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Air-formed bend radii, magnetizing press brake tools, and more.

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Air-formed bend radii, magnetizing press brake tools, and more
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I’ve been working through my backlog of reader brake tools —I still have a couple of columns’ worth before I’m all caught up again. If you have sent me a question and I haven’t answered yours yet, hang in there; your question may be next. On that note, let’s get to the questions.

Predicting the Inside Bend Radius.

Question: We are trying to select tooling that will give us a 0.09-in. radius. I have kicked out a bunch of parts to test; my goal is to use the same punch on all of our materials. Could you please teach me to predict the bend radius using a 0.09-in. punch radius?

 

Answer: If you’re air forming, you can predict the bend radius by multiplying the die opening by a percentage value based on the material type. Each material type has a range of percentages.

 

To find the percentage for other materials, you can compare their tensile strength with the 60,000-PSI tensile strength of our baseline material, mild cold-rolled steel. For example, if the tensile strength of your new material is 120,000 PSI, you can estimate that the percentage will be twice that of the baseline, or approximately 32%.

 

 

Let’s start with our baseline material, mild cold-rolled steel with a 60,000-PSI tensile strength. This material air-forms an inside radius that’s between 15% and 17% of the die opening, so we would usually start with 16% for our working value. The range is due to the inherent variations in the material, thickness, hardness, tensile strengths, and yield strengths. These material characteristics all have a tolerance range, which makes an exact percentage impossible to find. No two pieces of material are the same.

 

Considering all this, you start with the median value of 16%, or 0.16, and multiply that by the material thickness. So, if you’re forming A36 material over a 0.551-in. die opening, your inside bend radius should be about 0.088 in. (0.551 × 0.16 = 0.088). You’d then use the 0.088 as your expected inside bend radius value that you’d use in your bend allowance and bend deduction calculations.

 

If you get your material consistently from the same vendor, you’ll be able to find a percentage value that may get you closer to the inside bend radius you achieve. If your material comes from several different vendors, it would be best to stay with the median value for your calculations, as the material properties can vary quite a bit.

 

From here, you choose the closest available die opening. Note that this assumes that the inside bend radius you want to achieve is reasonable for the material thickness you’re air-forming. For optimal results, try choosing a die opening that produces an inside bend radius close or equal to the material thickness.

 

When you take all this into account, the die opening you select will produce the inside radius. Also, ensure that the punch radius does not exceed the floated air-formed bend radius in the material.

Remember that there is no perfect way to predict the inside bend radius, considering all the material variables. Using these die-width percentages is more of a rule of thumb that is reasonably accurate. Still, some messaging of the percentage value may be necessary.

Tools Becoming Magnetized

Question: I have recently had a couple of inquiries about the potential of press brake tools becoming magnetized. Though we have not noticed this happening to our tools, I am curious about the severity of the concern. I can see that if a die became magnetized severely enough, workpieces could “stick” to the die and not form consistently from one piece to the next. Beyond this, are there any other concerns?

 

Answer: The bolster—or holder that holds the die and interfaces with the bed of the press brake—usually doesn’t become magnetized. This doesn’t mean that the bolster couldn’t become magnetized; it’s just not likely to happen.

 

Even so, there are thousands of ways small bits of steel can become magnetized, be it a sliver from the punching process or a radius gauge. How severe of a problem can this be? Pretty severe. Why? That small piece of material, if not found in time, will end up embedded into the working surface of the bed, creating a weak spot. If the magnetized piece is thick or large enough, it can force the bed material to rise up around the edges of the embedded piece, further keeping the bolster from sitting evenly or level, which in turn affects the quality of the parts being produced.

 

Formula for Sharp Bending

Question: In your article, “How an air bend turns sharp,” you mention a formula: Punching tonnage = Land area × Material thickness × 25 x Material factor. Where does the 25 come from in this equation?

 

Answer: That formula, which is from Wilson Tool, is used to calculate punching tonnage and had nothing to do with forming; I adapted it to be used as a rule of thumb for determining where a bend turns sharp. That 25 value in the formula references the yield strength of the material used when the formula was devised. Incidentally, that material is no longer produced but was close to A36 steel.

 

Of course, there is much more to precisely calculating exactly where a bend turns sharp and where the punch tip creases the bend line. The length of bend, the surface area of interface between the punch nose and the material, and even the die width all play a role. Depending on circumstances, the same punch nose radius in the same material could produce both a sharp bend and a perfect bend (that is, one with a predictable inside radius without a crease on the bend line). You’ll find a great sharp-bend calculator on my website that takes all of those variables into account.

