Half Moon and "S" Shaped Wrenches

[Adam McLaughlin]

Hey Everyone,

What are the intended applications for the "S" shaped wrenches and the half moon style wrenches? What were those things really designed for when they were thought up?

And..... How come they get such a high premium when sold second hand?

Adam

 

[tatra]

starters/ waterpumps etc..........i use a specific snap on wrech on locomotive emd[ gm] diesel engines........usually used on inaccesible locations........normally sit languishing or getting in the way in the box , but when you need them, you'd trade all your high end tools if given the choice of having them or not..........and that includes all the hard handled s/o screwdrivers in moose's box........

 

[Diesel-Mech]

They are obstruction wrenches, the idea is that you can reach around something (starter, injection pump, air compressor etc) to get to the fastener on the other side and still be able to turn the wrench. They are not needed very often but can be worth they're weight in gold when you do need them. I'm guessing the high premium is because they are not very common compared to other wrenches and because the initial purchase price is pretty high.

 

[Jbullfrog]

They work to get into tight places and behind things. They are nice for starters, alternators, generators, pwr steering pumps, and other places you can't get a strait wrench into.

 

[Dust]

I used one once when removing a transmission from a diesel Ram 2500. I probably could have used a standard wrench, but the half-moon just made it much easier.

I'd love a set of ratcheting half-moons, or at least a 13/15mm combo.

 

[J.A.F.E.]

S shaped wrenches have been around a very long time as have other wrenches with various curves. As stated they are obstruction wrenches. One place not yet mentioned is automotive door hinges.

 

[Stick Figure]

i bought my half moons, the snap on 30°/60° wrenches, as well as a similar part to these only from craftsman/matco

combinded w/ a crowsfoot. Anyway all of these are used to do twin turbo kit design/manufacturing/installation on 350Z/370Z, and the sibling G chassis cars. While you can do the install w/ out a lot of these things, its far easier to use these to turn the nut/bolt more than a fraction of a turn at a time. Since i sometimes have to do the install/removal several times making small changes, it was WELL worth the investment from my perspective.

 

[scottmlew]

Stick, can you tell us more about those? I'm trying to figure out what they are, and how they work.

 

[knucklehead]

i use them for '36-'84 Harley-Davidson cylinder base nuts & head bolts.

 

[Stick Figure]

Stick, can you tell us more about those? I'm trying to figure out what they are, and how they work.

the craftsman/matco version looks far more simple (i just can't find a pic), but its really nothing more than a 1/4 (or 3/8 or 1/2) driver w/ a nut on it. It was designed to allow a wrench to act as a low profile driver for a socket. But if you combine and open end crows foot w/ the 12 point boxed side of a regular wrench, you can get all sorts of interesting angles to get to things.

 

[scottmlew]

the craftsman/matco version looks far more simple (i just can't find a pic), but its really nothing more than a 1/4 (or 3/8 or 1/2) driver w/ a nut on it. It was designed to allow a wrench to act as a low profile driver for a socket. But if you combine and open end crows foot w/ the 12 point boxed side of a regular wrench, you can get all sorts of interesting angles to get to things.

Oh ok, I get it now...now that I understand, the design actually looks quite clever. And yes, I see how you could get some really useful angles when combining those with crowfeet and (offset) box ends. Thanks for the explanation!

 

[dede2897234]

Stick Figure,

Gearwrench makes a 4 piece adapter set like the Snap-on low profile wrench socket adapter. Sears sells it here: http://www.sears.com/shc/s/p_10153_12605_00942803000P?keyword=ratchet+adapter. However, according to the 2 reviews on Sears.com, it is not a good design. In your first thread reply, you attached a picture of the Snap-on low profile wrench socket driver. Do you know its part number?

Thanks,

Dave

 

[Stick Figure]

I do not know its part number because its not actually Snap On ... i found those on the stanley/proto site. Of course i also found them on the harbor freight site this morning looking for something else.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=99618

and the same style as the ones i actually have .....

