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dcygan 03-13-2018 08:19 AM

B-Post / Rear Door Jamb forming
 
3 Attachment(s)
I hate to say it, but I'm stumped on how to best fabricate a set of rear door jambs for a vintage BMW. I want to be able to reproduce them for other cars and so I'm looking for consistency and quality in each part. I have made one set by making small components and then tig-welding them together (see attached photos), but I'd rather try and make them from one piece of sheet metal. The originals are 0.035"-20 gauge steel. The complexity is in the double stepped flange that tapers and joins as one at both the top and bottom. The door jambs have a subtle arc before making a tight curve at the bottom forming a "J".

I have tried using my bead roller with an angled die on top and a flat die on the bottom to allow me to make the stepped flanges, but it causes a lot of distortion that needs constant attention. I have not yet made dies for my Pullmax types machines yet because I'm not sure if that's the best method since the stepped flanges all taper to nothing on both ends. Plus the top portion of the door jamb panel has a tight bend in the stepped flanges.

I'm now in the process of making a set of hammerforms, which seems simple enough, but they're not due to the arc and forming the stepped tapered flanges at the bottom.

If anyone has made any parts with similar tapered stepped flanges and can provide any guidance, I'd greatly appreciate your input.

Attachment 45997

Attachment 45998

Attachment 45999

Peter Tommasini 03-14-2018 06:40 AM

Douglas there is a few ways to make that panel depends on how original you want it to look?
That panel has 3 surfaces all step out.
you can use a solid piece of ally and machined it to the last face shape with the same thickness and taped shape
and fabricate the panel with the second face, or make the panel only with the first face and machine the rest, then using counter sunk screws you can screw all together
in another words fabricate the panel with one or two steps and screw the rest on it. to make the screws invisible simply counter sunk the screws down enough, then lead load the remaining holes dept....Yes you can lead load ally:D
In order to make that panel from a sheet of ally with all those taped swages it's a lot of work, .... there is a need of a lot of pre stretching and at the end of the day it might not come out right.... UNLESS.. you have a proper expensive former like the factory had back in those days

PS I have done many door shut faces as I suggested above...the like of Lancia fulvia / flavia and some alfa as well, once painted they look original

crystallographic 03-14-2018 03:22 PM

Quote:

Originally Posted by dcygan (Post 144550)
I hate to say it, but I'm stumped on how to best fabricate a set of rear door jambs for a vintage BMW. I want to be able to reproduce them for other cars and so I'm looking for consistency and quality in each part. I have made one set by making small components and then tig-welding them together (see attached photos), but I'd rather try and make them from one piece of sheet metal. The originals are 0.035"-20 gauge steel. The complexity is in the double stepped flange that tapers and joins as one at both the top and bottom. The door jambs have a subtle arc before making a tight curve at the bottom forming a "J".

I have tried using my bead roller with an angled die on top and a flat die on the bottom to allow me to make the stepped flanges, but it causes a lot of distortion that needs constant attention. I have not yet made dies for my Pullmax types machines yet because I'm not sure if that's the best method since the stepped flanges all taper to nothing on both ends. Plus the top portion of the door jamb panel has a tight bend in the stepped flanges.

I'm now in the process of making a set of hammerforms, which seems simple enough, but they're not due to the arc and forming the stepped tapered flanges at the bottom.

If anyone has made any parts with similar tapered stepped flanges and can provide any guidance, I'd greatly appreciate your input.

Attachment 45997

Attachment 45998

Attachment 45999

You can make this as you see it, but by looking at the back side you can see more of how it was made - pieced and welded, maybe?

Forming the base piece with a form block is a good way. Then adding the face pieces by forming them in another set of blocks and then soldering them on. Many ways to skin a catfish - or to make metal parts.

neilb 03-14-2018 09:30 PM

i would make a pair of dies and see what i could get by pressing the part. i got a 10mm raise using a home made press and dies for my door bottoms, but mine were not a vertical raise they had a taper to them. but as peter said its a lot of work

what have you got to loose by trying?

John Buchtenkirch 03-14-2018 11:58 PM

You might consider trying something like what I did some years ago http://allmetalshaping.com/showthread.php?t=406&highlight=cent+dies<O:p</O:p
with just scrap plywood. Or if you need to make a short run of these parts the next and likely needed upgrade would be the right thickness of scrap aluminum with metal guide pins. Actually the part you have looks to be low production or patched by someone, certainly not something from expensive high production dies IMO. ~ John Buchtenkirch<O:p</O:p

neilb 03-15-2018 06:10 AM

hey douglas,

this was the quick press i made to do the door bottoms...

http://allmetalshaping.com/showthrea...=11485&page=10

may give you some ideas, maybe try mixing ideas from john's post too? steel faced dies with a hardwood backing maybe?

greenfield 03-16-2018 06:51 PM

Evening Douglas,
Hopefully I wont screw you up or confuse the points I am trying to get across, since some one the heavyweights have chimed in the topic and dont wont to be the fool....I am however the comic relief.

Work the section with the tools you have readily available, we know you have a pullmax, a bead roller and hopefully a brake. I think a hammerform for this is a waste of time since you stated you wanted to make multiple sets hence the need making one from tool steel (I could be off base on this one). And I dont think stamping it will work in your favor since the radius will pull first and stretch the middle too thin.

If you break it down into 4 parts, the step, the flat and the 2 buttes (these also have a separate U shape formed flat) fabbing the two buttes is just really making two upside down pans, bend the straight 90' on the brake and the curved section can be tipped and then brought 90'. you can Shrink-stretch the 90' flange to get the desired radius at top and bottom, then just trim the flange to fit the flats radius.

The flat looks like it has a .062 step on the rear portion that can be beaded in. The front flange can be tipped and then hammer into 90'. Then that can be Shrink-stretch to the radius needed and trimmed to fit. and tucking the hard belt line reverses and radius. The hardest part is the cutouts this would need underneath of the buttes.

The step would just be a 90' angle bend, Shrink-stretch to desired shape to fit the flats shape.

Tack weld all together and solder all intersections from the backside if you can solder well if not a good solderer, all the intersection should be open corners on the backside to weld up easy enough.

Hope I made sense and you should be able to make this out of a single piece of metal. A 48 x 96" sheet of metal.....

dcygan 03-17-2018 07:45 AM

I want to thank al lof you for your input and guidance and I am working toward making progress utilizing recommendations that all of you have provided. I will post photos as I progress.

I wish I could respond to each and every one of you individually, but I haven't figured out how to other than replying to all.

Doug

dcygan 03-22-2018 05:18 PM

1 Attachment(s)
I decided to make solid hard wood hammerforms to create these door jamb / shut faces. The first one is finished, which is for the right side and I started the left side earlier today. They are carved out of solid Hard Maple and the thinnest section is 1.25" thick, which is where the outer / lowest stepped flanges are. The center section is 2" thick. This all should hopefully ensure they produce perfect parts without warping or breaking.

Attachment 46201

neilb 03-23-2018 03:37 AM

looking good douglas, it'll be interesting to see how you get on.

i don't think i would have routed out the centre 'hole' which is cut out any way. but we shall see what comes of it, we maybe surprised :)


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