dumb question, making a snaplock 90 into a 45

[Jim Andrew]

I need to make a 10" offset in my 8" exhaust, and thought I would just twist each snaplock elbow into a 45, and it is not working. Is there a secret to making this happen?

[Ole Anderson]

When I was doing my dust collection system, Oneida sent me a 4 meg .pdf file called "Ductwork Resource Kit". It has tips how to rotate a 90 and keep it straight while reducing the angle of deflection. It is a great resource for all things related to shop dust collection, particularly duct layout and flow needs of various equipment. Being 4 megs, I can't post it as an attachment. Any ideas how to make it available here on the Creek? MAYBE AN ADMINISTRATOR can make an exception and post it as a sticky in the Workshop forum? I think everyone would agree that it is an exceptional resource once you see it.

[David L Morse]

This (https://www.youtube.com/watch?v=cYO47IqF1zI) might help.

[Marty Schlosser]

Jim,

I had to do this with virtually all the DC ducting arrangements I've had in my three last shops, and found it to be relatively straight-forward. I've enclosed one photo that shows a few 90 degree elbows I've turned into 45 degree elbows. In most cases I then put two of these 45's together to create a gently-sweeping 90 degree elbow.

One thing I've noticed that I was never able to acheive a "flat" 90 elbow this way, as all of the 45's have a slight bit of a twist to them. They're very close to 45 degrees and when two of them are brought together, the resultant 90 degree isn't exactly 90... but they're close. In practice I don't think these inconsistencies matter, thought, so I've simply accepted them for what they are. Life in the shop is seldom a perfect thing!


331841

[David L Morse]

Here's (https://www.youtube.com/watch?v=hoaSWx60rMI)a better video than the one I posted earlier.

[Frank Pratt]

If the elbow has 4 sections with 3 seams then you can't get a flat 45. You can only get 90, 60, or 20 degrees. Any angle between will introduce a little bit of twist, which is mostly just cosmetic.

[Jim Andrew]

Last night, I just could not get the angles adjusted correctly, but today I tried again and got it connected up. Had to drop 10 1/2" to get below the header around the perimeter of the building. Turned one elbow to about 45 then added a short piece of pipe, then the other about 45, and the piece going to the edge of the building is just about level. Not perfect, but almost level.