Wiresaw from Guitar String

A wire saw is piece of wire used for cutting. It's kind of like a band saw blade, except instead of having teeth, it cuts using abrasion - like a Dremel cutting disc does. It's a useful addition to the toolkit - it's one of those tools that might not see everyday use, but those times when you do need it, it more than pays for itself.

Most retail wire-saws tend to be aimed at the military / survivalist market, but I find mine most useful in trimming supports from 3D prints and cutting in hard to reach spots when dismantling electronics.

The great thing about wiresaws, is a lot of people will have one in their home, even without realising it. My wire saw is a string from a guitar.

The wound nickel creates the abrasive surface, being nickel it's quite resistant to the heat from the abrasion, and being a guitar string, is designed to withstand bending and flexing.

the downside to this, is they can be a pain to keep tidy. As they bend, they become more difficult to keep tidy.

So as a weekend project I made a simple case to store the wiresaw, helping to wind it neatly, yet keep it accessible.


As this was an off-the-cuff project, these measurements were not measurement by design, but what they ended up as after the fact, and are just there to give a rough indication of the sizes required.

I started with a 35mm length of dowel (10mm diameter). which i drilled two small holes through.






I grabbed a scrap piece of pine and cut a 20x35x55mm piece. I used a 20mm spade bit to drill partially into the 35mm side, and then used a 10mm drill to cut the rest of the way to the other side.

I used a router to carve out a groove from this hole to the short edge of the wood. There was a bit of tear out, but it doesn't affect it. The staple across the groove it there to act as a guide for the wire. I put the dowel in place, so that one of the drilled holes is on each side.




The guitar string is threaded through the carved channel, threaded through the dowel hole and tied. A piece of hardboard was cut to size, a 10mm hole drilled in line with the dowel and nailed to this side, effectively 'closing' the case. A small drill bit was pushed through the protruding dowel hole on the other side, and turned to wind the string in. A keyring was tied to the other end of the string, as a handle for the saw.

The drill bit was replaced with a loop of copper wire to provide a winding handle.

In an ideal world, this would have auto-retracted, like a tape measure, but some testing that I did showed that wasn't really practical.

Finally everything was trimmed to size and sanded down.

The finished project, closed (left) and open (above)

Old Hand Saw Restoration

I found these old saws in my local scrap store for a quid. I've always been a fan of the old-fashioned aesthetic of wooden handles. So being just a quid, I thought I'd grab them, although I wasn't really sure what I wanted to do with them.

Before

A post shared by Anthony (@darkmidnight_diy) on Mar 14, 2017 at 6:23am PDT

The Blades
The blades were very rusty, and I wasn't sure if they'd be salvageable. I was only really after the wooden handles anyway, but thought it'd be worth a shot restoring them.

One of the "old-wives tale"-type solutions for rust is white vinegar. I was sceptical, but it's a cheap option, so I gave it a shot, and it worked surprisingly well.

It takes some time, but takes little actual working time - I just set up the blades soaked in the vinegar (I found it easier to wrap the blades in kitchen roll/tissue paper and soaking that, rather than trying to find a suitably sized container).

I did that first thing in the morning, left them most of the day and later rinsed them off and scrubbed the blades. It got the worst off, but there was still a few spots of rust that remained. For that I used a wire brush.

The screws were brass, and cleaned up easily with Brasso.

The Handles
The handle of the tenon saw was in the worst state of the two - removing the blade revealed quite a large crack running from the near screw hole to the hand opening. During disassembly this caused a fragment to break away, but I was able to glue it back neatly with Superglue and it's not noticeable unless it's being looked for.

The flat sides of the handle I sanded with an orbital sander, but sanding the curved areas required a Dremel and a lot of patience.

Once sanded both handles were stained with a redwood stain, applied using a cloth rather than a brush (I find this highlights the natural woodgrain better).

After

A post shared by Anthony (@darkmidnight_diy) on May 3, 2017 at 6:27am PDT

Now they're restored, I'm still not entirely sure what to do with them. I have plenty of other saws, so it's not like I'll particularly need them for actual work, so I'll likely just use them for some artsy display or something in the workshop.

Side note: After removing all the rust, I discovered this faint engraving on the side of the tenon saw. It says PT2250, and appears hand-engraved.

It's very faint and difficult to photograph clearly, but it's hand written and says "PT 2250". Wonder what it means?

Tool / Drill Bit Demagnetiser

The End Result

 

The Build
 
The downside to the magnetic drill bit organiser that I created in the last post is that the drills themselves end up becoming magnetised.

This isn't really a problem for woodwork, but can get a bit annoying for drilling metal, so I started looking at building a demagnetiser.

Research online showed lots of examples (such as this) of powered demagnetisers, often using dismantled power transformers, mains power and over-heating risks, which was a bit off-putting.

However, there are passive (unpowered) demagnetisers available to purchase, so there must be another way.

It's well known that metal can be magnetised by rubbing it against a magnet. There is, of course, a lot of dry and boring scientific explanation about why it happens, but in layman's terms, the punchline is that metal stuff gets magnetised when the electrons in it get aligned. So to demagnetise it, just screw up their alignment. Simple, right?

Yeah, really, it is. If putting a bit of metal near one magnet pulls the electrons into line and magnetises it, sit the metal between two strong magnets, and the electrons can't agree which way to point, so they end up pointing in conflicting directions, and become demagnetised.

The magnets were provided courtesy of an old, broken hard drive. Unfortunately the shape of the drive magnets is a bit awkward to work with. To overcome this I took photos of the magnets, imported the photo into Inkscape and drew around them, exporting the resulting SVG into blender to turn into a 3D model for printing (a similar process that I used in this post)

The HDD magnet, and the shape drawn around it in Inkscape, ready for extrusion into Blender.

A photo posted by Anthony (@darkmidnight_diy) on Nov 27, 2016 at 1:00pm PST

A bit of hot glue was used to fix the magnets in place, and they were covered with Sugru to avoid tools just sticking straight to them.

To join the halves together, I would typically just glue them together, but this time I wanted to test a technique I've not tried before - plastic friction welding. It sounds fancy, but can be done with a Dremel and a bit of 3D printer filament - see the clip below for an example. I used orange filament against the black used for the printed body of the demagnetiser - it's not the most aesthetic choice, but it does help highlight the plastic weld technique a bit more easily.

 

The resulting join is plenty strong enough - as evidenced by several spontaneous shock tests, and totally not by accidental dropping.

The demagnetiser works simply by waving a magnetised tool through the gap in the gadget, as seen in the video at the top. It won't necessarily remove magnetism entirely, but as you can see, it significantly reduces it.