is not straight. When cutting a 90, it doesn’t matter because it’s just moving up and down most of the time. But when cutting a mitered edge it causes it to move away from the blade or toward the blade. Though not ideal from a setup standpoint, the best way around this in my opinion is a sled as has been suggested but made so that the work is held at 45°, and the blade stays vertical.

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I concur with David that a sled that presents the work at 45° is the best solution. I use one in my shop and it works well. The challenge is to make one for a long workpiece. Mine maxes out at 13"

A good exercise in developing skills is to make a jig.


The easiest way using our table saw is to use a 45 degree cut and use the fence. The yellow, magnetic featherboard will help to lock your piece to the fence, nice and tight. You just have to ensure the piece stays flat on the surface during the process.

If you’re making a cube (which is what it sounds like), cut 2 of the miters on each piece before slightly re-adjusting the fence to make a crisp miter on the remaining two cuts.

Makes sense. Thanks all!

Are you around this Saturday? 1/29/2022 I can show you how to make perfect miters on large pieces. Let me know.

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Not available tomorrow, but thanks for the offer. I’d love pick your brain another time, however. How often are you at Make?


I would be interested in knowing your technique. How about a little document on your procedure ?

Thanks, Bill

I’m not there as much as I’d like to be… Unfortunately I have to work for a real living. Lol. I have time some evenings if I can help.

I’m going to try and cut out a couple cabinets tomorrow… Saturday. Like I told Sean, I’m available some evenings.

I understand working for a living and availability which is why I asked for documentation not on site instruction.


Ah! Onsite demonstration would be easier!

At 80 miles round trip to see your demonstration documentation makes more sense. And it is more durable :slight_smile:


I understand! I’ll see if I can photograph my process. It’s pretty simple. It works for compound angles and straight angles on larger pieces.

I look forward to seeing your process.

Thanks for sharing.


I have a similar question - although about an artwork frame that was not right at 45 deg. We had a frame precut and sent to us (too many details to go into why we chose this route) for a piece of artwork a family member did in Maryland. When we took the frame to a local frame shop to mount the artwork they found the angles to be off (see attached

I understand frames usually use a special saw blade and even saw. Is it possible to recut this frame using the woodshop miter saw and 1) get an true 45 angle 2) not damage the finish on the frame?

The frame is about 3.5" wide and about 1.25" tall.

Any thoughts on how to recut this? Or should we just find a frame shop that could fix it?

Thanks for your advice!

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There is a sled for cutting frame corners on the shelf

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Either the miter saw or a sled on the sawstop “could” cut an accurate 45° angle. But avoiding damage to the finish requires some finesse and maybe luck.

Accurate miter cuts are not a simple set and go technique. Testing and measuring with scrap pieces is absolutely required. And then there’s getting the recut lengths right which may also be messed up as received.

But doing eight (8) separate cuts with zero chipping of the finish sounds more difficult, and that finish doesn’t look amenable to touching up.

I’d be inclined to ask for replacement from the original seller, if possible. Barring that I’d rely on the local frame shop’s recommended action.

If you decide to try recutting, I’d ask for hands on help here.