Hello all,

Just a couple of lines and pics about some recent repairs using 3D-printed parts which might be of interest.

A couple of knob repairs: A nice little AWA Transistor Eight and an older valve Radiola had smashed knobs. Repaired these by removing the broken sections and printing new parts, then super-gluing them together.

The same Transistor Eight needed a new Eveready 276-P battery. Others (including 'batterymaker') have made battery packs holding up to 12 AA cells. My version has a tidy printed container for these which also includes the connector.

Last example is a replacement grille for a Stromberg Carlson.. The plastic is too white, so I'm ordering some ivory coloured stuff.

So what process did you use to smooth the printed items . I will need to spray mine with ivory paint . Mine is the Healing L502E discussion in this group.

Very nice work, Bernie.

That grille must have been a pain to draw.

Wow
love that grill. I have a STC bantam with that style grill, thats broken.
Gives me some hope of a repair one day.


Ben

Nice. I also have STC radios with broken cases and grills. They can break at the slightest touch.

While visiting Sutherland Shire Library at Sutherland recently I noticed that they have a small display case with 3D printed items. Most have the
TV raster-like surface finish shown in the items in this thread. One however is much smoother and looks like it would respond to polishing.

On looking into this on their website, the library has a craft group called MakerSpace.
http://www.sutherlandshire.nsw.gov.au/Community/Library/Services/MakerSpace

Among their equipment a 3D printer.
https://www.instagram.com/p/BQKMCLchC06/?taken-by=sutherlandshirelibraries

Their equipment list includes other craft equipment as shown in the link below.
http://www.sutherlandshire.nsw.gov.au/Community/Library/Services/MakerSpace/MakerSpace-Meetup

There is an invitation to bring along your project though this may be limited to Sutherland Shire residents. This is not mentioned in their Guidelines and Policies, but it maybe elsewhere on the website.

I had occasion to call into Sutherland Library again today, and was lucky enough to see their 3D printer in action under the care of it operator.
The printer has a large bed in the order of 300mm square, and can print through an orifice as fine as 100microns.

I asked about finishing options and he mentioned that ABS items can be finished with a process called vapor smoothing - this accounts for the smoother item I mentioned in a post above. Bead tumbling is also effective. Use of automotive spray putty normal practice.

Autodesk® Fusion 360™ - Cloud-Based 3D CAD/CAM Tool was demonstrated, which is free to use online for non-commercial applications. In minutes a circular knob was designed with a rounded leading edge and rounded gripping flutes.
A demonstration of this software is on Tuesday, 18 Apr 2017 at 5:30PM -MakerSpace: Introduction to 3D Design (CAD)

Use is not limited to Sutherland Shire ratepayers, and files sent in will be considered and accepted at their discretion. Items requiring extended time to print may not be accepted. There is no charge for materials, though a $3 per hour machine time charge is made.

Thanks for the comments everyone!

Hi GTC
I used a program called "OpenSCAD" to design the grille... It's a bit of software that describes shapes using xyz coordinates and formula.. for something as repetitive and geometric as the grille, it works fine, bur normally I'd use a CAD drawing program (such as Fusion 360 or similar). Here's a small chunk of the OpenSCAD code for the grille..

// The tiny inner subsections
for (y = [0:num_y_insub*num_y_segments] ){
translate([sub_x,sub_y+.5+y*insub_height,sub_z])
cube([speaker_grille_width,insub_thickness,insub_depth]);
}

for (x = [0:num_x_insub*num_x_segments] ){
translate([sub_x+.5+x*insub_width,sub_y,sub_z])
cube([insub_thickness,speaker_grille_height+2,insub_depth]);
}

// The little sub-sections for the RH grille
// Y
for (y = [1:num_y_segments-1] ){
translate([rh_grille_x,sub_y+y*sub_height,sub_z])
cube([rh_grille_width,2,rh_grille_depth]);
}

...as you can see, it can be a bit of a pain, but good where there is a lot of repetition.

STC830
Sadly Sutherland shire is a long way from Geelong.. Interesting stuff though
I printed using PLA

https://en.wikipedia.org/wiki/Polylactic_acid

It's easy and safe to work with.
Tallar Carl
Didn't use any smoothing process (and you can see that in the poor finish).
ABS plastic can be smoothed in Acetone vapour.. I may try this.
I plan to reprint with ABS, assuming I can get the right colour and vapour-finish. Otherwise, like you I will spray.

One trick with using a 3D printer for knob repair is to just print the part that fits onto the spindle/shaft, remove the broken bits from the original and then superglue the new to the old.

Photos uploaded to Post 8.

Nice trick with the knobs.

"Sadly Sutherland shire is a long way from Geelong.."

It is possible that there are similar craft groups around the country doing the same thing as 3D printing catches on. 3D printers now are in the same order of cost as my first printer a Canon BJ inkjet, so people would be buying them. Craft and educational organisations like Sutheland Library are apparently trying to react to interest in 3D printing. Their printer has been lent to other libraries in Sydney, so similar things will likely be happening elsewhere.

Hopefully someone will offer a 3D printing service for the VR community for those who don't want to do their own.