Metrinch wrenches

I recently came on information on a brand of wrenches/spanners called Metrinch, which supposedly puts the pressure not near the corners of hex bolts and nuts but more towards the middle of the flats, and hence, it is claimed, there is less danger of damaging the hex and one wrench can serve several (near) sizes. This is of interest because my 5/16 Whitworth wrenches are very tight on the corresponding nuts and bolts in my old car, and the next size up metric socket (16 mm) is too loose.

Has anyone experience with Metrinch wrenches, in particular with the sockets? I note that the local Orchard Supply Hardware stocks them but I don't want to spend the money if they turn out to be useless.

Ken G, 1925 Rover 16/50 (San Francisco)

I have never heard of this product, but the feature you've described sounds like a similar feature of "Snap-On" sockets and hex wrenches.

aeronca65t

There are similarities but also significant differences. I looked up the patents. They are both designed to avoid making contact near the points of a hex.

However, the Snap-on socket profile, when fitting on a hex head, contacts each flat with two sharp-edged narrow flats and like a conventional wrench is tight, so that there is very little play; like a conventional wrench, you must have exactly the right size socket corresponding to the nut or bolt. If you apply a lot of force, the sharp edges will leave scars (but not near the points).

In contrast, the Metrinch profile contacts each flat either with one gradual curve near the middle of the flat or two gradual curves at two points. Since the precise contact lines are not critical, the socket will grip a range of hex sizes; on hex heads at the small end of the range, there will be some slack, but there are no sharp edges to leave scars. This sounds a very clever idea, but I would still like to hear from anyone who has experience in using the Metrinch wrenches.

Ken G, 1925 Rover 16/50 (San Francisco)

Hello Ken,
I have seen but not used them, but my personal feeling is I would not buy them for my own work. I prefer, and do have sockets that, fit specifically, Unified, Whitworth and Metric rather than a one type fits all. If a fastner is that tight that it becomes damaged when removing it then I renew it.
I know that, as Aeronca states, Snap On do flank drive, as do other quality tool manufacturers and they are better.

Hope my twopence worth is of help.

Alec

https://www.metrinch-tools.com/

Tells a little more about them, and where they're available.

No experience with them, but it seems a little gimmicky to me... but I'm still using tools I bought 30 years ago.

The best test, if you could, would be to buy and try out one of the "popular" sizes and see how well it worked before springing for a full set.

Piman and James,

I take your point, Piman, but I think it is rather perfectionist. I have no convenient, and more significantly, quick source of small numbers of nuts and bolts with the same threads, dimensions and appearance as those in my car. I cannot simply walk into a hardware store and buy for instance 5/16 inch BSF bolts 2 3/8 inches long, nor 3/8 inch Whitworth castle nuts. Hence it is necessary to rescue as many fasteners as possible.
When I acquired the car, I bought sets of Whitworth/BSF wrenches, both conventional and sockets, which in most cases are very satisfactory, but I find that the 5/16 ones (both sorts) are tight on some of the nuts and bolt heads, and when I find such examples I need an alternative. An adjustable wrench works when there is space, but there isn't always.

In a different forum, I asked the same question and received two instant enthusiastic positive replies, so I think I shall invest $50 in a set of Metrinch sockets. Alas, I don't think single pieces are available, or I would simply get the nearest to 5/16 Whitworth.

Ken G, Rover 16/50 (San Francisco)

Hello Ken,
Fair comment, and I suppose that your location does make it harder to source such hardware. I do tend to stock my workshop with the most common sizes of fastners as a matter of course. I do not understand why some sizes are tight on your tools though. Anyway, I would be interested in hearing your experiences with you new tools.
good luck,
Alec

I have the snap-on flank drive wrenches, and yes, they will leave scars on some nuts. On the other hand, it only happens to the ones that are so tight, any normal wrench would slip off the nut to begin with, and really screw it up. I have a set of line wrenches, and haven't touched them since I bought the snap-ons. In my opinion, they are the best wrenches to be had. Problem is, they are also the most expensive. A single 1/2 wrench is over 20 bucks. I'm a mechanic though, so its just something I have to accept.

For what it is worth (Not WHIT-worth), I acquired sets of Metrinch wrenches - both combination and socket - about seven years ago and have carried them in various British cars ranging from a '47 Morris "8" to a 1961 Morgan at events. I was suspicious of them at first, primarily because of the "Taiwan" label they bore. However, I have found them very useful and dependable and now count upon them if a problem develops (as it often does!). Norm Kear

I have been using these wrenches for years, they work very well on worn or rusted nuts or bolts got me out of trouble many times
If i lost them i would buy new ones
bill cove

I have a set of the Metrinch wrenches and sockets. I got them fron Eastwood Company 7 or 8 years ago. I have a 1955 MG TF which uses Whitworth, an MGB which uses American Std and my son has a rice burner which uses alot of metric. We use the Metrinch on all three cars.