Irony
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| posted on 23/6/13 at 09:18 PM |
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which is stiffer, A2, A4 or BZP threaded bar. Twin Photons
Been trying to think of a way to mount my headlights. They're twin photons from russbost. I was doing a few experiments and I reckon they could
be mounted on a M8 threaded rod that is clamped to the chassis by three jubilee clips. Sticking out through the nosecone on either side. Tried it
with an offcut of box section held in the vice and it seemed to work. Bit worried about it rotating under vibration. Screwfix do cheap threaded bar,
A2, A4, bzp, or mild steel. Which is going to be best for this application?
I have no welding facilities.
[Edited on 24/6/13 by Irony]
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jon200
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| posted on 23/6/13 at 09:27 PM |
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A2 will be fine or A4 as they are both stainless steel. bZP and mild steel are essentially the same.
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clairetoo
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| posted on 23/6/13 at 09:37 PM |
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quote:
Originally posted by Irony
Been trying to think of a way to mount my headlights. They're twin photons from russbost. I was doing a few experiments and I reckon they could
be mounted on a M8 threaded rod that is clamped to the chassis by three jubilee clips. Sticking out through the nosecone on either side. Tried it
with an offcut of box section held in the vice and it seemed to work. Bit worried about it rotating under vibration. Screwfix do cheap threaded bar,
A2, A4, bzp, or mild steel. Which is going to be best for this application?
I have no welding facilities.
You cant be serious........
Jubilee clips are not the way to hold headlights on !
Its cuz I is blond , innit
Claire xx
Will weld for food......
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Slimy38
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| posted on 23/6/13 at 09:53 PM |
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Silly question, if you're using threaded bar why aren't you using nuts instead of jubilee clips?
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Irony
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| posted on 23/6/13 at 10:01 PM |
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If I had a picture it would help. On the bottom of the photons the are to metal eyes designed for M8 rod. If I thread a long 300mm m8 rod through
the eyes (and bolt up) and into the nosecone the threaded bar could be clamped to the top chassis rail. I tried it with three jubilee clips per side
clamping the rod to the top front chassis rail. It seemed to work okay.
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Hector.Brocklebank
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| posted on 23/6/13 at 10:22 PM |
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where is the face palm emoticon when you need it 
Some people can never handle the truth and always try to shoot the messenger instead of taking an honest look in the mirror (its always easier to
blame another than to face reality), but secretly they wish they could grow a pair and be the messenger !!!
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Slimy38
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| posted on 24/6/13 at 07:07 AM |
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quote:
Originally posted by Irony
If I had a picture it would help. On the bottom of the photons the are to metal eyes designed for M8 rod. If I thread a long 300mm m8 rod through
the eyes (and bolt up) and into the nosecone the threaded bar could be clamped to the top chassis rail. I tried it with three jubilee clips per side
clamping the rod to the top front chassis rail. It seemed to work okay.
OK, I get what you mean now. Unfortunately I would expect jubilee clips to be unable to cope with the movement of a car, having tried similar things
on my bike I can tell you that about half an hour in the rod will start to slip and you'll be lighting up the floor, about an hour later the
threaded rod will have probably cut through the jubilee clips and I'm not sure what will happen there. I suspect the IVA inspector will also
take a poor view of it.
I think using a threaded bar seems to make sense, you just need to change your fixing plan. You mention no welding, that's fair enough.
Here's a couple of thoughts that I had;
1. Instead of going on top of the chassis rail, go through it. Drill a couple of 8mm holes either side, thread the bar through then fix it in place
with a couple of nyloc nuts.
2. Stick with on top of the chassis rail, but bolt a couple of short pieces of metal to the top of the rail (again, bolt through the rail), then put
the threaded bar through those (with more nyloc nuts to hold it in place).
There may still be an issue with rotation though, I'm not sure.
Hope that helps.
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nick205
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| posted on 24/6/13 at 07:23 AM |
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You need a proper light bar made from box section and either welded or bolted to the chassis. The threaded stud idea WILL fail by rotating and/or
bending/snapping. Using M8 rod like that will also leave your lights shaking and vibrating all over the place...hopeless for night driving.
Once you have a rigid fixing bar in place, the lights sound like they need a U bracket to to attach them. If you make a U bracket with a single bolt
hole in the base, you will then have up/down and side to side adjustment to set the beam angles correctly too.
Most of the kit makers sell suitable light bars for this, MK certainly do one that would work for you.
Hope that makes sense and helps.
[Edited on 24/6/13 by nick205]
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plentywahalla
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| posted on 24/6/13 at 08:22 AM |
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To answer your original question .... It depends on the grade, 12.9 mild steel will be the strongest whether its plated or not, although what you get
from Screwfix is unlikely to be more than 8.8. That will still be stronger than Stainless which is less ductile and will work harden under vibration
and eventually fracture. The only difference between A2 and A4 is the addition of Molybdenum to assist anaerobic corrosion resistance. Structurally
they are identical.
