Socket for old shower valve bonnet needed

I'd like to service a shower valve in a 1957 house with original plumbing.
The bonnet nut uses a round boss 7/8" in diameter with two flats milled in it about 3/4" apart. It'd be a cinch if the valve stuck out of the wall, any open-end would fit. Unfortunately it's recessed about an inch behind the tile, so a socket is reuquired.
All the wrenches I can find fit hex nuts, does anybody know the correct name for the required tool? From time to time "nuts" like this have crossed my path, but I've never encountered one used in a position that requires a socket to grab it.
At this point I don't even know what to look for. Correct terminology would help a great deal.
Thanks for reading, and any guidance.
bob prohaska

"bob prohaska" wrote in message
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Big question is how big is the hole in the tile? If it's big enough you could get a crow's foot wrench in there, or a sink wrench (think right angle pipe wrench on the end of a T handle). Google or search amazon.com for pictures of both. Or make a socket by milling a deep 3/4" wide slot in the end of a piece of 1" square bar and turn it with a big adjustable wrench.

On Mon, 10 Dec 2018 15:52:53 -0500
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Too funny Carl. My post sounded like an echo of your's :)

"Leon Fisk" wrote in message wrote:
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:-)

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Nowhere close to big enough for a crow's foot. I'll have a grind out some of the tile and grout to get a relatively thin socket on the bonnet fitting.
If I just hammered a pair of flats on a 7/8" ID tube it _might_ work, but any wrench I can make will be a worse fit and weaker than the worst wrench I'm likely to buy. If I damage the valve it'll mean taking out tile, that could easily turn into a bathroom remodel 8-|
There's nothing particularly special about the house or the way it's built, I'm sure the valves were common before the advent of single-control valves. If I knew what the needed wrench was called I'd have a chance of finding one. Terms like "2 flat socket" and "2 point socket" find nothing. "Valve bonnet wrench" finds many matches, but they're all hex.
A search through McMaster-Carr catalog 117 found nothing even close. That could mean the valve is rare, but nore likely it just means the valve is a purely residential product.
Thanks for writing,
bob prohaska

On Monday, December 10, 2018 at 4:43:20 PM UTC-5, bob prohaska wrote:
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If I wore going to make a special tool, I would think about using a deep socket and a nut that fits the socket. And modify the nut by cutting it so it converts the socket to what you need. THen hold the pieces of the nut in the socket with glue
Dan

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If you make a socket by milling a 3/4" slot in the end of round stock, there's no need to match the 7/8" circle at the ends, the slot can just be longer.

If you have a socket with flat to flat distance suitable for the shower, remove the unwanted flats with a bench grinder. Handy tools, those.
Hul
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Rather than butcher a good deep socket I decided to try making one out of steel tubing. The valve bonnet needn't be extremely tight since it seals with gaskets (though of course it could be siezed) and in any case the valve is suspended on the piping, which won't take a whole lot of torque no matter how strong the socket is.
It turned out to be surprisingly easy to craft a socket out of 3/4" thinwall conduit, flaring the tube on the horn of an anvil and hammering in the flats. If it proves weaker than the piping support making a stronger socket out of better-quality tubing promises to be quite easy.
Perhaps this is why nobody bothers to sell sockets for this application; they're easy enough to make. There are photos at http://www.zefox.net/~bp/shower_valve/ in case anyone's curious.
To my relief (and some embarrassment) it was pointed out to me that the tile on the back side of the shower wall stops below the shower valves. If all else fails the valves can be replaced without disturbing the tile.
Thanks for reading, and everyone's counsel!
bob prohaska
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On Fri, 14 Dec 2018 17:18:34 -0000 (UTC), bob prohaska
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I was curios why "valve_1.jpg" reminded me of my dial-up days.;-) 2.8 MB verses ~150 KB... Nice wrench though, a bit crude, but made of metal!

