[project] The Ultimate Track 205

[Cameron 16]

115mm angle grinder FTW.

 

The handy thing about having modelled it all in CAD is that I already know what my tube profiles need to be, so there's only minimal fiddling about required to get the angles & profiles right and means I reduce the risk of getting a cut wrong and wasting material. What I've done is extract surfaces from all of the tubes and "unrolled" them to get a flat surface with the profile on it. These are then put onto 100% scale drawings then it's just a case of getting them printed. I've sent them all off to my brother (see avatar) then it's a case of wrapping the printout round the tube and cutting / shaping to suit.

 

I've used the process before to build a space-frame chassis and it drastically reduces the time taken as well as any waste material. Some may call it cheating, I call it being resourceful.

Edited July 19, 2012 by Cameron

[welshpug 1,645]

just what I was going to say, not sure where I saw that first but likely to have been on the Mig Welding Forum, just tape the appropriate template down and tickle away with the grinder

 

awesome when you can use CAD! shame I can't

[johnnyboy666 195 1 Cars]

can't remember if you've already said, but do you have an estimated completion timescale/deadline/ due date?

[alexcrosse 124]

Just a note cam - make sure you put datums on the print outs so that the axial position of your notch templates on the end of each tube line up. Then you can score a line down the whole tube against a piece of angle or box and rotate the paper to suit. Turns into a ball ache getting the axial alignment right.

[Mad Scientist 106]

Nice solution there. Shame I can't use/don't have CAD! I built a locost 7 chassis a few years ago and wasted a fair amount of box section! Tube is even more of a mare without something like the above.

Steel was a third of the price then too!

[Cameron 16]

I'll be printing off the full length of tube, so there shouldn't be any issues with alignment.

[alexcrosse 124]

Sounds like alot of paper for no reason lol

[Cameron 16]

It is a lot of paper, but he has a proper roll printer so shouldn't be an issue! Certainly saves me a job trying to get the lengths and alignment spot-on, so definitely has a reason.

[Weser 30]

Can I just ask how come you didnt get the tubes all cut to length with the ends correct trout mouths etc already on? Being that you have CAD it would be easy to get the idividual components done. Then surely it would just be a case of welding it all together? Is it because you wanted to do it yourself or saving money? - Not a dig by the way, just wondering!!

[shalmaneser 26]

Can I just ask how come you didnt get the tubes all cut to length with the ends correct trout mouths etc already on? Being that you have CAD it would be easy to get the idividual components done. Then surely it would just be a case of welding it all together? Is it because you wanted to do it yourself or saving money? - Not a dig by the way, just wondering!!

 

Cheaper to do it yourself especially if you've got contacts for the printing!

 

EDIT (I imagine)

Edited July 19, 2012 by shalmaneser

[Cameron 16]

Bingo. Much cheaper to do it myself, but also there will be a small amount of fettling required. Bent roll hoops are pretty difficult to measure accurately, especially their position in the shell. If I were to make several of them then that would be the approach I'd take, but only once I had confidence that what was on-screen matched what was being built with high accuracy. For a prototye such as this, I can't afford to be too cocky.

[Weser 30]

Fair enough. I just thought that getting the trout mouths lasered would be much easier? I see your point there will be a fair bit of trial and error to get it all together nicely. Cant wait to see it progress!

[Rippthrough 98]

Problem is the laser cut edges aren't very smooth, they're also full of carbide precipitates from the heat, and half the time unless it's a serious piece of kit the angle of the wall will only every be 90*.

I've had tubes lasered and it's just as much hassle tidying them up to fit as it is to just do them with a grinder to start with, you'd be amazed how fast you can grind a notch with an angle grinder - much faster than setup in a milling machine, etc.

 

The only thing I have is a little abrasive belt/roller setup just to put the final finish them - so I can use a really coarse pad on the grinder for speed.

Edited July 19, 2012 by Rippthrough

[Cameron 16]

I do as follows: cut to length and trim rough profile with a worn down 0.8mm disc, then use a tapered flap-disc to get the profile 100%. It's amazing how accurate you can be with a grinder, you just need to be gentle.

[Rippthrough 98]

Yeah, that's what I do, apart from I use the sanding belt/roller setup for a quick tube cleanup and to get the shape perfect at the end, saves having to be gentle with the grinder

[Cameron 16]

But being gentle with the grinder saves having to put down the grinder! Mmm.. grinder.

[HERMAN 33]

Are these any good?

http://www.frost.co.uk/tubing-notcher-hole-saw-set-combo.html

Neil

[Rippthrough 98]

But being gentle with the grinder saves having to put down the grinder! Mmm.. grinder.

 

I don't put the grinder down, I just stick the end of the tube on the belt, not catch me putting a grinder down if I don't have to, I cut my bacon with one for breakfast

 

Saves swapping discs/grinders if you get close enough with the slitting disc.

Edited July 19, 2012 by Rippthrough

[Cameron 16]

Get 2 angle grinders - one for cutting, one for sanding. Problem solved.

[Rippthrough 98]

I've got 4

[welshpug 1,645]

how many work

[davenport 51]

those holesaw tube notchers are ok, but cheap ones tend to flex a bit and if you get a bit brave you can end up ripping the teeth off the holesaws...

 

we have a belt type notcher at work and by changing the diameter of the roller you can accomadate various tube sizes,,,

 

the ends of my customcages kit were plasma cut and took quite a bit of cleaning to get rid of impurities, i just used some of these:

 

 

but do agree with a bit of time you can get acceptable results with a grinder...

[Cameron 16]

So, keeping true to the tradition of this thread, I started work on the shell today by not starting work on the shell.

 

Instead I dealt with something that has been bugging me since last week, which is a problem with the work frame. The base of the car sits 0.5m above the top of the frame, which is great as I can get under it easily, but it doesn't make measuring things very easy - the slightest angle at the ground (say if my square isn't quite square) means that I get quite a big deviation up at the point I want to measure / position. So I've made 2 little tables that bolt down to the frame and represent ground level, which makes things much more accurate.

 

 

The ground clearance is 70mm, and combined with chopping the floor out (which sits some 100mm below the base of the sills) makes the car really quite small - 1.2m from ground to the roof, which is just about half way between my nips and navel.

 

 

In contrast a standard GTI is 1.35m high, so this will be around 150mm lower.

 

Anyway, tomorrow I'm going at the shell with my angle grinder until not much is left.

[alexcrosse 124]

Almost a GTI40 then?

[Cameron 16]

Almost.. you reckon a 4mm roof chop would be worth it?