As per previous comments, I still wouldn't use studding in the way described.
Rules are for the guidance of wise men ... and the obedience of fools. (anon)
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phelpsa
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| posted on 24/6/13 at 10:15 AM |
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quote:
Originally posted by plentywahalla
To answer your original question .... It depends on the grade, 12.9 mild steel will be the strongest whether its plated or not, although what you get
from Screwfix is unlikely to be more than 8.8. That will still be stronger than Stainless which is less ductile and will work harden under vibration
and eventually fracture. The only difference between A2 and A4 is the addition of Molybdenum to assist anaerobic corrosion resistance. Structurally
they are identical.
As per previous comments, I still wouldn't use studding in the way described.
Stiffness wise they're all as good as the same.
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Irony
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| posted on 24/6/13 at 10:42 AM |
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hmm, thanks for the replies. I was worried about the solution. I will have to have a rethink then.
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mcerd1
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| posted on 24/6/13 at 11:33 AM |
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I sounds to me like you'll need to fab up some kind of mounting, but if you can post up some pics we'd be able to give you some better
suggestions....
quote:
Originally posted by phelpsa
Stiffness wise they're all as good as the same.
^^ what he said, whatever the strength of the steel, they are all approx. the same stiffness....
we use 205 - 210 N/mm˛ for mild and high yield steel and 200 N/mm˛ for the common stainless grades
the standards I have don't quote figures for the bolt grades (4.6, 8.8, 10.9, 12.9......) but they won't be far off
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plentywahalla
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| posted on 24/6/13 at 12:11 PM |
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quote:
Originally posted by Irony
Screwfix do cheap threaded bar, A2, A4, bzp, or mild steel. Which is going to be best for this application?
I was answering his ultimate question. As stated stiffneess is not an issue as they will all flap about to the same extent. In his application mild
steel would be the best material as it is less prone to fracture.
Rules are for the guidance of wise men ... and the obedience of fools. (anon)
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mcerd1
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| posted on 24/6/13 at 01:24 PM |
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quote:
Originally posted by plentywahalla
only difference between A2 and A4 is the addition of Molybdenum to assist anaerobic corrosion resistance. Structurally they are identical.
thats assuming they are of the same property class.... (ie. 50, 70, 80 from EN ISO 3506)
for commonly avalible stuff most A2 bolts are actually A2-70 and alot of A4 bolts are A4-80
these are the cold worked ones, the 80 having similar ultimate strength to an 8.8 and the 70 a little less
quote:
Originally posted by plentywahalla
I was answering his ultimate question. As stated stiffneess is not an issue as they will all flap about to the same extent. In his application mild
steel would be the best material as it is less prone to fracture.
fair point, but I think his headlights flapping about is what he's looking to avoid - so a better mounting method will be needed rather than
just the best material for his original idea...
[Edited on 24/6/2013 by mcerd1]
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Irony
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| posted on 24/6/13 at 02:19 PM |
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Okay so M8 rod is not meaty enough and might rotate. Has anyone come up with a good solution to mount these twin photons?
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plentywahalla
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| posted on 24/6/13 at 05:15 PM |
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quote:
Originally posted by mcerd1
thats assuming they are of the same property class.... (ie. 50, 70, 80 from EN ISO 3506)
for commonly avalible stuff most A2 bolts are actually A2-70 and alot of A4 bolts are A4-80
these are the cold worked ones, the 80 having similar ultimate strength to an 8.8 and the 70 a little less
quote:
Agreed mild steel 8.8 is exactly the same as A2-80 or A4-80 in tensile strength (i.e. 800 Newtons per sq mm). but the reason that no yield strength is
quoted for stainless is because it is so unpredictable.
That's why stainless steel bolts are rarely used in critical load bearing applications such a vehicle components.
[Edited on 24/6/13 by plentywahalla]
Rules are for the guidance of wise men ... and the obedience of fools. (anon)
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The Black Flash
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| posted on 25/6/13 at 04:24 PM |
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Hmmm. I've used them (though without the mount supplied by Russ), but it required lots of fabrication.
You need to think about adjustability in both horizontal and vertical planes, or you'll never get them aligned (I tried!).
Is there any sort of mounting bracket on the car to start with? Any pics of the front end? And what do you have to work with on the light bracket?
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SteveWallace
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| posted on 25/6/13 at 06:19 PM |
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This is how I made mine. Obviously this picture is just the template and I actually made them out of mild steel! I cannot weld either, so I just cut
the bits and took them to a local small business that makes garden gates etc and he welded both sides for a fiver.
 
carboard headlight mount
The triangular bit bolts to the chassis triangulation and the lights mount on the square bit, which is folded to meet IVA radius.
I was thinking that you could use your threaded bar where I used steel tube and dispense with the square bit as you have a different sort of lights.
There must be someone local to you that can weld them up for beer money.
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