Julie, do you think thread milling would be an option for internal threads? though a bit beyond what the OP wants to get into.

Not tried any tungsten myself so can’t comment on how it machines or what would be the minimum setup but the average Minilathe is probably not going to be rigid enough.

The need for consistant grooves and particularly scallops over a set of 3 would also want something more than freehand knob twiddling and form tools, at the minimum some form of copy attachment or automation.

You would not want to try power tapping in tungsten alloy!  Especially in a drill press.

Can you just make a brass decorative jacket with fancy patterns etc then epoxy a bit of tungsten inside it?  Brass is easy to machine if it’s the right grade.

I have a piece of tungsten alloy of the same grade as a larger lump that forms a pendulum bob which was pre-machined to shape.  As I was interested in the possibility of drilling another hole in the bob I thought I’d practice on the small bit using a cobalt drill which will happily chew through hard steel.  Went in a few mm and lost its edge.

There is no need to use taps and dies on the lathe under power if you don’t want to.

However the lathe is a very good tool to ensure the thread they cut is true to the lathes axis and therefore the part you hav ejust turned. The work is left in the chuck after drilling the tapping size hole and then the tailstock is used to guide the back end of the tap so it doe snot wobble and cut a wonky thread. Same for using a die, when guided it is far more elikely to cut a true thread than if there is no means to keep it true. The chuck, tap or die can be rotated by hand.

I play darts so I get what you are trying to do. I’ve considered making a set myself many times. One of the things you would need to consider is that all of the threads would need to be exactly the same depth, otherwise the weights wouldn’t be equally matched.

Some of the older darts I’ve used have a piece of threaded brass pressed into a plain hole at the back. This obviously makes tapping and threading much less of a problem, and drilling a hole to a set depth is much easier than tapping a blind hole to depth.

As for which lathe. I think you would need at least a mid size lathe just for the rigidity, especially when using carbide and grooving tools.

On 24 January 2026 at 15:15 JasonB Said:

…at the minimum some form of copy attachment or automation.

One advantage of ex-industrial machines is that there are, in theory, a range of accessories available which don’t exist for most ME lathes:

Julie

I’ve looked into machining Tungsten for my clock’s pendulum because they work best with a high-density bob.  By all accounts Tungsten is pig difficult.   Otherwise, Tungsten is a good practical choice because it’s twice as dense as Lead, isn’t toxic or radioactive, and is available and affordable.  Alternatives include:  Osmium, Depleted Uranium, Platinum and Gold.

Not tried to machine Tungsten yet, but being brittle and very hard, there’s a high risk fine details like threads will break.  See Julie’s comments. Therefore I suggest a design that minimises the amount of machining needed.

As designing from scratch is interesting, I had a go.  Comments welcome, I don’t claim the result is perfect!  It’s an Aunt Sally, presented for review in hope most defects and improvements will be spotted rather than wasting time on a prototype full of avoidable mistakes.

Practical men are encouraged to join in.  Armchair and computer job: I used SolidEdge CAD supplemented by the web and a dash of AI.

First try and get the requirements right!  Note use of “should” and “must”.  I suggest:

1. Materials must be available.
2. Materials should be affordable.
3. Design must, as far as possible, be doable on a mini-lathe.
4. Operations that cannot be done on a mini-lathe must be doable by other basic workshop methods.
5. Dart must:
   1. Outperform lesser darts (Top priority – this is why we’re making it!)
   2. Be of reasonable size and weight
   3. Be comfortable in the hand
   4. Fly straight and stable, point first
   5. Stick into a dartboard without breaking
   6. Allow easy replacement of delicate parts – spike and flights
6. Dart should:
   1. Survive hitting hard objects accidentally
   2. Look good

Requirement 1:  Tungsten, Brass, Silver Steel and Aluminium are all available.  Also paper or plastic for the flights.

Requirement 2:  All the above are affordable except Tungsten is pricey!

