Reports From the Manufactory

Well I’ve been posting a fair bit on the 3D printed side of things, but with the printer busy doing some very repetitive parts runs I thought I should start posting up on the metalwork side of things.

So here’s my small shop projects, tips, tricks and demos thread. Anybody feel free to post up your own metal projects and questions too.

So to kick things off, I finally got around to building a mount for my hi-lift jack. If you don’t know the ‘farm-jack’ [or often called by brandname, hilift] is kinda like a radial-arm saw: It will absolutely eat you for lunch if you don’t know what you’re doing, but man when you need it it just does things no other tool can do.

Started by rooting through my box of knob stock.

These aluminum extrusions already have those spline cuts down the outside. They come in very long bars, and I was gifted a bunch of short cutoffs from a company making conveyor systems 2’+ wide with the stuff. They had no need for little 1.5" scraps, but I saw that and thought I have a bunch of threaded knobs I could make with that!

So all I did there was clean up the ends and drill/tap 3/8-16 down the center.

Now here’s some 3"x1/4" HRS bar drilled and marked for bending.

They sell these ‘angle cubes’ for setting up angled cuts on table saws and similar, but I love it to slap on some steel stock in the press brakes.

Much hand pumping the hydraulic press later and we have something bracket shaped.

There seems to be about 4 degrees of spring back in this material. So overbending to about 50 degrees got very, very close to what I needed.

So weld a bolt on the back, prime, paint, and I made some Delrin bumpers for the mount face because why not?

Fits the jack nicely.

1/4" stock was total overkill for this, but it is what was handy. I needed 3" wide, as where I intend to fit this they only work oriented horizontal, so I wanted some more vertical distance between the bolts.

Check back later when I get around to getting this mounted up. It’s going to be some possible over-stressing of rivet-nuts.

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I have an interesting hardware project in progress I hope to show in a day or so, but here’s one brief setback on that.

I shoulda figured this but didn’t. Don’t drill direct into grade-8 threads!

RIP 11/32 drill.

I did manage to fix this already. Chiseled the broken bit pieces out of there, then plugged a 3/32 carbide end mill down the hole to create a flat spot for the drill to get started on. That kept me from breaking another drill bit. So the drilling, reaming, and pin press-fit can continue.

Except for paint and a couple 5/8" washers I forgot to buy, the articulated hitch project is complete!

Ball-couplers don’t have that much range of motion when off road, and can tend to bottom out in places. Also, this looked like fun to build as an accessory for another trailer project that I hope to have postings of soon.

I didn’t actually make any drawings for this. Just looked at some pictures online and experimented with the bits and pieces I’ve got around.

Many designs start by just stacking random stuff together, deciding how everything should fit. This hitch needs 3 separate joints for pitch/yaw/roll; essentially forming a stretched out universal-joint.

So the roll element will be brought about by this 1"-8 bolt here. Nylon bushings on both sides of a 1/2" plug that gets welded in the end.

In order for that rotation to happen properly, this bolt gets the hex part removed.

So now I’ve got a stack going through the 2" box tube: Bolt → nylon bushing → plug → nylon bushing → locking collar. I shoved a piece of .030" sheet metal between the collar and nylon bushing, so I could stop the whole thing from turning in the mill, but still have clearance to rotate properly when I took it out.

Shop tip: putting long and/or narrow press-fit pins in things can be a pain to get in straight without bending or breaking something. Use a drill chuck should at least get it started, so it’s straight and lined up before taking it to the arbor press [or vise or hammer]

So here’s that test fit into the receiver tube, which will actually be the front of the trailer.

Now for the front half. Clevis parts machined and ready to assemble.

I’d say those welds turned out alright.

Forgot to get a pictures of machining the parts for pitch movement. 1" ID tube for the cross-piece, but I didn’t have any thick wall tubing with a small enough ID to tap 1"-8, so I machined that from solid and milled a fishmouth on the front end.

Fitup in a vise for tacking. I stuffed bits of sheet metal scrap in both sides to center it up.

Then weld that at look at the pretty colors!

