First of all, I’m sorry to disappoint the filthy-minded amongst you but this is not a review of some eye-watering anal sex toy! This particular "Ring Stretcher" is a gadget used for increasing the size of the kind of ring worn on your finger.
This is another of those generic Chinese products which is available under a plethora of brand names and at a range of prices. It’s kind of OK for one-off use for stretching one or two rings, but poor design makes it pretty useless as a general ring-stretching tool you might want to use fairly regularly:
- As other reviewers have said, the smallest size is quite big to begin with, so it’s only really suitable for rings that are fairly large to start with.
- The mandrel part is stepped and the step sizes are just annoyingly spaced so that, after stretching the ring as far as it will go on one size step, it’s still not quite big enough to fit over the next step size up, for further stretching. So you end up having to force it onto the next step size and thus risk scratching the inside.
- Knocking out the 'plunger' [?] bit after you’ve hammered it in as far as it will go [which you’ll need to to if stretching by more than one step. See point 2] is hard work and, as no tool is supplied for that, you’ll need to hoke around til you find something just the right size to fit the hole in the bottom of the tool and just the right shape and strength to drive the plunger out, without breaking or slipping off the end. I ended up using the hub core out of an old bicycle wheel!
- I used the tool with a hydraulic press, so I was able to gently control and direct the pressure with which the plunger was driven in. Even then, I found the tool hard to work with. I’d imagine that having to rely on thumping it with a hammer would add a whole new level of "hit & miss fun" [pun intended] to the proceedings.
The plunger which you drive in to force the mandrel wider is tapered and, unlike with the bench-mounted ring stretchers, it drives in from the top [narrow end] of the mandrel, not the wider bottom end. So, as you’re driving it down into the mandrel, it’s splaying out the larger step sizes on the mandrel in front of it less than it’s splaying out the smaller step sizes behind it. This means that, when it’s driven into its full length, the biggest step sizes at the bottom are only being splayed a tiny bit by the narrow tip of the plunger, whilst the smaller step sizes at the top are being forced really far open by the wide end of the plunger.
Therefore, once you’ve driven the plunger in to its full depth a few times, the sections of the mandrel start to remain permanently splayed apart, as the metal hasn’t got enough spring in it to close up properly again. This adds to the annoyance of trying to fit a smallish ring size on the mandrel as you’re now having to do so whilst simultaneously squeezing the splayed ends of the mandrel together again.
It’s a bizarre [and badly flawed] design decision and, as I said works in the opposite way to the bench-mounted ring stretchers, where the tapered plunger fits inside the mandrel from the bottom end, so that the 'splaying' effect is proportionally the same all the way along the mandrel.
So, in summary; probably worth buying if you’ve a couple of rings you need to resize and are prepared to chuck the tool away afterwards. As a potential addition to your ring-making tools arsenal it’s not worth the hassle. Do what I’m going to have to do now and save up for a proper bench-mounted one.