Alignment

Now that the Chinese New Year celebration is over, & the main machine structure is up. It is time to proceed with the critical rail alignment work.

This is the most dreaded part of the build. Why so? We all know that we can ride smoothly on a bumpy & winding  road. It is the same with machine. without a through rail the machine can never travel straight & smoothly.

What is the primary objective ?
1) line the rail as straight as possible. Here, I set out for within 0.1mm which is equivalent of +/-50micron. which is about the diameter of my hair (which I had just measured...)
2) straightness of within 0.2mm along the 4.4m length x-rail & 1.73m y rail
3) parallelism between the 2 x-rail of 0.2mm

Secondary objective?
1) Using the most primitive tools & equipment I can lay my hands on in my tool box.
Tools I used
1) Filler gauge with 0.05mm to 1mm
2) 30 lb fishing line
3) Aluminium shim salvaged from Coke can.
4) Hole punch
5) a few clamps
6) an aviation straight cut snipplet
7) some spanner
8) a 3lb hammer

No rullers, no micrometer, no dial gauge, no vanier calipers...

Can this be done? Oh Yes.
The last time I lay my hands on similar work was like 2 decades ago, after which I get to supervise/instruct others just by pointing my fingers + a bit of shouting when it calls for ;) . While they slough it out in tropical heat, I get to take refuge in nice air-conditioned office sipping coffee. The for another few year, I don't even get close to job like these...

It was tough at the beginning when I got rusty over the years, but like riding a bicycle, everything came back after a little fiddling.

Will post more on details... once I get everything organized...

MechMate Gantry & Y-Car Assembly

With the availability of CNC laser cut machine, fabricator's life gets a lot easier then it use to be. BUT that doesn't say one gets a free ride when fitting them accurately.`

Here are the laser cut profiled components. Most of them will be "Lego-ed" & weld into usable Monocoque Y-Car chassis & Box Beam Gantry

Level & alignment is of paramount important in this excercise. 

Hence, I build 2 adjustable trestle from C-Channel off cuts.drill & tap M12 holes for attaching adjustable leveler legs.

Setting up the box section beam on  the trestle.

• Using Spirit level to line them on horizontal plane. 

• Align the box section beam by measuring the parallel distance. Comparing diagonal distance to ensure they are square to each other.

• Clamp down to hold the position.

Rubber mallet for fine movement by tapping them lightly on the correct places without damaging the paint work. 

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When you are ready, spot weld to hold the assembly together & check for distortion.before doing the final welding.

Here are the Gantry & Y-car after welding & a coat of red oxide primer on the weld.

Closser view of the Y-car, The original paint was severy damaged by welding spatters....Shouldn't have painted...

.....Nothing I can't sort out with a coat of paint.

MechMate Table Assembly Works

From previous post, I shown the fabricated steel parts for the MechMate build in total loose form, all cut, dressed & painted. A friend who visited asked if they are kit supplied? Luckily, the scent of wet paint proved that I did the fabrication works.

This post will show the progress of assembling the "kit".

BTW, the table is good for 1220mm x 2800mm (8'x 12.5') working area.




The welding set










The "precision" measurement equipment I need for aligning the assembly.








Some of the welding were done on this make-shift welding bench. :)

The tube truss fitted & welded






How I fit the leg perfectly square & perpendicular to the main channel rail.

Completed table side frame

Both side frames completed

Aligned the two complete side frames square & parallel to each other

Place the table cross bearer on its appropriate position accurately. Then weld...







Fit & weld the cross pipe & diagonal pipe brace & you have a table.







There you have it, what is left is to get a group of 6 full muscle grown-up to flip this chunk of metal over...

This is only the table, we have gantry, Y-car....

Stay tune ;)

PS,
Is there anyone out there???? Give me a sign...
please do leave your comment & response in the comment lines...

Paint Job

After some back breaking working with steel, All the steel (at least what I know is requires) are cut, drilled, taped, ground, de-burred and painted.

This is the hardest part of the whole build as I have to lift serious weight, endure flying sparks, deafening power tools noise, work in dust filled environment, work on my knees, squatting for long hours & drinking 3 litter of water each day for over 2 weeks...

My advise, get a helper....

The dust is intensive, I lost count after I swept up two 50 liter buckets of grind steel dust...

I then decided to paint the steel before welding to avoid the intensive Yoga exercise session if I were to paint the table after the table is completely welded... Can always repair the scratches & welding burnt paint with a tat to extra paint...

Painting is a PITA task, easy to do but takes ages to reach a competent level of finishing...

How much PITA? Before you paint, one has to prepare the steel...

• Firstly, you have to remove loose scale & rust with grade A60 sand paper or power brush with an angle grinder, 
• Secondly, you have to rub down the dust & any oil stain from the surface with solvent, I use patrol for this task as they are great solvent that are easily available & they will evaporate without a trace. There are other practices such as wahing the steel with light detergent but I alway prefer how I did it...

• Then you get to paint...

Now, you can op for spray painting or hand painting... as my body is all sore after the earlier works, I hate to haul all the steel into the open & haul them back to the workshop after they are done... AND its raining season... a bad bad thing for wet or half dried paint...

*ps, It did rain a few time (per day) during the 3 day span of my paint job.

I use 4" paint roller for the job, some how, I can't paint with normal paint brush & roller saves me from the emberresment. AND with rollers, it is easy to control paint thickness & produce a even matted finishing which I like.

My paint selection :- 1 coat of Red Oxide primer & 2 coat of Enemal Alkyd paint (commonly know as Glossy paint).

More painting PITA....

1. Apply the 1st primer coat after the patrol had evaporated & squeaky clean...
2. Wait...... 4~6 hours for the primer to cure enough for the top coat... Too short the curing then the primer will be too wet for the top coat, too long the primer will harden too much for the top coat to "bite" on to the primer coat...
3. Apply the 1st coat, do not brush over the same spot over & over again, this will make the top coat to mix with the primer coat... Nevermind if you can still see the tint colour of the primer coat on this 1st top coat, you can get this corrected with the 2nd coat.
4. Wait..... read the instruction on the paint can, it says 4 hour for touch dry & 6~8 hour to re coat.... I waited 8 hours & they still feel too tacky for the second coat so I left them over night to cure properly...
5. The 2nd coat will be a breeze as you had already 2 coat of practice & finish in no time.

This is what I got

 The laser cut profiles.

The table parts including the rails in black

The table bearer channels 1 1/2 x 3" channels

Close up of the main 3" x 8" channel

The table leg & supporting tube trusses

Not forgetting the rails, with 2 coat of smooth black Hammerite paint...