Liebherr LTM 1250 scale boom

[mike os]

thats whay I envisioned hitch,,,, spot on even if I say so myself note section in hitches pic looks more square than rebeccas illustration?

Rebecca... now you have a real idea of what you want, decide what you want to use re materials etc & someone will do it... but while you are "fishing for ideas" most will avoid because it can just end up taking a lot of non productive time for them

we know what we want, the shapes and how to form the multiple curved sections to nest properly ... so should be a little more straightforward now.

doing it yourself would be a pita... too much kit and tooling

 

[tigler]

There are definitely engineering companies that will have facilities for fabricating that sort of thing. Look for metal forming, section bending, plate forming etc.

 

[madkayaker]

speak to the facilities management company on base they will have a pet suppler they can recommend

 

[Delgado]

Depending on if/what you want to hang off the end of it, and if you really want to do it yourself, I would have thought that you could make the sections out of 16swg (or possibly even a bit thinner) mild steel sheet. If, for example, you fab up something like this on the end of your bench you could fold the channels and develop the bends, although 70mm OD might be a bit on the tight side. If you look at TigPaul's "square to round hopper", you do a similar thing with the folder. You'll need to work out the angle of each step though, or make some kind of template to check it as you go, because it'll be hard to put it through again if you over/under bend it. Obviously it would be easier to roll the sheet with something like this, but not really something you can quickly fab up to do a job.

 

[Hitch]

thats whay I envisioned hitch,,,, spot on even if I say so myself note section in hitches pic looks more square than rebeccas illustration?

Neither here nor there.
Draw up a set of plans, with specific measurements, for each section, take to a sheet metal shop, and get them to fold it up. The time and effort it would take to mess about making press affirs that wont even work, will be more than it costs to get it done by someone with the equipptment.

I expect everyone you have asked so far has been reluctant to touch it because its all up so in the air and you havnt supplied dimensions as such, or angles.

 

[Welderpaul]

Agreed. Spend some time drawing up some decent plans/elevations/sections (which often helps you get things straight in your head/highlight things you may not have thought of), and take them into a few fab/sheet metal shops. If they know exactly what you want and don't have to ask too many questions, they are more likely to give you a quote and be willing to do the work for you.
Probably better to walk in and explain what you want/put a name to a face, that blindly email it to companies.

 

[rebekah_harper]

I have put this together and I believe it to be complete.

it's the details I would present.

 

[madkayaker]

looks very comprehensive to me

 

[Hitch]

Radius for lower sections? They don't look like full semi circles...

 

[Welderpaul]

Radius for top corners too.

 

[tomb]

You need to treat the fabricator as a muppet, a skilled muppet. The more info you can give him the better. As said above radius's, distances between,length, material type and section, No. of pieces , primer type/color and tolerances you will accept, is a pressed radius ok or does it need to be rolled and any other info you think may be relevant. You may be better splitting the above detail into individual components.
Ive just searched for model fabrication on the net and there are firms out there if your local fab shops are a no go.

 

[rebekah_harper]

right on that one then.

what do you mean by distance bewteen lenghts? I believe you mean the space around the section within another.

If pressed or rolled is fine how would I let them know both options are acceptable.

I have to plead ignorance as I thought there was only one type of primer. Could you tell me how this would effect it.

I will add a text box with the above details. seperately and then seperate the profiles to include the radius.

many thanks

I will post another for your hawk eyes to glance over so that I can get this right.

Becky

 

[Drains]

IMO, the wall thicknesses are too much. They are small radii, so not easy to roll in 2 or 3mm steel. The clearances are also fine, so the work will need to be very accurate with little chance to fettle to fit, which you could do with rubbing strips.

Don't underestimate the strength of steel - those sections in even 1.0mm sheet would be very strong.

Good start with the drawing though. It will be demanding to make correctly.

 

[rebekah_harper]

using 1 mm thickness, will that not cause problems with welding?

 

[madkayaker]

not for a decent welder

 

[Drains]

using 1 mm thickness, will that not cause problems with welding?

