Guide to Steel
You will probably be scratching your head when seeing lists and spec sheets for steel sections and steel plate. It is not really difficult if you know what the specifications mean.Your build for your Locost will use Sheet plate, RHS, round steel tube, seamless steel tube, RSA, and Aluminium sheet. RHS is Rectangular Hollow Section (box section). RSA is Rectangular Angle Section (angle iron). Round Steel Tube is hollow tube that has been rolled and welded. Seamless Steel Tube is hollow tube extruded not welded, stronger. Sheet plate in steel or aluminium usually comes in full sheets 8feet long x 4feet wide and ordered in your chosen thickness as below.
The sizes for the steel sections can be listed in mm or inches and you will often see the thickness of the steel listed as swg. SWG is an old standard of sizing for thickness of round wire and also steel plate. Although the swg range is very long, I don't think you need to know any more than the range in the table below.
|
SWG |
MM |
INCHES |
|
8 |
4.06 |
0.160 |
|
10 |
3.25 |
0.128 |
|
12 |
2.64 |
0.104 |
|
14 |
2.03 |
0.080 |
|
16 |
1.63 |
0.064 |
|
18 |
1.22 |
0.048 |
|
20 |
0.914 |
0.036 |
|
22 |
0.711 |
0.028 |
|
24 |
0.558 |
0.022 |
mm measurements are quite straight forward but if you are not too good with inches I will explain. Each inch is divided up into a thousand parts which is abbreviated into Thou. So in the table above 10swg is actually 3.25mm thick or 0.128inches. 0.128 inches is equal to 128 thousandth's of an inch. If you have to measure this accurate obviously it cannot be done with a tape measure. A micrometer in either mm or inches will be needed, or a vernier caliper. Originally you had to know how to read a vernier scale to read both these instruments, but now they are available in digital format. This makes them easier and quicker to use, and digital vernier calipers can be switched from mm to inches, and also measure internal, external dimensions and also depth as well. I think you will agree a very versatile tool for the money.
You can visit some local engineering fabricating companies and they will probably let you take any off cuts from their scrap bins for your smaller pieces, or you will have to buy your steel from steel stockists, delivered to your door. Remember when handling steel the edges after cutting are razor sharp, so wearing gloves is a very good idea. ALWAY'S deburr the sharp edges after cutting any steel, box section, angle and solid block is best done with a sanding disc in 4 1/2 inch grinder or a hand file. Sheet metal can be deburred very quickly and easily with a simple de-burring tool as below. This is pulled along the edge of the plate and the small tip automatically sets its own cutting angle to the edge of the plate and slices off the sharp edge.
