[Chips O'Toole]

I'm putting together a Swag Offroad finger brake kit. The bottom part is a thick piece of channel, and the die that sits on it is angle iron, open upward. You're supposed to weld the sides of the angle iron to the channel. It's about 20" of welding on each side.

The part tends to bow upward from the welding. Jody put a similar product together, and his warped. He was able to fix it later with heat. I don't have that option. My biggest torch is MAPP gas.

My question: what if I put the parts in the hydraulic press and crank it until there's a slight bend in the other direction? If I did that, I would expect it to be straighter when the pressure was released.

The big problem is finding out how much bend to put in it while welding.

[cj737]

Is it possible to clamp it intermittently along its length? If not, small tacks to hold it? Start in the middle, tack outwards.

[LtBadd]

So the angle (open upwards) is going to be the bottom part of the die? I don't see why it needs to have a full length welds

[Chips O'Toole]

So the angle (open upwards) is going to be the bottom part of the die? I don't see why it needs to have a full length welds

I don't get it, either. The bottom of the angle iron will rest on the channel, and the pressure will be on the center of the angle iron, along the long axis. You would think there would be very little pressure on the welds. I would expect the bottom die to work even if it weren't welded in place. I'm just giving Swag Offroad the benefit of the doubt.

I finally had a day of acceptable welding. I noticed that other people, who are much better at metalworking than I am, were having problems getting the guide rods in straight. You have to press them into a couple of holes in the channel and then weld inside the holes. I used a machinist's square and a 1/4" parallel to align them along two perpendicular axes, and when I was done welding them, there was less than 0.020" of light between them and the square.

I think the welding is okay. I couldn't practice on anything remotely resembling these parts, so I used a piece of 1/4" diamond plate to set the welder. It was too hot when I actually welded the parts, so I turned it down, and the results were acceptable. If I had had two or three of these to practice on and scrap, the results would have been a lot prettier.

I deliberately tried to stay on the hot side, because the last thing I wanted was to have to do this again because a weld was no good.

I didn't go all the way around the rods. They will never see much force, so I thought it was a waste of time, and if, for some reason, I ever want to remove the rods, four globs of weld will be easier to cut out than one huge mass.

I have had a lot of trouble seeing what I was welding, but with the new lamp, some practice, and a special effort to clean the helmet, I saw things very well today. That was a big deal for me, because I had been wondering if I was going to have to give up welding. I had been completely missing seams I had been trying to weld.

09 10 19 Swag Offroad finger brake kit guide rod weld 01 cropped.jpg (131.29 KiB) Viewed 1297 times

09 10 19 Swag Offroad finger brake kit guide rod weld 02 cropped.jpg (117.88 KiB) Viewed 1297 times

[weldin mike 27]

What you are talking about is call pre setting. It's an extremely common way of distortion control. You don't need a press, a solid table, some decent clamps and a packer will do the trick. Place the packer under your job and clamp down each end to form the bend away from the welding. Then weld. You need to be wary of when to release the clamp, because it may stay bent if you hold it for too long and may bow from the welding heat if you release it too soon. Another pre set method is to simply bend the part away from the direction of welding and allow the heat to bring it back. This is not as easy as simply clamping

[Chips O'Toole]

The other day I picked up a book called Design of Weldments. Lincoln sells it. A Youtuber recommended it, not so much for welding as for the basic engineering.

Anyway, I realized the information I needed might be in this book, so I took a look. Sure enough, presetting is the best option for this type of weld. It's in chapter 6.

I think the best thing is to weld it in the press. If I can't make that work, I can clamp it to my table saw and cover the saw's surface with sheet metal to protect it. The book says to do it in small segments over a long period of time. It also says peening the welds is a waste of effort.

The book says that if I still get warpage, I can take it out by heating the long side and letting it cool, but since I only have small torches, I don't think I can pull that off.

[homeboy]

I have straightened tubing that arched due to welding on one side by running short hot beads on the opposite side. Run a short hot bead or 2 and let it cool to see what you've got. Repeat if needed. Grind off the welds after. I don't have a torch either!

[MinnesotaDave]

When I welded mine I back-stepped the welds in about 6" increments.

I did not get any warping using this method.

[Chips O'Toole]

I decided to use soapstone to mark the bottom die at 1" intervals. I put 4 tiny tacks at the corners, which I later found out was not the right thing to do. I then started welding from the middle out, skipping inches. I never did more than four welds at one sitting. I got up and came back after it cooled off.

The part has not moved measurably. The guide rods are about a millimeter farther apart than they should be, but that's because Swag cuts the top die clamp a little short.

I used a machinist's square to scribe lines across the tops of the tubes at the exact centers, and I used a caliper to do the same thing to the fingers. This way, I got the tubes and fingers aligned to within a few thousandths. I couldn't think of a better way to do it.

I don't see any point in welding the entire thing up. It will be prettier, but it seems to be completely unnecessary, and I don't want to push my luck with the warping.

I didn't weld the guide tubes all the way up the clamp, as the instructions suggest. The welds only have to survive the force of the springs, which isn't much. I didn't realize the instructions said to weld them all the way until I looked at them again later. It seemed to me that adding all that welding would invite warping and make spatter problems more likely.

I wonder if people who are having warping issues are just putting too much weld on the project.

I only wish I could see soapstone better while welding. Some of my welds are not exactly one inch long, to put it mildly. I couldn't always tell when I was at the end of each segment.

I could not weld the bottom die while it was clamped in the press, for various reasons. I think it was a good idea, but too hard to do in practice. I needed something to fit between the fingers and bottom die, and I didn't have it.

The bolts they included are fat. They don't like to go in the threaded holes. I chased some of the threads with a Greenlee tap, which is not likely to be inaccurate, and the bolts still didn't want to go in.

My welds were small, but they interfered with the beam clamp, as the instructions predicted, so I beveled the plate on the belt grinder.

The brake is wonderful. It will allow me to create a lot of very useful stuff.

09 16 19 Swag Offroad finger brake guide tube welded to upper bar 01 small.jpg (78.33 KiB) Viewed 1182 times

09 16 19 Swag Offroad finger brake guide tube welded to upper bar 03 small.jpg (95.15 KiB) Viewed 1183 times

09 16 19 Swag Offroad finger brake bottom die welds 02 small.jpg (119.09 KiB) Viewed 1183 times

09 16 19 Swag Offroad finger brake assembled small.jpg (133.19 KiB) Viewed 1183 times

The welds may not look great, but by my standards, they are spectacular. Things are getting better.

[LtBadd]

Good job Chips!

[Chips O'Toole]

Thanks. I'm feeling a lot more able now that I'm making some things.

I welded up the collar today. That had slipped by me. Also put an air jack on the press.

[JayWal]

Looks great chips. Having a brake is definetly handy and as I’m getting more and more into it I realized fast it’s an art too. Knowing how the metal stretches when you bend it, and predicting how much it will, still hurts my little brain sometimes. If you want to get more info on accurately bending parts, This Old Tony on YouTube has an awesome video called “How to Bending” that’s pretty easy to understand and has some great easy to follow info.

As for the soapstone marks i like to take my time and make perfectly spaced stitch welds too. Usually I mark everything with soapstone then make small tack welds at the beginning and end of each weld. That keeps warping down somewhat since it’s tacked so well, then I go back and simply weld in between the tacks.


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[Chips O'Toole]

I'm going to use that tack idea. Thanks.