Thread: allowance for a wired edge?

Originally Posted by Stustoys

Anyone following this part of the thread is advised to go and get themselves a nice cup of their favorite hot drink.

Or a cold beer?

Originally Posted by Stustoys

"I've tried to be diplomatic here."
You have? I must have missed that part.
You have yet to show me where the math is my previous post are incorrect. (remember how much you love the math)

I never said it was incorrect. I offered an alternative.

Originally Posted by Stustoys

You have no idea what experience I have, nor do I care about your life history, Oprah might.

Most of my history was added as an attempt to find common ground. Also, to show how much I love this game. It is always challenging, always with something new to learn. So many different things to try. For me it's not the end result that matters, it's the journey to get there.

Somebody once said to me, if you want to learn to play music, first you must buy the instrument. I have the parts to build my own pan brake (not the design from this forum, but my own- but trust me I will read the entire thread to see if I can improve it!) and one day soon I will own my own press brake. Not a new one, it might not even have an NC backstop, perhaps even purchased at scrap value (like of a lot of my gear) and repaired. Then I can be a wanker draughtsman and a bonehead brake press operator at the same time!

Why? you ask. Perhaps little boys never grow up, they just want bigger toys. I'm not into fishing etc. I'm happiest in my shed turning or milling or welding (and soon) bending. My children will not have to miss out on access to real machinery, like I did at school, where they sacked the metalwork teacher and sold the gear. I have already had my five year old MIG welding. He looked kind of small buried in my Speedglas helmet and the gauntlets came up to his armpits, but he never stops pestering me to do it again!

I would sincerely like to try your method, and one day I will. Mine (or the one I am using, I don't own it) has given good results so far, but it doesn't have to be the only one.

Originally Posted by Stustoys

"Obviously you perceive me to be a representative of the draughtspersons (and perhaps management?) in the places you have worked."
I believe I answered your post in the same tone as yours was written.

"However it appears you like to slag people off who have a different viewpoint,"
Please show me where I did this.

Example: Tolerances help draftsman that don't know what they are talking about draw something that can be made.
I can say the math is wrong.

Originally Posted by Stustoys

"Basically I got sick of brake press operators etc blaming the draughtsman for their own failure to read the drawing properly, so I educated myself, and hopefully them a little as well."
Damn uneducated brake press operators messing up my pretty drawings with corrections.

My drawings are works of art. Perhaps better, because they relate to something useful!

I wouldn't say uneducated, perhaps some of them are closed minded.

Perhaps some of the best drawings I have ever seen have the boldly printed words: 'IF IN DOUBT, ASK' !

Originally Posted by Stustoys

I asked you a simple question. Did they have the tooling for a 12mm radius bend? Or did the draftsman call for a radius they couldn't make?
As with most of the other questions I have asked about some of your claims, you choose not to answer.

Surely consultation would have solved the problem? The drawing in question does not belong to us, we only developed it and sent it to a third party who owned the brake press. Brake press operator could have read drawing and said to foreman, hey, we cannot achieve this fold radius (perhaps he did?), foreman said fold it anyway, we can always blame the draughtsman, because if I don't understand it it must be wrong. The flip side is they phone us, say we can only achieve an R8 radius with our tooling, we consult original customer, we adjust flat pattern, and we don't end up collectively looking like a bunch of wankers.

By the way, these parts are now made in China. I suspect the incorrect folding might have had something to do with it, caused simply by this 'us and them' attitude and unwillingness to communicate.

Originally Posted by Stustoys

"By no means am I saying that your experience is not valuable, but I hope that you are not such a Luddite to suggest that the technology out there can't make life so much easier."
So I am a Luddite, just the degree of my Ludditeness varies.

"One such shop had the usual 'subtract two material thicknesses per fold' then add their own internally created 'fold allowance' from folding known lengths of material when the inside fold raidus was the same as (or close to) the material thickness."
Which is the only way to be sure what the K factor is. If you want a different radius you have to start over. Different V block, start over. Different material, start over. As to the 'subtract two material thicknesses per fold' one can only assume that they were interested in the outside size of the finished it item.

