At what angle do you cut banisters




07.06.2012, 6:58 pm

Ralf27
Posts: 2779
Users
I have a little geometric problem here. The following is given:

A banister handrail is to be made. For this, the handrail must be cut to angles. All is well and good if two inclines in the room did not meet at right angles. How do I calculate the angle of intersection of the two pipes? I can get the length already, but not because of the angle for cutting and the twist required for cutting.
I hope I was able to get across the problem in a way that was understandable.

Or typed differently:
the upper handrail has an incline of approx. 33 degrees, the lower one of 56. When viewed from above, both handrails run at right angles to one another. The "kink" cannot be done in 90 degrees.
How can you best figure that out? I can also draw the imaginary center line in 2D, but since the whole thing is in 3D, I unfortunately get into a lurch.

Grateful for any help.
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

June 7th, 2012, 7:55 pm

tick23
Posts: 114
Users
@ Ralf27:

what kind of profile shape is the handrail anyway?
The easiest thing would be to let the railing run straight up and straighten out just before the bend ...
because even with a pencil cut it will be almost impossible, depending on the profile shape, to get it 100% clean ...




[This post was changed by zecke23 on 07.06.2012 at 19:56. ]

[- Answers - Quoting - Direct link -]

07.06.2012, 8:02 pm

Ralf27
Posts: 2779
Users
Sorry, you are right. The whole thing does not work with a square tube. It should be round pipe. The stairs are already there. Nothing more can be rebuilt there, but the handrail has to adapt to the stairs.

Or a short piece is just not manageable in terms of design.
--
http://www.alternativencomputerclub.de.vu

[This post was changed by Ralf27 on 07.06.2012 at 20:03. ]

[- Answers - Quoting - Direct link -]

June 7th, 2012, 9:43 pm

Thomas
Posts: 7666
Users
@ Ralf27:

Do the railings have to be brought together? Nobody will ever go into a corner with their hand anyway. My parents also have a staircase with a right-angled bend in the middle. The two railings (made of wood) are not together either, but stop about 5 cm before the (theoretical) meeting.

--
Email: [email protected]
Home: thomas-rapp.homepage.t-online.de/

[- Answers - Quoting - Direct link -]

June 8th, 2012, 11:05 am

DrNOP
Posts: 4118
Users
@ Ralf27:
Is that still that railing?

Have you just left it for two years and now try again?
--
Signatures with more than two lines annoy me

[- Answers - Quoting - Direct link -]

June 8th, 2012, 8:17 pm

Ralf27
Posts: 2779
Users
Quote:
Original from DrNOP:
@ Ralf27:
Is that still that railing?

Have you just left it for two years and now try again?

No, it's not the same handrail.

Is the following problem:
So far I've been cutting and grinding my way to the result, but that's not really satisfactory. So, professionally!
Especially when I have two handrails in the same way as described above, then I simply cannot calculate it correctly. Because if that were possible, then I could save myself a lot of work on the construction sites.

PS: This is about stainless steel, mostly round tube 42.4.

--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

June 8th, 2012, 8:21 pm

Ralf27
Posts: 2779
Users
Quote:
Original from thomas:
Do the railings have to be brought together? Nobody will ever go into a corner with their hand anyway.

That is better, because the handrail usually sits on a railing and the whole thing is much more stable when the railing is connected to the handrails.
"Unfortunately" it is usually the case that customers want a continuous handrail.

The main thing here is to save me work on the construction site and to be able to do as much and precisely as possible in the workshop.

About 2 years ago I wanted to solve the problem, but didn't really bite through, now I have an order where I have to connect a lot of handrails and on site that's a huge time problem.
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

06/09/2012, 7:39 pm

tick23
Posts: 114
Users
don't you have a protractor on site that you can use?

I did the math ...
if I have now understood the course correctly, I get 116.8 ° every time. would be 58.4 ° when cutting ...

