Technical Not a typical Step Notch question

I could not disagree more but I will bow out and not hijack this thread. Carry on.


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I'm pretty sure that properly welded the piece will be as strong as the parent metal was before it was cut.

Basic welding 101, why do people never trust their welding?

 

A straight vertical weld is often a challenge for beginning welders, which it sounds like the OP probably is. Then we suggest he grind the welds flat so the fish plate lies flat against the frame rail., and add more 45 degree welds. I can see the concern. The advantage is this area is not a high stress area, and welding a seam, then adding a plate on both sides will give enough support for the area we are addressing. Gene

 

Let's look at it, it seems to be a common theme.
Welding machines are across the isle from the dog food and down from the toilet paper in today's stores.

First you said a mouth full with just two words. "Properly welded"
How does one who truly understands what "properly welded" means begin to explain it to someone who doesn't? It takes years of study, years of practice and years of seeing the welds in service and even perhaps experiencing a failure and studying why. There's also a distinct difference between knowing and understanding. Ever hear the phrase "doesn't understand everything they know"?

Analogies always go way off but here's a good one from yesterday.
Talking with my lovely wife yesterday she asked me if I "understood" what she was explaining. I said I now know Xyz and Abc of what you're saying but I don't think I understand and I'm not sure I will but that isnt important as long as I know. She says well how can you "know" if you can't understand?
I told here to look at it like this: honey you "know" that when you turn the key in the ignition the car Starts, right? Well I understand exactly why that happens or doesn't happen. It's not important for you to understand all of that as long as you know it's doing or not doing what it's supposed to do. She giggled and snuggled up.

So the phrase "properly welded" is explained in chapter after chapter of 1000s of books. Nobody reads them nor will they read the long winded explanation we might write about it.

 

31Vicky with a hemi gave some good words, I say.

So first off, to clear this up, (sense it's been said a couple of times that this area that will be the connection of frame rails once the center of the rail is cut out, is not a high stress area) WILL or WILL NOT the plate as I have represented it in the first two photos be acceptable?? I'm talking just welding up the V groove, not grinding, and welding up the rhomboid and rosettes on the back side. I just want to clarify wether my design will be just as strong if not stronger than base metal. I can see how a fish plate might hold better it being spread out, but will the holes for rosette welds I've drilled give any strength?

I'm no professional welder, what I know I've taught myself from performing and watching videos and reading about it. Don't use brake cleaner mixed with argon! I've welded my fair share of things, like transmission crossmember mounts, floor boards, nothing this major though. I will have to do some form of vertical welding going uphill since I've read it's not a good idea to do flux core downhill because you'll run over slag. It'll be more like an incline up weld rather than straight vertical weld since the notch is slanted on the sides.

I've tried butt welding 3/16 plate together, with a small gap between, and first started with welding only one side. When I went to bend it snapped right down the center of the weld.
Second time I welded both sides. I bent it about 5 different ways, all the way one direction and all the way back and the weld did not tear or crack. So after I satisfied my curiosity I was thinking to myself how strong is the weld bead actually suppose to be since it split on the single sided pass??

 

So I guess your point is nobody here knows if they can weld properly, thus the need for extra doublers and gussets and reinforcement ad infinitum...........

 

No, not "nobody here" because there are a some and they share and a bunch more who remain silent while laughing their asses off.
There's even more that live by - "if you can't weld good then weld a lot" and they even spout off with the "welded properly"

 

Weld up another test piece and post up a picture of the back side. It should look like you actually did weld it from the back side. While you're welding from one side the weld should be burning thru the shoulders of your bevel and leaving a key hole at the foot of the puddle and running a bead on the back side. If you did this on a steel table you're test piece would be stuck to the table because it very certainly and correctly got welded to the table.

 

These days I won't even try to explain in an online message what I have learned over 44 years as a professional pressure welder and instructor.
At times it can be hard enough getting the message across to the apprentices in my shop.
The majority of them get it as they progress in training for their profession as skilled tradesmen.

 

Not sure if this will help in your situation, but here's a link to our step notch kit pieces: http://www.welderseries.com/Step-Notch-Kit-Pieces-p76110016

Thanks
DW Horton

 

I worked with welder who did a lot of truck frame work. Mostly leightening or shorting frames he was not a fan of fish plate. His thought was look at the joint and figure out which side was under tension a crack will start there add reinforcement there. If you stop a crack from starting there it won't brake.

 

I went ahead and had new pieces cut to size.
One thing I'm curious about is the inner part of the notch where the frame gets cut out. If the material has the be 3/16 as well like the side pieces, or if it can be a thinner metal? Can I do the inside top 3/16 and the inside sides like 1/8? I'm curious because I seems the sides and top of the notch are the biggest structure, and the inner seems like it gets welded just to cover up the cut. Again this is just my thought. Any ideas?

 

The bottom is in tension
The top is in compression

The side plates are carrying most of the load and redirecting that force up and over the axle but they need to be tied together quite well to do that. If they wobble buckle Twist Or spread they loose capacity. It's one of those things where the Whole is greater than the sum of their parts.

 

Believe it. These guys make good stuff. Nice people, too.

