Finger Brake: Useful Tool or Waste of Money?

[warmstrong1955]

You won't need any shims or things like that. The brake is very capable of bending 90 degrees plus some.

What he is saying, is that when you want a 90 degree bend, you can't stop at 90 while pressing and you are done. If you do, when you release the press, the work-piece will spring back, and you will have something closer to 85 degrees.
This is normal. To get a 90, you have to go past 90.

The last 3 or 4 brakes I built, were all skip welded. Started welding at the center, one side to the other, and about an inch apart, like Russ did. Only exception was in the middle, where most of the work gets done. I filled in the two gaps from the center, on each side.

[SteveHGraham]

I found their claim as to capacity: 3/16" steel, full width, or 6" of 1/2" steel. That's pretty good. I'd like to make mobile bases from 3/8" steel, and I won't need 6"-wide strips.

[warmstrong1955]

Here's a chart to give you an idea what you can do.
FYI...a little oil, makes a difference when you start approaching capacity.

Tonnage Chart.xls

(30 KiB) Downloaded 277 times

[spro]

Bed rails. Very hard to cut or drill thru but they have a tight 90* angle for some reason. Could be useful in placing atop the die sometimes.

[SteveHGraham]

The other day I got a great book called Design of Weldments, and this morning I looked at it for help. The material I needed is in chapter 6.

It turns out "presetting," or clamping the channel before welding it, is the correct answer for this particular type of weld. I may get away with clamping it as it is, but it may be better to bend it slightly away from the anticipated warp. I can clamp it in the press, or I can clamp it to my table saw and put sheet metal under it to keep spatter off the saw.

The book says to weld in small segments and to do it over a long period of time. Apparently, I need to do one pair of welds at a time, put down the torch, and come back later for the next pair.

It also says that if I get warpage anyway, I can bend it back toward the bottom by heating the bottom and letting it cool, but I don't think my torches will produce enough heat.

The book is great. Costs $17.50 plus shipping, from Lincoln.

[warmstrong1955]

I think I said that......

And....it sounds like a god book!

[BadDog]

I said that too. Including clamping, and alternating with letting it cool.

[Harold_V]

Right now, all I have are MAPP torches. I need to get some kind of heating/cutting rig. I wanted acetylene, but it's starting to look like there is nearly no reason to ever weld with it, so maybe propane is the answer.

Without oxygen, you'll never achieve the heat required for heavy heating. Mapp gas is good, but works even better with oxygen.
Should you make the decision to go to an oxygen torch, make sure the provided hoses are acceptable for use with propane. The regulator for acetylene can be used with propane without alteration. The only difference is you must buy the proper bottle (acetylene, or propane). There are times when acetylene is a must (can't weld with propane, should you need that feature).

H

[BadDog]

IIRC, you also need a different tip for cutting. It appears my memory didn't fail me this time. But in searching to confirm what I thought I recalled, I found this web site which appears to mesh with my vague memories. Might be worth a read for information on O/A vs O/P.

https://bakersgas.com/pages/converting- ... tive-fuels

And another with what appears to be good info

https://www.genstartech.com/blog/replac ... lication-1

[SteveHGraham]

I think I said that......

And....it sounds like a god book!

You guys didn't quite say that. One of you said it might work, and the other said he clamped his (didn't mention clamping it with a bend) but didn't commit and say it was the correct way. The book spells the whole thing out in detail and makes the best choice obvious.

It's a fantastic book. I can't do it justice here. You can probably find a PDF online if you want to check it out.

[BadDog]

I find that as long as you provide minimal heat management, simply clamping to a rigid table before welding is more than enough for a typical weldment. Again, that's how I did mine, and what I do all the time. The result is easily flat enough for the purpose. Before you say something, what I mean is that I've noted no rocking on the press plates, but didn't set it up on a surface plate to do a detailed survey with a comparator or the like. Good enough is good enough, at least for my purposes.

As for the "correct way", I don't know enough to say my way is the correct way about much at all, and certainly not welding (or machining, or forging, or...). I wouldn't even commit to what I read in a random book as the correct way (unless maybe Connely, or MHB). I've got a variety of books on related subjects that differ in their description of correct ways. Maybe it's like the guy with 2 watches that never knows what time it is?

[warmstrong1955]

And the reason we said it might work, is much depends on how you weld it. In what order, with what method, and how fast.
That, and seldom are things 100%.

I have many parts that I build, that I have made weld jigs for. Not only for set up, but to prevent things from warping when the complete welding is done.
Most of the time, they work great. Little or no straightening is required, but sometimes...... you get an oddball. maybe pull the part out of the jig too soon....whatever.
I know how to straighten them too. Been doin' this a year or 40.