Gauge won't tighten to face out. HELP PLEASE

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I bought a replacement PSI gauge for the Acetylene side on this Port-a-torch but when I tightened it down it faces backwards.  If I turn it around it is too loose.  How can I fix this.. I have read that you are not supposed to put Teflon tape on it so what do I do? Attached ImagesLast edited by cnyeco1; 09-05-2010 at 03:07 AM.
Reply:can you move the seat?
Reply:loosen it and tighten it a half turn more..
Reply:watch out for the 1/7   /  1/10 rule , cutting with that puppy...
Reply:Originally Posted by cnyeco1I have read that you are not supposed to put Teflon tape on it so what do I do?
Reply:A little bit of oil on the threads would do no harm as long as this is on the acetylene gauge.  NEVER PUT OIL ON ANY PART OF THE OXYGEN SYSTEM CONNECTIONS/THREADS!You could try another gauge, could be a bad combination of tolerances.You could get a pipe die and turn the gauge into it a little farther.  I would hate to put a pipe tap into the gauge itself unless nothing else works.The advice on teflon tape and pipe dope are good, anything approved for gas fitting should be ok. Normally a brass to brass threaded fitting doesn't require sealing as the brass will deform enough to provide a good seal.Can't think of anything else offhand, let us know how it works out."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:Originally Posted by weldbeadwatch out for the 1/7   /  1/10 rule , cutting with that puppy...
Reply:Found it.  I read up on it. Sounds like what everyone is telling me about not setting the PSI above 5-6 pounds.
Reply:Weldbead was referring to the rule that the acetylene should not be drawn off at a rate faster than 1/7th the capacity of the tank per hour; if the cylinder holds 49 cu ft, then no more than 7 cu ft per hour should be used. I'd guess that the size of the cutting torch vs bottle size was what gave him the idea to mention that, since cutting can use quite a lot of gas, at least with the larger tips. The manufacturer's website should have tables of gas usage per tip size. Might be a good idea to print and post it somewhere in the shop or garage.
Reply:Is this really going to be a concern with this tank though.  From info I have gathered this tank only lasts about 30-40 minutes. It is used for carrying and doing a small job or two then back to have it refilled.  I also don't see how I could go wrong with using 5 psi.  The instructions say between 4-7 psi for cutting.  The tip is probably the one that came with it.  The number is 6290-1, I assume that is a #1 tip?  I'll have to look it up. Someone explain how I could use the gas too fast if the mixture is at the recommended setting, meaning the 5 PSI for Acetylene and 10-15 PSI Oxy? I am still reading all the instruction manual before firing this thing up, so I haven't seen this at all in the manual yet.  But I definitely want to know more. Thanks to all for chiming in here.
Reply:I am sure there is some relationship between the pressure set on the regulator and the flow rate, but it will change with other variables too, like the size of the tip. For example, if the torch acetylene valve is open all the way and no tip is in place, 5 psi. will allow a very fast flow. I don't know if you found the reason while reading between postings 7 and 8 here, but it's because the acetylene which the gas is dissolved in gets carried out with the gas if the flow is too great---lots has been written here and elsewhere about what that can lead to.I wouldn't be surprised if smaller cylinders like that one were even more affected by high gas flows, so maybe  a 1/9 rule would actually be better here. In any case, how long the cylinder lasts when used at reasonable flow rates is not the significant factor, except for the fact that it too depends on the cylinder size.Last edited by Oldiron2; 09-05-2010 at 04:34 PM.
Reply:you need to get the mfr's recomm endation  for the tip you are using. the recommended flow is designed to cool the tip..run it too low and it will backfire ..take too much  acetylene out oif that little tank and  it will entertain you by spitting liquid acetone...
Reply:Originally Posted by cnyeco1Is this really going to be a concern with this tank though.  From info I have gathered this tank only lasts about 30-40 minutes. It is used for carrying and doing a small job or two then back to have it refilled.  I also don't see how I could go wrong with using 5 psi.  The instructions say between 4-7 psi for cutting.  The tip is probably the one that came with it.  The number is 6290-1, I assume that is a #1 tip?  I'll have to look it up. Someone explain how I could use the gas too fast if the mixture is at the recommended setting, meaning the 5 PSI for Acetylene and 10-15 PSI Oxy? I am still reading all the instruction manual before firing this thing up, so I haven't seen this at all in the manual yet.  But I definitely want to know more. Thanks to all for chiming in here.
Reply:It's only a quarter turn away from home.Seems like pipe thread will always go another quarter turn. Is it bottoming? Not jamming fine and coarse thread is it?Harris was into fine thread.Or was it Victor?But maybe not on gauges anyway.  I can't remember for sure.If it's loose when backed up, and not bottomed, it should go another quarter forward.Good Luck-----------------------------------------------------I have a little kit like that. Although for fuel I use propane in disposable cylinders.It fits in a suitcase and can flop around without much worry.It'll do some serious heating and heavy cuts too; like 2" plus cuts.By making every second of burn time count, the set will do a fair amount of emergency work before time's up.Good LuckLast edited by denrep; 09-05-2010 at 10:15 PM.
Reply:It is bottomed out. I absolutely cannot turn it any more. When I back it up a half a turn so it faces out, it is loose. I believe it is fine thread.