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=67011

again i know sears sells them, as does matco, but i can't find them on either site. I can't comment on the original ones i posted since those are intended for a ratcheting wrench, and i don't own any of those.


http://www.stanleyproto.com/default...ETS&strSiteName=PROTO&strDefaultCatalog=PROTO link to the original ones i posted the pic of

 

[G1GRANDEUR]

working on imports, i never seen techs use S or Moon shape wrenches. at least our shop.

however, when i was at dodge, moon shape was used alot on diesel trucks.

 

[Moose-LandTran]

when you need them, you'd trade all your high end tools if given the choice of having them or not..........and that includes all the hard handled s/o screwdrivers in moose's box........

I already have a bunch of S-shaped/obstruction/distributor wrenches. No need to trade my hard handles.

How many wrenches does 189 hard handled tools buy?

 

[jhn9840]

If you had to choose between a half moon or an s shape which one are you more inclined to grab? Would you pick one over the other to have in your box, or does each one have it's place?

jhn9840
John

 

[Adam McLaughlin]

Did you guys see this auction? I put in a couple of bids but WOW the eBay sale price went above the Snap On "New" price.

Dannnng!!

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=320412966312&viewitem=

Adam

 

[Gary S]

i use them for '36-'84 Harley-Davidson cylinder base nuts & head bolts.

Same here. I bought my Craftsman "bent" wrench to work on the cylinder base nuts and the head bolts on my old Panhead. I couldn't get to the head bolts with any other wrench in my toolbox. Sears calls it an obstruction wrench. That name fits it.

 

[Moose-LandTran]

If you had to choose between a half moon or an s shape which one are you more inclined to grab? Would you pick one over the other to have in your box, or does each one have it's place?

jhn9840
John

I have S-Shaped ones. They work great for me. But i will also add half-moons too at some point, for situations where only they will work.

 

[rsanter]

I actually think that the ratcheting half moons (or S shaped) would be better than the standard wrenches.
if you are already in a tight spot, it would go faster to not have to remove and then re-install the wrench. much easier to just ratchet it

bob

 

[MB2forU]

30 year old son said same thing about these wrenchs and 1 day while helping him pull the transmission out of his chevy 4x4 truck and watched him struggle trying to get the top 2 bolts for about 20 minutes I told him try one of those funny wrenches you thought had no purpose and 30 seconds later the transmission is out

 

[gtsgarage]

Never found much use for mine but they did look great back when I had all my wrenches on peg board! Mine are SAE so who knows if they will ever get used. Haven’t found a use for them on my ‘67 Mustang and I’ve removed every single bolt in the car several times.

 

[Matt XYZ]

Did you guys see this auction? I put in a couple of bids but WOW the eBay sale price went above the Snap On "New" price.

Dannnng!!

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=320412966312&viewitem=

Adam

They sell HF quality wrenches at Norma, a discount grocery store like Aldi, over here for about $8 a set. Of course they are metric only but I picked up a set of S and C obstruction wrenches just in case. I haven't used them and I'm not expecting much but as long as they don't round off a fastener they will pay for themselves after one use. I am shocked at the price on eBay now. Of course mine are average quality at best.

I do have a mix of decent quality SAE half moon from Hazet, Cman, and proto that I got on eBay or at flea markets. I got these on for probably less than $2 a wrench.

 

[PartsGuy]

"I already have a bunch of S-shaped/obstruction/distributor wrenches. No need to trade my hard handles."

But there's no need to trade, you can have BOTH!!!!!! And you can get ratcheting wrenches..... or just hard-handled box wrenches. (The yellow set is ridiculously hard to find anymore, unless you want to pay an arm and a leg....)

 

[Dave455]

I’ve got probably 4 or 5 of these - total! We call them ‘obstruction’ wrenches in the U.K.

Most of them have been bought to do one specific job - for example the 7/16 x1/2 ‘half moon’ was bought by my father specifically for removing the dynamo from his Morris Oxford! The car is long gone, but I still have the tool!

I come across some applications where they might be useful, but most times you can get by with some combination of socket/extension/universal, or some other wrench!

I have none of these in metric, and I see Nepros offer some well thought out wrenches with a different radius at each end. If I needed one, that’s probably the way I’d go!

