Fabricating a Radius Elbow

today i'm going to try and lay out a eight by six radius elbow with a five inch throat first of all we need to find the cut sizes and the cut sizes typically come from the working drawing here we are going to need a piece eight plus five plus a half plus a quarter let's go ahead and chop two pieces thirteen and three quarters by thirteen and three quarters required for both cheeks [Music] now that you have both pieces cut we are ready to scribe i am now doing the one inch working lines i'll now set the dividers to a half inch for the s and drives i am now using the steel square to scribe a quarter inch for the allowance on the male end of the pittsburgh okay let's add the duct dimension in this case eight inches i am now using the dividers to scribe the throat radius i'm now subtracting or adding 3 16 of an inch for the male end of the pittsburgh and i will be doing the same for the heel yes this there both cheek patterns are cut what's left to do is notch often we will stack the two patterns and notch both at the same times but for a beginner i recommend doing one at a time it's always good practice to mark the inside of the fitting with an x to identify a right and a left hand pattern now you see me going to the power flanger on top of the pittsburgh lock machine the main purpose of this flanger is to turn and 3 16 edge up 90 degrees i have two ways of doing it i can use the slot on the machine or simply use a pair of vice grips to turn a small edge i am now using the peewee tape to find the distance of the curve from working line to working line which is 9 5 eight nineteen and five eighths plus one inch and one inch for my connectors therefore i will need a piece 21 and 5 8 by 8 for the heel next i do the same for the throat i measure from working line to working line or the one inch line to the one inch line and you'll find that you get 7 and 1 16 plus your two inches for your connectors final cut size 9 and 1 16 by 8. this is the math that explains the 9 and 1 16 by 8. i will need one heel and one throat double check to make sure your calculations were correct then go ahead and scribe one inch pittsburgh's one inch working line same thing for the throat adjust your dividers to a half inch for the s and drive connector now they're ready to notch again once you get used to this you can stack your patterns and cut two corners at a time but for now this is fine i'm simply double checking my measurements my cheek is eight inches and the throat you can see that will finish six inches after running it through the machine i'm now going to the pittsburgh lock to form a female pocket so now that that's done my next step is to roll the heel and throat to the proper radius of the cheek you notice i have the cheek pattern there to give me an idea what to roll this in this case looks like i overrolled but don't panic it's light gauge metal and you can properly unroll it the throat needs to be rolled opposite to the heel often the books will say roll down for the throat and hold up for the heel again i like to [Music] overroll my throat i am now adding the drive cleat connector on the narrow side of the ductwork in this case the six inch side and i will do this four times two on the throat two on the heel again the drive cleats go towards the outside of the pittsburgh lock we will now get ready to assemble the elbow there you see i got six inches wide this is a tool that some people use to open up the pittsburgh lock i have always preferred to use my hammer once the pocket is completely opened we can begin by inserting the cheeks into these good practice is to tack the complete fitting before finishing their seams for elbows i prefer doing the heel throat and finishing off with the last cheek this little hand dolly is often used to prevent hammer marks all over your fitting [Music] our working drawing said that we wanted a five inch throat radius i have marked on the steel square five inches therefore if you notice we do have a five inch finished throat radius you

Channel: Duane Maillet

Views: 107,234

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Id: OW2Mk7tuaJQ

Length: 22min 14sec (1334 seconds)

Published: Mon Nov 16 2020