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Author: Subject: Aluminum scuttle (again)
C10CoryM

posted on 28/12/09 at 05:45 AM Reply With Quote
Aluminum scuttle (again)

Hey guys,

Some time ago I asked about making an aluminum scuttle and got some good help. Now it's time to actually design and build the thing and I would like some more .

Firstly, I need to make a flange in the front of the scuttle so that the hood will sit on it, and be flush. What is the best way of doing this? I was playing around with a flange tool used for lapping panels and it seemed to work well even on the curves. Only thing is it only gives about a 1/2" flange and it's not very deep.

I have access to a big english wheel (which I could buy some roller bearings for and make a "joggling tool out of), a tig welder, a shrinking tool and a stretching tool. Thing is I have never used any of those tools

Will I be able to flange the front before/after bending the curve? Or am I better off learning how to TIG weld and just welding a flange on? Or is it time I get the resin and kevlar/carbon fibre out and make the scuttle of that?

I have some other questions I would like some input on, but I will take some pictures tommorow to explain what I mean. Cant decide the best way to do my panelling under/to the scuttle.


Thanks for any help.
Cory





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907

posted on 28/12/09 at 10:56 AM Reply With Quote
Hi.

I can think of three ways to make a scuttle.
1. Develop, or copy from another car, the shape on paper and cut the ally to the paper template.

2. Make a metal frame to knock the ally over that may or may not become part of the structure.
Form ally over frame and cut ally to suit.

3. Make dash and bulkhead plywood formers and screw to cross members to make a frame to knock the ally over.
Cut ally to suit as you go.
The dash former could even be used as the dash if covered with foam and vinyl.

I don't like the idea of welding due to distortion otherwise this would be number 4.


I wanted my scuttle to be removable so I did number 2. My column has a joint and all the wiring has multi pin plugs.
The only other connections are water heater, oil pressure pipe and speedo cable.
The whole thing lifts off, steering wheel and all.


I did have a problem on the top corners, (125 rad) as 25mm is too much to knock over so I cut a bit out
with an air nibbler to reduce the flange width. (see pic)
I used a length of ally angle for the bonnet seal support and stuck 6mm foam rubber on it.
This covers the rough nibbled corners up.

I now have a shrinker which I bought to make my rear arches (see pic) so if I were to make another
I would use that on the scuttle corners.


If I can be of any more help feel free to ask.

Cheers
Paul G


[Edited on 28/12/09 by 907] Rescued attachment scuttle pm.jpg
Rescued attachment scuttle pm.jpg

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trextr7monkey

posted on 28/12/09 at 12:24 PM Reply With Quote
Good to see some high quality sheet metal work, well impressed!
atb
Mike





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907

posted on 28/12/09 at 02:16 PM Reply With Quote
Thanks Mike.


I too was impressed with the way it turned out; but then again, I'm very easily impressed.

Cheers
Paul G

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RK

posted on 28/12/09 at 02:26 PM Reply With Quote
Paul, you're a barsteward. That looks too good to be on this forum! VERY nice!
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C10CoryM

posted on 29/12/09 at 02:21 AM Reply With Quote
Thanks Paul.

I think I will just use the shrinker and make an aluminum scuttle with no frame for now. I am going to run this summer (hopefully) without a windshield etc. The only thing the scuttle will support now is itself, a wind deflector and some mirrors. When I add a windshield and wipers I may have to make a new one.

I was hoping to have a flange like the one attached for the hood to sit on, but I doubt I would be able to bend the scuttle with it. I think I will use the shrinker and make front and rear like the rear of yours, and rivet on a flange to support the hood.

I think I figured out the panelling for now too. Going to try to pick some aluminum up tommorow and play. What thickness/type would you recommend? Do you anneal?
Cheers.
Cory Rescued attachment joggle.jpg
Rescued attachment joggle.jpg






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Ivan

posted on 29/12/09 at 07:06 AM Reply With Quote
I've been thinking about my scuttle as well - what I thought of doing was to make the scuttle & bonnet in one piece as my nose cone isn't flat on top and to get matching curves is difficult with the risk of bulging and denting.

Once all bent up would cut off scuttle and rivit or sloder to flat to create the indent for the bonnet.

Would end up with perfectly aligned bonnet, nose cone and scuttle from all views.

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C10CoryM

posted on 29/12/09 at 07:42 AM Reply With Quote
Not a bad idea really Ivan. It would give you a good line between the scuttle and bonnet. Just rivet or weld a flange on the scuttle to support the hood after. Also have to make the bulkhead attach to the scuttle top somehow.