I offered to send them a bunch of rectangles in various thickness so that we could get on the same page while this drama was played out. Years passed, and they have not taken me up on it.

Originally Posted by Stustoys

I don't believe I have said that there is only one way to work out the allowance for a wired edge. What I have said more than once is, you can't do is mix systems. If you are going to use the rule of thumb 2.5 x dia then use it and be happy. If you want to careful calculate the mean line (and a few other things) then use that and be happy. What you cant do is to use all of one and some of the other.

I can't recall mentioning that the two systems should be combined. Yes you should use one or the other. Correct me if I am wrong please?

At the end of the day a sheety should use whatever method that they feel comfortable with if it obtains the desired result. Maybe they can invent their own- who cares, if it works?

Originally Posted by Stustoys

Are we having fun yet?

Yeah baby!!

Originally Posted by Stustoys

Stuart

P.s. In case you are worried that this Luddite doesn't know about structural pop rivets don't, because I do. But they sure would look ugly on a S/S bucket.

I am sure they would. Can you get the old fashioned rivets in stainless? The ones you peen over with a rivet set? These would look great, but I am sure there are people out there who would take the path of least resistance! Perhaps solid rivets are as rare as hens teeth, but not as rare as spring lid oil cups.....

I hope we haven't deterred the OP with our arguement. Perhaps the take home message is that there are many alternatives to the one problem. The path you choose is up to you. There will be differences of opinion and the path will not be easy. The last thing we want is the OP to to give up and try a different career!

Originally Posted by Gerbilsquasher

Or a cold beer?

Was way to cold for beer when I wrote my last message. Now today on the other hand, lovely afternoon for a beer.

Originally Posted by Gerbilsquasher

I never said it was incorrect. I offered an alternative.

I don't see how your first post could be seen as anything other than an addition to the rule of thumb(see below).

Originally Posted by Gerbilsquasher

Most of my history was added as an attempt to find common ground. Also, to show how much I love this game. It is always challenging, always with something new to learn. So many different things to try. For me it's not the end result that matters, it's the journey to get there.

Somebody once said to me, if you want to learn to play music, first you must buy the instrument. I have the parts to build my own pan brake (not the design from this forum, but my own- but trust me I will read the entire thread to see if I can improve it!) and one day soon I will own my own press brake. Not a new one, it might not even have an NC backstop, perhaps even purchased at scrap value (like of a lot of my gear) and repaired. Then I can be a wanker draughtsman and a bonehead brake press operator at the same time!

Why? you ask. Perhaps little boys never grow up, they just want bigger toys. I'm not into fishing etc. I'm happiest in my shed turning or milling or welding (and soon) bending. My children will not have to miss out on access to real machinery, like I did at school, where they sacked the metalwork teacher and sold the gear. I have already had my five year old MIG welding. He looked kind of small buried in my Speedglas helmet and the gauntlets came up to his armpits, but he never stops pestering me to do it again!

I would sincerely like to try your method, and one day I will. Mine (or the one I am using, I don't own it) has given good results so far, but it doesn't have to be the only one.

My drawings are works of art. Perhaps better, because they relate to something useful!

My drawings aren't that bad either. Partly dew to a teacher that only allowed the use of a 2H pencil............. sure you can do it, by is it ever slow. I have a beautiful old drawing board that uses a cast iron counter weight that is about 3ft long and 3" in dia.

Originally Posted by Gerbilsquasher

I wouldn't say uneducated, perhaps some of them are closed minded.

Perhaps some of the best drawings I have ever seen have the boldly printed words: 'IF IN DOUBT, ASK' !


