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Aluminum fan shroud

Posted: Fri Nov 29, 2013 5:24 pm
by Metalman
Thought the sheet metal section could use some input.
Needed a fan shroud for the table feed motor on the Bridgeport (old type), so I made one from .063 aluminum. I used a process know as hammer forming over a hard wood form. The rim of the blank is gradually shrunk down over the form to make the vented end and the return is welded on.

Re: Aluminum fan shroud

Posted: Fri Nov 29, 2013 5:29 pm
by Metalman
And here it is installed on the motor.

Re: Aluminum fan shroud

Posted: Sat Nov 30, 2013 1:05 am
by Harold_V
Beautiful job! Thanks for sharing.

Harold

Re: Aluminum fan shroud

Posted: Sat Nov 30, 2013 12:46 pm
by Metalman
Thank you Harold.
The fan shroud was the finishing touch on the project of getting that old power feed system working.
I fabricated the missing parts with aid of photos you provided me 6 years ago! Better late than never.
The photos were of the center stop bracket with which the stop rod passes. Your photos:

Re: Aluminum fan shroud

Posted: Sat Nov 30, 2013 1:05 pm
by Metalman
Here are some photos of the parts I had to make. Also Had to make one of the sliding clamp stops that go directly on the rod.
I suspect the roll pins you see on the rod were not original and added by a previous owner?

Re: Aluminum fan shroud

Posted: Sat Nov 30, 2013 4:22 pm
by warmstrong1955
Your fan shroud shows some real craftsmanship!

I'm curious....what kind of hammer do you use?
(I'm assuming you use a hammer...similar tobody & fender work)

?
Bill

Re: Aluminum fan shroud

Posted: Sat Nov 30, 2013 4:38 pm
by Harold_V
Metalman wrote:I suspect the roll pins you see on the rod were not original and added by a previous owner?
The roll pins are factory installed. They ensure that you can't set the stops such that you can damage the unit by running beyond it's travel.

Harold

Re: Aluminum fan shroud

Posted: Sat Nov 30, 2013 4:51 pm
by Metalman
warmstrong1955 wrote:Your fan shroud shows some real craftsmanship!

I'm curious....what kind of hammer do you use?
(I'm assuming you use a hammer...similar tobody & fender work)

?
Bill
Despite the name "hammer form" the metal is worked with a hardwood stake, picture about 1/2" X 3/4" X 6" depending on the size of the work, starting from the backup block out. The metal needs to shrink as it is worked around an outside radius. I have also used forms made from metal, hard plastic as well as hard wood and in any case the wood stake prevents stretching (and marring) the metal.
The opposite is true if the form is an inside radius, the metal needs to stretch. On that I sand an appropriate crown on the business end of the stake. The stakes get beat up from the hammering and need to be refreshed or replaced but come from scrap so no big deal.
This works for steel sheet also I have formed up to 16 gauge. I think thicker steel sheet would be a bear.

Re: Aluminum fan shroud

Posted: Sat Nov 30, 2013 4:59 pm
by Metalman
Harold_V wrote: The roll pins are factory installed. They ensure that you can't set the stops such that you can damage the unit by running beyond it's travel.
Harold
Got it. Just seems like they could have been placed to allow more safe travel (a bit wider) but likely done on the side of caution.
It has not been and is likely not going to be an issue. I replaced them as is and that is where they will stay.

Re: Aluminum fan shroud

Posted: Sat Nov 30, 2013 5:02 pm
by ken572
Ernie, :D

Beautiful Workmanship on the Fan Shroud,

as well as your replacement Center Stop Bracket

which also turned out Very Cool.. 8)

Ken. :)