3D Print Thread Inserter

[awemawson]

I've been playing with 3D printing recently and wanted to insert some thread inserts into mechanical parts - ie things that are functional rather than artistic.
Doing it with a normal soldering iron is perfectly feasible however I found it difficult to keep it truly vertical. So exploring making a press, or a fixture for the Bridgeport I realised that this particular wheel has been designed before and Amazon have several offerings already manufactured !

Not expecting much I ordered one and found when it arrived that actually it was quite well made and stout. Two things need tweaking:

Firstly the mains plug purports to be a standard UK 13a one however totally illegally and unsafely is unfused - I knew this from the illustrations and it was a simple job of cutting off the the dangerous one and replacing it. (*)

Second issue is that although it has an upper stop and a depth stop setting the depth stop with the required accuracy to get an insert sunk to exactly flush with the surface isn't possible - far too much wiggle while tightening it. Now they have just used a Tee nut in an aluminium extrusion which is cunning but something more robust is needed. At the moment I'm thinking to use Tee Nuts to fix a brass block to the extrusion, with a fine pitch screw acting as the actual stop.

Experimenting with my Planer Gauge gave me something solid to bring the hot tip down onto while locking the knurled screw, but that's only a temporary solution.

* (For our over seas friends UK 13A sockets are fused at 32 amps at the consumer unit and plugs carry a fuse to protect the flex rather than the appliance - this wire would smoulder nicely well before that limit)

[vtsteam]

That's pretty neat. Took me awhile to grasp from the description what the device was, but the pics explained all. The plunger heats the insert, and then presses it into the plastic part, controlled by a stop.

And the fused plug, if accurately labeled, would pass something close to 7 Kw before blowing? So the cord is more likely to protect the fuse than vice versa!

Aaah, got it Andrew. I'm slow some mornings...

[BillTodd]

Always amazes me. They go to all the effort of making a plug and then not make it compliant (even if not actually tested)

I was eyeing up one end of that scanner I'm scrapping, it'd make a nice little press like that ;-)

[awemawson]

I actually like the way the (presumeably) Chinese designer has used several standard parts to make it. For instance the clamps holding the (repurposed) soldering iron are a pair of hydraulic pipe clamps intended for use for surface mounting. The frame is made from standard aluminium extrusions - even the thing the counter balance spring hooks onto is just a wiring 'Pee Clip'. Just a stamping for the base which is pretty heavy duty, and a folded piece to form the upper bracketry.

Reminds me of British Leyland where many parts were common across models - the lights - the instruments - the brake components. Whereas nowadays every thing is unique and stupidly expensive.

[Country Bubba]

They sure make it easier to get the inserts square!  I cobbled one up out of some 3D prints, a piece of countertop, a piece of square tube, and cheap $10 iron similar to the one in your picture.
Makes life a lot less frustrating. One thing I did find is make the iron on the "cooler" side and let the insert slowly go into the piece as there will be less "dribble" and excess mess to clean up.

[ddmckee54]

Andrew:

If you haven't already discovered it, when you're putting an insert into a blind hole you need to make the hole a couple mm deeper than the insert.  The hot insert will push molten plastic ahead of it as it is inserted and if you don't leave a place for that to go, it WILL fill the insert's threads - DAMHIK. 

If you're setting the inserts by hand, a trick I picked up from Clough42 is to take the heat away while the insert is still a little proud of the surface.  Then quickly flip the part over and press it down on a flat surface.  The insert will retain heat for a while and pressing it on a flat surface does 2 things, it sets the insert flush with the surface and it also wicks some of the heat out of the insert. 

When I was installing the inserts for the track drive motor plates into the frame for my Terramac RT7R I discovered that the idiot who put the 6 heat-set inserts between the frame rails never considered how it would be possible to fit over 150mm of soldering iron into an 80mm gap.  What I finally did was to set the insert into the hole, I used the soldering iron to get the insert hot - but not try to seat it in the hole, then I used a piece of flat bar to seat the insert flush with the surface.  The flat bar I used was a 6" piece of 1//4" x 3/4" HRS, I set the 6 inserts in less than 5 minutes and it barely got warm.

Don