Freak_NL

That was spot on. I replaced the buckle, and that basically fixed this belt.

Not a bad idea. I think I'll give a longer buckle a go.

Two months ago I made another belt incorporating the advice given here. These photos are after two months of wear. Here I used strips of 6 oz leather cut from a half hide, starting from the back. The belt has a strip of 0.6 mm reinforcement sheet sandwiched in the middle with a margin of about 5mm from the edges. I hand stitched the belt (in addition to glueing). Overall I am not dissatisfied with the end result. It is, at the very least, a functional belt. There is none of the bunching up from my first post, only some deforming of the tongue where the buckle sits. Eventually I intend to make a simple belt single layer belt out of a piece of 8/9 oz side to see how that works out. The thickness seems to be the cause of me misjudging the belt's length a little. As you can see my standard wear hole is the second one instead of the (ideal) third out of five. For this buckle this 12 oz thickness is a bit too much I feel, so my next attempt will use two 4 oz strips.

Nope. No rock (or mountains for that matter). Just clay below sea level.

@chuck123wapati I guess I'll bite the bullet and order me some side (I haven't used anything except for shoulder until now). I'll be sure to report back when I've given that a go.

I'm cutting them from a piece of shoulder. I'll definitely give that approach a go sometime (despite being limited to hand stitching). I did do a belt with two straps of 4 oz leather before, but the same effect happened there as well (just not as quickly). That one did not have any stitching though. Perhaps I should consider oblong hole punches as well for belt holes? By the way, I love the sturdy look of that belt. That's something I would consider making as a gift if I manage to sort this problem out. @Dwight I'll give your tips on Resolene some careful consideration. I've been using a small wet cube of kitchen sponge with a small amount of Resolene in a container for applying. I'll mix it up the next time. Now that you mention it, I think I've read that tip about prestressing the belt with an iron bar before, that could be worth a go. When in the whole process do you do that exactly? Thanks all for the help so far.

This week I reused an old buckle and made a new belt for daily wear. Nothing too fancy, just a single strip of veg tan 7/8 oz leather. For the finish I went through these steps: Dye-prep, and then dye (Fiebing's Pro Dye) Wait an hour or so Apply neatsfoot oil (not too much) Wait a day or so Burnish the flesh side with Tokonole Wait two hours or so Finish with Resolene Now, I am not dissatisfied with the resulting belt, but whenever I make a belt like this, the backside quickly develops this — what to call it? — buckling? crackling? bunching? On this photo the middle image is the backside at the tongue end: Is this simply inevitable with a belt made from a single strip of 7/8 oz leather? I've read some topics here about problems with a Resolene finish cracking, but this seems to be the leather itself which bunches up. I get the feeling I am missing something really obvious — either that this is just how it works, or that there is a better way to do this.