[- Answers - Quoting - Direct link -]

June 9th, 2012, 11:10 pm

inq
Posts: 445
Users
Hm,
what is that supposed to look like? The way I imagine it, two ellipses meet, which can never be brought congruent. Do you "fill" that with the weld?

What about bending? You bend the part that you need (I also count kinking as bending here) and then weld it in between.

greeting
inq

[- Answers - Quoting - Direct link -]

06/09/2012, 11:20 pm

inq
Posts: 445
Users
Icke again.

Do that in a 3D program and then measure it with the functions you have there (or print out the views and measure it out analogously).

Simply push two tubes together, it can't be that difficult ...

inq

[- Answers - Quoting - Direct link -]

06/10/2012, 8:15 am

tick23
Posts: 114
Users
Quote:
Original from inq:
Hm,
what is that supposed to look like? The way I imagine it, two ellipses meet, which can never be brought congruent. Do you "fill" that with the weld?

What about bending? You bend the part that you need (I also count kinking as bending here) and then weld it in between.

greeting
inq

the cut then has the shape of an ellipse, right ...
You don't need to "fill" because the cut surface is the same ...

bending would be a possibility. however, a 42.4 mm stainless steel round tube is used here. you cannot bend it so sharply without damaging it. the kink would then be a bow ...

Quote:
Original from inq:
Icke again.

Do that in a 3D program and then measure it with the functions that you have there (or print out the views and measure it out analogously).

Simply push two tubes together, it can't be that difficult ...

inq

yes, a program is of great help here.
the railing must have been designed by someone, according to which corresponding plans should / should be available ...

you can also determine the angle with a simple triangle calculation ...

In my opinion, the easiest / fastest would be to work with a protractor ...




[This post was changed by zecke23 on June 10th, 2012 at 8:34 am. ]

[- Answers - Quoting - Direct link -]

06/10/2012, 10:18 am

hjoerg
Posts: 3794
Users
Practitioner:

Digital spirit level

Chop saw


Measure the angle and twist, clamp in the same way in a chop saw (stainless steel blade) and weld.


Pickling, passivation, polishing ... done.
--
WinUAE fan
hjörg
Nethands

"If I agree with you, we're both wrong"

[This post was modified by hjoerg on June 10th, 2012 at 10:18 am. ]

[- Answers - Quoting - Direct link -]

06/11/2012, 9:14 am

Ralf27
Posts: 2779
Users
Quote:
Original from inq:
Hm,
what is that supposed to look like? The way I imagine it, two ellipses meet, which can never be brought congruent. Do you "fill" that with the weld?

What about bending? You bend the part that you need (I also count bending here, sometimes kinking) and then weld it in between.

greeting
inq

Well, the cuts have to be made the same on both pipes, otherwise it really doesn't fit together. Only the twisting of the pipes is different.
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

06/11/2012, 9:16 am

Ralf27
Posts: 2779
Users
Quote:
Original from inq:
Icke again.

Do that in a 3D program and then measure it with the functions you have there (or print out the views and measure it out analogously).

Simply push two tubes together, it can't be that difficult ...

inq

It's good. In which 3D program? What could you take there?

I can also simply push two pipes together in MaxonCinema (I haven't done it yet, so for this purpose), but I guess I won't get anywhere.

Seriously now, that's harder than it looks later.
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

06/11/2012, 9:23 am

Ralf27
Posts: 2779
Users
Quote:
Original from zecke23:
yes, a program is of great help here.
the railing must have been designed by someone, according to which corresponding plans must / should be available ...

you can also determine the angle with a simple triangle calculation ...

In my opinion, the easiest / fastest would be to work with a protractor ...

Well, I would like to do that with a program, because unfortunately I get this problem again and again (rarely).

Well, the railing is mine too. There are also plans for this, that's no problem. The only problem is that there is no plan for the handrail, because I want to do this.
Only the handrail connects the individual railing parts and only through this connection there is a correct hold.