Not if it's tigged. Even with Mig it's easy enough with the right set-up. But if the joints are nice and tight it can be tigged without filler, which will make a neat job.

 

[Hitch]

Pah, rolling shmolling. Step bend it.
Simplify it by asking for self colour steel. No concern about the type of primer. I doubt many shops use pre primed sheet under 3mm.

 

[Shox Dr]

Pah, rolling shmolling. Step bend it.
Simplify it by asking for self colour steel. No concern about the type of primer. I doubt many shops use pre primed sheet under 3mm.

2nd the step bending, trying to roll to those dims will take far too much time. As for the material 1mm will more than likely be Zintec. Not the best stuff to be TIG'ing but it's not that hard.

 

[jugs]

Step bending will give a pleated surface

the best way to produce these sections is press-forming. (it's a bit like hydroforming).
You will have to find a company that uses Urethane bottom tooling, - see this video at 5.5min > [URL]http://www.polyprod.com/Vidopopout.html[/URL]
Nb; it's NOT the same as PROTECTIVE FILM

but you can make/use very low cost tooling.

Make a MALE top tool - from 1.2m of ALU or hardwood, mill & sand to a shape to fit the inside of smallest tube section.

Fit into press-brake & press into smallest section blank, as sheet is pushed into Urethane base the sheet will form around top tool, leave it there as it is now the tool for the next section.

Repeat for each section, as no of tube sections grow around the tool.

Slide the nest of sections off & do at least 3 full sets (just in case of accidents in welding .) 90% of this job is setup time, not material or production time.
The natural spring back will give the clearance for sliding

Do same procedure for other shape section.

start welding Simples


Brief explanation of processHERE

It's simple but a bit specialized so ask the press-brake makers & press-brake tooling suppliers which of their customers could help you.
(they'll be suppling the aircraft & motor racing trades, & you wont find them in yellow pages )

I've been out of it too long, all my contacts retired or gone bust.

We used to use -

http://www.polyprod.com/
http://www.pressbraketooling.com/catalog/130/plastic_polyurethane
http://www.amada.co.uk/
http://www.pressbraketool.com/othertools.htm

You could also try -
http://www.ttlconsultants.co.uk/home.html?gclid=COOwgvarp6kCFYob4QodtQ78tw

 

[Hitch]

Step bending will give a pleated surface

the best way to produce these sections is press-forming. (it's a bit like hydroforming).
You will have to find a company that uses Urethane bottom tooling, NOT the same as PROTECTIVE FILM

but you can make/use very low cost tooling.

Make a MALE top tool - from 1.2m of ALU or hardwood, mill & sand to a shape to fit the inside of smallest tube section.

Fit into press-brake & press into smallest section blank, as sheet is pushed into Urethane base the sheet will form around top tool, leave it there as it is now the tool for the next section.

Repeat for each section, as no of tube sections grow around the tool.

Slide the nest of sections off & do at least 3 full sets (just in case of accidents in welding .) 90% of this job is setup time, not material or production time.
The natural spring back will give the clearance for sliding

Do same procedure for other shape section.

start welding Simples


Brief explanation of processHERE

It's simple but a bit specialized so ask the press-brake makers & press-brake tooling suppliers which of their customers could help you.
(they'll be suppling the aircraft & motor racing trades, & you wont find them in yellow pages )

I've been out of it too long, all my contacts retired or gone bust.

We used to use -

http://www.polyprod.com/
http://www.pressbraketooling.com/catalog/130/plastic_polyurethane
http://www.amada.co.uk/
http://www.pressbraketool.com/othertools.htm

You could also try -
http://www.ttlconsultants.co.uk/home.html?gclid=COOwgvarp6kCFYob4QodtQ78tw

Just like a real one.

Made loads of press tooling for forming like that, its not rocket science.
I can think of plenty of places that could do it.

Some decent places wont need to make top tools, theyll have a nice set of that top tooling with the slied over sleves for adjusting the radius.

Depends how much you want to spend really.