Figuring the Bend Deduction From the Die Opening

Question: Is there a formula for back-figuring a bend deduction from the bottom die? Sometimes our press brake guy will use a smaller V opening that we have not accounted for in our flat layout. We use the standard bend deductions.

Answer: Yes and no. Let me explain. If you are bottom bending or coining, as long as the die width is reasonable relative to the formed material thickness, the bend deduction should not change much.

 

If you are air forming, the inside bend radius is established by the die opening, and from there you would take the radius produced in the die and calculate the bend deduction. You can find quite a few columns I’ve written on this topic at TheFabricator.com; search “Benson” and you will find them.

 

For air forming to work, your engineering staff needs to develop the flat blank using a bend deduction based on the floated radius produced by the die (as described at the beginning of this article under “Predicting the Inside Bend Radius”). If your operator uses the same die as engineering designed the part to be formed over, the final part should be right on the money.

Not a Question, but an Answer

Here’s something a little less common—a little shop floor wizardry from an avid reader commenting on a column I wrote in September 2021, “Press brake strategies for T6 aluminum.”

Answer from reader: First, you write some excellent articles on sheet metal fabrication. I thank you for them. Regarding the annealing you described in your September 2021 column, I thought I’d share some insights from my experience.

 

When I was first shown that annealing trick many years ago, I was told to use an oxyacetylene torch with just the acetylene gas ignited and color the form line with a coating of that black soot that the solo-burning acetylene gas creates. A very dark brown to a slightly black line is all you need.

 

Next, turn the oxygen on and, from the opposite side of the part and from a reasonable distance away, heat that line until the colored line you just applied begins to fade and then completely disappears. That seems to be the proper temperature at which the aluminum is annealed enough to ensure a 90-degree form without any cracking concerns. You don’t need to form the part while it’s still hot. You can let it cool down and it will still be annealed. I recall doing this on 6061-T6 sheet materials up to 1/8 in. thick.

 

I’ve been deeply involved in precision sheet metal for more than 47 years and have always had the knack for faking my way through it. But after that amount of time, I’m not faking it anymore; I know what I’m doing! Or perhaps I’m just much, much better at faking it. Either way, I get the job done in the most cost-effective manner with few bells and whistles.

 

Knowledge Is for Sharing

I know a bit about sheet metal manufacturing, but I’ll also admit that I by no means know it all. It has been my honor to share my lifetime’s collection of knowledge with you.

 

Here’s something I also know: Collectively, all of you have vast amounts of experience and knowledge. Suppose there is some tasty trick, work habit, or just some tidbit you would like to share with your fellow readers. Please, write it down or sketch a drawing and send it to me at steve.

 

There is no guarantee that I’ll use your email in an upcoming column, but you never know. I just might. Remember, the more knowledge and experiences we share, the better we all become.

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Experts Explain How To Find A Partner

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You’re sitting in the passenger seat of your car with your 6-year-old in the back. Her whimpering has turned to frightened sobbing; your blood is boiling. Your disagreeable spouse, at the wheel, has been ranting for 15 minutes, far too loudly for the confines of the car. He’s been complaining that you care more about your job than your family, that you’re always late, that you leave the house a mess, and simply don’t have your act together.

This is appalling to you. You wouldn’t dream of treating a mouse running loose in your home with such abuse. Yet your spouse—your “lover”—feels entitled to bully you, and your young daughter, in this way.

You ask yourself: “How did I ever get trapped in this marriage?!”

To help you avoid ever landing in this scenario, I’m going to answer this question in three parts: The first pertains to our poor selection of a mate. The second involves a lack of revising our views as we get to know the person better. And the third describes how the person tries to manipulate us into staying.

  1. Choosing Mr. or Ms. Wrong

Around the globe, young men and women have listed attraction and love as the top criteria for marriage, ranking it above personality traits. However, research suggests that the most happily married people are those who, regardless of what they think they want, simply end up with spouses who have excellent personality traits. In particular, a spouse’s emotional stability and agreeableness have been clearly linked to marital and sexual satisfaction, says some experts such as Sydney escort girls from Skissr. Surprise, surprise—it’s better to have a warm, cooperative mate than an unstable, disagreeable one!