That with the protractor on site at the construction site is a good idea, I've already tried that (on another project), but it turned out to be so that I worked on the angle, length and twist with the Angle grinder worked on. This is a long tinkering that costs time and unfortunately can lead to problems even with finished staircases (flying sparks, dirt, etc.)
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

06/11/2012, 9:29 am

Ralf27
Posts: 2779
Users
Quote:
Original from hjoerg:
Practitioner:

Digital spirit level

Chop saw


Measure the angle and twist, clamp in the same way in a chop saw (stainless steel blade) and weld.

I have the tools for that, that's less of a problem.

Quote:
Pickling, passivation, polishing ... done.

You have to be careful, because if you polish at the end you will damage the surface of the stainless steel again, or the protective surface will be damaged. If you still have a "fat finger" on it, then there can be problems. It can take a few days for the protective surface to form again without doing anything. There could be problems (seldom, really seldom), but unfortunately it has happened before.
It is a long and interesting topic, but a different one.
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

06/11/2012, 6:16 pm

DrNOP
Posts: 4118
Users
Quote:
Original from Ralf27:
It's good. In which 3D program? What could you take there?
Now that you haven't specified a preferred operating system, I'll just list the ones for Windows:
  • AutoCAD 3D
  • CATIA
  • SolidWorks

All not cheap, but common. And for your purposes, probably the famous howitzer used to shoot the flea. If you're lucky, there might be some freeware that can't do much more than what you want.

That's why I was with a colleague who studied civil engineering with your problem, but here we do designs with sheet metal and control cabinets and such. Incidentally, he and his two design colleagues use SolidWorks. He is also a big fan of the DMAX series "American Chopper" and knew that at some point they also bought SolidWorks to build their bikes with ...

In any case, my idea was that your problem was a classic case for vector calculation. Unfortunately, I can't help you that much in this area because I pushed this topic aside as soon as possible.

But my colleague civil engineer, after he had finished listing textbooks for higher mathematics where something might be found about your problem, came up with the idea that you might look in surveying. There you always have the problem that you have wildly distributed several points in space and want to know slopes, angles and distances between them.

In the end, however, he agreed with me that he would start with vector calculations, develop the general formula and type it into a spreadsheet or something so that you only have to adjust the parameters on a case-by-case basis.

--
Signatures with more than two lines annoy me

[- Answers - Quoting - Direct link -]

06/11/2012, 6:17 pm

DrNOP
Posts: 4118
Users
Quote:
Original from zecke23:
I did the math ...
if I have now correctly understood the course, I get 116.8 ° every time. would be 58.4 ° when cutting ...
Maybe it would be helpful if you would tell us * how * you calculated that? Then Ralf27 could perhaps use your bill in the future?
--
Signatures with more than two lines annoy me

[- Answers - Quoting - Direct link -]

06/11/2012, 6:24 pm

George
Posts: 107
Users
@ Ralf27:

Isn't it actually just a 2D problem? If I take two pencils and hold them together at any (3D) angle, they are always within a plane, so you can lay them flat on a table and then you see the 2D angle and then calculate with it as if everything would be 2D.


[- Answers - Quoting - Direct link -]

06/11/2012, 7:00 p.m.

Holger
Posts: 8076
Users
Quote:
Original from Georg:
... so you can lay it flat on a table and then you see the 2D angle and then calculate with it as if everything were 2D.
Well said. I didn't know the mathematical operation “lay flat on a table” before.

I believe that exactly implementing them is Ralf's problem.

--
Good coders do not comment. What was hard to write should be hard to read too.

[- Answers - Quoting - Direct link -]

06/11/2012, 7:38 pm

George
Posts: 107
Users
@Holger:

Look for a 90 degree inside corner somewhere. There, from any point P in the corner, draw a line with 33 degrees on wall A (left of the corner). And from the same point P draw a line with 56 degrees on wall B (to the right of the corner).

