128 SL Coupe Project
- Thread starter 128kid
- Start date
128kid
Courtney Waters
Thanks! I took all the pics hoping it would help others out, and help me remember what I did when I get to the next project 
There's quite a bit of metal shaping info out there (forums, youtube, tv, etc.) but I picked up a lot (especially the hammer forming stuff) from Ron Fournier's books (Sheet Metal Handbook, Metal Fabricator's Handbook) and Advanced Sheet Metal Fabrication by Timothy Remus.
There's quite a bit of metal shaping info out there (forums, youtube, tv, etc.) but I picked up a lot (especially the hammer forming stuff) from Ron Fournier's books (Sheet Metal Handbook, Metal Fabricator's Handbook) and Advanced Sheet Metal Fabrication by Timothy Remus.
Simon Oaten
Daily Driver
that is a darn neat job !
I would have cheated and made strip to do the compound return !!!!!
you also did a great job on the bar stock, so it locates on the lip on the nut.....nice !
rgds
simon
I would have cheated and made strip to do the compound return !!!!!
you also did a great job on the bar stock, so it locates on the lip on the nut.....nice !
rgds
simon
kmead
Old enough to know better
I will have to look into these, knowing there is a good resource is sometimes half the battle.
Thank you for sharing!
128kid
Courtney Waters
Thanks, Simon! Yes, there are definitely other ways one could make an equivalent part. I find it pretty thrilling to produce something with low-volume techniques that looks like it was made with high-volume tooling (stamping). Plus, there is less metal finishing this way and I'm much better at machining & fabricating than I am welding
I can't claim design credit on the centering of the nut - I just copied what Fiat did (although it's a method I've used often in designs at the day job). I used 4130 for stronger threads than mild steel. I think I just used a regular tap though, which is a bummer since I just came across the thread forming tap that I used on a similar repair that I did on a '73 sedan many moons ago.
I can't claim design credit on the centering of the nut - I just copied what Fiat did (although it's a method I've used often in designs at the day job). I used 4130 for stronger threads than mild steel. I think I just used a regular tap though, which is a bummer since I just came across the thread forming tap that I used on a similar repair that I did on a '73 sedan many moons ago.
128kid
Courtney Waters
Frame Rail Fabrication
Top of frame rail bent:
Profile trimmed:
Sawing hammer-form at an angle for spring-back compensation:
Radii filed by hand:
Figured offset to get flanges to end up in the correct location:
Lots of clamps to prevent the panel from moving during forming and to provide support at the bend:
Relief sanded into the corner of the corking tool to clear the adjacent flange:
Support blocks had to be moved or changed to provide clearance to complete forming:
Curved flange being formed in frame rail. The form is made with an angle slightly greater than 90-degrees to provide compensation for spring-back. Hopefully the formed flange will end up at 90-degrees without additional work after removing it from the form.
Just needs a final trim to fit what’s left of the original frame rail:
Fit up of parts so far:
Top of frame rail bent:
Profile trimmed:
Sawing hammer-form at an angle for spring-back compensation:
Radii filed by hand:
Figured offset to get flanges to end up in the correct location:
Lots of clamps to prevent the panel from moving during forming and to provide support at the bend:
Relief sanded into the corner of the corking tool to clear the adjacent flange:
Support blocks had to be moved or changed to provide clearance to complete forming:
Curved flange being formed in frame rail. The form is made with an angle slightly greater than 90-degrees to provide compensation for spring-back. Hopefully the formed flange will end up at 90-degrees without additional work after removing it from the form.
Just needs a final trim to fit what’s left of the original frame rail:
Fit up of parts so far:
Last edited:
motoTrooper
True Classic
Dude! So awesome!
Fantastic fabrication. (I may be repeating myself) You are cultivating some great skills, to what end I wonder. Is a handmade Ferrari GTO next?
Fantastic fabrication. (I may be repeating myself) You are cultivating some great skills, to what end I wonder. Is a handmade Ferrari GTO next?
128kid
Courtney Waters
Thanks! There are several why's...
