How to bend shallow pan...easy question for the experienced.

[slimline]

I'm trying to bend a U-shaped pan using a Tennsmith 48" finger brake (16 ga capacity). The pan side are 2" long and the bottom is 1.75". It's a very simple shape.

After the first bend I have an L shaped piece of metal (.063" AL). One side is 2" wide and the long side is 3.75" wide. When I try to bend the second side to for the "U" I can't get to 90 degrees becaus ethe first side hits the fingers on the brake. Since I'm working in fairly heavy material and the length of the pan is 24" it's difficult to bend the second side the final few degrees by hand.

Does anyone know the way around this problem? I'm open to suggestions...Scott

[Wray Schelin]

Hi Scott,

I make driveshaft tunnels which are U shapes, using my English wheel. You need a rubber top wheel set up to do it. The e-wheel with a rubber top wheel set up does the most accurate and best surface finish bends of that type.

Forming it on a Tennsmith box and pan brake might require you to do it in two pieces and expect it to be notchy.

A press brake with urethane tooling can make that shape and a radius brake can too. Both solutions are expensive and will require special tooling.

Looks like you need a English wheel if you don't have one already.
:D

Wray

[Dutch Comstock]

Scott,You can do a lot of tricks with your brake as you get more experience.The best way to do a test part is to use a 1 inch strip the correct length and practice different approaches untill you can get it to work.You have to figure out what is the best bend to do first and then # 2 and so forth.Sometimes you make the bend and then take some of the bend back out of it to get it to fit in the brake for the next bend and then that first bend will be easier to hand form back to where you want it to go a it has allready been there.A lot of the time you have to start in the middle and work back out both sides. Dutch

[thefabman]

Well with only 1 3/4" width I could not use my slip rolls witch i normally would for a shape like this, but I can only go down to 3" diameter. Since I have a wheel now i would use it like Wray said. With out the wheel at hand I would resort to doing it by hand. By forming it around a piece of 1 3/4" solid bar with a little heat and a hammer, take a little time but can be done. I have rolled 16 galv steel on a 2" radius this same way.

Scott

[awolff]

Wray,how tight can you make the radius of a tunnel that way?

[Nortonscustom]

Scott,
When I run into problems like that, what I do is lay a piece of angle iron or flat stock into the U-shape and clamp it down tight to my welding table. Then take a piece of wood and a big hammer and slowly hammer it the rest of the way. If you start at one side and work your way across it goes pretty easy.

norton

[Wray Schelin]

Wray,how tight can you make the radius of a tunnel that way?

Hi Al,

The driveshaft tunnels that I make are tapered with a 5" distance between the legs in the rear and about 3.5" wide in the front.

I have never tried to do tighter a radius but it can be done. You lay out the bend zone and start forming by going back in forth under the rubber. I use a series of rubber top wheels ( 4 in all) that start at flat and then they have a progressively concave working surface to them.

I also use a series of true radius lower wheels. The trick is to do the sides first and then do the center section allowing the sides to come down over the yoke. I have a special narrow yoke also.

These are accesories that you add to your English wheel to increase it's frorming and shaping potential.

If you run the panel in the rubber wheel you will train it to want to bend like you want it too. So if you get it started and then have inadequate tooling to finish it , you can finish it on a bench in the manner John described. It will go easier though .

Wray

[slimline]

Thanks for the quick and informative responses. I've used the technique before where I take some of the original bend out and then form the second bend. After that the original (first) bend can be more easily pushed back into shape by hand.

I'll try this technique and the angle iron and workbench approach since I only have about 8-10 degrees to complete on the second bend.

This is definitely a job for a brake press but that is out of my league - at least something big enough to handle a piece 24" long. I'd like to get an english wheel in the shop but haven't hand time to identify a good one and make room for it - I have some floor space but bench space is at a premium.

Thanks again and great forum!
Scott

[Peter Miles]

Previously, on "This Old MetalMeet", Wray said:
The driveshaft tunnels that I make are tapered with a 5" distance between the legs in the rear and about 3.5" wide in the front.

That 3.5" number makes me wonder about your tool clearances.

Are you using a special narrow lower anvil yoke for this operation, and are you wheeling in the 'normal' direction or 'into' the throat towards the column on this operation?

If your tunnel is more than a couple of inches tall, this would seem to be an operation where a 3"-wide anvil's yoke (let alone anything wider) might not fit, and where one might want a tall, vertical lower post despite rigidity issues.

[Wray Schelin]

Hi Peter,

I guess you missed this sentence in my previous post. :D

I have a special narrow yoke also.

You must have also missed the rubber wheel seminar I gave at MM03 :D

see pictures:

http://www.metalmeet.com/photopost/data/520/8Tunnel_Demo_1.JPG


http://www.metalmeet.com/photopost/data/520/medium/8Tunnel_Demo_2.JPG



http://www.metalmeet.com/photopost/data/520/medium/8tunnel_Demo_3.JPG


http://www.metalmeet.com/photopost/data/520/8Tunnel_Demo_4.JPG
Here is a picture of my skinny yoke. Remember you do the curve on the legs first then finish the center region. The key is working the metal , once you start to bend it it wants to bend where you told it to.


http://www.metalmeet.com/photopost/data/3001/medium/4wheels3.JPG

Wray

[awolff]

Wray, thank you, a picture is truly worth...........

[slimline]

Looking at Wrays photos brings-up a couple new questions...not related to the origin of this thread...

I need ot fabricate some aluminum tanks that will have a flat back but the front needs to be elliptical shaped. That is, looking at the top or bottom of the tanks, they will have a "D" shape where the curved portion is not really round but elliptical. The height wil be about 48" and width is about 12". Material will be .040 AL, probably 5052.

It appears as thoug Wray formed a very similar shape using only an English wheel - is this correct?

I've been looking for a good project to put an English wheel in the shop. Does anyone have recommendations on brand or where to find a high quality floor standing (preferable) wheel? I'm familiar with Irvan, Tinma and, of course, Eastwood. Cost isn't a huge issue although I'd like to keep it under $3-4K
Thanks,
Scott

[Peter Miles]

Thanks for the pictures, Wray.

Yup, I missed your previous comment.

And, yes, unfortunately I missed the first half of your rubber wheel seminar at MM03 :( It was another one of those situations where it hadn't been previously announced or posted, so I wasn't aware it was occurring until I walked in on it partway through it. Addressing the advance scheduling and posting of events is, in my opinion, the most valuable organizational improvement we can make for MM04. :D :D

That vertical post seems sized very well for that size yoke. Is that the standard vertical post for that eWheel or is it only used for that narrow yoke?

Thanks for the clarifications!

[fordguyfordman]

There is another option,all depending on how visable the part is.
I run various hydralic power brakes and there are times we have that same problem.Our solution normally is to use a false bend if the part is hidden in that area.
A false bend is simply a bend down the mid point between the 2 sides that are the problem. We only bring it up enough to held clear the final bend from hitting.
After the part is finished you simply flatten the false bend. That may be the only problem area for you thou,it can leave a line from forming.
Hope it helps,
Tom

[Boogiemanz1]

Look at one of Kerry Pinkerton's Imperial wheeling machines. Probably the stoutest on the market, and that shape can also be made using a go-kart slick and wooden anvils...check the forum or contact Kerry at http://wheelingmachines.com/

He can explain the machine and the go-kart slick! Probably won't be home until friday...........john