Daddylonglegs
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| posted on 2/8/05 at 09:22 PM |
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Rear Suspension Arms
I have noticed on some pictures of other people's builds that they have used 1" square ERW tube for the rear suspension arms. 'The
book' et al suggests using round tube for the same. My understanding is that round is stronger than square tube. Is using square not a bit risky
for such a highly loaded are?
JB
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Triton
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| posted on 2/8/05 at 09:58 PM |
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Easier/quicker to make in square tube.......as only have to hit the sides with a sander to get the profile right......If you use Oval it gets even
easier.
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erbieb02
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| posted on 2/8/05 at 11:14 PM |
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Square tube is not weaker than round, just heavier for the same amout of strength. And it is significantly easier to work with. No extra risk as
long as the builder dosen't undersize it. In other words, if the builder is going to use 1 inch round tube he would also most likely be fine
with 1 inch square tube, or they could go to 1.25 inch square tubing to get an even stronger member.
Eric B
Eric B
So many choices, way to much time (until I can afford to build).
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britishtrident
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| posted on 3/8/05 at 06:43 AM |
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1.25" square isn't a good idea as it places the sides of the arm to close to te ends of the bush eye. With 25mm square the ends can be
cut quite easily and accurately with a decent bi-metal hole saw
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Daddylonglegs
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| posted on 3/8/05 at 07:14 AM |
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Thanks guys. As I bought plenty extra 1" box then I may as well go with that. I am all for easier 
JB
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Triton
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| posted on 3/8/05 at 07:25 AM |
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If using square, cut a length that will allow you to get all 4 arms out of..then mark it out at 12" ctrs....drill these centres with hole saw to
match bush tube.....lot of farting about though.
I would opt to use the bush tube as a template to scribe the trailing arm ends then buzz them with a sander with a flap disc as easy to control....and
quick and accurate providing you mark them out right.
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Triton
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| posted on 3/8/05 at 07:30 AM |
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If you go the holesaw route everything needs to be clamped down as holesaws move all over the place and if it grips the job....umm.
Use a pillar drill with the drive belts slackened off ....not ideal but saves a smack in the face as the drive belts will slip rather than want to
keep driving if drill bit of holesaw grips......use plenty of suds or even wd40 at a push.
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MikeRJ
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| posted on 3/8/05 at 07:32 AM |
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I scribe the arc that needs to be cut out, get it close as I can with an angle grinder and then use a die grinder to finish off. Not the quickest way
but I have the tools around me.
I'd rather use a holesaw but decent bimetal saws are quite expensive, and cheap ones...well lets just say they are good for about 1/2 a hole.
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britishtrident
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| posted on 3/8/05 at 10:38 AM |
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If you live closer I'd loan you mine -- Bosch hole saws seem last forever (well almost)
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Daddylonglegs
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| posted on 3/8/05 at 11:41 AM |
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quote:
Originally posted by britishtrident
If you live closer I'd loan you mine -- Bosch hole saws seem last forever (well almost)
Appreciate the offer. I did think of using my stepped drill which goes up to 22mm. I could use a single length as suggested then measure the 3 centres
and use it to give me 6 ends. I would then only have to dress them out to the required size and do the 2 final ends. Suppose I could get affluent and
buy  another step drill which goes to the required diameter which would be even better
JB
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