Thanks so much! There are a number of motivations for doing this. A handmade GTO? Well, maybe in the far distant future. I do hope to develop my skills to the point that I wouldn't be afraid to take on restoration of more valuable/exotic/rare vehicles in the future, should I have the opportunity to do so.
Primarily, I just love these old Fiats and enjoy saving the ones I can. I'm hoping that documenting this project will inspire fellow Fiat nuts to tackle some of those bigger repair jobs instead of scrapping the cars since they are getting harder and harder to find. I don't see many coupes for sale out there so this might be my one chance to own one. With so few OEM repair panels available - escpecially when it comes to the structural parts - it seemed impossible to make a car look (close to) factory again. I'm proving to myself (and hopefully others!) that it's possible to make this stuff. While I use some bigger equipment because I have it, a lot of this could be done with hand tools and hand-held power tools (jig saw, angle grinder, body hammers, files, etc). Another nice thing is with all the online metal retailers now, you can get all sorts of materials (sheet metal, bar stock, whatever) that make for a more "appropriate" repair than the hot-rolled angle iron and strap available at the home improvement store.
As a kid I loved to build things, and having a father who is a contractor certainly helped. Fiats (got into them in high school) really cemented my interest in vehicles and led to my pursuit of a mechanical engineering degree. Now I spend a ton of time behind a computer doing automotive design so getting out into my shop and building things is a great escape. As a bonus, it helps with my design work - understanding more about what metal will and will not do, how machine tools are used to make parts, etc. There are definitely af ew Fiat-inspired features in the stuff I have done.
Engineers are often accused of not knowing "how to make things in the real world." I find that having some practical hands-on experience helps me ask the right questions and develop good relationships with fabricators, weldors, and machine operators, whether in-house or at a vendor. And I can also tell when someone is BS-ing me. Same goes for bosses. Ha! I've even made my share of parts for work when lead times were too long or our vendors said a part was beyond their capacity.
Thanks so much! There are a number of motivations for doing this. A handmade GTO? Well, maybe in the far distant future
. I do hope to develop my skills to the point that I wouldn't be afraid to take on restoration of more valuable/exotic/rare vehicles in the future, should I have the opportunity to do so.Primarily, I just love these old Fiats and enjoy saving the ones I can. I'm hoping that documenting this project will inspire fellow Fiat nuts to tackle some of those bigger repair jobs instead of scrapping the cars since they are getting harder and harder to find. I don't see many coupes for sale out there so this might be my one chance to own one. With so few OEM repair panels available - escpecially when it comes to the structural parts - it seemed impossible to make a car look (close to) factory again. I'm proving to myself (and hopefully others!) that it's possible to make this stuff. While I use some bigger equipment because I have it, a lot of this could be done with hand tools and hand-held power tools (jig saw, angle grinder, body hammers, files, etc). Another nice thing is with all the online metal retailers now, you can get all sorts of materials (sheet metal, bar stock, whatever) that make for a more "appropriate" repair than the hot-rolled angle iron and strap available at the home improvement store.
As a kid I loved to build things, and having a father who is a contractor certainly helped. Fiats (got into them in high school) really cemented my interest in vehicles and led to my pursuit of a mechanical engineering degree. Now I spend a ton of time behind a computer doing automotive design so getting out into my shop and building things is a great escape. As a bonus, it helps with my design work - understanding more about what metal will and will not do, how machine tools are used to make parts, etc. There are definitely af ew Fiat-inspired features in the stuff I have done.
Engineers are often accused of not knowing "how to make things in the real world." I find that having some practical hands-on experience helps me ask the right questions and develop good relationships with fabricators, weldors, and machine operators, whether in-house or at a vendor. And I can also tell when someone is BS-ing me
. Same goes for bosses. Ha! I've even made my share of parts for work when lead times were too long or our vendors said a part was beyond their capacity.Simon Oaten
Daily Driver
Courtney,
your attenstion to detail is excellent, and the hardwood formers show "how to" make a curve properly. I also like the small drill hole so that you don't get a stress point at the junction of cut lines and fold points !!!!