Requirement 3:  Met by limiting cutting to Turning, Drilling, and Threading. (Knurling optional.) Threading may not be necessary.   See Requirement 4 below for machining that can’t be done with a mini-lathe.

Requirement 4: (Non-lathe operations)

• Design calls for a R20 radiused bull-nose, suggested because it looks pretty.  Could be replaced with a plain chamfer, or shaped by hand.  Doesn’t need to be accurate.
• Design calls for the flights to be held in 0.2mm slots cut 15mm deep in the tail. Difficult to cut accurately by hand. I’d use a slitting saw on my mill.  Not ideal, suggestions welcome!
• Silver-steel spike easily turned on a lathe, but requires a small blowtorch for hardening and tempering.  Or accept it will bend, and make lots of spares.

Requirement 5-1:  inkmonkeh suggests Tungsten, a good choice, except it’s hard to machine, likely to break Requirement 3.   I suggest a simple Tungsten cylinder inside a shell made of a heavy metal that can be machined.  Brass is suitable for the body.  It’s a compromise.  The mass (35g) is lower than a solid Tungsten head (50g), but much easier to make, and less likely to shatter.  The extra 15g provided by solid Tungsten is tempting though!

Requirement 5-2 (size/weight):  Bad requirement, incomplete, because I guessed.  The proposed dart is 121mm long, diameter 10mm and weighs 41g.  Back to the customer, is that OK?

Requirement 5-3 (comfy): Bad requirement, forcing another guess.  10mm diameter feels about right to me but I’m a fountain pen wielding bureaucrat, not a dart player.  Jason mentions the advantage of thin darts being able to cluster; is that a requirement?  Customer to clarify diameter!  (Or, inkmonkeh experiment to see what works best for him.) For grip, I suggest a heat-shrink silicon sleeve rather than grooving or knurling the body.

Requirement 5-4 (flying):  Proof of the pudding is in the eating.   However:

• Design positions the centre of mass forward of the mid-point.  (The head is heavier than the tail)
• I don’t know what the optimum position for the centre of mass should be,  There’s an interaction with the flights, and whether or not the projectile is spin stabilised.  Getting this just right may be critical to meeting R5-1, making this better than other darts.

Requirement 5-5 (penetration):  Met with a steel spike, suggest home hardened Silver-steel.

Requirement 5-6 (breakages):  I suggest the spike be a replaceable push fit inside the body.  Accessed by unscrewing or unpinning the tail and dropping out the Tungsten core.

Requirement 6:

• My design’s Brass body is deliberately thin to maximise space for the Tungsten core.  Not much metal left at the body and tail joint, less if it’s threaded.  (M8 fine or extra fine).  It’s a weak point.  Could be pinned, but that’s weak too.  Don’t know how to calculate the strength, or what the worst case shock load might be.  More work needed.
• When the dart hits, inertia will hammer the Tungsten against the Brass body, and is likely to damage it.  A small replaceable O-ring would stop that.
• Replaceable spike and flights.

The Dart.

Outside view, the Green Dot marks the centre of mass, total weight less flights, 41g:

Spike, steel, weight 1g:

Tungsten Core – just a cylinder, weight 24g:

Brass Body – front, weight 11g:

Brass Body – Rear

Brass Body – Inside:

Tail, Aluminium, weight 4g:

Tail Inside – drilled out progressively to reduce weight.  Slotted at rear for flights.  4x 0.8mm holes drilled on rear-face to reduce tail weight.

Not happy with the tail.  Looks good, but Requirement 6-2 is a should, not a must.   Replacing the tapered and much drilled Aluminium with a simple straight wooden shaft is well worth consideration.  A straight shaft would move the centre of gravity forward, reduce the overall weight, and be much easier to make.   My 0.2mm slots for the tail need looking at too – must be a better way!

Dave

I’m afraid you would be sorely disappointed trying to machine tungsten on the usual mini lathe.  They just don’t have the rigidity.

When I was an aprentice we would make darts from tungsten copper. It was bought to make spark erosion electrodes but perfect for darts and machined easily.

David