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frame extensions part number

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ponkokanada
Posts: 182

Re: frame extensions part number

Post#11 » Wed Apr 15, 2020 7:46 am

I am in the process of extending a 2400mm frame to 3100mm. New project thread coming up within days, stay tuned.

My plan is to use 4"x8" 0.25 wall rectangular tube. The tube will be split into two angle sections which will go over the existing G frame with overlap at each end.

Since bottom and outer walls of the frame are under more stress these will get welded first to the "red" angle on the inside and outside as well as through a cut out holes. The angle will be cut to exact length to butt against the trailing arm brackets (not shown the model below) while giving desired extension. In my case the trailing arm brackets are 17" apart and I'm looking at 27" frame extension so the red part must be 44" long. This gives 8.5" overlap with the frame.

View from inside
1.PNG


view from outside
2.PNG


Once the red angle is welded on I will box the remainder with the "green" angle. This one I won't be able to weld fully to the existing frame on the inside due to lack of access but the structure will be sound once welded to the red tube. I also plan on making the green angle a bit longer to stagger welds on to existing frame. Making the "green" angle longer is possible because the trailing arm brackets will not be in the way on the inside of the frame.



view from inside
3.PNG

Cross section
4.PNG


one additional clarification: Although not shown on the model, both angles will need circular cut outs i to clear the transverse tube that holds the frame sides together.

I hope this helps. Stay tuned for photos of the actual mod in a new thread soon.

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diesel_jim
Posts: 965

Re: frame extensions part number

Post#12 » Wed Apr 15, 2020 9:47 am

Nice

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Otiswesty
Posts: 5922

Re: frame extensions part number

Post#13 » Sat Apr 18, 2020 10:40 am

Ya, good plan

McBride
Posts: 734

Re: frame extensions part number

Post#14 » Sun May 10, 2020 9:25 am

Here’s the frame extension setup on the camper. It looks like they welded in a piece of frame from another G wager and then used a sister member to span the splice...here are some pics...
Attachments
971B719E-C00A-4547-B28D-454FA129D4BB.jpeg
C9030450-4289-4B91-9AB3-47F3F0F813D9.jpeg
DE9C6A4E-5FC1-443B-9159-3F2BC9A834B4.jpeg

McBride
Posts: 734

Re: frame extensions part number

Post#15 » Sun May 10, 2020 9:39 am

And sorry about the mud... I have a rough driveway:) Also, this splice is still perfectly straight. I recall Dave saying that this work was done at some frame specialist shop in Albuquerque....

jtrein
Posts: 372

Re: frame extensions part number

Post#16 » Sun May 10, 2020 6:17 pm

ponkokanada wrote:I am in the process of extending a 2400mm frame to 3100mm. New project thread coming up within days, stay tuned.

My plan is to use 4"x8" 0.25 wall rectangular tube. The tube will be split into two angle sections which will go over the existing G frame with overlap at each end.



In case you didn't already know if you are going to do this make sure you taper your frame splices so you don't create any stress risers in the frame when welding. The picture that McBride posted above shows this. You want the ends of your added section that go over the existing frame to be like <> not like this []. Do a quick google search on chassis fish plates to get some rules of thumb for spicing frame sections together.
1981 280GE Ambulance - full restoration in progress
1985 280GE

ponkokanada
Posts: 182

Re: frame extensions part number

Post#17 » Mon May 11, 2020 4:15 pm

In case you didn't already know if you are going to do this make sure you taper your frame splices so you don't create any stress risers in the frame when welding. The picture that McBride posted above shows this. You want the ends of your added section that go over the existing frame to be like <> not like this []. Do a quick google search on chassis fish plates to get some rules of thumb for spicing frame sections together.


Thanks for the tip.

Since I am working with the short wheelbase I can only overlap the frame by 8.5" or so (working with 17" of straight section between the trailing arm mounts). For that reason i can't fabricate a conventional fish plate ends and sacrifice the overlap length which is more important. Instead I'm going to tie the extensions into the trailing arm mounts and the cross tube where the original frame is reinforced by them.

I've actually just fabricated the outer extension angles and cut the frame. I'm posting more details in my build thread viewtopic.php?f=18&t=16525

Once I finalize the shape of inner and outer extenders I will post a dimensioned drawing in this thread for those who are interested

autonovice
Posts: 2164

Re: frame extensions part number

Post#18 » Tue May 12, 2020 2:36 pm

The frame on this 6x6 is huge comparing to 2850mm. Wonder if the frames for 3120mm and 3400mm are also bigger than the typical 2850mmm frame or they all are the same height. May be my eyesight is off :?

Capture.JPG

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Chris
Posts: 3525

Re: frame extensions part number

Post#19 » Tue May 12, 2020 4:23 pm

There is an additional u channel section welded to the frame, making the bottom of frame hang about an inch lower on all of the extended wheel base G frames I have seen photos of.

I’m sure it adds a lot of stiffness, whatever it is.

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nbutze
Posts: 203

Re: frame extensions part number

Post#20 » Sat May 16, 2020 4:36 am

Johnny Christensen wrote:
offroad-world wrote:it is not legal to make this work in germany , MB will not allow you to weld on their chassis because of crash test safety , parts like that at not avail . many people don`t care and weld what they want ! there is a paper from MB that it is only allowed to weld outside the ladder , like bodymounts , shock absorber mounts and coul spring mounts and these are avail as spares .

mfg. guido .


How do ORC go about doing their frame extentions, as you can take any wheelbase G to them and have it build to a 3120 or 3400 specs. They offer that in their camper segment.

Did they have to present a prototype for destructive crash testing and based on their specific method, where allowed to register the following builds under German rules?

They use a real MB long frame. That is part of the extreme cost.
You can still buy a real MB 6x6 frame, but I think just the frame rails are 75,000 euros or something crazy like that
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G63 - G280 - G500

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