 

Thanks for that 31Vicky. Here's another curious thought, instead of placing the plate directly on the 3/16 and welding in, can the plate be cut to fit in between the two sides welded in? Im aware in order to do, after that frame rail is cut out, another portion (about 1/4 in) of the frame rail between the two side pieces would have to be trimmed with say a die grinder, in order to fit the 3/16 plate between the side pieces. Can that be another route that will work too? I hope that's not too complicated to understand... Here's a rough sketch, red line indicate side plates, top notch with them outside, bottom notch with them between side pieces...

Yes I've always had an eye out for those notches. I didn't even see their post until you quoted it. Nice product.

 

Your pic loaded as an error.
If you want to step your 3/16 plate in you need 3/8 clearance or you'll have to bevel it.
Are your plates too small and not enough axle clearance
It that why you are fighting for 1/8s and 1/4s

Here's your options for the weld joint.
Corner to corner, stepped with fillet, beveled

 

Thanks, I think I fixed the error.

Haha, yeah I'm a little paranoid now about clearance. The clearance is pretty equivalent to a 4" pipe notch, however the main reason I'm concerned with clearance is because it will still have the leaf springs in the rear, but mono leaf, so just the main leaf, with coil springs over axle to support weight. So the concern is when the REAR is lowered and axle is in the notch, what's the axle/leaf spring going to do when the FRONT of car is raised up? Will the frame hit the axle now that the front has moved... Will it stay centered in the notch... If it has a 4 link it would stay centered. I just don't know what the leaves are going to do since they extend and reduce in length.

 

Oh yeah , lol
Thought we covered all that a couple weeks ago

 

I know how to weld properly, but I rarely do anything over sheet metal now. Even that is hard.

I am having some nervous system issues that cause me to shake like a Parkinson's patient. Until I get that sorted, I have a dedicated TIG welder on call, and a structural welder for all else, on-call.

It is not like I can share nearly 40-years of welding experience in a post on this board, or 10, or 100.

 

Well I guess we did then huh lol

I didn't go with that square notch I drew up. I did sketch another picture of the piece I had cut with the 3/16 plate on the outside of the notch (yes I asked if they could be welded inside for clearance purpose) The perforated line would be car frame. For another reference point I drew a 4" ID pipe notch people tend to do sometimes. Purple cap is 3" diameter like axle tube

 

Even if you know how to "properly weld" that type of joint is prone to failure. Seen it with my own eyes many times.

Not going to throw anyone under the bus but a friend of mine had a professional build a frame for his model A with both ends kicked up. When I was doing some sheetmetal for him I asked him why no fishplates, he told me that the guy that built it says that if you know how to properly weld you don't need em. Less than a year later he was tearing the car all the way down to have fishplates added because one side had already cracked and he wasn't taking any chances with the rest of it.

For the record I prefer oval or heavily rounded fishplates instead of diamonds. They look better and in my opinion have less stress risers as the there are no corners and the welds are constantly changing direction.

 

Was your friends frame mitered tube?

The first sketch is mitered tube, it is always is best with a plate, internal or external. It's more work and sometimes the plates take away from the sleekness, so does a hard corner.

The second way doesn't require plates but it does need a cap. If I have my choice I run with #2. Now I can cut the tube ends with a radius and do all sorts of cool stuff.

I've seen guys pie cut frame rail tube every 1/2" to curve it and weld it up. There's more weld than tube- it scares me cause every joint is a miter with no plates. Making that section from 4 pieces would be a lot better.

My Vicky frame has 2x6 tube rails that follow the contour of the body. I split those tubes into channels and bent the halves separately then joined them back together. That was challenging but a lot of fun.

 

When it comes to clearance, all you really need is just enough.
Leaf springs get longer in the (Eye to center to eye) as they get flat. The more arch the longer they get. Since the are solid mount at the front the axle moves back as they go flat.

A 4" pipe notch is great for a little nip, I personally wouldn't take a 4" notch deeper than 2".

 

That sucks, Hope you get it sorted quickly.

Even if you could share it in 100 posts and take your time to pass it down - you'll be lucky if anyone reads past word # 7

 

It was mitered joints, but I go ahead and plate a stacked joint too. Not really worth the risk on a frame.

Overbuilt is way better than underbuilt. Since I started playing with Jeeps in stupid places I have figured out "finesse" strength is all well and good till you bash it with a boulder. Brute strength on a frame and suspension mount is the only way to go.

 

YES...

 

That could depend on the suspension if the load is being carried in front of the notch as in 1/4 elliptic springs the tension side would be on top because the notch would be holding up the back of the body. In most cases you are right.

 

Here's what 31Vicky is talking about, this guy welded it up and plated everything too:

 

Think safety third!

 

I've never welded with solid wire and gas before. All I've welded with is innershield. Can't I use innershield and it be fine?
I would like to hear why MIG is recommended, or better...without being bias about it. The reason I hope to use flux core and be fine is because I don't know how well my MIG weld would be since I have never had practice with it before. I don't have knowledge on how to regulate the gas flow for thickness of metal, if a certain setting is required given metal gauge.