DIY: Carving a Leather iPhone Case to Fit a Peak Design Strap Adapter Flush

This is the English edition of a review from my Japanese YouTube channel, iestaLife. I review gadgets from my home studio in Japan, so product links go to Amazon Japan.

Quick take

Phone strap adapters that sit between the phone and the case, with the cord coming out through the charging port opening, make the case lift slightly. I carved out the inside of my leather iPhone 17 Pro Max case so a Peak Design strap adapter sits flush, centered at the bottom. After carving a wider area than I first expected, the case fits properly again.

What I tested

A leather case for iPhone 17 Pro Max that I had already carved once for a metal strap holder
Peak Design Mobile Crossbody Multi Strap and its strap adapter
A rotary tool with a sanding bit and a pointed bit

What I found

A rotary tool was by far the fastest method. Cutters and files took too long on my first attempt months earlier.
Carving only where the adapter sits was not enough. The bottom of the case still lifted and the side looked slightly bent.
Once I carved a wider area around the adapter, the phone seated properly.
With the adapter in the center, the strap hangs straight, and it no longer gets in the way of the charging cable.
A cord-type adapter does not rock when the phone stands on a MagSafe ring, unlike the metal holder I used before.

Earlier attempt

In December 2025 I carved the same kind of pocket for a MOFT metal strap holder, about 0.4 mm thick, in a SHIELDON leather case. I started with a nail file, switched to the rotary tool, finished the edges with a cutter and held the plate in place with double-sided tape. It was much better, but not perfect, which is why I redid it for the Peak Design adapter.

【DIY】スマホショルダーの「ストラップホルダー」でケースが浮く問題を削って解決してみた

Other cases

My leather case was easy to carve on the inside. Other cases vary by material and build.
Some silicone cases have a felt-like lining. Peeling that lining where the adapter sits can free up enough space.
Without a rotary tool, cut and peel the lining with a craft knife rather than trying to carve.

I have only tried the leather case. Carving makes that part of the case thinner, and I have not tested long-term strength while hanging from a strap, so only try it on a case you are willing to lose. If you do not want to modify a case, buy one with a built-in strap hole.

Watch the video

【DIY】ケースの浮きを解消！iPhoneのレザーケースを削ってピークデザインのクイックリリースを美しく埋め込んでみた

The video is in Japanese. The carving starts around 2:00, and the fit check around 4:30.

Limitations

This is a DIY modification on my own case, not a product test. Results depend on the case material and thickness.

Products

Peak Design Mobile Crossbody Multi Strap: on Amazon Japan

MOFT phone strap with metal holder: on Amazon Japan

SHIELDON leather case for iPhone 17 Pro Max: on Amazon Japan

The Amazon Japan links above are affiliate links. As an Amazon Associate, I earn from qualifying purchases. Check the listing for the exact model, current price and shipping availability in your region.

More reviews in English