Surely consultation would have solved the problem? The drawing in question does not belong to us, we only developed it and sent it to a third party who owned the brake press. Brake press operator could have read drawing and said to foreman, hey, we cannot achieve this fold radius (perhaps he did?), foreman said fold it anyway, we can always blame the draughtsman, because if I don't understand it it must be wrong. The flip side is they phone us, say we can only achieve an R8 radius with our tooling, we consult original customer, we adjust flat pattern, and we don't end up collectively looking like a bunch of wankers.

Well I think its a little harsh to blame the brake press operator

Originally Posted by Gerbilsquasher

By the way, these parts are now made in China. I suspect the incorrect folding might have had something to do with it, caused simply by this 'us and them' attitude and unwillingness to communicate.

I find that mostly its people covering their own ass, instead of saying "well how can we make this right"

Originally Posted by Gerbilsquasher

I offered to send them a bunch of rectangles in various thickness so that we could get on the same page while this drama was played out. Years passed, and they have not taken me up on it.

I can't recall mentioning that the two systems should be combined. Yes you should use one or the other. Correct me if I am wrong please?

From your first post in this thread
" What has been said about the 3/4 circumference of the wire is correct but the allowance for extra material should be calculated on the neutral plane of the sheet being used rather than the inside face. The neutral plane for mild steel is about 0.43 of the thickness on the inside of the fold. For harder materials such as stainless I believe it is somewhat less but I will leave you to do your own research.

For a wired edge, the calculation should use a radius which is a combined total of the radius of the wire plus 0.43 of the thickness of the material. For instance , if using a 2.0mm diameter wire with 1.0mm mild steel, the radius becomes 2.43 mm (although rounding to 2.5mm would probably be close enough)."
You offer no other multiplier, so I at least assumed you intend the use of the 2.5 from the "2.5 x Dia"

Originally Posted by Gerbilsquasher

Yeah baby!!

Sure we're having fun.. but is anyone else?

Originally Posted by Gerbilsquasher

I am sure they would. Can you get the old fashioned rivets in stainless? The ones you peen over with a rivet set? These would look great, but I am sure there are people out there who would take the path of least resistance! Perhaps solid rivets are as rare as hens teeth, but not as rare as spring lid oil cups.....

Strangely the local bearing shop has spring lid oil cups in two sizes. But I have no idea where to even start looking for S/S tinmans rivets, but I am fairly sure they will still be available as the food industry uses lots and lots of S/S

Originally Posted by Gerbilsquasher

I hope we haven't deterred the OP with our arguement. Perhaps the take home message is that there are many alternatives to the one problem. The path you choose is up to you. There will be differences of opinion and the path will not be easy. The last thing we want is the OP to to give up and try a different career!

Never fear, I'm sure most people stopped reading a page and a half ago

Originally Posted by Stustoys

Was way to cold for beer when I wrote my last message. Now today on the other hand, lovely afternoon for a beer.

Oops, as you may have gathered, there is still a lot of pom in me, but not enough that I need to microwave my pint! Ambient temperature is not a consideration.

Originally Posted by Stustoys

I don't see how your first post could be seen as anything other than an addition to the rule of thumb(see below).

Perhaps I could have been more specific.

Originally Posted by Stustoys

My drawings aren't that bad either. Partly dew to a teacher that only allowed the use of a 2H pencil............. sure you can do it, by is it ever slow. I have a beautiful old drawing board that uses a cast iron counter weight that is about 3ft long and 3" in dia.

Trained in 'old school' draughting, not with these fandangled contraptions. I dips me lid!

I find it incredibly tragic that the 'old school' (ie drawing by hand) draughtsman is no longer an essential commodity to engineering. Years of training, skill and experience dashed by computer aided design (CAD) and spotty teenagers who only have to do six months at TAFE to (sort of) learn how to use the software.

I have known some of these 'old school' draughtpersons. Some ended up changing jobs because they wouldn't adapt to the new technology. Perhaps you can be harsh (or objective?) and say in a Darwinian sense, 'adapt or die'?

