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Chassis boxing. How much? - cardiffrob - 04-02-2018
I was wondering if some kind soul could perchance direct me to images of chassis that have been boxed in a manner that could be described as 'correctly'. Google tends to turn up Pugilists in Texas if you ask for Austin Boxing. I am repairing some previous dodgy welding on this one. Maybe he needed a few more Amps???
Is it best to remove the crossmembers to utilise a single strip? Should the strip be perforated with lightening holes? Should crossmembers be similarly boxed over?
I light of the new UK rules coming in, should I avoid this or is that an unnecessary worry?
Thanks
Rob
RE: Chassis boxing. How much? - Ruairidh Dunford - 04-02-2018
I don't consider this necessary Rob - invest your time in ensuring the rivets are tight and all should be good for many years to come.
RE: Chassis boxing. How much? - Ian Williams - 04-02-2018
I guess it depends on what you intend to do with the car Rob, if it will only be used as a road car I completely agree with Ruairidh. However if you are going to race seriously my experience is that there are advantages to stiffening the chassis.
RE: Chassis boxing. How much? - Alan - 04-02-2018
Well, to do it properly, yes, you do need to take the chassis apart and refit the cross members afterwards, and you need to be really careful that the welding doesn't distort things. I'd consider bolting or riveting But, if you look at what bends in a chassis it's not the side members. What happens is the whole thing twists because the cross members aren't all that rigidly fitted to the sides. Boxing the cross members and tying them properly to the side members will have far more effect. Then you need somehow to stiffen the nosepiece. As far as drilling holes is concerned, don't. It's the wrong thing to do. The bending load is carried in the top and bottom rather than the sides - it's there you'd want to drill holes, if at all.
RE: Chassis boxing. How much? - Charles P - 04-02-2018
In the articles that John Miles wrote about building his heavily modified Ulster I recall that he found that brazing all the cross members and nosepiece fully into place made a big difference over just the usual rivets.
Charles
RE: Chassis boxing. How much? - Ian Williams - 04-02-2018
Here are pictures of my current chassis in the early stages, everything is hot riveted together rather than welding, the additional sections, besides boxing the main rails and tying together the cross members will carry a stressed under tray. I will take pictures of this in a more advanced state if they are of help.
DSC05864.JPG (Size: 245.25 KB / Downloads: 668)
By using the late Girling brake cross shaft the weight saving from this is off setting the additional weight of the alterations, will it have been worth the trouble? Time will tell
RE: Chassis boxing. How much? - Ruairidh Dunford - 04-02-2018
Very impressive Ian, as ever.
If I have given Rob a bum steer I apologise - I assumed he was referring to a road car, I only have experience in this area.
RE: Chassis boxing. How much? - cardiffrob - 06-02-2018
Thanks, everyone.
It is a road car, however, I noticed that the last chassis was quite flexible/twistable and thought I'd try to help the next car whilst it was still unbuilt.
It might be a silly question, but why does the front cast piece need bracing? Surely it is more rigid than the open side members???
RE: Chassis boxing. How much? - Ian Williams - 06-02-2018
Think about it Rob, bring two steel sections together in a V and where would most movement be if you twist the ends relative to each other, also think about what Alan mentioned with the cross members requiring stiffening and bracing.
RE: Chassis boxing. How much? - merlinart - 06-02-2018
(04-02-2018, 09:26 PM)Ian Williams Wrote: Here are pictures of my current chassis in the early stages, everything is hot riveted together rather than welding, the additional sections, besides boxing the main rails and tying together the cross members will carry a stressed under tray. I will take pictures of this in a more advanced state if they are of help.
By using the late Girling brake cross shaft the weight saving from this is off setting the additional weight of the alterations, will it have been worth the trouble? Time will tell
That's a marvellous bit of work! Did you bend/fold those yourself, after drilling those large holes. Have I missed a post...what is the chassis about to be used for?
Arthur