Misc. Mechanical & Metal Fabrication

[Loren]

Mangusta, more, would be how it'd end up. I'd have some pondering to do, about proportion, height of the grill etc., but I'm liking it, knowing I'd get some haters for sure. Generally Corvettes look best kept with Corvette lines but I've never liked the C4 front.

[DanStokes]

I'm OK with the C4 front but it's not a favorite.

[SuperBuickGuy]

Mangusta, more, would be how it'd end up. I'd have some pondering to do, about proportion, height of the grill etc., but I'm liking it, knowing I'd get some haters for sure. Generally Corvettes look best kept with Corvette lines but I've never liked the C4 front.

it's your car, do what you wish with it. I think that as long as you stay within the design language, it's perfectly fine to modify. But, again, my opinion. I think the idea is interesting - and think you should pursue it.... but again, my opinion.... your car.

[Loren]

the design language...

...my opinion....

Four big round things at back on a slanted surface, which I like quite a bit; same at front then? Of-course I don't have the DoT circa 1984 to please, although nowadays we know we can have a grille if not lights low up front, just make it be fake and made from rubber. Separately, other peoples' opinions keep us from doing silly or self-destructive things at times but yes you gotta pick a path through and as Rick Nelson might say before that crash thing, "Please yourself".

I have to go to the metal supply Monday, maybe I'll pick up some materials for this. It'll be a side project to a side project while the Camaro needs to finally get wrapped up.

[SuperBuickGuy]

I wouldn't be terribly surprised if I found out GM designers at least touched on that idea when they designed it - and likely didn't do it for the very reason you mention - DOT headlight height regulations.

[Loren]

And yet another new project idea, with the others still unfinished. Look, something shiny... So far so good w/ engineering etc., I expect to make my offer on the L.A. County hillside view lot next week.

[Loren]

Another fifteen rusty mid-year Corvettes saved so far this year w/ OEM-quality frame and birdcage parts. My, where do I get the time.

[Monster]

Birdcage parts ... ooooooh !

[Loren]

Have: 3-axle boat trailer. Need instead: Heavy(ish) cargo trailer. Found a 24' ex-rental truck box on CL for a couple grand.


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Remove the array of roller things, chop up the frame, add kickup and gooseneck hitch. I do not like heavy conventional-hitch trailers. The chart says .035" mig wire is OK for 1/4" steel but if I did it again I'd go up a size.



Craigslist again, six trailer-specific wheels and "roller" E-rated tires for 15k gross. I will probably only need it to be 12k, and will buy new tires when it's time.



Lots of electric brakes to replace the boat-trailer hydraulic ones. The drums are the same for either type, fortunately.



With all that I need 10' more of frame length. The metal supply had .187-wall 3x5", while the trailer now is .25 wall but I think it'll be OK. I think I'll tig-weld the splice and mig on some doubler plates.



A Saturdays-only project for the moment. Once the frame is under it, hopefully weekend-after-next, I'll decide if I want to add to the box over the hitch.

[Loren]

Birdcage parts ... ooooooh !

Just the drip rails and extensions for the coupes, which is a tough part. I think all the convertible stuff is available re-pop.

[Loren]

I thought maybe someone would be interested in this; heat and warpage in steel. Tig-welding two ten-foot pieces of 3x5" tubes together end-to-end, even clamped down, gets this amount of not-straightness (my word). A 1 1/2" square piece of aluminum extrusion 8' long is laid on top as a gauge here so you can see that with the rect. tubing laying on its side, at 4' away from the weld things are about 5/8" out.
Why? Heat makes steel expand until it gets red hot then it loses strength and collapses, then when it cools it starts from there and goes the other way, shrinking. With this thick material (quarter-inch on one side, 3/16ths on the other) I was doing some pretty warm welding to make sure I was getting good penetration, it was straight after doing one side but then doing the other caused it to pull in. You can clamp something down as hard and straight as you want but steel being steel, if there are any warpage factors at all within it it'll just wait 'til you remove the restraints and then do its' thing. That is something lots of guys get wrong, they believe if something is jigged up straight then welded up it'll stay the way.



If this were at the ol' aerospace shop we'd have a 10' press brake, I'd lay it across the lower jaw with wood blocks at either end then press it down 'til it were good. Wouldn't that break the weld? It better not, if it's a good weld. Without that available here, I'll use heat. I run a gas torch along the weld seam where I want it to shrink down, getting it red-hot but in a limited area at a time so the red-hot spot is pushing, pushing against surrounding material as it tries to expand then when it reaches red-hot it turns to mush and stops pushing...then as it cools it reverses course and pulls in. Here, I did the top area first then down each side a ways.



The more shrinkage I need, the wider area I get red-hot, how much is something I'll just take a guess at. Any time this is done, the whole area needs to cool enough to be stable before you check it. One pass got me about halfway straight, so I did another the same and now it's close enough.



As it happened, I didn't have any issues with straightness on what in this view would be side-to-side or I'd have had some work to do that way also.

Does getting the steel red-hot hurt its strength any? If this rectangle tube were made from cold-roll steel which is around 45-60K psi tensile strength, the area gotten red-hot would become same as hot-roll, about 30K and the same as a welded area which of-course got red-hot also. This hot-roll tube frame member will never be stressed enough to bend and all we're worried about is flex, so we're well within any ultimate-strength considerations.