Those 'old school' guys who picked up CAD would be streets ahead of the spotty teenagers. Having gone to TAFE to find a find a few pointers myself, there is absolutely nothing mentioned about AS1100 or any other draughting standard. When it comes to creating a third angle projection, the software does it for you!

Mate, don't get me wrong, I would rather do 'old school' any day of the week, and where I can't go somewhere to be taught, I will teach myself. I have learnt more from 80 year old books than I have from TAFE (except welding- at this point the knowledge is more or less ageless). Of course reading and learning from the machines in your shed alone will not give you that piece of paper!

Not that pieces of paper are that important.... if I was (theoretically) hiring someone I would look at their qualifications and then give them a task. The guy with less paper and more experience would probably get the job.

Most businesses, perhaps of the 'skills shortage' will give anyone a go. The old saying '90% of success is turning up' but maybe we should add: 'if you have a heartbeat you're a winner!'?

Nowadays it is all about risk management. A guy with an impressive resume will get the job, because they look like less of a risk.

Then again, how many emails have you had for $50 degrees?

Originally Posted by Stustoys

Well I think its a little harsh to blame the brake press operator

I've met good and bad, perhaps the bad are more memorable? I worked with one bloke, John, a pom from Birmingham (I think) who was absolutely brilliant. Every second word he spoke had four letters and started with 'f'. His second greatest asset was, if he had any doubt at all, he would stop and query anything he didn't agree with. His first asset was, of course, his knowledge. Sadly he is no longer with us.

Originally Posted by Stustoys

I find that mostly its people covering their own ass, instead of saying "well how can we make this right"

Could not agree more. People should be a little less fearful, in my opinion. It doesn't turn them into 'sucks', but a willingness to speak out should be commended.

Originally Posted by Stustoys

From your first post in this thread
" What has been said about the 3/4 circumference of the wire is correct but the allowance for extra material should be calculated on the neutral plane of the sheet being used rather than the inside face. The neutral plane for mild steel is about 0.43 of the thickness on the inside of the fold. For harder materials such as stainless I believe it is somewhat less but I will leave you to do your own research.

For a wired edge, the calculation should use a radius which is a combined total of the radius of the wire plus 0.43 of the thickness of the material. For instance , if using a 2.0mm diameter wire with 1.0mm mild steel, the radius becomes 2.43 mm (although rounding to 2.5mm would probably be close enough)."
You offer no other multiplier, so I at least assumed you intend the use of the 2.5 from the "2.5 x Dia"

Perhaps I should have been more specific. What I meant was the 3/4 should have been calculated on the circumference after the 0.43 of material was added to the wire radius: 0.75 x (pi x 2 x (wire radius + 0.43) x material thickness). I assumed the 3/4 related to the length of the material being added.

Originally Posted by Stustoys

Sure we're having fun.. but is anyone else?

I hope so, this has been a healthy dabate!

Originally Posted by Stustoys

Strangely the local bearing shop has spring lid oil cups in two sizes. But I have no idea where to even start looking for S/S tinmans rivets, but I am fairly sure they will still be available as the food industry uses lots and lots of S/S

A few years ago I bought a 1930's Alba shaper and went to Blackwoods for the replacement oil cups. Alemite had some 'old' stock which I have not seen on the Alemite website since. These were small drive-in oil cups to fit 1/4" holes. Back then, I purchased everything they had available, so I have a few spares.

If I looked hard enough I might be lucky enough to find some more!

Originally Posted by Stustoys

Never fear, I'm sure most people stopped reading a page and a half ago

Perhaps we agree on some things, on the others I am sure we can agree to disagree. You are right, we don't need to turn this into War and Peace.

