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LeadHead 06-28-2006 08:54 PM

Educate me about TDF/TDC
What does TDF and TDC stand for? What is the difference between TDF and TDC?

tinman9765 06-28-2006 10:05 PM

TDC = transverse duct connections. basically they are conner pieces that go into a groove that is formed into the ductwork.

TDF transverse Duct flanges, basicaly "f" corners. They are nicer to use, and snap into place. Unlike Tdc, the normally do no need to be crimped like "c" corners.

Both type of corners have bolt holes, and two pieces of duct are bolted, and clips installed (usally 6" long, about 6" apart). I myself, pefere TDF, just nicer to work with.

I may suggest finding information on a product called Ductmate 35, which makes an awesome flange that screws onto the duct if a machine is not avaiable.

any question, ask, I hope this is clear. It maybe one of those have to see to understand?

LeadHead 06-29-2006 04:52 AM

Thanks tinman9765. Thats very helpful. I've been using Ductmate for a while now. You're right. It is some good stuff.

JCrosby 06-30-2006 11:00 AM

If you are doing contract work from an engineers design be sure that TDC or TDF is approved by them. Often they will spec out additional stiffeners because neither connection offers the strength of a Ductmate connection.

benn 03-07-2007 09:47 AM

Does anyone has the drawings with measurement on both TDF and TDC?

There is another standard I have encountered, TFD. Please advise, thanks

legacy 03-07-2007 12:51 PM

TDC and TDF are both recognized in the SMACNA manual (T-24 and T-25), you can find the recommended stiffeners and spacing in the duct construction manual.

I believe that while Ductmate, MEZ, WDCI, and Nexus are recognized by SMACNA, they are all considered proprietary, and therefore SMACNA can not dictate standards for each (due to the fact that each has its own characteristics).

It is hard to avoid the use of some ductmate type flange even when you are making TDC/F duct. Field trimmed pieces and square top rounds will still require its use.

jm413 03-07-2007 07:30 PM

i believe another differnce is that the lockformer tdc ends up having somewhat of a raw edge where the engel tdf does not. if u look up pictures online u will see what i mean

legacy 03-08-2007 05:52 AM


You are correct, the TDF has a hem IN while the TDC has a hem rolled OUT. This leaves a nasty little raw edge.

tryduck 07-19-2007 05:57 PM

I just have a very simple Question which relates to this , I am looking for a Good Cleat tool , meaning the one that installs the clip/clips on the seems of TDC duct so you dont have to zip screw the seems ( which strip out very easy if your not careful), I have called several HVAC places here in PA but these people act dumb founded , and have no clue as to what I am talking about , I even stopped by a few Local HVAC installers here and asked , they hadnt a clue , even asked where they purchased their tools from and their tool suppliers do not know what I am looking for even after telling they what it does. I have been wanting to replace my very worn/used one. I have had to weld it back together and after 5 years it is about useless , heck after the second tdc duct job it was this way . I feel sure others have had to weld theirs and have had the other open end strech.Heck I would settle for one like this only new but would like to get one that is of a heavier duty if I could. I really hope that someone knows what I am talk about , I dont care at this point on prices , but I sure would buy a few if I could find out where to get them. Thanks

07-19-2007 06:25 PM or call charlie at north machinery a call. Your not going to get this unless you go to a machiney dealer.

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