Acetylene Withdraw Question

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New to the forum so I ask for patience if this is a stupid question.I have inherited my grandfather's OA setup which includes MECO regulators and a MECO Weldmaster torch.  The acetylene tank was "like" a size B (40 cf) which I just exchanged for a full B bottle at the welding shop.  The old tank was very unusual as it seemed like it had a round plate bolted to the top with a valve attached.  They charged me a fee for having to test my old tank since it hadn't been done in 50 years or so.  I think this rig dates to the '50s.  The oxygen tank is 37" tall measured from the bottom to the top of the valve.  I don't know if that's a standard size anymore or not since I couldn't match it up with charts on the Internet.  I'm guessing it's a 80 cf.My question is regarding the 1/7 withdraw rate for acetylene.  I have a cutting tip for the MECO cutting head.  It's labeled "MECO L-1 STYLE A".  There is what looks to be a small half-circle which may be a poorly stamped "0" but I'm not sure.Would it be correct to say I must determine the flow rate of this tip in relation to my pressure to insure I am not exceeding the 1/7 rule?If so, how would I go about doing that? I've searched the Internet and haven't found anything definite about this tip or flow rates.I took gas welding in high school and there was never any mention of acetylene withdraw rates believe it or not. I'm wondering if this B tank is too small for cutting or rosebud.  I've been using it that way for a while and just didn't know any better.Thanks for any input or suggestions.
Reply:The manufacturer of the torch should publish the flow rate at the recommended pressure. That flow rate will be in standard cubic feet per hour (SCFH) most likely. divide your bottle size by 7 (40/7=5.7 ) as long as the published flow rate is less than 5.7, you should be all setMiller Multimatic 255
Reply:Every rosebud I've ever seen listed exceeds the 1/7th rule even with my 75 cf cylinders. Even using the smallest one, I limit myself to only using it for a few minutes to try and stay under the withdrawal rate. I wouldn't even try one with a B size.You may have to dig thru a few different references to get the info you need as I couldn't find a readily available chart. You might have to locate a tip chart comparing say Victor tips to your Meco tips. To do this you might have to use the drill size of the welding tip to locate the closest size to what you have, then use a more readily available chart for flow. The only chart I could locate quickly for MECO was for the tiny Miget torches. Same goes for replacement tips. Looks like your cutting tip is an LA style from the Goss chart I located.http://www.google.com/url?sa=t&rct=j...68445247,d.aWw.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:bigk'Spam' gravy ain't wavy?Ask a singular question.Opus
Reply:You might find that that best way to go is to switch the rig to propane.   Especially if you want to use a rosebud or cut anything beyond thin metal.
Reply:Thanks for the replies.  I use this OA for very brief heating and cutting and only occasionally.  If I ever need to do big cutting or heating I think I'll have the welding shop help me select a propane regulator and tips (if they even have a propane cutting tip for this old Meco).  Of course I'll have to learn to cut with propane first.
Reply:Originally Posted by k45You might find that that best way to go is to switch the rig to propane.   Especially if you want to use a rosebud or cut anything beyond thin metal.