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Sheet Metal Talk - Chinese Roof Jack/ Round Cone Roof Track

epdukes13 - Jul 06, 2004 - 05:32 PM
Post subject: Chinese Roof Jack/ Round Cone Roof Track

I’m taking the practical exam in New Mexico for the “Journeyman Sheet Metal” through Experior. Two of the fabrications to be made are;

1- Chinese Roof Jack

2-Round Cone Roof Track

Can any one explain what these are? I may know them through the trade lingo but not the exam name.

Bud - Jul 06, 2004 - 05:38 PM
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The first is more then likely the sane as the chinamans hat / cap I'll put up a drawing of it tonight. When is the exam?

Bud

I'm not sure on the other one, tell me more about it and I'll too get that drawing to you.

Bud - Jul 06, 2004 - 05:40 PM
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Will you tell us more on the exam? what are they expecting, so we can be of better help?

bud

epdukes13 - Jul 06, 2004 - 05:53 PM
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The exam is July 21.

The shop project is two hours, construct one of three fittings (chosen by numbers), one sheet of metal provided.

Fittings are;
1-Sq. Round

2- Round Cone Roof Track

3-Flat roof Jack w/Chinese cap @ 30degree pitch

Drawings are;

1- Elbow

2- Based on scale

Bud - Jul 06, 2004 - 06:27 PM
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I would take the Square to Round and the Flat roof Jack on 30 deg. (Correct me if I'm wrong, but the jack is on thirty degrees not the cap?)

marky - Jul 07, 2004 - 02:47 PM
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Is a conical roof track a cone shaped skirt that fits round a flue [chimney ]as it exits through the roof ?.This is just a guess .aw ra best marky

epdukes13 - Jul 07, 2004 - 03:25 PM
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I see I’m not the only one here ‘thrown for a loop!’

Bud, I have the same idea that it was the roof pitch rather than the cap.

Marky, these exam companies need to be out in the field for awhile! I call that a vent pipe roof flashing, but not sure if that is what they mean.

I called to talk to the person who grades the exams at Experior and they refer me to Contractors Licensing Services, Inc., and then they refer me back to Experior. So now you know what I’m going through.

EPDUKES13

Bud - Jul 07, 2004 - 10:42 PM
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I guess what we need to do is to get you to thoroughly understand triangulation and this will solve for any problem you come accross?

Click on printable practice problems on the "Shop Menu" and there are three different problems with square to round that will allow you to print and practice. I'll get the other ones together..what are your strong points in layout and what do you need help with? Knowing this we will be able to help you in a more timely fashion...

Bud

bowsmurf - Jul 13, 2004 - 05:09 AM
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it seems to me that a flat roof jack is a flat roof jack. the cone should be at a 30 degree angle to deflect the elements.

Triple - Jul 16, 2004 - 12:17 AM
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Bud wrote:

I would take the Square to Round and the Flat roof Jack on 30 deg. (Correct me if I'm wrong, but the jack is on thirty degrees not the cap?)

It's been awhile since looking at the layout book for the chinese cap, but if memory serves right, one of the layout parts is that the cap slope should be 30 degrees angle to the pipe it is covering.

Could be wrong who knows?

Bud - Jul 16, 2004 - 02:17 PM
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That makes sence to me as well, then we need to determine the cut out for the cap that when pulled together the cap becomes 30 degrees?

marky - Jul 16, 2004 - 02:55 PM
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What we really need here is a drawing ,because different countrys and even areas have different names for the same thing,what i call a chinamans hat was called a cooly hat when i worked down in england,so different areas different names ,who knows this exam board may have thrown us all a curved ball [in cricket thats a googlie .]and we all have the wrong answer or not . aw ra best Marky Embarassed

Bud - Jul 16, 2004 - 03:13 PM
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How to develop the conical section of the cap can be very easy at any angle. Draw the elevation of the cap at the desired angle shown as 1 to 2 to x being the apex [Dark Shaded Area]. The circumference of the cap would be the length of A to B as shown in red. The radius of the cap will be X to 1. The red section would be the actual cap. It does not allow for seams and edges. The rest of the chimney can ce developed as parallel line? The stretchout for the pipe is the circumference plus the seam.

Bud - Jul 16, 2004 - 03:40 PM
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Here is a link to more stuff that I had on and through site changes forgot to put back the link, it has a link to the Emerson ventilator

http://www.thesheetmetalshop.com/pn/ind ... ay&pid=121

Bud - Jul 17, 2004 - 03:04 PM
Post subject: An old Neubecker article I found

On Flaring Tops and caps, etc.

bordontn - Jul 18, 2004 - 12:30 AM
Post subject: an easy way....

