How It's Made
Axle construction.
As I mentioned previously, when I designed this axle, I knew it would require inner bracing.
Here is an original drawing of the axle and how the inner pieces were to be welded in.
View attachment 380000
Looks like it ougth to help, though I don't know if it would have prevented a tear across that stress line.
A weld bead across the inner elbow of the z, that thoroughly penetrates both parts and fills part of that elbow, and is then filed (round rasp, etc) to a curve as gradual as possible, would help remove or at least reduce the stress riser that elbow creates.
Even better would be a continuation tab of both of the two pieces along that face, just like the one left to help cover the curves, so those two flaps would be shaped to overlap and "interlock" at that elbow, and then be welded together along their edges and thru faces to get the ending edges conneced to the faces.
Not sure if this gets it across very well, but:
where the straight sideways fold on the angled piece gets inserted into the top horizontal brace above it's angled fold, and then the two folds are welded to the other tubing.
Senior Moment
I have to be honest. I'm having a senior moment...I have no photos showing the bracing being welded in ??????
I see no signs of rosette welds where there should be numerous. Maybe I ground the welds down too well.
OR! I never completed that part of the build. That's not good,
Well, I guess it's possible...I have certainly accidentally skipped steps in various projects over the years, nearly always because one of the dogs distracted me for attention or a medical thing or whatever, sometimes because I was so exhausted I dozed off, etc. :/
In my limited experience, I have been able to tell where a weld was (even when ground and "polished") by oiling the area (it was an accidental spill, not intentional to find the weld, but there was a color change in the welded area vs unwelded, visible only in the direct sunlight outside). I don't know that this will always work, though.
I remember something from an "engineering mistakes" series where they used some acid to lightly etch the surface to show a weld pattern that also exposed flaws in the weld; don't know the details.
So far, I've not detected any other signs of weld cracking anywhere else on the axle.
Finding this crack (one side only) warrants a complete removal of all paint and a close examination of all joints.
Unfortunately, yeah, an inspection would be good to do.
I googled diy magnaflux a while back when I was having some issues with the sb cruiser keel, and saved this tidbit
How it works, is on a smooth surface you sprinkle/blow (use a small turkey baster/ear wax sucker)some particle dust and straddle the magnet across it. If theres a crack it will form a new North/South attraction and the dust will attract to the crack.
Which appears to have worked when tested on known-cracked steel tubing like yours. I didn't find any cracks in the stuff I tested with it, but it should work as some of the test parts were not visible cracks (I just already knew they were broken from distortions in the paint; when the paint was peeled off in that area later I still couldn't see the crack but the magnetic stuff still showed it was there, and when I banged on the part with a hammer right there the crack was very obvious.
I just used angle-grinder leavings for the powder, and some finger-sized magnets with shaped steel backers (that I usually use for holding stuff whiel tack-weldiing shapes) across the suspected crack areas.
A second method given in the same place I found that was
Its been a number of years since I've done crack testing but one of the easier methodes was to use a spray on method. A red liquid was sprayed on a surface and allowed to sit for a while then it was gently wiped off and a white powder spray was applied. The way it worked is that the red liquid was fine enough to hide in the cracks and when you wiped the red off the surface, the applied white powder would soak-up the red showing you where the crack was. I used this method mostly on non-magnetic materials. Like the magnet method all the surfaces have to be really clean.
but I never tried that one out.
Possible upgrade
Maybe an ornate bracing added externally. Something that will blend in with the overall theme.
I already have a design in mind. I'll work on that and get back to you.
Sure--I can't think of anything at the moment (but I don't know for sure all the details you have in mind for the finished appearance / style, while you probably do.
) .