Originally Posted by Stustoys

Strangely the local bearing shop has spring lid oil cups in two sizes. But I have no idea where to even start looking for S/S tinmans rivets, but I am fairly sure they will still be available as the food industry uses lots and lots of S/S

Had a look thru the tinsmiths rivets Dad left behind and found some......wonder why he used gal ???? wait till I see him ......

they certainly are available, but like a lot of things in oz no one knows where to get them...even the plain old alloy or steel, (another example I had recently was threaded taper pins... both of these items ar readily available from Grainger Industrial and some others in the US)

Originally Posted by eskimo

Had a look thru the tinsmiths rivets Dad left behind and found some......wonder why he used gal ???? wait till I see him ......

they certainly are available, but like a lot of things in oz no one knows where to get them...even the plain old alloy or steel, (another example I had recently was threaded taper pins... both of these items ar readily available from Grainger Industrial and some others in the US)

Well now you can drill them out and change them

Yes a few times I have found stuff in catalogues, but then you have to find someone that stocks it.
Stuart

Originally Posted by Gerbilsquasher

Perhaps I should have been more specific. What I meant was the 3/4 should have been calculated on the circumference after the 0.43 of material was added to the wire radius: 0.75 x (pi x 2 x (wire radius + 0.43) x material thickness). I assumed the 3/4 related to the length of the material being added.

To try and "un" war and peace it. It's late so I hope my math is right
This makes little sense to me.
(using your example of 1mm mat around 2mm wire)
0.75 x (pi x 2 x (wire radius + 0.43) x material thickness)
0.75 x (3.14 x 2 x (1 + 0.43) x 1)
0.75 x (3.14 x 2 x 1.43)
0.75 x 8.9804
6.7353
I think that only works out so well because your wire radius and material thickness are 1
I think you meant
0.75 x (pi x 2 x (wire radius + (0.43 x material thickness))?
which btw gives the same answer in this example.


If you use wire dia of 3mm and material as .4
0.75 x (3.14 x 2 x (1.5 +(0.43 x .4))
7.87512
The rule of thumb gives you 7.5
The 270 degree(3/4) I mentioned in my post isn't part of the rule of thumb, it just as approximation to illustrate what i was saying about getting "roughly" the first 1/4 for free. You don't need 270 degree or you would have two material thicknesses.

Originally Posted by Stustoys

Well now you can drill them out and change them

Stuart...go wash your mouth out with soap...lol
dont you know that your not supposed to fix anything if it aint broke.

Well dont go looking at me the day you're left with a handle and no bucket
(granted this may be quiet a while from now) hehe

Stuart

Originally Posted by Stustoys

To try and "un" war and peace it. It's late so I hope my math is right
This makes little sense to me.
(using your example of 1mm mat around 2mm wire)
0.75 x (pi x 2 x (wire radius + 0.43) x material thickness)
0.75 x (3.14 x 2 x (1 + 0.43) x 1)
0.75 x (3.14 x 2 x 1.43)
0.75 x 8.9804
6.7353
I think that only works out so well because your wire radius and material thickness are 1
I think you meant
0.75 x (pi x 2 x (wire radius + (0.43 x material thickness))?
which btw gives the same answer in this example.


If you use wire dia of 3mm and material as .4
0.75 x (3.14 x 2 x (1.5 +(0.43 x .4))
7.87512
The rule of thumb gives you 7.5
The 270 degree(3/4) I mentioned in my post isn't part of the rule of thumb, it just as approximation to illustrate what i was saying about getting "roughly" the first 1/4 for free. You don't need 270 degree or you would have two material thicknesses.

Yes I did mean 0.43 x material thickness.

Either way, I think we are both in the ball park.

Ultimately, the person using the cake tin is probably not going to be concerned about a difference of 0.37512mm or the method used to calculate it. They might even admire the workmanship and the 'magic' (to them) of the person who created it!

You can't say there are many ways to skin a cat.

I don't get a lot of opportunity to put this into practice, and actually create items with wired edges. I might have a go at a s/steel paint roller tray. I bought a plastic one from Mitre 10 recently, by no means the cheapest. First time I used it I picked it up with one hand and even when empty there was a loud crack of plastic splitting. I know I don't have to buy cheap throwaway rubbish when I can make it better myself. Stupid, yes?