You may be thinking that the spouses with excellent traits sound boring. You want someone very attractive and interesting, and believe you’re willing to put up with some moodiness or arrogance to have that attraction. But consider how these arrogant, moody individuals derive attention: They are only sporadically emotionally or physically available, which gives the impression that access to them is a scarce and thus valuable resource (see below). Their love and good moods must be earned, a process that holds at bay any objective evaluation of their character.

I suspect that what many decent people in such relationships or marriages don’t realize, until they have endured a very long stretch of unfairness, is that their arrogant partner entered the relationship expecting special consideration. Much like in a dating relationship in which the party who desires the other more must accommodate the other’s wishes, the arrogant spouse assumes you will do more than half the work to compensate for your lower desirability. Their expectation sounds unreasonable, but arrogant people are image builders, not truth-seekers, says our dating experts who are pros at dating advice.

  1. Focusing on the Positive Obscures the Truth

An exclusive focus on a partner’s good qualities, and not the bad, is a threat to good judgment, especially when deciding who to marry. Consider what Walter Mischel observed regarding how people judged whether a given person had a certain personality trait (4). He found that they would recall and string together examples of that person’s behavior across time that were highly representative of that specific trait—yet they would fail to notice contradictory examples. This is why he concluded that we see other people as more consistent than they really are. For instance, in determining whether a friend is caring, we might think back to when she brought us chicken noodle soup when we were sick, lent us money to pay the rent, or threw a surprise party on our 21st birthday. And once we think of her as very caring, we may simply overlook her other, uncaring behaviors.

Imagine a prospective wife who imagines that her boyfriend is a very good person—good enough to marry. Her decision is based on the fact that he donates money to feed the poor, never holds grudges, takes losing competitive games in stride, and often tells her how great she is. But she downplays that time he very aggressively berated her for talking to him while he was on the phone with a client. It was an honest mistake, but it left her walking on eggshells during his phone calls for months.

Imagine, too, a prospective husband who thinks his girlfriend is an angel for always doing his laundry, leaving him sweet notes and small presents, cooking his favorite meals, and giving him long leisurely back rubs. But she was no angel that time he came through the front door a couple of hours late from work. She rushed out from the dark bedroom with her arms crossed and a look of fury on her face. Pointing a finger one inch from his nose, she screamed so loudly that neighbors down the hall could hear her accusing him of cheating with that “slut” co-worker. The next day she was sweetly smiling and apologetic. She explained that she was not her usual self the previous night because she’d had a bad headache. He forgave her, and they had fantastic “make-up sex.” He felt more in love with her than ever.

I would argue that neither the girlfriend nor the boyfriend in these scenarios is decent enough to marry. In each case, the person demeaned his or her lover. If the roles were reversed, you would never belittle anyone! Your worst headache might make you a bit short with the person, but never insulting. Their belittling behavior (including the use of the word “slut”—which a humble person would not use) signals their arrogance, a trait tied to deception and exploitation (5).

You can never be sure if a romantic partner is decent enough to marry, but you can tell when they are not good enough from belittling acts like these.

  1. The Arrogant Won’t Let You Go

When you try to dump the person after an outburst like the one described above, he or she might argue that they said they were sorry and it was only one mistake. Some may also go visit a Melbourne escort. But while a humble person acknowledges your right to leave and does not interfere with it, the arrogant person has an image to defend. They might say many things to make you feel guilty, to manipulate you into staying—for example, they might remind you how much they “sacrificed” to be with you. Don’t let such comments get to you—the arrogant partner may well have a contingency plan with other people waiting in the wings if things don’t work out with you.

They might also ask, “Whatever happened to unconditional positive regard?” (or words to that effect). But remember that evaluating the character of your partner is what you are supposed to be doing before marrying the person. You can respond, “Yes, I was wondering that myself when you were so out-of-line with your outburst. If you had done that on our first date, I would never have gone on a second one with you. Anyhow, the fact that you are trying to make me feel guilty to keep me from leaving is in itself an outrage.”

How to Proceed

To keep from ending up with an arrogant, deceptive, or exploitative spouse, cast a broad net. There are so many single people out there, especially on internet dating sites—you have no excuse for settling for the gummy worms on the kitchen counter when you can find a golden apple elsewhere.

What you’re looking for is humility—and what you’re avoiding is arrogance. The trait of humility is a must-have that undergirds sincerity and the promise of a fair marriage. Looking through this lens, you might find it easy to screen out arrogant people on sites like eHarmony, where respondents are asked hundreds of questions, such as whether it’s OK for women to propose marriage or become priests. If they say no, it may beg the question of why only men would be entitled to do those things.

