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I Forge Iron

old style 250 pound little giant


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  • 2 weeks later...
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Finished installing the new drive. Hitting about 30% faster and noticeably harder now. No more stalling! It is however doing the little giant dance. A new spring and new pins are definitely in order. The switch was never right by the belts. It was disconnected since the new motor mount is occupying the space where it originally was mounted. The old motor is no longer attached and the switch is on the guard frame- which I should have done originally. I will replace the switch with a proper magnetic starter, but chose to keep it for the time being. It has a worn blade in the contacts that causes starting issues.

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  • 4 weeks later...
  • 3 months later...

Put the break together again today. The mount for the actuating lever was too near the frame and had to be moved. Welding it back on, I seem to have sent welding current through the ground. What the hell? My ground was placed an inch away from the weld, the electrical was on the other side. I have never had this issue before. Hopefully the motor is ok. I will megger the motor in the morning before I replace all this fried electrical components….

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Found the issue. Spent most of the day getting all the wires replaced- just to be safe. Nothing much was harmed and it gave me the opportunity to reverse the motors rotation- which I had been intending to get to for a while. It turns out, turning counter clockwise now the motor climbs the belts which then jump off. An improvised tensioner solved this and now I am getting single controlled blows. Well on the way to running like I want…

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  • 4 weeks later...

It has been almost a month and while the break is an improvement, it seems to have some issues. The clutch doesn’t pick up like most little giants for starters. The motor and jackshaft seem to be working their way loose as it runs. I need to add tensioners to both. The clutch lining, and likely Babbitt are not in top shape and the arms/ pins are pretty worn- all items I need to get to. Thus far it seems that keeping bolts and belts tight and fiddling with clutch/ break engagement makes things better, at least in the short run. 

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  • 8 months later...

The adjustable arm developed a serious bend. It seems to be smacking the guides occasionally and perhaps this is what happens when it hits stuff that is way too tall. I took it off to straighten it only to find a crack. The link arms are both shop made, and the t bolt is quite a creative part. The t end was a steel bit  cleft welded into the wrought body. I can’t quite tell but it looks like the threads are steel also, but I haven’t identified a seam or weld. The wear on the t end was pretty extreme so I welded a 4140 pin in its place (7018, with heat treat) the wrought body shows a bad crack. Looks like I will be making new arms next week…

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I'd just replace the bolt all together. 

I use a piece of Grizzly screen as a shield in front of the spring, that way I can see the problems to the components before they become issues. A coat of paint is a way to know things are  bending, stretching, etc. BEFORE they start cracking or fail. Good old enamel paint doesn't have much flex and no stretch, it will flake before the steel or even wrought stretches of bends far enough to weaken. IF you can see it.

Make sense?

Frosty The Lucky.

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Two pieces of 8640 cut to forge new arms. The old arm straightened v’d deep into the crack into sound metal, then a bit deeper) and filled with 7018. I don’t really trust it but the 2 3/4” round will forge better under the 250 than the 100. An odd aside, I measured the spring, and compared it to factory spec. It is a full coil shorter, and 1/2” by length as well as 1/2” smaller diameter than little giant spec. Probably the original. I ought to replace that as well… I wish I could find my notes on Clifton’s springs. He went oversize on his and had a place that custom wound them for him. Anybody have that info? 

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Did you fish plate the upper arm welds? When repairing breaks or cracks like you describe the difference between welding rod and base metal cause conducted forces to concentrate at the edges of the weld. That's why welds break right next to the bead, it's not a matter of the weld being stronger it's a basic physics thing that requires heat treatment to mitigate. Orrrrr, you can distribute the conducted force over a large area that doesn't include the weld.

I'm sure you've noticed the diamond shaped plates welded over welds on structural members. If you take a closer look you'll notice many if not most are thinner than the member and offer little real reinforcement. What they do it conduct stress over a longer section of the parent shape. The taper and relatively sharp point is important as the forces dissipate over an area many times larger than the weld and becomes consistently more flexible until it reaches the pointed end. If you look closely you'll see the weld beads (On serious stress bearing shapes anyway) end with a little curl or swirl.

All that serves one purpose, it leaves imparted forces no single place it can concentrate to become stress. 

Fish plating a long narrow member can be as simple as a pointy cigar shape. There is a rule of thumb I don't recall clearly but the fish plate extends 3x the weld length on each side of it. 

The thing that occurred to me first was. Is it necessary to be round bar? Will (to pick a number) 3" x 1.2" rectangular bar work? It'd certainly be easier to make and WAY strong. Even plain old A-36 is tremendously strong, far stronger than the original upper arms.

Hmmm?

Frosty The Lucky.

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These were some heavy chunks…the 2 3/4” round knocked down to 3 1/4x1 1/2, then drawn to 1 1/2”square, rounded, straightened and cooling. Turning and threading these is going to be a trick, my small lathe isn’t up to it and I still haven’t worked out the thread gears for my 1880s lathe…but that adventure is for another day

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