I am a rank amateur as far as bending metal, and I am greatly enjoying learning from your posts ! Lets hope that a few more 128SL's and 3P's (and sedans of course) get saved rather than end up being crushed.
rgds
simon
your attenstion to detail is excellent, and the hardwood formers show "how to" make a curve properly. I also like the small drill hole so that you don't get a stress point at the junction of cut lines and fold points !!!!
I am a rank amateur as far as bending metal, and I am greatly enjoying learning from your posts ! Lets hope that a few more 128SL's and 3P's (and sedans of course) get saved rather than end up being crushed.
rgds
simon
128kid
Courtney Waters
You have sharp eyes, Simon!
Yes, each bend corner has a radius formed by punching or drilling a hole prior to cutting the straight parts leading into the corner. For thin sheet my preference is to use a hand-held hole punch (Roper-Whitney No. 5 Junior). The punches locate on a center-punched mark that you place in the sheet so they are super accurate, they don't tear up the metal, and any burrs are very minimal and easy to clean up. Second choice, if material is thick or the hole is too far into the panel to reach with the punch, is a Unibit step-drill. Nice clean holes and the bit doesn't lift up the sheet when you punch through. Once the holes are there, I cut up to them with tin snips or a band saw (leaving a little extra material) and then file or belt sand straight.
Every edge - straight or curved - gets deburred before bending. I hate cut fingers and it's just good practice to prevent cracks down the road. It also helps keep the flanges sitting tight against their mating panels.
One of the great things about forming metal with hammer forming is it's so cheap to do! If you didn't have a sheet metal brake you could probably do lots of straights this way (just more labor intensive). I did a few of the forms out of metal, mostly because I had it or wanted something more rigid. Since I'm not expecting to make lots of these parts, hardwood is just fine. I actually used MDF (medium density fiberboard) for many of the forms. It doesn't chip easily (like particle board), is very smooth, and easy to cut and sand accurately. Hardwoods would work great too. I use Oak for the corking tools when forming aluminum. Since this was all steel I used aluminum for corking tools at times, and some oak just because they were already made for a previous project. Basically, you want something hard enough to do the forming (and not split easily) but softer than the material you're forming so you don't put a bunch of little dents in it that can't be smoothed out.
Yes, each bend corner has a radius formed by punching or drilling a hole prior to cutting the straight parts leading into the corner. For thin sheet my preference is to use a hand-held hole punch (Roper-Whitney No. 5 Junior). The punches locate on a center-punched mark that you place in the sheet so they are super accurate, they don't tear up the metal, and any burrs are very minimal and easy to clean up. Second choice, if material is thick or the hole is too far into the panel to reach with the punch, is a Unibit step-drill. Nice clean holes and the bit doesn't lift up the sheet when you punch through. Once the holes are there, I cut up to them with tin snips or a band saw (leaving a little extra material) and then file or belt sand straight.
Every edge - straight or curved - gets deburred before bending. I hate cut fingers and it's just good practice to prevent cracks down the road. It also helps keep the flanges sitting tight against their mating panels.
One of the great things about forming metal with hammer forming is it's so cheap to do! If you didn't have a sheet metal brake you could probably do lots of straights this way (just more labor intensive). I did a few of the forms out of metal, mostly because I had it or wanted something more rigid. Since I'm not expecting to make lots of these parts, hardwood is just fine. I actually used MDF (medium density fiberboard) for many of the forms. It doesn't chip easily (like particle board), is very smooth, and easy to cut and sand accurately. Hardwoods would work great too. I use Oak for the corking tools when forming aluminum. Since this was all steel I used aluminum for corking tools at times, and some oak just because they were already made for a previous project. Basically, you want something hard enough to do the forming (and not split easily) but softer than the material you're forming so you don't put a bunch of little dents in it that can't be smoothed out.
128kid
Courtney Waters
Definitely don't sell the bandsaw! Of all the equipment I have, I probably use my vertical bandsaw the most. That, a good (old) benchtop drill press, and a Craftsman 6x48" belt sander are the real workhorses for all the stuff I do.
