More Bracket Drilling and Adjusting...

After drilling holes in the first two frame angle brackets I was not happy with position accuracy and spent a couple days experimenting with various setups until achieving a solid, accurate, and repeatable configuration with drill vice plus clamps and 123 blocks. Also, filming with a storm roaring and poor lighting slowed things down.

I also found out the t-slot clamp set I had ordered earlier in the year was 5/8" imperial rather than M10 (or M12) metric that I thought had been ordered, and unfortunately the 5/8" t-nuts did not fit in the pillar drill base nor the milling table attachment. So the first setup used regular M10 and M12 bolts and wide washers until sets of M10 and M12 t-slot nuts, studs, and clamps arrived and everything could be redone properly.

While replacing the bolts with t-nuts and studs I also used a dial test indicator to align the milling table attachment and mill vice relative to the pillar drill table which was locked firmly in position. This wound up saving a lot of headaches as the milling table attachment could then be used for reasonably accurate X and Y travel - essentially turning the pillar drill into a poor version of a vertical mill, but without DRO or high quality quill bearings...

Drilling Channel Beams

Once the 4 angle brackets were completed it was on to drilling matching 8.5mm holes in steel channel which makes up the side and end beams of the frame. The setup with clamps

turned out to be very useful for repeat operations. I also found using a #3 centre drill was much faster and more accurate than pilot drilling - most likely due to the shorter travel and larger diameter body for clamping in the drill chuck. There was a bit of chatter when the centre drill bevel was cutting through, but no worse than going from 3.5mm pilot to a 6mm or 8.5mm twist drill.

There are two holes at the ends of both side beams, and I mistakenly also drilled the same positions on the end beams only to realise later the holes in the end beams are further in to set a roughly 26cm distance between inside of the side beams which aligns with pillow blocks on the axles. So there are extra holes in the end beams in this unit. However, not all is lost - two of the four holes are well positioned to hold the wooden end beam :)

The side beams also need 4 holes on the bottom for bolts to attach pillow blocks which hold the axle assemblies.

Then 4 more hole positions were marked on top of the side beams and drilled 6.5mm for M6 coach screws to attach the wooden beams which sit above the steel frame and provide a base for the deck planks.

Assembling The Frame

Steel beams and angle brackets are drilled and now it's time to bolt them together. Part of the design process includes finding problems and solving or working around them. In this case the inner holes in the angle brackets were too close together for the flange head bolts to fit, and regular (non-flange) bolts just barely fit, however, there is not enough clearance for a socket so spanner (wrench) had to be used on the inside of the corner.

Attaching The Axles

This part went much smoother. With the frame upside down, pillow blocks were bolted to bottom of the side beams. The hole slots on the pillow blocks are elongated M12 but the bolts are M8 due to width of the 50x25mm channel beams. So in order to minimise any side-to-side movement I installed 8mm-12mm bushings inside the pillow block slots.

Lots of fun and plenty of learning so far. Next step is adding wood beams and decking...