Thread: Chassis Holes and Other Pitfalls...

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I am keen to avoid drilling holes in my new 3"x2" chassis.

I am going the long way round, welding and doing anything to avoid drilling holes, based on the view that less holes equals more strength. For example my radiator bracket is welded not bolted - and it took a little bit of extra cost and fiddling to do it this way. Four holes would have done it, but I could do it safely without the drill.

So - am I paranoid newbie - or taking the right course?

Am I wise to avoid holes in a chassis?

Max Christoffersen

Originally posted by maxcat
I am keen to avoid drilling holes in my new 3"x2" chassis.

I am going the long way round, welding and doing anything to avoid drilling holes, based on the view that less holes equals more strength. For example my radiator bracket is welded not bolted - and it took a little bit of extra cost and fiddling to do it this way. Four holes would have done it, but I could do it safely without the drill.

So - am I paranoid newbie - or taking the right course?

Am I wise to avoid holes in a chassis?

Max Christoffersen

What kind of car or truck are you building? Will it have a lot of H.P.? You said it is a 2''x3'' chassis, so I am assuming you are going to stiffen it up with a roll cage? I think 2''x3'' may be a little lite if your not using a cage. You can bolt the radiator to the chassis, because the radiator is in front of the front suspension (I assume) so there isn't much stress there. Same with the back of the chassis beyond the rear suspension, there isn't that much stress.
Are you planning to race it? If you are there are specific guidelines you need to follow that will cover chassis construction.
Where you want to be careful is in the passenger area. Rails and cage around the passengers, is the most critical stress area. You can drill holes as long as you reinforce the hole with a gusset or a brace of some sort that will equal or surpass the original strength of the tube.
Do you have pics.?

It's a street rod T-Bucket.

So not a racer, but still some horsepower there. But my main concern is 'unecessary' drilling into a chassis when there are other ways to do the same job. I'll go the long way instead of drilling - irrespective of where the stresses may lie.

I'll check out the way the brake system is going to be mounted as this may be the area where I have no choice. Thanks for the gussetts tip!

Max Christoffersen

Drilling a hole and put a spacer in will be infinitely stronger than a
weld ,every time you weld something to the likes of a chassis
you create a soft point ie the heat of the weld will anneal the
metal adjacent to the weld and soften the metal around it
probably for what you are aiming for it will not matter that muchbut for any high stress joint in (and Im assuming you are
using m/s tubing )a welded joint will weaken the parent material
anywhere from 5-15% depending on the welders skills.I f you
are not confident in your welding ,hire a professional for the critical welds ...