2011-Sep-24 - Wooroloo - Steelworks #7
I had originally planned to erect the veranda columns myself but at the time realised that I was not well enough to complete the work on time.

I have just finished cleaning up from the tree felling and it doesn't look like any more progress will happen with the steel fabrication for a few weeks.

This gives me a chance to nip in and do some work and save some money.

Every spare moment this week I have been working on a jig to allow me to place and hold the columns for welding.

After talking to Ross, the plan is that I will lightly tack weld them on to the screw piles, brace them with timbers, and he will come along later and weld them down.

The jig is based on a 3, 4, 5 right triangle and will allow me to drop a plumb bob to mark the position of the column on the screw pile, measure off the height of the column, and hold the column in position while I tack weld it.

I will create a left handed as well as a right handed jig.

At the corners, I will use the left and right handed jigs together, as well as some extra pieces to locate the corner column.

The first step was creating two 5m scribes out of light 25 mm angle iron.

I needed to butt weld three pieces of iron together in order to form each 5m length.

I then reinforced this with additional angle iron welded in to create box sections.

Although light enough, the scribes bowed too much when lifted up in to the air.

I ended up underslinging each piece with 4m or 10mm reinforcement rod set up in tension.

This created a length that could still be deflected, but returned to its inherent position and length.

By Friday evening I was creating the 3m arm of the jig.

This consisted of a piece of 75mm SHS with a bracket welded to it to take a 3m length of C100 purlin.

I decided to complete this out on site on Saturday morning.

Saturday morning, I was up at 5.00 am, but had a lot of materials and tools to load, so was out to site at 8.00 am.

I attempted to make the 3m arm out of scrap pieces joined together.

However, when I hoisted this up in to position I found that there was too much twist in the C100 purlin and the 75mm SHS head could easily rotate through 30 degrees.

I realised that I needed to bite the bullet and use up some of my good stock lengths. Each arm needs to use 2 x 3m of good purlin tek screwed back to back to improve rigidity.

There was no room to work in the garage section and I was getting tired of squatting on the ground.

I realised that I needed to set up a work bench in the incomplete workshop area.

This meant I needed to spend an hour or so cleaning up all the fire hazards I had not dealt with last weekend - piles of leaves and twigs.

Once this was sorted I was able to set up a bench consisting of horses and scaffolding planks.

While I had this section of the grid down on the ground, I also added some thin fingers of sheet metal to the head, projecting downwards, to allow clamping to the column prior to welding at the screw pile.

This time when I hoisted the purlin arm of the jig up in the air, I found it was much more rigid but the head piece was rotated about 15 degrees out of position.

I found that by clamping the purlin against its support stand I could rotate the head back in to a vertical position.

I had a good look at how the jig was performing, made some notes and decided to construct the rest of the jig back at home.

After unloading some materials from the trailer and reloading some of the jig components it was already 6.30 pm so I headed home.

The next day (Sunday), after a leisurely start (breakfast at the local cafe), I headed out to Wooroloo with all my tools and welder.

The first job was to accurately survey the height of all the veranda screw piles relative to the finished floor level in the garage.

I found that two of the screw pile tops are too high to be hidden by the paving.

I also found that two of the screw piles are too low for my stock of 2.9m 75mm SHS to span.

I pulled out all of the stock of SHS and measured every piece.

After some juggling I came up with an allocation that would work.

For the piles that are too high I need to cut the top off and weld a new disk back on, lower down into the ground.

The corner pile will need to be sorted out first if I am to install the back veranda line of columns.

After some vigorous digging I exposed sufficient stem to get in with a large angle grinder and hack the top off.

I then cut the pile down to the correct height using a small 4 inch angle grinder. This was a slow process but it gave me the fine control I needed to make an accurate, level cut.

It was getting to the end of the day by now so I decided to leave the welding until next weekend.


Head of jig, from outside

Head of jig, from inside

Support arm/adjustment and torquing clamp

5m arm meeting 3m arm at head

3 m arm meeting side of building

5 m arm meeting side of building

75mm SHS brought out of storage and counted

Screw pile cut down to height

Screw pile off cuts

Surveyed column heights