Bending Steel on a Carry Rack - Heat or no Heat?

[pete]

Not sure if this is the most appropriate forum for this question but it didn't seem to fit anywhere else...

I'm trying to replicate the optional sports rack for my 450 by cutting down an after market carry rack and welding it to the grab rail as I really like the integrated look of the genuine one but they're made of unobtanium.

I cut the aftermarket rack this avo and now I need to bend the bottom rails out to go around the tail piece.

So far I've only worked with aluminium in this regard, and it's been fine with cold bending, however I'm not so sure if that's going to be safe to do with steel.

Should I be heating it up before bending or is it safe to do cold? If I can do it cold, I can keep working on it at night. If I have to heat it, I need to squeeze that in on the weekend or something as I don't want to run the oxy torch with two cars and my bike in the garage at night.

I'm mainly concerned that bending it cold might do something bad to the steel as opposed to bending it hot...

Here's what I've cut down:



The bottom rails are what need to be bent and they're solid steel:



They need to bend a bit wider than appears in this photo as the perspective makes the tail piece look narrower than it is:

[john82q]

if its solid steel just bend it, the chrome will be toast either way.

Heat will just make it easier to get the bend it just right.

For tube you will need a mandrel, or it will crush. you know where you can get that ;-)

[pete]

if its solid steel just bend it, the chrome will be toast either way.

Heat will just make it easier to get the bend it just right.

For tube you will need a mandrel, or it will crush. you know where you can get that ;-)

Cheers John! It's only the solid lower bits that need bending so that's cool, I can take care of that

As for the mandrel, yeah I reckon I might know a guy... Haha

I'll let you know once the grab rail lands if you're still keen for the welding job, not sure I want to trust my... Ahem... "skills"...

Oh, and the chrome's already a bit dodgy and I'll be going black anyway so not worried about that at all.

[GateKeeper]

If you don't have a mandrel handy, you can fill the steel tube with sand, plug up the ends and start bending, I have heard this works......but please try it on a test piece first...

[spyug]

Its easier to do with heat as long as you can generate enough. The hand held propane welders torches don't put out enough but Mapp gas (yellow cylinders) should get it cherry and allow you to bend it like a pretzel. an Oxy rig would, of course, be best.

You likely could bend that rod cold but you might not be able to get as fine a bend that way.

I'm looking forward to seeing how this turns out.

Cheers,
Spyug

[Johnny Drummond]

bending possibilites

Hi Pete, if its solid bar you can bend hot or coldn but Spyug's right oxy-acetelene is the easiest way to heat and also most accurate as it only heats a 10-15mm area at a time.There will be no adverse affects on the metal as you aren't going to be exceeding the tensile strength of the bar(unless you intend to put a 100kg pillion on it).However it can be done cold,if you use a well mounted vice.Mark the area you wish to bend,clamp it in the vice 8-12mm back from the mark and using a piece of reasonably well fitting,1.5-2mm wall piping about 900mm long slid over the bar, GENTLY and slowly pull in the desired direction(I know that sounds wierd but steady pressure is easier to control than sharp harsh movements).If I may also suggest that a trick I use is to mark the shape you want out on a piece of hardboard sheet or in chalk on the floor (as used in most every shipyard and structural steel firm) then you can know when you have reached the desired shape with the minimum of hassle.Sorry if this sounds like I'm insulting your ability,Believe me that is NOT the case as you are a very good alloy fabricator,it's just my silly little way.Hope this is of some use. Johnny

[landshark]

if its solid steel just bend it, the chrome will be toast either way.

Heat will just make it easier to get the bend it just right.

For tube you will need a mandrel, or it will crush. you know where you can get that ;-)

I dont supose you have a mandrel that can do 2 inch pipe?

[john82q]

Landshark,

Sorry but I dont have one that big...

John

[pete]

If you don't have a mandrel handy, you can fill the steel tube with sand, plug up the ends and start bending, I have heard this works......but please try it on a test piece first...

Thanks GK, yeah I think I saw that done on here somewhere with an exhaust pipe.

The tube needing bending is solid so all good there

Its easier to do with heat as long as you can generate enough. The hand held propane welders torches don't put out enough but Mapp gas (yellow cylinders) should get it cherry and allow you to bend it like a pretzel. an Oxy rig would, of course, be best.

You likely could bend that rod cold but you might not be able to get as fine a bend that way.

I'm looking forward to seeing how this turns out.

Cheers,
Spyug

Cheers Spyug, I have an oxy but if I can I'd prefer no heat as it gives me a heap more time (at night) to do it and take my time with it.

