Here is a how-to link for you. Look around at Chap 8 and then at Chap 12 where the fabric is wrapped around the chair arms. Actually Chap 3b shows a corner too.

Try this with a piece of scrap muslin first to make sure you have the corner sized right.

Good Luck!

Here is a link that might be useful: How to upholster a chair

Post a pic of the chair so we can 'see' what you mean.

I looked at most of those videos. While there's a lot of great info, the corners on that chair are all hidden by the frame, so the construction is different.

Here's the furniture in question:

Three of the seat corners go around a leg:

I've done enough regular chair seats that I can get a pretty smooth, tight corner on the square, but this was as good as it got:

I will ask my upholstery teacher at my Saturday afternoon class.

You make a diagonal cut inwards from the corner, just at tiny smidge shy of all the way to the inner post corner. Then you fold both sides under to make your L.

It feels odd at first if you're used to sewing lighter-weight clothing where you always have to edge or hem things -- not in upholstery. The corner won't tear out. Just slice and fold.

Circuspeanut, that sure looks like the way to do it. I tried that corner with a scrap of fabric, and I think it's going to work. Maybe I should use a little Fray Check on those cut edges, just in case?

You could, but the texture of the dried fluid might stand out more than you like? Experiment first and see how it looks. Most upholstery fabrics won't need it; they're made to resist fraying.

Happy cornering! Show us how it turns out --

Thanks!

I'm excited about this project. It's going in my craft room, so it's going to be very, um, colorful...when it's done.

Our weather has been either too windy, too cold, or too humid to paint anything, so someday it will get finished. Oh, and I had to redo the new chair padding THREE times, because the seat cusion has to actually go under part of the chair frame at the back. The padding can't be taller than 1", not even by a little bit.

The way circuspeanut displayed is correct...
just one thing after you make the cut (stopping
at the edge) pull your fabric STRAIGHT under tightly on both sides --
paying close attention to the thread of the fabric, in other words,
the fabric should be straight while pulling.

You got wrinkles in your fabric because you pulled
the fabric sideways. Remove the corner staples make
your cut and pull it straight down and staple.

Then give us another pic.

Look! This is so much better!!! Thanks again!

yeah, You've nailed it!

I was trying to figure out a similar issue I'm having and stumbled across this post and these comments. Was just wondering if anyone had any suggestions for a rounded inside corner (as opposed to a 90 degree corner)? The other issue is the piece I'm securing the fabric to extends out from there. I've attached a picture from the Internet as an example of the inside rounded corner I'm referring to. This isn't my project but this is very similar. The fabric was already secured to the top of the table insert with spray adhesive. Any help would be greatly appreciated.

I also have an inside corner problem, not not the same one as the original question.

I have made a curved bench, and the woodwork turned out great, but my upholstery is off the mark. The problem is the inside edge of the bench where the fabric would need to be made of rubber to stretch far enough. I ended up cutting a slit in the fabric and putting a patch piece behind it, but it does not look great.

Any help would be much appreciated.

I know this is an OLD thread, but let You Tube be your friend. To search, try words like “upholstering rounded cushions” and “ upholstering a rounded cushion with ease”. It’s all about the slow, gentle clipping ( cutting) of the fabric which allows it to stretch vs bunch. Good luck.

Thanks, but I tried YouTube before asking here.