Not really an option in my case because my bonnet is going to be a bit difficult due to the large lump sticking through it. Also Im not sure I like the look of a sharp bonnet edge against a sharp scuttle edge.

Im just going to get the scuttle and bonnet done and expect to be re-doing it eventually





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Mark Allanson

posted on 29/12/09 at 10:08 AM Reply With Quote
This is how I did mine





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907

posted on 29/12/09 at 12:06 PM Reply With Quote
Hi All,

Bearing in mind Ivan's post, I ran a string line down the centre of the car that just cleared the engine.
By laying a straight edge across the top chassis rails I measured up to the string at various points.
This gave me the height and slope angle of the scuttle, front and back, and the height of the nose,
and ensured that when the bonnet was fitted in between it would be one line from top edge of the
dash to where the nose drops away.

Cory, I think you are right to dispense with the frame. Mine is there just to support the column. (see pic)

Having worked out the slope angle / bonnet line I sloped the dash forward at the same angle to give 90deg
between the two. This seemed an easy way to do it as the scuttle sheet edge is then a straight line and I
could work from the edge of the sheet of ally. One edge less to cut.

With the scuttle top & sides formed and a lip knocked over all round this would hold shape.
With a dash on one side and bulk head the other I think it would be quite solid.
An angle could be added when riveting the bulk head, the rivets holding all three thicknesses.
(I'll do a drawing to explain it better)

Cheers
Paul G Rescued attachment scuttle dash.jpg
Rescued attachment scuttle dash.jpg

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907

posted on 29/12/09 at 12:12 PM Reply With Quote
On reflection I should have mounted the column on the chassis as Mark has done.

Anyway, (rough) drawing below.

Cheers
Paul G Rescued attachment scuttle drw.jpg
Rescued attachment scuttle drw.jpg

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C10CoryM

posted on 29/12/09 at 09:20 PM Reply With Quote
Thanks guys.

Paul, that is pretty much what I have in mind. When I install a windsheild and wipers I will add some framework to support those.
One more question for now: My shrinker/stretcher jaws are only about 1" deep. Does that mean I should bend a 1" flange then shrink to get my scuttle curve? Will I get ripples on the visible part if I go over 1"? I will be painting so a little filler is fine.

Cheers.





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907

posted on 29/12/09 at 11:30 PM Reply With Quote
Hi again.

If you were to bend a 1" flange then it is the edge that needs to shrink the most, so you only need the jaws to cover say 1/2".

I stuck a piece of the rubber that I used to pad the dash on the front of the shrinker to act as a spacer. (see pic)

This process will put "tuck" marks in the rest of the flange but these can be dressed out with a flat faced hammer and a heavy block on the other side.

You may need to shrink, then dress the tucks, then shrink more, etc.

Any remaining marks on the outside of the flange can be taken out with wet & dry. No need for filler.

The inside will not be seen and most of the outside will be covered by the angle & rubber bonnet strip.

Practice on a piece of scrap first.

I hope this is of help.
Cheers
Paul G


Edit to add: material was 1.5mm (16g) half hard ally.


[Edited on 29/12/09 by 907] Rescued attachment shrinking.jpg
Rescued attachment shrinking.jpg

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907

posted on 30/12/09 at 12:08 AM Reply With Quote
Since I've not posted a pic of the car for ages, see below.
I'm just a bit proud of it. (smug grin)

Paul G Rescued attachment suttol ws s.jpg
Rescued attachment suttol ws s.jpg

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C10CoryM

posted on 30/12/09 at 04:14 AM Reply With Quote
Definitely helping Paul. Thanks. I got my front bulkhead and my dash to shape today. I do plan on making a carbon dash, but the aluminum will do for now. Will have to wait until the weekend to play anymore.

Since you are being so helpful I will ask another question. Refer to the attached drawing. Say that is a cross section of a rear fender, how do you go about getting the nice radius curve w/o ending up with flat spots? If the bend is a tight 90, you should be able to just shrink it and nothing more correct?

Thanks again Paul. Alway nice to have someone helping me for a change

You car looks good. Didnt I remember some pictures of a hard top? How did that end?

Ivan, I realized one problem with your idea while measuring. The top piece of the scuttle will be over 4ft wide. Meaning its going to be hard to find a sheet of aluminum the size you need.

Cheers. Rescued attachment aaa.jpg
Rescued attachment aaa.jpg






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907

posted on 30/12/09 at 08:11 AM Reply With Quote
Hi Cory,

Trev D is making a hard top for his 7. Now there's a true craftsman.

Epona is the car designed by my son (Gaz1977) and is on hold at the moment.
I think everyone is awaiting better times before spending money.

