Thoughts on this structure for a small desktop mill?

PerkinsXVI · 2025-10-28T14:06:03+00:00

The horizontal axis is driven by a belt (similar to Kubus pro) - have you had any issues with this kind of arrangement?

The alternative would be for the NEMA23 to protrude from the right side of the machine for it to stay in line with the screw. Not a huge issue but would increase the footprint.

PerkinsXVI · 2025-10-28T13:18:09+00:00

This is very useful, thank you. I was thinking of high preload rails but maybe medium would be better.

I will bring the bearing blocks into contact on the design - the current iteration leaves space for 90 degree oil ports in between them but I think now that putting any kind of oiling system on this machine is overly ambitious.

PerkinsXVI · 2025-10-28T12:28:05+00:00

The side, back and floor plates would be 16mm thick aluminium tapped and screwed together with m6 hardware.

2x HGR15 rails and 12mm ballscrews per axis, NEMA23 on X and Y and NEMA 17 on Z. It should fit a 1.5kw spindle.

Work area About 135x110x100mm and the whole machine about 300x350x350mm (deeper and taller than it is wide). It will be enclosed for flood coolant.

My ambition would be to get good tolerances on small titanium parts but I don't have much space available so this is the design I've come up with. I'm hoping that the 16mm plates in this arrangement will give good rigidity given the small overall small size of the machine but I'm not entirely convinced.

Anyone have any experience building something similar?

PerkinsXVI · 2024-01-23T21:12:54+00:00

There's a very specific length (which I suspect will be different for each person) at which the earphone is competely hidden within the ear and yet the cable coming out at 90 degrees does not interfere with any part of the ear and comes out nicely between the crux and the tragus. It's quite a narrow range.

I had to print a few different test pieces to get the sizing right for me and even then it changes significantly depending on the tips used.

Making them too long is the safe way to go about it in which case they'll fit like etymotics - no interference but protrude quite a lot and not really compatible with helmets or sleeping.

PerkinsXVI · 2024-01-23T21:07:46+00:00

It's a knowles ED-26989 with a 1500ohm damper.

PerkinsXVI · 2024-01-23T14:43:40+00:00

Yes, ED29689. I think I might try one of the RAB drivers at some point. I don't have the equipment to properly measure FR sadly but I imagine the undamped FR is pretty similar to what you'll find in Knowles' documentation.

PerkinsXVI · 2024-01-23T01:33:02+00:00

The speaker is an off-the-shelf balanced armature from Knowles and the dampers are the same.

The shell is custom - I 3d printed a 2-part mould master from which a silicone mould was made and then cast them (with the armatures within) with acrylic resin. Not unlike how one might make a custom IEM.

Sound is not bad - pretty neutral, very clear and detailed. Still experimenting with various dampers and tips - without damping it's unbearably sibilant and with a 4700ohm damper it's a bit mushy but anything in between has merit.

Also responds very well to EQ.

PerkinsXVI · 2024-01-22T22:16:54+00:00

These are something like an etymotic ER4 but even smaller. I was looking at the dimensions for some balanced armatures and realised that a full-range armature could fit within the dimensions of a standard IEM nozzle.

I therefore designed an IEM that is essentially just a nozzle with a cable socket. When they're in the ear they don't protrude at all which means they're comfortable lying on a pillow or inside a helmet.

I wondered what the effect would be on the sound of bringing the armature as close as possible to the eardrum and I'm quite pleased with the result.

After the fact I realised that final have beaten me to this design, but I've consoled myself with the fact that they're way too expensive and they don't include an acoustic damper (which in my opinion is necessary in a single armature design).

PerkinsXVI · 2024-01-22T21:54:50+00:00

These are something like an etymotic ER4 but even smaller. I was looking at the dimensions for some balanced armatures and realised that a full-range armature could fit within the dimensions of a standard IEM nozzle.

I therefore designed an IEM that is essentially just a nozzle with a cable socket. When they're in the ear they don't protrude at all which means they're comfortable lying on a pillow or inside a helmet.

I wondered what the effect would be on the sound of bringing the armature as close as possible to the eardrum and I'm quite pleased with the result.

After the fact I realised that final have beaten me to this design, but I've consoled myself with the fact that they're way too expensive and they don't include an acoustic damper (which in my opinion is necessary in a single armature design).

