I could just make one:

Although I'd have to make it by hand b/c I don't have a thin kerf blade.

 

Good luck!

I also have a 12" sliding miter saw and because I've been too lazy to make a sled for it to cut the small and somewhat delicate trim I usually make and use, I did some digging around to find a manual solution and wasn't very happy with what I found.

In my head, I wanted something like this:

But I found most of them weren't as cool as I thought they were and the ones that were decent were way too much money. Then there was the problem of where to store this thing when I wasn't using it which most likely would be 98% of the time.

I ended up using this old thing

I've probably had this for 10 years or so? The clamping pins are really helpful and for the foreseeable future, I'll probably just keep using it. I have an even older wooden miter box that's not as wide and actually better for small stock but it doesn't have the clamping pins so I don't use it.

 

Years ago I built over 90 fireplace mantels using a saw similar to the one below.

Don't know if I would want to do that now.

 

View attachment 475570

Years ago I built over 90 fireplace mantels using a saw similar to the one below.
View attachment 475569

Don't know if I would want to do that now.

i have made countless picture frames with the same saw

 

Does anyone have experience or recommendations?

When I was a kid, I had a wood miter box and a cheap backsaw.
That's all I knew, so I used it to make basic picture frames and crosscuts.
Skip about 20 years and I got a Craftsman 10: table saw which I used for crosscuts and miters.
I also acquired that slick, thin kerf miter saw as pictured above, but I found it slow and tedious compared the the table saw.
That fast spinning blade could shave off a 1/64" with no effort compared to the same attempt with a miter saw.
A hand plane and a shooting board would have worked far better.
Skip another 20 years and I acquired a 10" Craftsman miter saw, the simple hinge type, and that made miters real easy.
Skip about 10 years and I bought a 12" Dewalt compound sliding miter saw, the "king of miter saws" at the time.
Now we're talkin'. It is a beast, but makes short work of making any miter cuts I need.
I still use the miter gauge on the table saw with an extended wood face about 18", and that also works great.

 

Saws with a carriage like @Elisabeth_K. And @FrankC show are much more accurate than a box, and boxes tend to wear a bigger slot over time. The old Stanley’s work well, but be prepared to sharpen the saw.

 

I was fortunate, there was a saw sharpener in the same complex as me, would take the backsaw and miter box to him so he could test saw for a perfect vertical cut.
That same guy sold me a new fangled blade for my tabesaw that had carbide teeth.

 

I haven't been able to find something that fits that bill, neither on amazon, nor the woodworking stores.

https://www.highlandwoodworking.com/hand-miter-saws.aspx

20" Miter Saw

The Stanley No. 150 miter box, paired with the Bad Axe 20" Miter Saw, offers compact efficiency, making it ideal for miter cuts. Customize your order online.

badaxetoolworks.com

If you are looking for a miter box and saw for small delicate projects, this saw produces a .014" kerf.

Amazon.com: Olson Saw 35-241 Fine Kerf Saw 35-550 42 tpi with Aluminum Thin Slot Miter Box, Slot Size .014-Inch, Slot Angles 45, 60, 90, Cutting Depth 7/8-Inch, Pack of 1

Amazon.com: Olson Saw 35-241 Fine Kerf Saw 35-550 42 tpi with Aluminum Thin Slot Miter Box, Slot Size .014-Inch, Slot Angles 45, 60, 90, Cutting Depth 7/8-Inch, Pack of 1

www.amazon.com

 

thx Dave; I saw the $300 one, but that's also too much.

I think I'll just build a box and use the swanson square to make the initial cuts. Maybe use some oak or something. Like I said, when you have to make like 1 cut, it's not worth getting the full jig out

 

As it so happened, one appeared locally. An old craftsman. I just got done extensively cleaning - borderline restoring the piece, but it came out quite nice.

There's a screw missing at the top, and a knurled nut is missing, and that's about it. Very slick piece I will look forward to using for when I don't wnat to pull out the whole miter saw, although this piece isn't exactly small either. I'll have to find space for it in the garage.

What's extraordinary: the miter detent is far superior to my Bosch Glide miter saw. Very solid, very nice.