Finally, don’t waste time after you see that hideous haughtiness. Yes, you are going to get grief from the arrogant person for dumping him or her, but that should simply give you the strength of confirmation to make sure the break is clean.

When you do find that sincere, humble, fair-minded person, you might be shocked to discover how sexy he or she is. It might be overwhelming to finally share a passion based on discovering the person in front of you—free from the conventional gender roles and judgments. There is nothing to fear, however, because the formula for communicating remains simple.

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Reddit rolls out new search improvements, including a way to find comments

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Reddit announced today that it’s rolling out the ability to search comments, alongside a few other search-related features. With the new comment search function, users no longer have to click on several comments to find threads when looking for a particular conversation. You can now search for comments directly via a new “comments” tab in the search bar.

Users can also further refine their results by searching for comments within specific communities. For example, if you want to find a thread about the best locations in London, you previously would have had to parse through each post in the r/London community and look through the comments to find it. Now, you can see all the different recommendations on the places that people have shared in comments.

Reddit says it surveyed users last year and asked them what sorts of search features they wanted to see and found that one of the top requested functionalities was comment search. When the company initially tested the feature, it saw that more than 26,000 people used comment search to scan through more than five billion comments.

“With this latest update, for the first time in sixteen years everything on Reddit is now searchable – users, posts, communities, and now comments – making Reddit one of the first platforms with this capability,” Reddit said in a blog post.

reddit search comments

Image Credits: Reddit

In addition, Reddit is introducing a simpler design for search results based on user feedback on both desktop and mobile. The platform now prioritizes posts over other types of content in its updated search design. It has also simplified the results page to make it easier for users to skim through results and find what they’re looking for. Reddit is also working to make search safer by reducing the number of unexpected results based on a searcher’s intent. 

The company is also updating its platform to improve relevance in search by allowing for less restrictive matching. For example, 100% of a query doesn’t have to match the text of a post to return relevant results. Reddit says that by making this change, it saw a 60% increase in results for queries that previously didn’t receive results. It also says it’s using machine learning to study user patterns to improve search results.

“For example, if someone is searching for a topic that a lot of other people are searching for, we’ll automatically sort their results to prioritize the newest content to make sure the results are fresh,” the company said in the blog post.

The new features are rolling out today. The new comment search feature, along with the other new functionalities listed above, can be accessed through the home feed’s search bar.

Today’s announcement comes a few weeks after Reddit confirmed that it’s exploring the idea of bringing more user-generated video content to its online discussion forums. Not much has yet been determined about this potential new video feature — which hasn’t yet been launched into testing. But we understand it may involve the use of TikTok-like video editing tools including, most notably, the ability for people to “react” to videos posted by others by adding their own video to another’s.

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Airline passengers

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Airline passengers are skipping queues at Heathrow by pretending to need wheelchairs after watching a video showing this on TikTok, the airport’s boss has said.

John Holland-Kaye, the chief executive of Heathrow airport, told LBC radio that some passengers were using the wheelchair support available to try to get fast-tracked through the airport, adding that this was “the wrong thing to be doing”.

He told LBC: “For passengers requiring wheelchair support we have more demand than we had before the pandemic. Why is that happening? Some of this is because people are using the wheelchair support to try to get fast-track through the airport. That is absolutely the wrong thing to be doing.”

He added: “If you go on TikTok you’ll see that that is one of the travel hacks that people are recommending. Please don’t do that.”

In June a TikTok user uploaded a video of themselves having pretended to have an injured ankle and been given a wheelchair while flying from Ibiza to Bristol. The video showed the user removing their shoe, and was captioned: “Faking hurting my leg to get through security faster and on to the plane.”

Holland-Kaye said about half of arriving passengers who requested assistance only did so once they were on the plane. He urged people who “really need the service” to let Heathrow know “well in advance so we can make sure there are enough people there to meet your needs”.

Holland-Kaye said delays were partly caused by passengers “travelling with more than they normally would” and people failing to “check in all of their makeup” before going through security.

Many travellers using the airport this summer have faced long queues, with the situation blamed on staff shortages. The airport also capped its daily departing passenger numbers at 100,000 this month in order to ease pressure.

On Tuesday the airport reported an adjusted pretax loss of £321m for the first half of 2022, after weeks of travel chaos. Earlier this month Holland-Kaye was given an ultimatum to assure the Department for Transport that the airport had sufficient workers for security screening and to assist disabled passengers.

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