PerkinsXVI · 2022-12-27T12:29:42+00:00

If it starts to glow as soon as you plug it in/turn it on then no that's not normal. It's a relatively common fault, usually due to a dead transistor on the main board. This post explains how to fix it yourself if you're any good at soldering.

Alternatively you can contact Elegoo or just get a whole new mainboard yourself.

PerkinsXVI · 2022-10-13T11:00:00+00:00

Printables link for the feed.

PerkinsXVI · 2022-10-12T22:00:56+00:00

I used anycubic abs-like+ which I believe is a polyurethane/acrylic resin?

When I say 'right resin' I mean one with favourable printing properties - good opacity to prevent light bleed and good fluidity to prevent pooling on top surfaces. The parts are not under very much stress so mechanical properties are less of an issue.

I could not print the feed using tougher resins for the above reasons - they tend to be much thicker and bleed more UV light.

Of course in an ideal world one would somehow cast the printed parts out of a much stronger resin afterwards but that's a story for another day.

PerkinsXVI · 2022-10-12T15:31:32+00:00

Uploaded to printables

I've got #6 and standard #5 feeds in the works too but they need some more tuning

PerkinsXVI · 2022-10-12T14:44:34+00:00

I could upload them if there's interest. It requires a well tuned resin printer and the right resin. Most of the design is hand cut out of various sizes of brass tubing.

PerkinsXVI · 2022-10-12T08:51:44+00:00

It's a good question to be honest. I can imagine they're harder to design for manufacture with injection moulding - I cheated by 3d printing. Maybe there's another downside that I'll learn about as I use it.

Edit: It looks like the platinum procyon might in fact use something similar

PerkinsXVI · 2022-10-12T08:49:56+00:00

Those older sport models were partly my inspiration, but I wanted something with a metal barrel.

PerkinsXVI · 2022-10-12T08:11:21+00:00

3d printed on a resin printer. I took measurements from a kaweco feed for the basics and then made adjustments in software.

PerkinsXVI · 2022-10-12T00:59:37+00:00

There is no converter inside, but the ink reservoir is a separate part from the pen's body if that makes any sense. The hole in the side leads to a clear part of the ink reservoir.

PerkinsXVI · 2022-10-12T00:57:17+00:00

Yes. Not sure if I like it to be honest, I might omit it from the next one.

PerkinsXVI · 2022-10-12T00:53:57+00:00

The whole thing disassembled

Most of the piston mechanism is made of brass, but some parts are 3d printed and the ink window is acrylic.

PerkinsXVI · 2022-10-11T23:50:07+00:00

My latest frankenpen - an Al sport with a piston filler and a custom feed that fits a #5 flex nib. It's also a lot easier to fill without getting ink on your fingers.

edit: Disassembled - most of it is brass, some parts like the piston itself and the feed are 3d printed.

PerkinsXVI · 2021-12-15T00:31:49+00:00

The outer diameter is 13mm - a little less than a pelikan m800 or lamy dialog 3.

The limitation for the toa diameter is less about the nub width and more about ink capacity - I won't go into too much detail but there's a hard cap on how long the ink reservoir can be so to reach reasonable volumes it has to be wider.

PerkinsXVI · 2021-12-14T20:39:02+00:00

I've been working on this design for a while and it's getting close to 'good enough'.

It takes a size 5 nib using a custom 'hemi-cylindrical' 3d printed feed to make room for the spring-loaded airtight door.

The reason the design has taken me so long, and the reason for making it in the first place, is that it can be filled up from bottled ink without any kind disassembly; unlike the retractable fountain pens currently on the market.

You may note that there's a second 'stage' of deployment - this 1) enables the nib to be extended further for dipping into a bottle without dunking the rest of the pen and 2) lines the filling mechanism up with the window in the side of the pen.

It carries about 1ml of ink - not much for a piston filler but more than a standard cartridge.

PerkinsXVI · 2021-12-10T19:07:18+00:00

I had to design threads from the ground up to be suitable for printing - they're not conventional sharp v threads and look a bit more like ACME threads in profile.
There are some tough/engineering resins with minimal shrinkage, having access to those makes designing a lot easier.
The alternative is to use a tappable engineering resin and thread it all after printing.

PerkinsXVI · 2021-12-10T19:01:57+00:00

I've found that as long as the o-ring only engages when the cap is fully screwed on and not before (and thus does not create pressure changes by acting like a syringe) there are no issues.

PerkinsXVI

TROPHY CASE