John G
|
| posted on 22/6/16 at 10:11 AM |
|
|
Aluminium plate for handbrake caliper
I need to fit my willwood handbrake callipers to the rear hubs which I intend to do with aluminium plate.
What would be the best thickness for weight / strength, is there any other metal that would be better, and where is the best place to purchase? I will
be having them water cut.
Regards, John
|
|
|
|
|
JAG
|
| posted on 22/6/16 at 10:52 AM |
|
|
Steel would be a much better choice - less chance of fatigue cracking over time.
Steel plate at 6mm thick would be enough for the braking forces.
But I'd aim for at least 1.5 x thread diameter for thread engagement of any bolts that tighten into a thread in this bracket.
If you have a 10mm diameter bolt then I would allow 15mm thread depth.
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
|
|
|
John G
|
| posted on 22/6/16 at 12:03 PM |
|
|
Thanks for the reply. I will look at some steel plate. I was not intending to tap a thread in to the plate, just use nuts and bolts to hold the
calliper on.
John
|
|
|
nick205
|
| posted on 22/6/16 at 12:39 PM |
|
|
I'd go for steel plate as well for the long term strength of it. You could get the parts laser or water cut from a dimensioned drawing, which
would make it easy to fit.
|
|
|
Nickp
|
| posted on 22/6/16 at 05:25 PM |
|
|
As it's only a handbrake caliper you probably would be fine with alloy, unless you intend doing loads of handbrake turns of course 
|
|
|
Theshed
|
| posted on 22/6/16 at 08:44 PM |
|
|
Well the callipers are alloy.....why is it assumed that aluminium will crack earlier? Why is it assumed that if designed properly it will crack at
all?
|
|
|
JAG
|
| posted on 23/6/16 at 07:25 AM |
|
|
The issue is designing it properly.
I am assuming you don't have access to the right Finite Element Analysis tools nor have the expertise to use them. Like most on here 
If you had access to these things then you could design an Aluminium bracket where the overall stress levels would remain below the materials fatigue
threshold. Then the Aluminium part wouldn't crack and would be strong enough to resist all the caliper loads. Which is what the caliper
manufacturer has done.
If you don't have those tools/skills then you have to over Engineer the bracket and the best way is to use Steel 
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
|
|
|
peter030371
|
| posted on 23/6/16 at 07:45 AM |
|
|
quote:
Originally posted by JAG
The issue is designing it properly.
I am assuming you don't have access to the right Finite Element Analysis tools nor have the expertise to use them. Like most on here
If you had access to these things then you could design an Aluminium bracket where the overall stress levels would remain below the materials fatigue
threshold. Then the Aluminium part wouldn't crack and would be strong enough to resist all the caliper loads. Which is what the caliper
manufacturer has done.
If you don't have those tools/skills then you have to over Engineer the bracket and the best way is to use Steel
And you think RD did all that with this lumps of ally
http://www.rallydesign.co.uk/product_info.php?cPath=562_579&
products_id=4023
To the OP I assume you have looked at the 'universal' mounts that RD do? I bet one of them is close enough to only need a little tweaking
and maybe a few holes and bobs your aunties live-in lover 
The RD brackets that came with my front caliper kit are just bits of ally the right size to line the caliper up with the disk and then 4 holes in the
right place. No rocket science, no FEA and I doubt a degree in Home Economics (old school cooking!) let alone training in formal engineering.....but I
can't see them ever failing so well done RD for keeping it KISS
|
|
|
JAG
|
| posted on 24/6/16 at 11:03 AM |
|
|
RD have over Engineered in Aluminium.
I say it's easier and safer to over Engineer in Steel.
The OP can make his own decision in which he prefers - if you buy from RD at least you can get them replaced if anything goes wrong
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
|
|
|
coozer
|
| posted on 24/6/16 at 02:40 PM |
|
|
Easier for a home builder to over engineer in steel and sleep tight at night.
Calipers are ali but they are forged and designed with all the forces taken into consideration.
RD brackets may be ali but who knows what thought/development has gone into these? Or what grade of Ali they are??
1972 V8 Jago
1980 Z750
|
|
|
Kdempsie
|
| posted on 24/6/16 at 02:54 PM |
|
|
I used aluminium for my rear caliper mounts, similar in design to most radial mounted caliper brackets.
I'd suggest 6082 T6 as the material grade to use.
You can get a basic idea of what I did here https://jpsc.org.uk/forum/viewtopic.php?f=4&t=1209&start=10
Keith.
|
|
|