I'm hardly good enough to start a school! But we'll keep the "online course" in 128 repair going
I'm hardly good enough to start a school! But we'll keep the "online course" in 128 repair going
128kid
Courtney Waters
Haha! It was a thought but would be a ton of work for not many Fiat funds in return. But if someone was in a pinch we could make something happen. I have scanned my flat pattern templates and will make those available. Actually, the stuff with all straight bends would be easy enough to CAD up and have laser cut and bent. I'll get on it as soon as I hear the clamor for SL repair kits
boxy02
True Classic
WOW!! Truly inspirational work! I'm very much looking forward to your progress pictures and posts. Absolutely amazing!
dumb question: Are you measuring the thickness of the metal pieces to be replaced to know how thick a repair panel to fabricate? Or is this information in a manual somewhere? Also, when you bend the tabs, (like 90 deg) the "R" measurement you have noted next to your bend notations, is that R= radius? If so, how do you vary the radius when you bend on the sheet metal brake?
dumb question: Are you measuring the thickness of the metal pieces to be replaced to know how thick a repair panel to fabricate? Or is this information in a manual somewhere? Also, when you bend the tabs, (like 90 deg) the "R" measurement you have noted next to your bend notations, is that R= radius? If so, how do you vary the radius when you bend on the sheet metal brake?
Last edited:
128kid
Courtney Waters
Good question! I have been measuring each piece to determine the appropriate material thickness. The factory repair manual does not go into enough detail to callout thickness for every part. If anyone finds that info, I would love to know!
I try to find a clean/straight area to measure, where the dimension won't be thrown off by paint or rust. I either use machinist calipers or a micrometer, depending on where I'm measuring. There were a few times when the dimension fell in between gauge sizes. I'm not sure if it's a difference between US gauge sizes versus european or if it's just manufacturing tolerances on the sheet stock. In those cases, I either erred on the thick side or looked at other similar parts.
Yep, the R.XXX number on the templates is the inside radius of the bend. To achieve this on a sheet metal brake I fold one or more strips of material over the upper jaw (or fingers on my brake), going thicker for a larger bend radius. Basically, padding the sharp tip of the jaw so it will create the correct radius, rather than replacing the jaw with a radiused one. Then I just offset the upper jaw back from the edge of the lower jaw to provide enough room for the "padding"/shims and the material being bent. For smaller inside radii you can kind of cheat and just offset the jaw a bit more, without adding shims. But that can make for some pretty non-round bends.
I usually do a number of test bends on 1-inch wide strips of the material being bent to get my settings dialed in. It also helps me figure out where to offset the bend centerline so it ends up in the right spot. A press brake would be so much easier sometimes! I measure the radii with radius gauges. More machinist stuff, and they're not too expensive (for the ones that fold out like feeler gauges).
I try to find a clean/straight area to measure, where the dimension won't be thrown off by paint or rust. I either use machinist calipers or a micrometer, depending on where I'm measuring. There were a few times when the dimension fell in between gauge sizes. I'm not sure if it's a difference between US gauge sizes versus european or if it's just manufacturing tolerances on the sheet stock. In those cases, I either erred on the thick side or looked at other similar parts.
Yep, the R.XXX number on the templates is the inside radius of the bend. To achieve this on a sheet metal brake I fold one or more strips of material over the upper jaw (or fingers on my brake), going thicker for a larger bend radius. Basically, padding the sharp tip of the jaw so it will create the correct radius, rather than replacing the jaw with a radiused one. Then I just offset the upper jaw back from the edge of the lower jaw to provide enough room for the "padding"/shims and the material being bent. For smaller inside radii you can kind of cheat and just offset the jaw a bit more, without adding shims. But that can make for some pretty non-round bends.
I usually do a number of test bends on 1-inch wide strips of the material being bent to get my settings dialed in. It also helps me figure out where to offset the bend centerline so it ends up in the right spot. A press brake would be so much easier sometimes! I measure the radii with radius gauges. More machinist stuff, and they're not too expensive (for the ones that fold out like feeler gauges).