Then hold a protractor so that one leg of the protractor is on the line on wall A, and the other on the line on wall B?


[- Answers - Quoting - Direct link -]

06/11/2012, 8:46 pm

tick23
Posts: 114
Users
Oh oh oh...
if i'm already reading this, which 3d programs ...
that's simple geometry ...

Quote:
Original from Georg:
@Holger:

Look for a 90 degree inside corner somewhere. There, from any point P in the corner, draw a line with 33 degrees on wall A (left of the corner). And from the same point P draw a line with 56 degrees on wall B (to the right of the corner).

Then hold a protractor so that one leg of the protractor is on the line on wall A, and the other on the line on wall B?

I would do it exactly the same way ...
if you know how to use something that's not a problem ...


Quote:
Original from Georg:
@ Ralf27:

Isn't it actually just a 2D problem? If I take two pencils and hold them together at any (3D) angle, they are always within a plane, so you can lay them flat on a table and then you see the 2D angle and then calculate with it as if everything would be 2D.

this is how it looks too ...
that's nothing else, like a triangle which is at a certain point in the room ...
if you know the angle, you can put it together on a flat surface ...
the profile is round, so the same in every position ...
you don't need to make a pencil cut, a normal miter cut is sufficient ...

Quote:
Original from DrNOP:
Quote:
Original from zecke23:
I did the math ...
if I have now understood the course correctly, I get 116.8 ° every time. would be 58.4 ° when cutting ...
Maybe it would be helpful if you would tell us * how * you calculated that? Then Ralf27 could perhaps use your bill in the future?

no thing...
The angle between the two handrails is what you are looking for ...
the whole thing is now a simple triangle calculation ...
to calculate a triangle you need three pieces of information ...
in that case you simply set a size for the handrails ...
the angle remains the same, no matter how long / short the handrails are ...
In order to calculate the triangle, a third information is still missing ...
i have now simply calculated the hypotenuse (diagonal that connects the point between the upper end of the upper handrail with the lower end of the lower handrail) to determine the angle ...
to calculate this "diagonal" you have to divide the whole structure (complete staircase) into individual triangles ...
I calculated a total of five triangles to get the angle ...
the first is the lower triangle with the lower handrail ...
the second is the top one with the top handrail ...
of the two you need the next and the opposite ...
Adding up the opposite sides gives the "height" of the picture ...
the two ankatheten are needed to calculate the third triangle ...
the resulting hypotenuse virtually connects the lower end of the handrail with the plumbing down end point of the upper handrail ...
With this distance and the "height" one calculates the fourth triangle in order to determine the desired "diagonal" ...
the "diagonal" and the previously determined lengths of the handrails result in the desired fifth triangle ...
With these three lengths you get the angle you are looking for ...

I hope I was able to describe it in a reasonably understandable way ...




[This post was changed by zecke23 on 06/11/2012 at 20:50. ]

[- Answers - Quoting - Direct link -]

06/11/2012, 9:55 pm

Ralf27
Posts: 2779
Users
Quote:
Original from DrNOP:
Quote:
Original from Ralf27:
It's good. In which 3D program? What could you take there?
Now that you haven't specified a preferred operating system, I'll just list the ones for Windows:
  • AutoCAD 3D
  • CATIA
  • SolidWorks

All not cheap, but common. And for your purposes, probably the famous howitzer used to shoot the flea. If you're lucky, there might be some freeware that can't do much more than what you want.
That was good. Got the ultra-modern AutoCAD r14 here. It should also be able to 3D, but even that is too powerful for me.
I've heard SolidWorks before, but never had my fingers between them. I just want to assemble 2 stupid pipes ...: -I
Quote:
That's why I was with a colleague who studied civil engineering with your problem, but here we do designs with sheet metal and control cabinets and such. Incidentally, he and his two design colleagues use SolidWorks. He is also a big fan of the DMAX series "American Chopper" and knew that at some point they also bought SolidWorks to build their bikes with ...

