10 minute make; Alpine Butterfly Knot

Knot tying is a great skill to practice and makes a superb #10MinuteMake. This knot "the Alpine Butterfly" is of interest to me as I use it to tie loops in lines to attach parachutes too for rocketry. It's a good knot mechanically as it can be loaded on the loop and on either side. It can be tied into the middle of a line and also can be used to isolate a damaged piece of line or rope by tying the damaged section into the loop. Really handy! I found this copyleft license-free image that shows how to tie them. 

Machining Rocket Deployment Charge Wells.

Machined out these small aluminium charge wells for deployment charges for rocketry. I have used small copper plumbers endcaps before now but needed slightly more capacity and I  wanted to try and make them in a way that the E-match wires would sit flush through a small slot, making them easier to seal. As I use Pyrodex rather than BP it's important that the seal is good to contain the Pyrodex correctly. 

                           

Machining them was pretty easy, I turned some stock down to 20mm diameter and centre drilled a 5mm hole for an M5 fixing (I potentially could have used smaller but I needed 5mm to give clearance for the home ground HSS boring bar). Then I bored them out to leave a 3mm wall thickness and parted them off on the lathe.

Having parted them off I decided that they were a little too long for my needs and I milled a couple of mm off each of them as there is no use carrying that weight if you don't need it! I then used a small endmill to mill the small slot.

It's nice to be able to try these ideas and I love machining parts for rockets... I mean I could just buy everything but where the fun in that! :)

Upcycling Pallets for Vertical Gardening!

I'm always collecting pallets as they are a useful, often free, source of either wood for projects or, if a bit too far gone, can be split for kindling for the wood burner. I've seen loads of projects using and upcycling pallets and indeed I've seen a few variations of this project where you turn a pallet into a vertical planter for gardening. I'm no great gardener but do try and grow a small amount of veg each year more for fun than on any grand scale, but also bought veggies, especially salad greens are costly and usually come in loads of packaging. A vertical planter would be great for those short of space, which we aren't particularly, but we do suffer a lot with slugs and snails. It seems that a vertical system would be easier to defend from these critters by using some copper tape around the base, so I wanted to see if this works well this season.

To start with I looked through the few pallets I had and found a likely donor for the project. The above one seemed ok and had three feet that could be turned into planting areas at a reasonable spacing. One end had an extra reinforced bit which I considered removing for ascetic reasons but I'm not too worried what it looks like and wanted it to be as strong as possible to cope with the winds we get up here!

Making the planting areas is as simple as adding another plank to the sides of the legs to make a base. I did this with some other pallet timber, it's crudely done with just nails, I didn't even make any measurements but rather nailed on an oversized plank and then cut it flush at the edges. Inside the planting area, the planks weren't wide enough to completely span the base so there is a 10mm gap or so either side, this is better as it will act as drainage for each level but once the planters are lined with gardeners membrane they will still hold soil well.

Many people build these and screw the planter directly to a fence or a wall, I decided I wanted to have this more mobile so I can experiment with placing it in different parts of the garden at different times of the year.  I found some scrap timber and made 2 wide feet and screwed them onto each side to make it free-standing. 

Above is the completed structure and I decided to give it a coating of wood preservative to try and make it last a year or two longer in the weather. I dragged it into the porch and gave it a slapdash coat before stapling in some weed membrane to finish off the planting sections.

Its been a fun, quick project and I'll be filling it with soil and sewing some salad greens and other bits and bobs in it at some point, I'll repost hopefully later in the year with it brimming with life!

10 minute make; Magnetic Feet

Last week I was using the variable power supply I built some time ago. It's a great and useful little build that replaced a small trimming resistor on the DC-DC LM296 based board with a 10 turn resistor to increase the resolution. It's stood for ages on top of my old lab supply with a couple of small magnets stuck to the machine screws in the frame and the case of the larger supply. It's stopped it getting knocked off a little but becomes detached easily and I have been meaning to attach the magnets to it in a better way. 

So I quickly knocked up a magnet housing/foot in FreeCAD and chucked a couple on the 3d printer. A quick blob of superglue later and the two magnets pressed in and voila! It now stays in place pretty well just on the two feet, however, I might whip up another pair when I get another spare 10 minutes!

Flat Pack Workshop Rocket

I have some work coming up that requires me to take a rocket to a workshop overseas in my luggage so I decided I wanted to try and design a rocket that would break down to be easily packed. I wasn't initially concerned with it being a flying model but wanted it to have all the usual parts to act as a decent workshop prop. In case you are wondering the logo adorning the rocket is for a new non -  profit company I am in the process of setting up called Open Rocketry Research. More on that soon!

The hardest bit to pack is the booster section with the fins so I wanted to make the fins removable. I designed a set of conformal fin rails that have a radius on the back of 27.5mm to match a common 55mm postal tube. I've added escutcheons for M2 nuts and bolts to be able to drill and then mount the fins more securely. I printed the fin slot to accept 3.125mm plywood as I wanted to laser-cut the fins from this material, in the end, it doesn't (for workshop purposes) need the fins bolting in as they are a very nice interference fit into the slot. I'm tempted to fly the thing now, it certainly seems strong enough in terms of fin strength!

The conformal fin rails are superglued to the body tube and I've published the stl file and the FreeCAD file to Thingiverse, its trivial (if you know how) to use FreeCAD to change the dimensions for a longer or shorter fin root length (currently 100mm) or to swap the radius to fit a different tube. Get in touch if you need any help adapting this.

New Sewing Machine! Parachute deployment bag prototyping!

So sadly (and despite replacing the two drive gears for the feed dog mechanism at great effort) the older 80's singer sewing machine we had had some other terminal failures and was beyond economical or technical repair. I'm really lucky to have been long term loaned this new(ish) machine (around 2 years old). It's a Brother FS60 and today I read through the manual and got started with it. 

I LOVE IT! Such a different level of tool compared to the old one, despite only using a basic stitch it has numerous features already that make it excellent to use. It has a mechanism that enables automatic needle threading and a clever system to allow for a more drop in of the lower bobbin and the user not having to "pick up" the thread with the needle. It also ensures to stop with the needle always in the down position that means it is super simple to turn and continue seams etc. 

I've not gone too wild making things today, but I wanted to test how the machine performed on the very lightweight ripstop nylon I use for parachutes and it performs admirably. I quickly knocked up this useful storage bag for the annular parachute using some off cuts of the same material the parachute is made from. I then went on to do a quick and rough prototype of a small deployment bag using some dark blue nomex cloth and some 10mm elastic. Its great to confirm that this sewing machine can work across a variety of materials and deliver good results.... Now, if only the seamstress operating it (me) had some talent!!

Thoughts on the TCT show 2019 and picture dump

So yes, got to go to the TCT show last week at Birmingham NEC and see the huge array of snazzy industrial CNC equipment. Lots of 3d Printers and definitely a lot of multi material extruders and systems for tool changing on 3d prints seemed the de rigeur for this year. 

There seemed to be a lot of smaller, but still largely unaffordable outside big industry, SLS type machines capable of sintereing lots of differing types of metals. There was a tantalising machine that doubled a SLS process with a 5 axis CNC mill, enabling,  for every few layers of sintering, a pass with tooling meaning that internal geometries could be finished to a very high standard and tolerance. 

Other stuff that caught my eye was there are some interesting filaments starting to hit the market that are desinged to be used in lost filament types of casting in combination with vacuum furnaces etc. Again its stuff that is not even potentially affordable to academic "maker" spaces, let alone community spaces, yet, as ever, it would be amazing to see these tools given to the really creative end of the maker community to see how far they could be developed and pushed! I live in hope!