PartsGuy - I love those Mac wrenches! I think those were the sort of tool that earned Mac their followers - not flashy, but well thought out to fill a need, and of course U.S made! It’s a a shame that Macs current owners can’t be bothered to make these ‘niche’ tools any more, or indeed make anything except the essentials, and even those are hidden amongst a mass of heavily promoted Asian imports.

 

[Rico.]

I bought a very expensive set of Facom obstruction spanners over ten years
ago and it's a ****** good job I did as I haven't used any of them, not even once.

I keep telling myself if I didn't have them I would have needed them half a dozen
times by now.

 

[Tallpilot]

I bought a very expensive set of Facom obstruction spanners over ten years
ago and it's a ****** good job I did as I haven't used any of them, not even once.

I keep telling myself if I didn't have them I would have needed them half a dozen
times by now.

That’s exactly right. Think of all the frustration you’ve saved yourself.

 

[87FoRunner]

Am I the only one to notice this thread is from 2009?

And I’ve used half moons 1,000 time and “S” wrenches only a handful.

 

[PartsGuy]

I bought a very expensive set of Facom obstruction spanners over ten years
ago and it's a ****** good job I did as I haven't used any of them, not even once.

I keep telling myself if I didn't have them I would have needed them half a dozen
times by now.

I notice that some companies offer "half moons" that are't really "moon" shaped... they are more of a "flattened" arc. Sunex and those Facoms pictured above, for example. SO, MAC, and GW seem to be more "circular".... is there a reason? European design influence? Just to make dumbasses like me question it?

 

[Rico.]

I notice that some companies offer "half moons" that are't really "moon" shaped... they are more of a "flattened" arc. Sunex and those Facoms pictured above, for example. SO, MAC, and GW seem to be more "circular".... is there a reason? European design influence? Just to make dumbasses like me question it?

The Facom style just give you a miniscule amount of extra swing before
you hit the obstruction. Thats the only reason.

 

[homebuilt burner]

air compressor/fuel pump change on an 855 Cummins

Can not do it with out them.

 

[xxxstevemanxxx]

air compressor/fuel pump change on an 855 Cummins

Can not do it with out them.

That is so damn funny you mention this. I am doing that exact job on a N14 Cummins at work right now and need some good obstruction type wrenches to get the air compressor off so I came to this thread. Im about to get the cheap S-type Pittsburgh ones from HF...

 

[toolaholic]

starters/ waterpumps etc..........i use a specific snap on wrech on locomotive emd[ gm] diesel engines........usually used on inaccesible locations........normally sit languishing or getting in the way in the box , but when you need them, you'd trade all your high end tools if given the choice of having them or not..........and that includes all the hard handled s/o screwdrivers in moose's box........

I’m sooo envious of you! My favorite Emds are the F45,FP45, Sd45-2, and SD80MAC. Went to Altoona in 1996 for Rail fest and toured the Juniata locomotive shops. Love Alcos too! Saw the Delaware and Lackawanna C636 in Scranton Pa.

 

[Tallpilot]

air compressor/fuel pump change on an 855 Cummins

Can not do it with out them.

That is so damn funny you mention this. I am doing that exact job on a N14 Cummins at work right now and need some good obstruction type wrenches to get the air compressor off so I came to this thread. Im about to get the cheap S-type Pittsburgh ones from HF...

It is interesting they have become almost useless on modern passenger vehicles but remain essential on diesels and heavy equipment.

 

[2ndGearRubber]

It is interesting they have become almost useless on modern passenger vehicles but remain essential on diesels and heavy equipment.

They can be very nice for exhaust work even on modern cars. Lets you reach around the pipe to hold the bolt while you zip the nut tight. Used my moon wrench on a ford fusion last week; didn't want to bother with the mangled skid plate and the rotted bolts. Moon wrench wrapped around the manifold flange so I could tighten both fasteners for the downpipe through the same "hole" I wrangled my arm through.

 

[Tallpilot]

They can be very nice for exhaust work even on modern cars. Lets you reach around the pipe to hold the bolt while you zip the nut tight. Used my moon wrench on a ford fusion last week; didn't want to bother with the mangled skid plate and the rotted bolts. Moon wrench wrapped around the manifold flange so I could tighten both fasteners for the downpipe through the same "hole" I wrangled my arm through.