In any case, my idea was that your problem was a classic case for vector calculation. Unfortunately, I can't help you that much in this area because I pushed this topic aside as soon as possible.

But my colleague civil engineer, after he had finished listing textbooks for higher mathematics where something might be found about your problem, came up with the idea that you might look in surveying. There you always have the problem that you have wildly distributed several points in space and want to know slopes, angles and distances between them.

In the end, however, he agreed with me that he would start with vector calculations, develop the general formula and type it into a spreadsheet or something so that you only have to adjust the parameters on a case-by-case basis.

Yes, I found the last paragraph the best. That's it: simple, functional and flexible. It doesn't really have to be more, but more would be nicer.

Would it be enough if I entered the few parameters of the pipes (pipe diameter, pitch 1, pitch 2, (here maybe also the angle from "above")) and then got the cutting angle, twist 1, twist 2? The pipe extension that would result from the center-center and angle, I can just about manage myself. Or twist 1 and twist 2 should be the same, is that possible?

Oh yes, because of the angle definition: There are different ways to define an angle. With a straight cut through the pipe, the VKS says 0 degrees, while the reciprocating saw shows 90 degrees here. But I prefer the first definition because I work with the VKS (vertical circular saw).
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

06/11/2012, 9:57 pm

Ralf27
Posts: 2779
Users
Quote:
Original from Georg:
@ Ralf27:

Isn't it actually just a 2D problem? If I take two pencils and hold them together at any (3D) angle, they are always within a plane, so you can lay them flat on a table and then you see the 2D angle and then calculate with it as if everything would be 2D.

That's right, if you look at it correctly, this is a 2D problem. But how do I get the twisting of the pipes? Besides, I'm not that good at schepp guge ... :-)
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

June 11, 2012, 10:04 pm

Ralf27
Posts: 2779
Users
Quote:
Original from zecke23:
Oh oh oh...
if i'm already reading this, which 3d programs ...
that's simple geometry ...

Quote:
Original from Georg:
@Holger:

Look for a 90 degree inside corner somewhere. There, from any point P in the corner, draw a line with 33 degrees on wall A (left of the corner). And from the same point P draw a line with 56 degrees on wall B (to the right of the corner).

Then hold a protractor so that one leg of the protractor is on the line on wall A, and the other on the line on wall B?

I would do it exactly the same way ...
if you know how to use something that's not a problem ...
Well, that's only a fraction of the whole thing: On the one hand, the handrail comes onto the railing almost over the stairwell and, on the other hand, I didn't correctly record the twisting of the pipe. Or I already know that you could then go to the bevel with the angle spirit level ... but did you ever do it that way? Is actually more of a "it could get there" and not always possible.

And: the banister parts are not yet installed. There are individual fields that are assembled on site. The handrail should be on it here in the workshop so that I have as little tinkering as possible on site.
Quote:
Quote:
Original from Georg:
@ Ralf27:

Isn't it actually just a 2D problem? If I take two pencils and hold them together at any (3D) angle, they are always within a plane, so you can lay them flat on a table and then you see the 2D angle and then calculate with it as if everything would be 2D.

this is how it looks too ...
that's nothing else, like a triangle which is at a certain point in the room ...
if you know the angle, you can put it together on a flat surface ...
the profile is round, so the same in every position ...
you don't need to make a pencil cut, a normal miter cut is sufficient ...

