Testing the Waters - Harness Bar

[madmatt]

Not happy with it as it goes straight between the pillars of the car, meaning it won't fit in mine...

https://youtu.be/WrjwaqZfjIY :lol:

 

[madmatt]

Looks good mate...

Solidworks?

Cheers matey No actually, Autodesk Inventor

Anthony- Its going to go in the brackets which are next to the rear wheel arches

Link to Al's old thread;

viewtopic.php?f=29&t=5373

Thanks guys for clearing this up

 

[MovingShadow]

Out what material are you going to make this?

Saw this story on SH with the R33 : https://www.speedhunters.com/2013/01/his-premium-day-spotlight-o-rama/

And it shows a different approach on removable sidebars in titanium. Could be applicable to this too? Titanium is very light and has alot of rigidity.

 

[Matt]

Titanium is very expensive though and probably very overkill for such a piece of equipment.

 

[JE_GT]

Is this going to be strong enough to take the brunt of a crash though? And is it road legal lol

 

[133_Ads]

Maybe now is time for a shameless plug to mention I still have a pair of OMP subframes for the Twingo in my garage. Would go perfectly with this...

I'd be interested Matt!

 

[madmatt]

Glad to see someone looks at Speedhunters as much as me

RE materials:
Tube - will be made from 40mm x 2mm Wall CDS (Cold Drawn Steel) - one of the materials used in Roll cage manufacture (CrMo is also used, is lighter but more expensive)
End caps - manufactured from 40mm Bright Steel round bar and are through theaded with a fairly large thread.
Bolts - need to check bolt specs regarding head size/thread but will be high tensile steel to cope with as much sheer force as possible.

The bolts are a good thickness for the rear bench seat mount and the bar in of a length where the side catches will be used and catch over the top of the bolt.
The end caps are designed to be as tight as possible to the catches, without fouling either part.

The bolts will then be tightened on either end and Bob's your Aunty

With regards to road legality, I can't actually answer it...
Once I have the design finalised and I get it test fitted to mine, I shall do the MOT standard test for component play....The "GRAB-IT-BY-THE-BALLS-AND-SHOOGLE-THE-F*CK-OUT-OF-IT" Test.

If it doesn't budge, then I will be happy with it

 

[madmatt]

AND.....if you want to pay for a titanium version....feel free but also have Lube ready because you will pay through the arse for it!!

 

[133_Ads]

Get the prices sortedddd!

All sounds good!

 

[MovingShadow]

It was a suggestion to you, Twingo RS/GT owners, I don't need this as the Wind has reinforcement bars in the booth.

OT: I read SpeedHunters almost every day. It has widened my horizon on cars alot!

 

[singlespeed]

Titanium is very light and has alot of rigidity.

Well, when comparing two samples of the same size, Ti isn't as strong as steel Approx 70% strength depending on alloys.

However, being about 45% of the weight, you could increase the diameter and wall thickness and get a tube with the same strength as 40mmx2mm CDS but still be lighter. It's going to be costly

 

[yotah1]

Alright, sorry my bad, I didn't think that was going to be like Al's car.
Then, I'm in

 

[madmatt]

Alright, sorry my bad, I didn't think that was going to be like Al's car.
Then, I'm in

No worries matey :lol:

It will be same same basic design, just not the same cost....
Will pull my finger out and get prices and let you all know

 

[yotah1]

Got news here?

 

[JE_GT]

Got news here?

+1 I don't want to have to use bloody eye bolts that look messy

 

[madmatt]

Harro, I have found somewhere that does CDS at a decent price.

Just need a definite local (UK buyer) for the 2nd Prototype - will buy enough materials for the pair.

 

[madmatt]

OPTION TIME

A - The bar at a length where it meets the Latch face flush, tightening effect from bolt against back of face.

B - The bar at a length where there is enough room for a tightening nut and then a couple of MM space from nut to bar end - similar to adjustable strut braces.

Need to know so I can adjust the design.

Still need a buyer for the 2nd Prototype Bar as well
Current Costs:
CDS Tube (40mm x 2) - £18+
40mm Bright Mild Steel 40mm Round Bar - £5

Accurate cost will be updated once I get the final quote back from Custom Cages for the CDS Tube.

 

[singlespeed]

how variable is the width between the mounts? Would you need adjustment

a strut brace will normaly be loaded in compression/ tension. If required, the harness bar would have a shear loading on the bolts so keeping any unsupported section to a minimum would be better. Maybe make the bar a few mm too short and use large penny washers as spacer shims to fill the gap which can then be tightened down with the bolts.(all based on guess work :?)

 

[madmatt]

how variable is the width between the mounts? Would you need adjustment

a strut brace will normaly be loaded in compression/ tension. If required, the harness bar would have a shear loading on the bolts so keeping any unsupported section to a minimum would be better. Maybe make the bar a few mm too short and use large penny washers as spacer shims to fill the gap which can then be tightened down with the bolts.(all based on guess work :?)

The maximum void I would be looking at is 5mm in total, so 2.5mm "wiggle room" on each side - which in the grand scheme of things in minimal based on the size of the part.

I shall use Scotty with my bar, just to check there isn't too much variance between cars.

 

[the_notorious_C_A_T]

I'll fund the prototype if you can't find anyone to.