Hot Rods Metal working question: compound 90° bend curves

Hey all,

I know a 90° can be curved easily with a shrinker stretcher, but how about a compound series of 90° like this dogleg? A single dude in a shop makes these... for relatively little considering it's producing many... how does he do it?

Thanks


Member:
Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org
CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com

 

Easiest way is 2 pieces that have been stretched or shrunk, welded together.
Looks like that could be the case here, but hard to tell.

 

Looks to me like he'd start with a Z profile and then be progressively and continually alternating shrinking one leg of the Z and stretching the other leg. I'll bet he has 2 machines, else most of his time would be spent changing dies! The stretching could be hammered I guess, but the machine would afford more control?

 

Easily done on a big machine, like a Yoder, or Pullmax, with the right tooling.

 

I will never have large tools. Right now I have no tools at all just a saber saw and grinder and I do a lot but I'm going to start adding shrinker stretcher slip roller metal band saw break English wheel planishing hammer.


That said, maybe I'll start with the shrinker stretcher and make this. They weren't available until recently so I had my mind made that I would make make mine.... now I am committed. $200 for the pair or buy tools to make them and have them forever.


Just throwing it out there if anyone is me and has any metal working stuff for sale, I am in need


Member:
Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org
CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com

 

1pc and a Hammer form.
2pc and shrinker stretcher welder

From your list Id start with the shrinker stretcher. The HF stuff sorta works enough but a set of true Lancaster tools will be far better.
A nice steel table, my table is 3'x5'x1" and a few pieces of stock and good clamps and then you can bend anything you want. You'll use the table every day but not the break. And and and you'll get better bends off the table than a cheap break.

 

I have also seen crude home made dies and a good hydraulic press work surprisingly well

 

Yep!

 

If you have a log splitter you have 20-24 ton press potential with small home made dies.

 

Hard to tell the size but the first piece could have been through a bead type roller with a stepped die and then shrink stretch.
Made a similar piece yesterday.


Sent from my iPhone using The H.A.M.B. mobile app

 

Let's see it
Post up a pic

 

I am learning fast - thick steel fab and "engineering" parts that work is my background and as I work more toward sheet metal and body work/ ornate fabrication, every night in the garage is new info. For example, when I made my fresh air heater (pardon the link of the site hope it's not rude if so I didn't think it was http://www.chevytalk.org/fusionbb/showtopic.php?tid/339839/) I learned how amazingly I can move and shape metal by taping with pieces of 1 1/2" thick wall round and square tube. That will be huge for body work.


When I was building my semi concealed radio and didn't wanna move metal to close a small gap, I used a strip of sheet metal 1/8 thick as filler rod with MIG and got s gorgeous well across the gap.

So I am learning, had a fellow H.A.M.B.er locally show me some stuff that helped.

I want to know more about what you said - let's say a 1"x1"x10" 18g sheet metal 90°.... could you get a nice 1/4 circle out of it for like, a wheel well or dog leg using a table? If I see it done I can do it

Appreciate this gents. Clearing one side of my (1.3 car) garage for metal work and larger tools cause my little work bench work the 3/4"x2'x2' plate on top won't do it when I dive into my next project where I'll be creating massive amounts of body panels


Member:
Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org
CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com

 

Sure, but a shrinker/stretcher would make quick work out of that task.
Hammering the edge would make it stretch, but that's LOTS and lots of hammer work.
Making "tucks" and hammering them in wound make the edge shrink, but again LOTS and lots of hammer work. You could make relief cuts and weld them up too. You could make that from 2 pieces,1 cut to the curve and another to make the edge. You could also make a "hammer form" and beat the edge down forcing the metal to go where you want it, this would require a larger piece of metal and then trimming the 1/4 circle out of it.

All in all 1x1x10 into 1/4 circle is Less than 10 mins work with a shrinker/stretcher tools vs hours upon hours and thousands of hammer swings.

These buckets are from 5 pieces.
Made a wire skeleton for patterns.
Used the shrinker on all 5 pieces, used the E wheel on 4 of them.
Hammer form for consistency of shape and to hold it together for welding.
Hand planishing welds over a trailer hitch ball and oxygen tank cap.
Took about 8 hrs for 2.

 

You would be amazed at just what you can do with a shrinker /stretcher. HRP

I believe you can duplicate the pieces without the bigger pullman or yoder but it will more work intensive. HRP

 

Those buckets are top notch man nice job

Maybe they (shrinker stretcher) are the first thing I should get.... was thinking band saw but that's $$$$$$


Member:
Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org
CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com

 

Sent from my iPhone using The H.A.M.B. mobile app

 

The pics should get bigger if you click on them.
HF has them on sale, the stand is ok but the Legs are flimsy.
After a thousand strokes you'll need to redo the pedal pivots.



Then if you want a quality tool theses are way better.
You probably won't notice the difference until you get used to one then try the other.
It's a quality original vs cheapest bidder copy and no contest.
But they cost almost 4x as much

 

Get the shrinker/stretcher! I had a band saw for a while, and now its gone. I cut with a sawzal, cut off wheels, or a plasma cutter, and clean up any edges that need cleaning up with a grinder, or a flap disc on an air sander. But I seldom large diameter solid stuff. Gene

 

I agree with Gene on the bandsaw for car related sheet metal work. I have a Roll-in vertical and DoAll horizontal and they are useless for car related stuff. Much more useful in heavy production or fabrication projects.
I bought some cheap Eastwood shrinker/stretchers awhile back. They are not the best quality but they do the job. Just need to be patient and/or make the return spring modification. Basically HF stuff.


