I need suggestions on how to machine this item

B

blibecap

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I need to manufacture five dome shades. Dame shades are used in photography to protect the dome from accidental damage and also shield some of the light from the dome. The shades are basically tube about 8.5" ID 9" OD and have a scallop on the top edge that runs from .75" tall to 4.5" tall. The item is made from .25" 6061 aluminum sheet that has been rolled into a circle. I need suggestions as how to cut the scallop after the aluminum has been rolled. The person rolling the aluminum said he could not roll it properly if I cut it out beforehand. I am also not opposed to making it in sections and having it welded together. Please see the attached drawing.

I have available the standard hand tools and a band saw, lathe, mill, router grinder etc.

Bill Libecap
Cincinnati, Ohio USA

8 inch Dome shade-Model.jpg shadeJPG.jpg
 
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How accurate does the profile need to be? That seems pretty tricky to do, especially if you can't cut before hand. I guess if it doesn't have to be too accurate, you could print out a paper copy of the pattern, then wrap it around the rolled piece, then use a saber saw to cut out the profile, sanding/filing to the line. If you have access to a plasma cutter (and a steady hand) it would probably go faster.
 
It doesn't have to be too accurate as it's job is to provide shade and some protection to the dome. I do have to make 5 of these tho.
 
I'm with DMS on this one - sabre saw or maybe a Sawzall. Aluminum is soft enough that a sabre saw should be able to handle the job.
 
What is a 5 shades? Or are you making a light shade? If not What is it used for?

Has anyone ever made something like this before? Have a picture of what your talking about?

Scallops...please explain again what this is? I have been in mfg. for years and what your asking for is a bit confusing to me and I bet if you explained it a bit more, people could help more.
 
Richard King said:
What is a 5 shades? Or are you making a light shade? If not What is it used for?

Has anyone ever made something like this before? Have a picture of what your talking about?

Scallops...please explain again what this is? I have been in mfg. for years and what your asking for is a bit confusing to me and I bet if you explained it a bit more, people could help more.
Click to expand...


Ok Thanks

I revised the description and added a picture. Scallop - Carved in a series of semi-circles.
 
You might consider cutting the scallops on either side of a piece of plate then have it rolled and cutting it in half after it rolled, this is assuming the rolling problem stems from the piece being too narrow.

Why .250 thick?

The scallops could be cut with a plasma cutter as well.

Bob
 
sniggler said:
You might consider cutting the scallops on either side of a piece of plate then have it rolled and cutting it in half after it rolled, this is assuming the rolling problem stems from the piece being too narrow.

Why .250 thick?

The scallops could be cut with a plasma cutter as well.

Bob
Click to expand...

The dome wants to float so the aluminum will help holding it down. Thanks for the idea bob.
 
Tight tolerance: program the involute as a cilindrical cam.
low tolerance, buy aluminum pipe, draw the profile of scallops, saw them with jewlerer saw. If made from sheet, use a longer size to cut profile, roll, weld and then cut to height.
 
I have a convoluted idea,
cut the piece longer than you need it by say an inch, lay out the profile you want to cut, extra material at each end. Next cut your profile, but start your cut in a drilled hole so that both pieces remain attached to each other. Then have your piece rolled. The ends will overlap until you cut away the excess, but afterwards it should be perfect. As for the cutting? if you don't have a bandsaw, or the means to weld a blade inside your start hole, I guess I would use my powered Ryoba scroll saw.
It does seem to me that 1/4 inch will not be so easy to bend to such a tight radius.
It's also possible that the person who is going to roll your finished parts underestimates his ability to roll them after they've already received their profile. You should try and get him to roll one already profiled and see how well it turns out.
Levi
 
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