If I were doing a dozen of these I'd take my lessons on the first part, then alter the fixturing to compensate for the expected results and there wouldn't be any straightening necessary afterwards,

Now imagine what we're welding on is an axle housing where the straightness we want is measured in thousanths of an inch. This is why when building a rear we weld on bearing ends after doing any other welding on brackets, etc. Then when we use a jig to hold things in place we don't imagine that is going to mean the whole things is in alignment when we're done...let it cool then use the jig as a checking fixture and see what you got. If it's out of spec, you can fix it either in a press or by the method shown, just make sure to let it cool to even temps before doing the inspection.

[langleylad]

This is why I love it here , you can always learn something new . Thanks

[Loren]

Trailer work: I built this upside-down so I could do the underneath welding and then only have to flip it once to complete.



To do long-run mig welds that look -halfway- neat: (1) Be able to see what you're doing by achieving the fine line of best visibility with the combination of reading-glasses power (at my age) and shade darkness (experiment!), you need to clearly see the mig wire and puddle and how far out the puddle is going at all times and not flinch. I can't over-emphasize that, I think that a lot of really awful welding is just because the operator is stabbing away while accepting he can't see properly when he should be. (2) Have a steady looping pattern, imagine drawing loops on notebook paper and hitting the lines above and below with accuracy, then once you get going be a "machine" about it and continue on with consistancy. (3) Pick a line you want the weld puddle to hit each time either above or below or both, in this case I used the edge of the plate (4) Have something to rest your hand on and make a practice run across your work to confirm you'll be able to make the full run without lifting. (5) Of-course have the heat and wire-speed set for good penetration. I've seen guys who have been working on cars for years and doing ugly welds only need an hour of practice with the above advice to suddenly be producing work that like below isn't perfect but at-least would be commercially acceptable.



So once I got the frame built to where it was ready to have the cargo box dropped on, the longer I looked at it the more possible uses I saw for having it just be a flatbed. It could still carry the cargo box when I need, but also handle a larger tractor, long material etc.

So change of plans.

I'm sure that an additional pair of rails for stiffness, and all the added parts and wood deck will be another 500 lbs or more but so it goes, I think having the utility would be good. I've carried heavier loads on my other trailer than I was comfortable with and it only takes wiping out on the highway once to screw up your whole life. The one time I've carried a heavy load with a borrowed gooseneck it worked so well I've wanted one ever since especially since the guy I was borrowing from sold his.

I am actually going to use a 5th-wheel hitch, not the 2 5/16" ball goosenecks normally use, so that it's same-as the 5th wheel RV in the background.




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The lawn mower saga-for-the-year continues, you can see it in the above pic just left of center, now with the engine entirely removed. 20 minutes of use, a few hours of working on it, a few days of waiting for parts that have to be ordered, then another 20 minutes of use and repeat. I swore sometime back that Sears would never be getting another nickel of my money and they didn't.

Exploded Chinese ball bearing, this would be from the pulley side of the bearing stand and not the blade side which you'd figure gets more of a beating. Maybe I'm wrong? I do see corrosion showing it was affected by moisture, a good reason to not be just hosing off your mower deck to clean it because protection is poor. A local supplier had Japanese bearings so I replaced them all while I was in there. You can just buy whole new stand assemblies, but presumably with whatever the cheapest bearing they could get inside.



With the belt problem it had also been having apparently finally solved, low speed was not low enough and I imagine that continued start-and-stop on heavy grass overheated the engine and either the rings or head gasket or both let go. You can see how clean it is inside indicating low hours and proper care. Order a rebuild kit and wait for that, find out no store in town sells a cylinder hone so order that and wait for it, then after all assembly I pushed the crank seal in too far, nothing stops it and then you cover a small hole that I imagine is for something or they wouldn't have put it there. I will destroy the seal by removing it, so order another seal and I'm now waiting for that.



With that, the 21hp one-cylinder has been an interesting motor to look inside. 3.7" bore and a huge sliding counterweight with its' own pair of connecting rods on each side for that good-size slug going round. No bearings, just aluminum parts on steel, so I'd say it's important to have the right oil in there and have it be fresh. It all appears to be well-made, keeping in mind that the rockers came off in the first minutes of use (back when) because Briggs and Stratton didn't tighten them. Here's hoping I've hit the last problem that makes this thing finish the season with, as I always do usually in vain. Why do I keep doing this? I really don't want to spend the bucks for a new machine when this one may only have needed the one last repair, plus I am supposed to be able to fix stuff, and finally who says a new one wouldn't just turn out to be as big as a POS as this? I do not have the best of luck just buying new things.

[DanStokes]

Them's some nice welds. My issue is that I have some significant visual issues (laser correction of diabetic-induced blood vessel growth inside the eye) and therefore "missing pixels" that means parts of my field of vision are missing. I soldier on. But I have to agree that you can't weld well if you can't see well and I do everything I can think of to improve my chances. One trick I use from time to time is to draw a line in soapstone next to my weld area so I can follow the line (say, 1/2" away or whatever) and know that I'm on track - I can see the white line when I can't seem to see the weld joint area. My results vary but sometimes I can pull off a decent weld which feels great when it works.

[Loren]

I have used a machinist's awl and a straightedge to scratch in limit lines to make either side of the weld puddle hit. That might seem ridiculous but it helps develop technique and that weld will be there forever, whatever you can do to help yourself is worth an extra minute. I think the soapstone is a good idea, I've seen welds that really went off-track and I've done a few myself.

I get migraines where my vision gets all pixelated so I know the kind of thing you're dealing with.