Drum vanes...

[The_Blacksmith]

Hey all!
New to site, first post and hoping for some help. I'm a retired sheet metal worker and should know the answer but I just cannot get my "mind's eye" to see the layout.

I've got a 8.625" I.D. piece of pipe, 9.625" long. I want to fab some vanes (3) 1" wide that run from one end (on the inside) to the other. So, they will run from one 60* point at one end of the pipe to the next 60* point clockwise to the other end of the pipe.

I just cannot see the layout. Radial line? Triangulation? Insight would be helpful. Need more info? Let me know.
Thanks.

[Brink, M.E.]

I'd pop an arbitrary center-line down the length of the pipe, then mark each end in 60 degree incriments. Your vanes would be running from 0-60, 120-180, and 240-300 correct?

[Warpspeed]

What is the material, sheet metal, or thick walled black pipe?

Because those vanes are going to need securing somehow, and it will need to be done from the outside of the pipe.
Probably requiring some holes to be drilled along lines where where those vanes go.
And then either pop rivets, plug welds, or whatever.

[The_Blacksmith]

I'd pop an arbitrary center-line down the length of the pipe, then mark each end in 60 degree incriments. Your vanes would be running from 0-60, 120-180, and 240-300 correct?

Yes, that is correct.

[The_Blacksmith]

What is the material, sheet metal, or thick walled black pipe?

Because those vanes are going to need securing somehow, and it will need to be done from the outside of the pipe.
Probably requiring some holes to be drilled along lines where where those vanes go.
And then either pop rivets, plug welds, or whatever.

Sorry, left that out. pipe and vanes: .125"

I will mig vanes on inside.

[The_Blacksmith]

I know that I can take some 1/8" X 1" flat stock and bend by trial & error but I'm stubborn enough that I'm at least wanting to "see" how it can be laid out.

[forhire]

If I was laying this out I'd mark the mid point of the tube, then run a straight edge down the tube on the desired angle and measure the distance from the tube to the bottom of the straight edge. You now can use a string to transfer the radius because you have three points on the arc. Once you have a template... start cutting.

Here's a render of the model I made to visualize the problem. After I drew it the layout solution above became clear. I'm showing the radius should be about 15". Hope this helps. :)

Do you mind if I ask what your making?

[riley mcmillan]

If I was laying this out I'd mark the mid point of the tube, then run a straight edge down the tube on the desired angle and measure the distance from the tube to the bottom of the straight edge. You now can use a string to transfer the radius because you have three points on the arc. Once you have a template... start cutting.

Here's a render of the model I made to visualize the problem. After I drew it the layout solution above became clear. I'm showing the radius should be about 15". Hope this helps. :)

Do you mind if I ask what your making?

I will add something to your solution. Divide the straight edge into ten equal spaces and measure down from each space and record the measurement, then plot onto the vane material these measurements and connect the dots and you have your template.

[The_Blacksmith]

If I was laying this out I'd mark the mid point of the tube, then run a straight edge down the tube on the desired angle and measure the distance from the tube to the bottom of the straight edge. You now can use a string to transfer the radius because you have three points on the arc. Once you have a template... start cutting.

Here's a render of the model I made to visualize the problem. After I drew it the layout solution above became clear. I'm showing the radius should be about 15". Hope this helps. :)

Do you mind if I ask what your making?

Thanks Forhire! That will get me in the ball park.

Don't mind at all... I am fabbing (for my on use) a 2-3 lb coffee roaster. This will be the drum part of it. The vanes will be to stir the beans as well as to exit them when I open the door.

[Warpspeed]

Haha,
When I replied to your question above, I misread it as eight inch pipe nine FEET long.
A second cup of coffee first thing in the morning makes a very big difference.
Cheers!

[The_Blacksmith]

Forhire,

15" radius did the job. I will post pics today, as soon as I weld it up.

[The_Blacksmith]

Here's two pics of the drum with vanes. The outer ones help push the beans towards the front of the drum. The inner ones help in rotating the beans towards the rear.

As I continue this project I will post in appropriate forum. Just wanted to post results of the help I received here.

Ooops, noticed I didn't rotate 2nd pic before uploading :o