The shrinking machines used by professionals (like Trev) have a deep throat and allow you to shrink well into the sheet.
They are powered and the dies nip the sheet many times a minute.

For us Locosters another plan is needed.

I made a jig from a rolled length of pipe. It's down to what you have, so others might use wood and shape it with a sander. pic 1.

Pic 2 shows the flat sheet, 90deg fold, then pulled to shape with just the shrinker.

Pic 3 (yup, frightening isn't it? ) shows the next stage.
Clamp in the jig with the luggage strap and dress over with a rubber mallet.
Out of the jig and shrink the edge. Back in and dress. Shrink, hammer, shrink, hammer, till a rough shape is achieved.

Into the E wheel and take out the tucks, wheeling from the shrunk edge to the flat centre area and back, working round the fender.
Don't wheel into the area you want to stay flat.
(My first two ended up in the scrap bin. )

I then cut off the chewed edge the jaws had made and welded in a crescent shaped piece, wired the edges and we have pic 4.


I find shaping ally very time consuming but very satisfying. A sense of achievement and all that.

Good luck (and post pics)

Cheers
Paul G Rescued attachment rear arch pm.jpg
Rescued attachment rear arch pm.jpg

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NS Dev

posted on 30/12/09 at 03:32 PM Reply With Quote
very nice work there!





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C10CoryM

posted on 2/1/10 at 12:26 AM Reply With Quote
quote:
Originally posted by 907
Having worked out the slope angle / bonnet line I sloped the dash forward at the same angle to give 90deg
between the two. This seemed an easy way to do it as the scuttle sheet edge is then a straight line and I
could work from the edge of the sheet of ally. One edge less to cut.


Im a little confused regarding this. Because the front bulkhead is narrower than the rear bulkhead wouldnt you end up with a curved line? If you had a straight line and attached it to the dash, then tried to attach it to the smaller bulkhead, wouldnt you end up with a C shaped piece? Like attached picture. A straight line would be nice as it would let me just bend a flange and shrink it right? Then form the bulkhead over a wood former.

When forming a curved piece like that you bend it over until it starts to buckle, then just shrink beside the buckle until it goes away? Then run over where the buckle was with the shrinker and back to the former and bend it some more and repeat?

Thanks again.
Cory Rescued attachment cutt.JPG
Rescued attachment cutt.JPG






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907

posted on 2/1/10 at 10:09 AM Reply With Quote
quote:
Originally posted by C10CoryM
quote:
Originally posted by 907
Having worked out the slope angle / bonnet line I sloped the dash forward at the same angle to give 90deg
between the two. This seemed an easy way to do it as the scuttle sheet edge is then a straight line and I
could work from the edge of the sheet of ally. One edge less to cut.


Im a little confused regarding this. Because the front bulkhead is narrower than the rear bulkhead wouldnt you end up with a curved line? If you had a straight line and attached it to the dash, then tried to attach it to the smaller bulkhead, wouldnt you end up with a C shaped piece? Like attached picture. A straight line would be nice as it would let me just bend a flange and shrink it right? Then form the bulkhead over a wood former.

When forming a curved piece like that you bend it over until it starts to buckle, then just shrink beside the buckle until it goes away? Then run over where the buckle was with the shrinker and back to the former and bend it some more and repeat?

Thanks again.
Cory


Hi Cory,

The last bit of your post is spot on.

It's at times like this I wish I could draw in CAD
See Photoshop drawing below.

I have a book chassis (sort of) but 4" wider, so from the dash it narrows 11 deg per side, hence 79 deg in the drawing. Yours may differ.

Dim X is the metal required to go round the rolled rad.
My rad is 125mm all the way down to the nose cone, and is calculated using the formula Pi x D divided by 4.

i.e. 3.142 x 250 (twice rad) div 4 (90 deg of a circle)

785.5
______ = 196.375 mm (dim X)
4

A 5" rad would be:- 3.142 x 10 = 31.42 div 4 = 7.855 inches.

Even if you decide to have a slight curve to the top of your scuttle the cut out shape will still be a straight edge, till you come to the rolled corner.

Tip. Holes cut near the edge of your wooden formers will allow you to G clamp the sheet to it. ( with a wooden batten on the outside to prevent
marking the sheet and hold it tight to the former while you tap the edge over.

I was able to start with the dash top edge with no need to cut. Overlap the former by 1"and clamp.
Bend the sheet round the former, cut the sheet back at the ends to 1" overlap and dress over/shrink.

You will need to notch out a square where the dash flange meets the chassis flange.

Surplus material can be cut off and remaining edges knocked over, shrinking the red areas.

I used an air nibbler with a spacer against my frame to give me a nice straight cut with my 1" extra to be dressed over.

