cutting steel - accuracy

[cirrusjock]

Thanks for all the advice.

That tool for the grinder looks good. I will order one of those.

I have redone the sections that I wasn't happy with. Cutting long and grinding to the marked line works well.

I am only tacking at the moment and practising fully welding on offcuts as I go. One of the reasons I wanted to do the whole thing myself was to learn new skills like this so its good to get advice on here and see my work improving.

Thanks guys.

[TheArf]

Good on you, its always good to learn new skills. The closer and neater you can make your cuts the easier it will be to weld, also make sure that where you are welding it is clear of rust and any protective coatings, i.e. oil are cleaned from the area, remeber clean is good


Arfon

p.s. im cutting mine with a rage3 evolution chopsaw

[brainbug007]

I was in a similar boat and wanted to learn some metal working skills while building mine. I ended up using a black perm marker to draw the lines for the cuts, then cut slightly wide on purpose with a cutting disc. I then slowly grinded away all the black ink from the pen using a grinding disc to get my final line and then took a metal file to it if it wasn't a flush fit.

[vmax1974]

Will take about 20 thin cutting discs to do a full chassis

[alga]

Originally Posted by MarkB

If you are not sure then buy a ready made chassis, providing you don't modify that chassis you will be covered by their liability insurance should it fail.

Has anyone actually ever heard of a self-made chassis that failed catastrophically?

[minicountryman1961]

http://www.youtube.com/watch?v=5ZTqM...eature=related

Watch what happens at the 5:30 point in the video.

[AshG]

he forgot to weld the bracket it was doomed to fail.

as for your gaps as long as they are less than 1mm then you will be fine.

[HandyAndy]

All great suggestions / ways of cutting the steel

As you are cutting by hand, here is an easy way to cut the compound mitre cuts......hope it helps ( its a little long winded to write down & to read but it works )

Lets use the bottom compound mitre cut on FF2/FF3 as the example.....

firstly cut the 26 degree cut....

Place the steel down so the 26 degree cut is facing down onto the workbench,
then
Scribe the 14degree angle onto the upper face of the steel ( eg..top right to bottom left as you look at it )
then
turn the steel over 2 flats(away from you ) ( so now onto the original bottom from the first position of the steel on the bench )
then
scribe the 14degree angle from bottom right to top left as you look at it
then
turn the steel BACK 1 flat(towards you) ( in effect on its side from original position ) & using a straight edge line up the points of the previous 2 scribe marks & scribe a line.

You should now have 3 scribed lines showing the compound angle of 14 degrees.

Place the steel in a vice in position to cut the 2nd scribed line you made, you will find it easier to cut if the steel is positioned in the vice at an angle downwards ,
then using a hacksaw or ( depending how confident you feel...and angle grinder with a 1mm cutting disk ) & cut that scribe line ( do NOT cut all the way thru the 3 faces of the steel, just cut that 1 scribe line )
then
Remove the steel from the vice & turn over 2 flats towards you ( you,ll be cutting the 1st scribed line you made ) , position the steel so it is pointing upwards, then cut that scribe line ( again do NOT cut thru any other faces of the steel ),
then
remove the steel from the vice & turn the steel 1 flat AWAY from you & position the steel in the vice angled slightly downwards & cut the scribed line.

You should now have a perfect 14degree compound mitre cut , use a file to smooth out the cut lines so they all run in 1 direction of the compound cut.

Don,t forget that all the compound mitre cuts on the chassis apart from SW1 & SW3( these are singular pieces within the chassis) that have duplicates ( eg SB5 & SB6, FF2 & FF3 etc) are "handed".

hope this helps, & I hope it makes sense .....it does work


cheers
Andy

[shh120m]

Or...

Mark out the coumpound angle, place the tube in the vice so that one of the lines is vertical then cut the angle with the hacksaw so its like cutting a normal mitre.

[MarkB]

I don't have a problem with anyone having a go BUT if never welded before then making a car chassis is the wrong thing to learn on.