Reply:By "bottomed out" I mean that the bottom (or the wrench flat) of the gauge's threaded fitting is physically hitting bottom with the regulator - it shouldn't bottom. For tapered threads to seal, it's the interference between inside and outside  threads which must cause the fitting to tighten - not bottoming.It would be very unusual for small brass NPT to not "give" another quarter turn; that's why I suspect some other trouble.The fine thread I described is very fine and I believe proprietary, a standard NPT gauge would not thread into the fine thread properly. As I rethink that, I don't believe fine was used on regulator gauges, only on the stems.You could start by pulling the gauge and checking for evidence of bottoming. Or if you know for sure that it's bottoming, the replacement gauge's thread type and length needs to be carefully compared to original.Good LuckLast edited by denrep; 09-06-2010 at 12:02 AM.
Reply:I have seen fine threads on the stems which have the cylinder connections, but don't recall seeing anything other than standard pipe threads for the gauge fittings;  I must agree with Denrep's last reply.The best suggestion I can give is to either take it to a good LWS, if any are nearby and they work on such things (not likely) or PM "OA Doctor" and perhaps send it to him. Without seeing exactly what the problem is, I don't know what I'd do to fix it and also assume you don't have the tools to do what I might be able to do.[I started this before Denrep replied, but was called away to open a car door; I have posted an edited version]
Reply:Here is the old gauge.  The new one is exactly like it.  It has a weird nipple on the bottom of the threads.  When I put the new gauge on I used a good size crescent wrench to tighten it.  So I know it won't go any further. The hole where the gauge goes into the regulator, there is what looks like a clear plastic seat in the bottom. I assume that is where the nipple on the gauge seats down onto. I guess I'll have to take the whole unit down to the welder repair shop where I bought the gauge and see if he can put it in right. Attached Images
Reply:Four or more wraps of tape will cause the thread to seal at least 1/2 turn sooner.  You don't need to tighten the Bee Jesus out of fittings when using tape or dope (I hate dope), just tighten it enough to seal.I've seen more threaded assemblies ruined by folks that tighten until they can't tighten anymore"Any day above ground is a good day"http://www.farmersamm.com/
Reply:BTW...........I used the same size setup when I started welding.  It worked ok.  I just got tired of having to refill the bottles every ten minutes  I traded up to big bottles, but I still wish, on occassion, that I still had the little portable rig."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Those don't appear to be dryseal threads at all???? Maybe needs a gasket or shim in the seat???Matt
Reply:Originally Posted by Matt_MaguireThose don't appear to be dryseal threads at all???? Maybe needs a gasket or shim in the seat???Matt
Reply:I still keep a little portable rig around my shop for small jobs and what not.   Its handy to be able to throw the tiny bottles in the back of my pickup to haul out to cut something stupid than it is to drive my service truck out there.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:It needs the proper fitting put over that fitting.I wouldn't worry too much about the advice given here.  If you are going to cut something with that set up - you will need at least 45 PSI on the oxygen side to do so, probably closer to 60 PSI...If it was propane I wouldn't worry too much - because it doesn't take a lot of gas.
Reply:When I replied earlier I assumed you had NPT tapered pipe threads,you don't, I have never seen a  welding gauge like this before..By the picture you have posted the gauge is not NPT pipe thread, the stem looks like it has a seat for a seal washer or O ring or something like that.  Never saw a welding gauge with that type of fitting.  On this type the seal will be made at the bottom, not along the threads which are straight and not tapered.  Is this some special type for very high pressure hydraulics, fuel injection or compressed gases?What does the hole in the regulator  look like?  Does it also have a corresponding seat to match the stem of the gauge?   Is the thread course or fine?Probably you need a seal washer, O ring or quad ring for this.  When it compresses you will be able to align the gauge with a small amount of adjustment.What model/brand of acetylene gauge is this anyway?"The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25Originally Posted by norite.When I replied earlier I assumed you had NPT tapered pipe threads,you don't, I have never seen a  welding gauge like this before..By the picture you have posted the gauge is not NPT pipe thread, the stem looks like it has a seat for a seal washer or O ring or something like that.  Never saw a welding gauge with that type of fitting.  On this type the seal will be made at the bottom, not along the threads which are straight and not tapered.  Is this some special type for very high pressure hydraulics, fuel injection or compressed gases?What does the hole in the regulator  look like?  Does it also have a corresponding seat to match the stem of the gauge?   Is the thread course or fine?Probably you need a seal washer, O ring or quad ring for this.  When it compresses you will be able to align the gauge with a small amount of adjustment.What model/brand of acetylene gauge is this anyway?
Reply:Originally Posted by Oldiron2Yes, this is a good example of where more descriptive information, particularly including pictures, in the first post, would have greatly simplified the situation. I know, I too am often in a hurry to get answers or get things done.....I think it highly likely that a flat polyethylene 'washer', similar to the type used under airless spray tips, is used below that gauge. Perhaps it's a Teflon material instead, so the same type can be used in the Oxygen regulator.  In any case, the shop that sold the regulator or gauge should know and have the correct part. I too am curious which brand the regulators are, and where they were made/imported from. The torch closely resembles the Harris design; just looks much newer than mine.