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Just a matter of hoping the higher resolution might be helpful.
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You are being too polite. It fact it's _very_ crude and took only a few minutes to make. I think it might be strong enough as-is, but if not a much stronger example can be made in little more time once material is in-hand. Say, 7/8" ID by 1" OD DOM steel. I'm somewhat fearful of needing a wrench that strong. Number one on my list of things to avoid is damaging the pipes in the wall.
The wrench had to be metal, to keep this thread on topic 8-)
Thanks for reading!
bob prohaska

On Fri, 14 Dec 2018 17:18:34 -0000 (UTC), bob prohaska
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Very similar to my solution to second son wanting a better tool to operate the spare tire winch on his 2010 Grand Carravan. What was required was a 1/2" sq. drive extension with a female end on both ends. I took a length of 1/2" EMT and worked a modified 1/2' square bar into each end -took all of ten minutes.
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Dos it back up to a closet where you could cut an access hole and fit a cover?

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No, shower and tub are back-to-back, plumbing is in the common wall and both surfaces are tiled.
I suspect a lot of these valves were used in the '50s and '60s and quite a few of them are still in service. If I knew what they're called it's likely I could find a wrench, or at least what the wrench looks like.
I don't have any machine tools except a lathe, so cutting a pair of accurate wrench flats will be a "file and fit" proposition. Using the lathe to form a pilot hole that fits on the valve stem/bonnet will ease the fiting problem somewhat, but a purchased wrench of the correct type is much less likely to damage the valve.
Would posting a photo of the valve bonnet help with identifying it? I thought somebody would recognize it by the description.
Thanks for posting,
bob prohaska

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You can mill on a lathe, as long as the cutter in the chuck only pushes the work on the carriage downward.

On Monday, December 10, 2018 at 2:52:00 PM UTC-8, bob prohaska wrote:
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Yeah, that's do-able; just turn a thick disk, mark center and scribe lines at 3/8 inch either side; hacksaw through half or less of the thickness near those lines, and grind out the middle.
Then fine-tune with a file until it fits. Extra credit, weld a pipe onto the disk and make a T-element on the other end of the pipe for a handle.
Actually, welding a couple of bars onto the endface of a pipe wouldn't be too bad: clamp a right-thickness chunk between 'em to keep parallel.

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The idea of welding wrench jaws to a handle is a good one that I didn't think of. I do have a welder, trying to make a wrench would be an instructive exercise in any event.
In the ( probaby vain ) hope that somebody will recognize the valve's maker or the needed wrench type a few photos have been put at http://www.zefox.net/~bp/shower_valve/ For scale, the long threaded part is 5/8" diameter, the flats are about 3/4" apart and the OD of the boss is 7/8".
If the manufacturer is known it'd maybe let me anticipate what sort of seals are required before I take it apart.
Thanks very much!
bob prohaska

You are not ever going to find a ready-made wrench for that. The welded-up suggestion is a good one. Another approach might be to use a die grinder to cut the other 4 flats on your nut & turn it into a hex. The nut being brass would make it more easily done.
However, fitting a wrench to that nut is likely to be only the first problem in fixing that shower. After 60 years, that nut is not going to come out gracefully and there's a good probability that something will break in the process.
The right way to fix the valve is to replace it. I know, it's in a tiled wall, but they make large plates to cover the hole. Google/images "remodeling shower cover plate". Ask This Old House did a segment on it: https://www.thisoldhouse.com/how-to/how-to-install-anti-scald-shower-valve
You might be able to fix the old valve, but you _know_ that it won't be the end of it. Do it right, replace it, and be done with it.

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I've partly disassembled a tree of old brass pipe from a contractor neighbor's scrap pile. Some of the pipe-doped fittings unscrew fairly easily, others require enough vise clamping pressure to crush the pipe.
The pipe can be machined into 1/2" ID pivot pin bushings that withstand more force than Oilite.
-jsw

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I don't really disagree with you, but that's a can of worms I'd rather face on my own terms. If it's possible to fix the valves without too much trouble it seems foolish to do otherwise. If they can't be fixed, then the decision making process gets complicated rather quickly.
I'll take a look at the cover plate idea as a stopgap, thanks for pointing it out.
bob prohaska