Clear so far?

Cheers
Paul G

Edit to add:- The blue lines either side of "ROLLED CORNER" are the start and finish of the rad, and not realy fold lines.

[Edited on 2/1/10 by 907] Rescued attachment scuttle layout.jpg
Rescued attachment scuttle layout.jpg

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C10CoryM

posted on 3/1/10 at 04:19 AM Reply With Quote
Excellent help Paul. I appreciate you taking the time. I'm sure others will gain from this post as well.

I think what I will do is make a wood form and screw it to my wood table. Then get a paper template from it and transfer it to aluminum. Then bend the aluminum over the wood form. I have enough aluminum for two chances. If I fail at both I will make the wood form into a buck for doing carbon
BTW I went with .040" T3 (halfhard) which is about 1mm. I think I will go a bit thicker next time though.





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907

posted on 3/1/10 at 07:46 AM Reply With Quote
quote:
Originally posted by C10CoryM
Excellent help Paul. I appreciate you taking the time. I'm sure others will gain from this post as well.

I think what I will do is make a wood form and screw it to my wood table. Then get a paper template from it and transfer it to aluminum. Then bend the aluminum over the wood form. I have enough aluminum for two chances. If I fail at both I will make the wood form into a buck for doing carbon
BTW I went with .040" T3 (halfhard) which is about 1mm. I think I will go a bit thicker next time though.



You are more than welcome Cory.
It's always a pleasure helping some one willing to "have a go."

Before the Locost I had never seen an English wheel, shrinker, stretcher or a jenny, let alone used them.
My help and inspiration was Trev D, to whom I will always be indebted.


Screwing down to the bench sounds a good idea as the firmer it is the better the edges are to knock over.
Remember to space it up an inch or so (or work over the edge) as until the final end bends are done it will not sit flat.

I've modified the drawing a bit and posted it below.

All the best.
Paul G Rescued attachment scuttle layout2.jpg
Rescued attachment scuttle layout2.jpg

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C10CoryM

posted on 6/1/10 at 06:01 AM Reply With Quote
Well attempt #1 was a failure. I had too much flange, and the shrinker was hardening the metal too quickly. Eventually I tried to trim some of the flange off in the corners because it was folding too badly, but then ended up with a crack that went to a visible part. Attempt #2 will be with pre-trimmed and annealled corners. I dont think I will use the shrinker at all and just rely on the annealled aluminum to fold nicely. Or I could just anneal it after every shrinking I guess.

When you start hammering, do you start at the corners or the flatter parts? I think I made it worse by starting with the flat parts. Ended up with all my extra metal in one area.





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907

posted on 6/1/10 at 03:11 PM Reply With Quote
quote:
Originally posted by C10CoryM
Well attempt #1 was a failure. I had too much flange, and the shrinker was hardening the metal too quickly. Eventually I tried to trim some of the flange off in the corners because it was folding too badly, but then ended up with a crack that went to a visible part. Attempt #2 will be with pre-trimmed and annealled corners. I dont think I will use the shrinker at all and just rely on the annealled aluminum to fold nicely. Or I could just anneal it after every shrinking I guess.

When you start hammering, do you start at the corners or the flatter parts? I think I made it worse by starting with the flat parts. Ended up with all my extra metal in one area.



O Cory! Lesson one. There is no such thing as a failure.

Sometimes things don't turn out quite as well as we had hoped, but next time it will be better.
It's called a learning curve. Please don't give up.

Where to start? I'm asking myself the same question.

The technique is to tap the edge over to say 15deg and work along.
Go back to the start and work along again, this time to 30deg, but not as far.
Transitions should be gradual so that in no place does the edge go from 90deg to no bend at all, unlike the pic below.

I would start start with a centre line on the sheet corresponding with a centre line at the top centre of the dash former,
working outwards towards the scuttle corners, each time stopping a little shorter.

Another post to follow.
Paul G Rescued attachment edge.jpg
Rescued attachment edge.jpg

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907

posted on 6/1/10 at 03:37 PM Reply With Quote
Since I cut my flange down at the corners I thought I might have a go on a piece of scrap to form a full 1" corner with the shrinker.
At least it keeps me off the streets.

The technique is to tap the edge over till it ripples, then shrink, working round the rad of the scuttle corner and down the side.

The holes in the 1/2" ply are useful for clamping with G's.

see pics and following posts. Rescued attachment tc1.jpg
Rescued attachment tc1.jpg

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907

posted on 6/1/10 at 03:39 PM Reply With Quote
Starting the rad. Rescued attachment tc2.jpg
Rescued attachment tc2.jpg

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