Sent from my iPhone using The H.A.M.B. mobile app

 

Woh... I am really glad I bright this up... this is really helping. I thought band saw first but now you guys are making me glad I didn't run out and buy one. Funds are really tight for my hobby and come from fixing up cars on the side... hard earned cash. So I'll skip the bandsaw. Shrinker stretcher and steel table first?

I was thinking of not getting the stand because I have such little room. I wash thinking of mounting them to angle iron and sticking them in my vice whilst using. Wonder if it would be cumbersome?

I find it SO annoying to cut a huge piece of sheet or plate with a saber saw... mostly cause of the vibration. Maybe the steel table and clamps will help.

As for the steel table, what's the thickness I should go with? Will 1/2 do the job if it's welded up to a frame of angle iron? Perimeter and some crossmembers?


Member:
Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org
CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com

 

Nice work Vicky

 

1/2" is fine. Thicker is always better for a welding table but 1/2" would do just fine. I have an old injection molding base (1.25" thick) that I just keep sanded/prepped and spray a little wd40 or anti spatter spray on it from time to time.
As for tools, bandsaw should be at the bottom of the list IMO. The 4.5" cutoff wheel and flap disc get used way more than my plasma or bandsaws


Sent from my iPhone using The H.A.M.B. mobile app

 

There's no way I'd cut with a jig saw, it's so rare.
Electric shears do a great job! each style below has there place and usefulness. I use both of mine constantly when 100% accuracy Is not important. Most of the time in shaping the blank is at least 1" oversized so 100% accuracy doesn't matter.

Owning the best tin snips is invaluable , it's about the only way to cut steel 100% accurately and cleanly. Midwest makes the best and you could do 100% of all the cutting you'll ever need with just those. Using these snips will be faster and cleaner than a jig saw. Plus using them builds incredible hand and forearm strength.
I usually cut the piece to 1/8 or so from the line with the electrics and trim to my line with hand snips.





I'm not going to tell you a 1/2 plate won't work, because it will.
I know the difference so I'm spoiled and jaded, Since you don't know it won't bother you.
if I had a 1/2 plate table I'd be looking to trade it for 1"
If I walked into a fab shop, I'd want to work on the 1" not the 1/2"

A piece of 1/2" plate isn't flat. 1/2" stock is coiled shipped and then flattened, cut and stacked. Crane a 1/2" 4x8 plate with a couple hooks and it bends. 1" won't. Road plates are 1". All the of the angle under bracing in the world won't pull 1/2" plate flat. With a bunch of heavy fab skill wedges and dogs you could pull 1/2" plate flat to a 6" beam. But it's still not flat. Hitting on a 1/2" plate goes off like a gong.

 

Couple questions: doesn't your snips make a waviness in the metal? That's hard to get out.

Hate to ask, but 1"x4'x5' or so probly weights over 400lbs doesn't it?

In the back of my mind I always avoid choosing my cutoff at the bench because of sparks... think it's time to get some thin sheet metal and line the wall(s) near it. Will make welding safer too


Member:
Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org
CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com

 

Another question: I have a nice pair of straight yellow snips from when I was like 9. Always was into making things. They still work great, but once the cut is deeper into the metal than the tool is long, I am fighting one side up and one side down to fit my hand in there. Red and green are to cut left and right, so what's to cut say 4 feet into a sheet straight?


These may be incredibly elementary questions and I've made it very far without thinking of asking them, but they are really helping the basics. I just got done making a gorgeous fresh air heater for my car (http://www.chevytalk.org/fusionbb/showtopic.php?tid/339839/) with complex transitions (shapes outside of the other's perimeter and such) but yet dreaded every cut from the 20g 3'x4' stock



Member:
Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org
CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com

 

Great questions!

Yes Snips or electric shears do very very slightly stretch the slightest bit of the edges. It's not very deep into the sheet either, maybe 0.030 at most. Depending on the part you're making determines if that's a problem and the slightest pass thru a shrinker will correct it in seconds. Using a cut off wheel or plasma causes shrinkage on the edges.

1 square foot of steel 1" thick weighs 40 lbs. you can calculate off of that. 2sq feet x 1/2 weighs 40 lbs. 4 sq feet of 1/4" weighs 40 lbs. 8 sq feet of 1/4" weighs 40lbs

(1"x 4x5) x 40lbs = 800 lbs

A piece of tin on the wall helps with all sparks including welding. So will a another layer drywall. If it's wood frame construction, the Sparks rolling around on the floor that can get under a base board or drywall are the most problematic and they are stopped by a good caulk job.

Think about using the off set snips I pictured, your hand is way out of the metal. they can be used from above the sheet for cutting on a table, they can be used from below the sheet for greater visibility and accuracy.

 

Here is a very good video on using snips. Lots of good info on how to use them correctly lots of people do not.

 

Very helpful. I picked up some left and right traditional style, but I think I'm gonna return them for the offset ones, or at least by a yellow/straight offset one so I can cut very long distances…


Member:
Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org
CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com

 

Keep in mind that tin snips are only meant to trim about 1/4" or so off the edge of a piece of metal. If you are trying to cut apart two large sections with them, you are going to have trouble. A manual shear that doesn't take up too much space that will work better for that application is a Beverly shear.