I'll definitely update this thread once I get stuck in, hopefully later on this week...

Hi Pete, if its solid bar you can bend hot or coldn but Spyug's right oxy-acetelene is the easiest way to heat and also most accurate as it only heats a 10-15mm area at a time.There will be no adverse affects on the metal as you aren't going to be exceeding the tensile strength of the bar(unless you intend to put a 100kg pillion on it).However it can be done cold,if you use a well mounted vice.Mark the area you wish to bend,clamp it in the vice 8-12mm back from the mark and using a piece of reasonably well fitting,1.5-2mm wall piping about 900mm long slid over the bar, GENTLY and slowly pull in the desired direction(I know that sounds wierd but steady pressure is easier to control than sharp harsh movements).If I may also suggest that a trick I use is to mark the shape you want out on a piece of hardboard sheet or in chalk on the floor (as used in most every shipyard and structural steel firm) then you can know when you have reached the desired shape with the minimum of hassle.Sorry if this sounds like I'm insulting your ability,Believe me that is NOT the case as you are a very good alloy fabricator,it's just my silly little way.Hope this is of some use. Johnny

Cheers Johnny! See I knew you'd have more helpful advice over here

And I'm not in the least bit insulted... my alu. work has been what I would call passable, but steel is a new one to me, so all advice is very welcome!

I have some pipe here I can use for that, it's a little larger but I'm pretty sure it will do the trick.

Thanks for the tip on marking the shape out, I definitely hadn't thought of that!

And the other thing I figured out in my head is that I will need to add a cross piece below the top of the grab rail otherwise if I weld the top rails of the carry rack to the top of the grab rail it will be too tall, so I need to find myself some 12mm steel rod for that.

I think it would also be sensible to have another cross piece at the back of the tail piece between the two bottom rails to add some more support there, and that I believe will require some 6mm steel rod.

I hope that made some sense... but I'll sketch something up on the white board at some point and post a pic of what I'm talking about just in case I'm sprouting garbage again...

My house mate has a steel place near his work he believes may have some suitable offcuts, so I'll get him to try there later in the week.

Hopefully I can get bending by the end of the week and the grab rail isn't too far away.

John... you got ya welding gloves handy (if you're still keen that is!)?

[john82q]

welding,

Just sing out when your ready, not home tomorrow morning, (ANZAC day)
should be home after lunch... or any evening or this weekend.

[pete]

Just sing out when your ready, not home tomorrow morning, (ANZAC day)
should be home after lunch... or any evening or this weekend.

Cheers John, I'm off riding tomorrow morning anyway... at least that's the plan as long as the phone doesn't ring too much tonight!

Still waiting on the grab rail... it left an acceptance facility to go to a sorting facility on the 16th and that's where the tracking stopped... in Portland Oregon at present apparently so it's not gonna be here any time soon... I have a feeling I won't get a chance for a few weeks as we're off to Melbourne on the 5th of May too...

[Redneck]

Mr. Drummond has the right of it Pete. Another thing you can do is find a pipe with the diameter of the bend you want and using your cheater pipe that goes over the end and slowly bend the steel to meet the diameter of the pipe.

Good luck

Paul

[pete]

Mr. Drummond has the right of it Pete. Another thing you can do is find a pipe with the diameter of the bend you want and using your cheater pipe that goes over the end and slowly bend the steel to meet the diameter of the pipe.

Good luck

Paul

Cheers Paul, yeah, Johnny's method makes sense to me and I used it to do the first bend tonight.

Waiting for a bunch of pic's to upload from the ride today and from the bending so will come back and update this a little later...

[pete]

Ok, put Johnny's method to use tonight and looks like it's going to work well providing I make consistent bends on both sides of the rack.

First off I marked the grab rail out on some cardboard:



Measure the rear width of the tail piece and the width of the grab rail at the point where the lower rails will meet it:



Then determined the points at which to bend the lower rail, circled in red:



Marked those points with some masking tape and an arrow pointing to which end of the tape is the bending point (due to my sieve-like memory):



This is the tube I have available to do the bends, and I'm glad it's actually as large as it is as the bottom rail has a kink to bring it horizontal, meaning a smaller tube wouldn't be able to slip over that kink:



I wasn't able to locate the rack in the bench vice in such a way that it would line the bending point up easily with the top of the vice to make it a nice bend, so I ended up clamping it to the workbench instead:



Got the piece of tubing on and gently bent it down:



Continued...

[pete]

One photo too many for one post... here's the result of the bending, pretty much spot on:



The big thing will be repeating this accurately on the other side but I ran out of time to do that tonight so will keep going hopefully tomorrow night.