Bud wrote:

How to develop the conical section of the cap can be very easy at any angle. Draw the elevation of the cap at the desired angle shown as 1 to 2 to x being the apex [Dark Shaded Area]. The circumference of the cap would be the length of A to B as shown in red. The radius of the cap will be X to 1. The red section would be the actual cap. It does not allow for seams and edges. The rest of the chimney can ce developed as parallel line? The stretchout for the pipe is the circumference plus the seam.

BUD...divide the base (1 to 2) by 7...set your dividers with that dimension...step off 22 times your circumferance line (a to b)..that will give you the circumference of your china mans cap...[/quote]

steve2 - Jul 18, 2004 - 02:15 PM
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Ah yes, the old 22/7ths trick. So, 22/7=3.1428=pi Verrry interesting....

Bud - Jul 18, 2004 - 02:42 PM
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I'm learning something new all the time. This is a constant learning (or relearning) experience, thats why I hang out here, this is what it's all about! Thank you for the knowledge you take time share:) Tips like this will help thousands. Priceless!

bordontn - Jul 20, 2004 - 03:44 AM
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chinaman cap/flat roof jack
bordontn

epdukes13 - Jul 22, 2004 - 11:23 PM
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I PASSED!

A thanks for everyone’s input. I ended up fabricating the ‘square to round’ fitting. I practiced every one of the ideas posted from you techs.
The ‘Round Cone Roof Track’ is the roof flashing for a vent pipe/stack.
The ‘Flat Roof Jack w/ Chinese Cap’, the cap is at a 30 degree pitch not the RJ.
You know I posted these same questions the web site ‘HVAC Talk’ w/ only two replies.

Thanks One More Time,
Bernie L. Gonzalez
Principal HVAC Technician
El Paso Electric Co.

Bud - Jul 23, 2004 - 02:36 AM
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Congratulations!

Thats because we want you to learn and have a good time doing it...it is the only reason this site exist. What happens when you tell them you learned how at Thesheetmetalshop.com...Yikes.

locklin - Feb 19, 2008 - 11:22 PM
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Could any of these patterns been rolled?

rothalion - Apr 05, 2008 - 12:32 AM
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Today I had to make a conical Chinese hat, as its sort of called here, at a 5/12 pitch. Basically a cone shaped roof jack 6" on the bottom and 4 on the top angled to accomodate a 5/12 ptch. Had to do it in a HURRY....not good! I used the process for laying out a cone with the top cut off at 70 degrees and simply moved that angle to the bottom of my layout and pulled true legnths from there. Its difficult to explain....but it worked. I plan to visit the library and find the proper method.

Speaking of rolling and cone hats....can you roll a cone hat in a slip roller. I think I sed to do it but do not recall how.

rothalion - Jun 11, 2008 - 04:10 AM
Post subject: 5/12 pitch china hat

I know I asked this before and I kinow I can't vist regularly but is there a short method to laying cones out on a pitch? I manage it but my method is ify and slow. I checked the libray vut I guess I missed the layout. I can't really make and keep a template since no two ever seem to be the same. Help please!

http://i10.photobucket.com/albums/a135/ ... inahat.jpg

martyg - Jun 12, 2008 - 03:37 AM
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theres a book called "the new tinsmiths helper and pattern book" the newest copy ive found is from the 1940's . ive got a lot of books but thats the one i go to most. they turn up on ebay from time to time i think i gave $20.00 deliverd for mine.

Bud - Jun 12, 2008 - 09:56 AM
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I put together some material that will be in the Cone using the Short Cut method July issue of Snips. Send me your email address and I'll send you a copy tonight for you to read.

This is one way, and it's a bit more accurate then rolling the pattern. Here are a couple of images that are included in the instructions.

Edited-
(Sorry - I missed the part where you mentioned that you can't make the template)

Bud - Jun 12, 2008 - 10:35 AM
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martyg wrote:

theres a book called "the new tinsmiths helper and pattern book" the newest copy ive found is from the 1940's . ive got a lot of books but thats the one i go to most. they turn up on ebay from time to time i think i gave $20.00 deliverd for mine.

I have this book - I'll see why it's not in the library? It should be.

rothalion - Jun 13, 2008 - 01:21 AM
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Thanks Bud!!!!