Jiggy! – Building A Swing Arm Jig From Scratch

Building a swing arm jig for a new project…

So here’s a rather massive clue to whats going on behind the scenes.  Not got much to say about this, other than Im pretty proud of it! It definitely features some of my best and worst welding (and a lot of mediocre in between), as well as some of my best and worst machining!

It started life as a length of 2″ square box section, which was cut and welded together, and then I ran a cutter all over it on the mill to ensure that it was square and flat and all that.

Swing Arm Jig Box sections welded up and dressed
Box sections welded up and dressed

The next step was to drill holes in the correct places, weld in blank bosses and drill them to the required size…

Swing Arm Jig Boss location
Swing Arm Jig Reaming the 'rear hub'
Reaming the ‘rear hub’
Swing Arm Jig The 3 major points in and drilled
The 3 major points in and drilled

After that, the drilled bosses were milled to the correct heights, and with a lot of flapping and faffing and angle-grinding, the 4th pickup point was added.  That just left turning the whole thing over to mill the other ends to the correct height!  A bit of deburring and chamfering later, and she was complete!

Swing Arm Jig The beast lives! Huzzah!
The beast lives! Huzzah!

Its not that blurry in real life, honest!

My first creation for the build; a 6mm hex to 1/2″ square adaptor- now the mill has power feed courtesy of a drill!

Bodged power feed adaptor for the milling machine
Power feed adaptor for the mill! Bodger.

Next up, an extended 12mm reamer!  A tad prettier (and straighter!) this time…

Extended 12mm reamer
Pro tools, innit.

Creation #3 was a massive heap of mess.  I think I had the every tool on the bench at this point!

Messy workbench
Where is it? Its on the bench, gov.

Probably my worst welding moment yet…from trying to weld upside down, without gas because the cup wouldnt fit between the mill table and the piece.

Weld spatter on milling machine table
Cleaned milling machine table after weld spatter
Got away with it, almost!

Some better welding…smug. 🙂

TIG fusion - one of Tam's better attempts
Tidy, if I may say so myself!

One of 2 cutter casualties.  This little trooper did both sides of the box section, all of the bosses, a few other odds and ends, then finally died when I asked it to skim a piece of hardened flat bar.  Thats about 1kg of swarf…good effort!  The other one was half dead when I started, and just survived the remainder of the hardened flat bar.

BTR Jig Burnt Cutter

Its quite a marvel that any of it worked really though, considering this was the plan!

'Fag packet' swing arm jig design
Err, tekkersLAD?

How much does it weigh? 6.07kg. Solid.

Completed swing arm jig

We’re excited, are you?



Leave a comment