Quote:
Original from DrNOP:
Quote:
Original from zecke23:
I did the math ...
if I have now understood the course correctly, I get 116.8 ° every time. would be 58.4 ° when cutting ...
Maybe it would be helpful if you would tell us * how * you calculated that? Then Ralf27 could perhaps use your bill in the future?

no thing...
The angle between the two handrails is what you are looking for ...
the whole thing is now a simple triangle calculation ...
to calculate a triangle you need three pieces of information ...
in that case you simply set a size for the handrails ...
the angle remains the same, no matter how long / short the handrails are ...
In order to calculate the triangle, a third information is still missing ...
i have now simply calculated the hypotenuse (diagonal that connects the point between the upper end of the upper handrail with the lower end of the lower handrail) to determine the angle ...
to calculate this "diagonal" you have to divide the whole structure (complete staircase) into individual triangles ...
I calculated a total of five triangles to get the angle ...
the first is the lower triangle with the lower handrail ...
the second is the top one with the top handrail ...
of the two you need the next and the opposite side ...
Adding up the opposite sides gives the "height" of the picture ...
the two ankatheten are needed to calculate the third triangle ...
the resulting hypotenuse virtually connects the lower end of the handrail with the plumbing down end point of the upper handrail ...
With this distance and the "height" one calculates the fourth triangle in order to determine the desired "diagonal" ...
the "diagonal" and the previously determined lengths of the handrails result in the desired fifth triangle ...
With these three lengths you now get the angle you are looking for ...

I hope I could describe it in a reasonably understandable way ...
Sorry, not everyone here in the forum is a student, or there should be people who haven't studied. And if it were that easy for * me *, then I would not have asked this question in the forum and therefore hardly started the thread. In short, I don't see through ...
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

06/11/2012, 10:31 pm

tick23
Posts: 114
Users
@ Ralf27:

I didn't want to attack anyone here, or something like that, sorry ...
I'm not a graduate myself ...
but to calculate that is really nothing big ...
if the part only consists of one corner (seen from above) you don't need to twist anything, or something like that, that's just a normal miter cut ...
just imagine a 3d cube ...
and now try to put the railing in these ...
there are several triangles that you can easily calculate ...

if not, you just have to make it practical ...
I just don't understand your problem ...
when you're standing in front of the corner, you can just put on a protractor, and that's good ...



[- Answers - Quoting - Direct link -]

06/11/2012, 10:39 pm

Ralf27
Posts: 2779
Users
Quote:
Original from zecke23:
@ Ralf27:

I didn't want to attack anyone here, or something like that, sorry ...
I'm not a graduate myself ...
but to calculate that is really nothing big ...
if the part only consists of one corner (seen from above) you don't need to twist anything, or something like that, that's just a normal miter cut ...
just imagine a 3d cube ...
and now try to put the railing in these ...
there are several triangles that you can easily calculate ...

if not, you just have to make it practical ...
I just don't understand your problem ...
when you're standing in front of the corner, you can just put on a protractor, and that's good ...

Alright, maybe I wrote back a bit too hard in terms of the text. I just wanted to type with it if there was no problem, then I would not have opened this thread.

So far I have always done so that I cut and assemble the handrails on site.

At the moment, at this construction site, the order is approx. 300km away from me and the partial drawings have been created by me or by me. But I would also like to solve the rest with the handrail by drawing technology and not "by hand". I hope I have expressed myself appropriately, or hope that it is clear what I intend to do.
--
http://www.alternativencomputerclub.de.vu

[- Answers - Quoting - Direct link -]

06/11/2012, 10:50 pm

DrNOP
Posts: 4118
Users
Quote:
Original from zecke23:
just imagine a 3d cube ...
and now try to put the railing in these ...
there are several triangles that you can easily calculate ...
What I am still missing in your calculations is the transformation of the levels: You always stay in the vertical or horizontal position in your calculations. The angle you are looking for is crooked in space. How do you get from triangles that are in surfaces to an angle in space?

--
Signatures with more than two lines annoy me

[- Answers - Quoting - Direct link -]

06/11/2012, 11:01 pm

tick23
Posts: 114
Users
@DrNOP:

It doesn't matter whether the triangle is vertical, horizontal, or in space, it is always the same ...
you just have to know how to calculate the respective lines / lines of the triangle to be calculated, or the position of this ...

understandable?

[- Answers - Quoting - Direct link -]