Dedman
Forum Member
- Joined
- Dec 3, 2012
- Messages
- 766
- Location
- Perth Western Australia
- Car Year
- 1999
- Car Model
- Forester
- Transmission
- 5MT
I did consider this but there were a few reasons that i went for the angle instead;
1) As shown in the picture above the cross section of the rails is not constant internally meaning that cutouts would have to be made on the RHS to accomodate this which would weaken it which made me decide a more heavy angle would ultimately be stronger.
2) The approximate dimensions of the rail are 50x100mm (external dimension) which means that the RHS to sleeve that would have to be around 47x97 or something similar I size which does not exist meaning you would have to get a smaller size piece and put shims everywhere to make it fit or build your own section.
3) The internal corner radius of the rail: Im not sure if the corner radius on a RHS would be as large as the radius in the rail meaning it may have to be ground down to fit. Presumably if using RHS the wall thickness would be less than that of the thickness of the angle meaning grinding the corners would weaken it more.
4) Because of the way I designed the bar the angles do not have any real torsion induced in them (twisting about their length) meaning using open sections such and angles do not really weaken the design compared to closed sections.
5) Im not entirely sure the rails are perfectly parallel meaning that if the metal being inserted into the rails was the full width it would get stuck easily. This is also the case for taking the bar on an off. Even with my angle sections which were relatively loose fits in the rails the slightest twist and it would get jammed something shocking.
6) Its is easy to weld a nice thick single layer of metal to the nice thick winch plate than to join the more thin walled RHS and provided a strong structural load path all sides of the RHS
The main reason really was it was easily accessible/ strong and could be cut down to fit whilst still maintaining strength.
Yes those nuts are only attached to the face plate and the face plate its not really connected that well to the rails (especially not for a tensile load)
Also if you only attached to those nuts you are not going to provide a strong mounting point for when the winching load is not pulling directly forwards lets say its pulling up over a ledge or to the side. Think of it as comparing a fence post belted into the ground to a pole that is held upright by a big flat base that has bolts holding it to the ground. If you push sideways on the pole/post the fence post in the ground has to bend before it will fail as does something inserted into the rails (or the rail bends....) where as the pole with the flat base only has to pull out those bolts holding it down and the smaller the base the more stress in the bolts and the more easily it will fail. The bolt holes on the forester pretty close together meaning it can not provide much force that is not pulling straight forwards.
In my head all of that makes sense but to a third party it probably sounds like a load of gobbledygook :rotfl:
https://www.ebay.com.au/itm/ORU-9000L...item1c2cc5ce01
Cant really make any comments on if its any good or not as I havent tested it much yet. Seems to be well build. One down side I have noticed is that it is quite difficult to pull the rope out (this may just be because it is new and all the grease is still clogging up the gears)
You got it. Only a few months to go.
