Chassis modifications
Submitted: Sunday, Jul 13, 2014 at 19:34
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108727
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Member - iijmartin
Hi,
A technical question:
Can you drill and bolt through a 6" chassis and/or A frame without affecting the strength?
Or will it lead to a stress fracture?
Am thinking of attaching slimline ally tool boxes to the side of the 6" chassis just in front of the door (mid door style van), one on each side of van for light items such as wet/dirty shoes, fold up chairs etc. This attachment is not suitable for large U bolts.
Thanks
Reply By: Athol W1 - Sunday, Jul 13, 2014 at 20:00
Sunday, Jul 13, 2014 at 20:00
Ian
If you must attach anything to a chassis it is safest to attach it in the middle of the web (that vertical section), do not drill or weld anything to either the top or bottom flanges.
Should you decide to weld to the chassis rails then weld along the centreline of the rail, as this is the area of least stress. Avoid drilling or welding near either the drawbar or
suspension areas.
Any drilling or welding of any metal component will have some effect on its strength, it is just a matter of limiting that effect, and the effect is not always detrimental to its strength.
Hope this helps.
Athol
AnswerID:
536024
Follow Up By: Member - Andrew - Sunday, Jul 13, 2014 at 20:25
Sunday, Jul 13, 2014 at 20:25
Taking into account Athol's excellent advice, you might consider installing nutcerts instead of drilling through both webs. This allows you to bolt to the chassis without compromising both flanges.
This is feasible if you truly intend to limit the weight of the storage units and their contents.
regards
A
FollowupID:
820069
Follow Up By: Athol W1 - Sunday, Jul 13, 2014 at 20:37
Sunday, Jul 13, 2014 at 20:37
I agree with Andrew on the nutcerts, if you do drill both webs then a spacer tube would also need to be fitted to prevent crushing of the rail, and also to facilitate tensioning of the bolts
Regards
Athol
FollowupID:
820071
Follow Up By: Nomadic Navara - Monday, Jul 14, 2014 at 11:36
Monday, Jul 14, 2014 at 11:36
iijmartin said - "This attachment is not suitable for large U bolts." I think he has looked at the situation and decided that your solution is not on. ow do you get U-bolts between the chassis and the flooring?
FollowupID:
820104
Reply By: Ross M - Sunday, Jul 13, 2014 at 22:02
Sunday, Jul 13, 2014 at 22:02
What is wrong with a dedicated frame to hold/accept the two boxes. The frame can be attached with U bolts to the chassis. If only for light items the construction can be light and suitable for the task.
For such a minor reason there is no way I would be drilling into the A frame on large caravan. Some crack on rough roads from what the manufacturers have done in production. No need to accentuate any faults or create any either.
AnswerID:
536032
Follow Up By: Member - Scott M (NSW) - Sunday, Jul 13, 2014 at 23:44
Sunday, Jul 13, 2014 at 23:44
I second
Ross - U-bolts are the way to go - can get them in all sizes and thickness.
Wouldn't drill through the frame.
FollowupID:
820083
Reply By: Bob Y. - Qld - Monday, Jul 14, 2014 at 11:01
Monday, Jul 14, 2014 at 11:01
Ian,
Like the others, I'd be a bit hawky about drilling through the chassis. Even sleeving the holes, as Athol suggested, would be strong, but a lot of work to do it properly.
The side rails on my Toyota are mounted with 2 plates, and sleeves top and bottom, to give the bolts/nuts something firm to tighten onto. Will let the photos tell the story........
Side Rail Mounting
Inside Chassis Plate
Not saying that this method is any better than using U bolts, as suggested above. On rare occasions, I've used a high lift jack on the side rails to raise the vehicle, so the support system is strong.
Bob
AnswerID:
536041
Follow Up By: Echucan Bob - Monday, Jul 14, 2014 at 11:42
Monday, Jul 14, 2014 at 11:42
Bob
I agree with your comments, and the photos show a really sturdy arrangement. But note the inside of the chassis rail already has many quite large holes in it, and one of them has a thread. It makes you wonder how much these holes affect chassis strength. It might have been possible to use the existing threaded hole.
Bob
FollowupID:
820105
Follow Up By: Bob Y. - Qld - Monday, Jul 14, 2014 at 14:27
Monday, Jul 14, 2014 at 14:27
Bob,
Just re-read Ian's post and it would appear these mounts would not be suitable, if u-bolts aren't, can't be fitted.
Yeah, always seems to be a multitude of holes in landcruiser chassis. Some are threaded, some not, so maybe they are there for different options/fittings that we mere mortals know nothing about ?? :-)
What I do know is that there are plenty of holes to allow mud, dust, sticks and stones, to get into the interior of the chassis rails, and with a degree of moisture, start to corrode said chassis from the inside.
Think the builder of the bull bar/side rails may not have used these threaded holes, as often the point of mounting bolts rust in situ, making it difficult to remove for servicing/replacemant/repairs. Bars were made in the Alice incidently.
Bob.
FollowupID:
820111