So this part threads onto the bolt from the rear coupler. That jam nut and lock washer are really just to keep things from feeling sloppy. In order for this thing to actually come unscrewed in transit, it would require flipping the trailer over. To the left. Multiple times.

Overthought-out hitch complete!

An example of it’s movement range. This could pull trailers places I personally don’t really want to go!

Paint soon, test later. You’ll see this again when I get to go out and test it on the trail.

How is the yaw pivot joint lubricated? Or is it just a dry bolted together joint?

The 5/8 bolt runs through a hardened bushing that will get greased. The bottom of the clevis and top of the stinger are flat steel on steel. I’m trying to decide if I grease it a bit and try it, or maybe make a thin ~2.5" wide delrin spacer and see how it survives the pressure.

Macro etch testing

I’ve got some important welds coming up on some ~3/16 channel. I’m pretty confident in my flat butt and lap joints at current settings but this would be easier to do by welding vertical.

Different settings are required often depending on the weld position, and downhill welding reduces penetration further. I’m just going to leave my settings where they are though and lets see what happens.

First setup the test joint.

Hrm… well if the inside is anything to go by I should have probably doubled that gap width in the joint.

So then the weld gets cut in half, and polished up a bit with some sandpaper.

Ok yes, clearly very poor penetration there, but lets keep going.

Next you break out your gallon jug of phosphoric acid! Well alright, if you don’t keep any Alumiprep 33 around the local hardware stores do sell ‘Naval Jelly’ of which phosphoric acid is the main ingredient.

A cotton swab gets dipped and run over the still warm weld-bead. Here’s what shows up.

Hard to get the lighting just right for the camera. Zooming in helps. Even if the base metal and the filler rod are exactly the same alloy, the weld bead will show up since the grain structure between the two metals is different. The steel channel having more uniform grain distribution from the extrusion process, the weld bead having been a liquid is randomly oriented in the ‘as cast’ condition.

So obviously penetration only went about half way. The ~45degree angle it penetrated in at is a just ok depth-of-fusion. At the toe of the weld (that’s the left and right edges of the weld bead, right where that little hemisphere meets the base metal.) it’s pretty much just sitting on top of the steel channel.

So, options for improving penetration are:

  • Turn up the power on the welder (duh)
  • Increase the gap between parts
  • Bevel the joint so there’s a ‘V’ shape that increases lateral penetration
  • and when all else fails: suck it up and weld it out from both sides.

But I’m going to try and improve things mostly with techniques 2 and 3 and report back.

I’d sure like to make downhill welding work on this joint because it’s easy and looks nice and uphill welding on a non-fillet joint is like trying to push elmers glue uphill with a stick… and the glue is over 2000 degrees.

sigh I miss doing some welding. The hobbyist metal/welding shop closed up during the pandemic.

Just did a new search, apparently there’s a place down near Long Beach that has metal/welding/wood shops Hmm…must investigate.

Finally got the time to start the next fun project: an enclosure for the 3D printer.

Starting with cutting and coping the corners on the aluminum angle, and I decided to try another experiment with giving aluminum a ‘brushed’ look.

It’s an improvement. I tried this on some scraps with a belt sander and an 80grit belt and that was much too course. The finest grit zerconia belt they at at the hardware store was 120, and that’s what this is. Maybe not as nice yet as a proper SS wirewheel, but it’s nice to have an option to buff out the dings and scuffs from manufacturing when it matters.

So first the top and bottom frames:

Yeah, I can be content with those welds:

Next the verticals. I really thought this was a quick and clever way of squaring up one side of the angle, just checking the other with a square and tack around the edges.

It hardly worked at all :frowning:

I should have laid the front and back down on the table and clamped it that way. I ended up having to cut and fuss every single tack and angle back into square and straight and plum; lest I end up with a big 3D parallelogram and not a cabinet.

Partly this is recycled material too, so it’s not flawlessly straight in a few places.

So current status: it’s a box.

I’ve got rivets coming for the sheet metal siding and in the meantime I need to figure out how I’m going to make the doors.