Tuesday 31 October 2023

Desk Vice Restoration, 3D printed jaws from Pop/Soda Bottles!


I love having a desk vice at my workstation. For ages I used my small Record "Imp" vice but that is doing good work in one of the sheds. I'd been using a cheap new no brand clamp on vice for a while but I was fed up with the non replaceable jaws not closing true. I spotted this interesting vice on Ebay a while ago which, although unbranded, is a reasonable little thing that also can swivel on it's base. I liked the width of it and the general form factor and put in a very low bid. It was pointed out in the listing that one jaw had been replaced with a piece of wood so I won the auction for very little cash!

As arrived the vice was a bit sorry looking with it's one wooden jaw that had been glued on! I stripped off the wooden and the steel jaw and cleaned off as much glue as I could. The metal jaw was held on with 2 M4 bolts and, after cleaning and then re tapping, the holes behind the wooden jaw were ready to be used again. I don't really do anything heavy on my desk vice, small work holding is the order of the day with anything needing more than delicate handling going into a bigger vice in the sheds. Whilst I should have fired up the milling machine and made up a set of aluminium soft jaws for this I decided to do a quick experiment and 3D print some jaws. After a quick digital caliper session on the original steel jaw I quickly knocked up a jaw in the amazing FreeCAD

Finally, I printed the jaws and fitted them. Interestingly I've recently written a series of articles over on RS Designspark where I built a "pullstrusion" system capable of turning plastic pop/soda bottles into decent 3D printable filament. So these jaws used to be about one and a half 2 litre lemonade bottles. You could probably make 2 jaws from one bottle but I bumped up the infill to around 50% to make them a little durable. So far the jaws have held up well. You could also consider them semi sacrificial as it's trivial to print up a new set. Speaking of which I definitely plan to print up a set in flexible TPU filament to create a proper set of soft jaws. 


Wednesday 18 October 2023

FreeCAD and Openrocket, a fabulous combination!


FreeCAD, aside from generally being an excellent free and opensource CAD environment is ever developing and being extended. Over the last year or so a really interesting development has been the Rocket workbench. If you are new at the zoo, FreeCAD works with a workbench system where different workbenches contain lots of different tools grouped into themes. So for example if you want to convert a 3D part into a technical drawing there is a specific Techdraw workbench which, when you switch to it, has all the tools to lay out a technical drawing. Many workbenches are built in but you can also download and install extra workbenches of which the Rocket workbench is a good example. I’d love to see more rocketry people using FreeCAD and so this post is aiming to show why FreeCAD, as well as Openrocket, might be well worth learning!


Openrocket and FreeCAD have lots of active development happening and it just happens that an amazing contributor, Dave Carter, AKA DavesRocketShop, is contributing development to both these excellent opensource pieces of software. Further than that Dave realises how powerful interaction between Openrocket and FreeCAD might be and is working to make both these packages work together usefully.


As a starter example (but frankly enough of a reason for many rocketry types to learn some basics of both these packages) is the built in parts database. In Openrocket if you are designing a rocket from scratch you might chose to incorporate an off the shelf nosecone for example. Clicking the Nosecone icon in openrocket the component database will either launch automatically, or you can launch it from the regular nosecone dialogue window by clicking the “parts library” button in the upper right hand corner. Either way you’ll see a well maintained and curated list of commercially available nosecones from a range of manufacturers.

OK, Over to FreeCAD. Say we now can’t find that commercial part to buy in our local rocket shop we might think about having to draw it in CAD and perhaps 3D print it. Well, the exact same database is available in the Rocket Workbench in FreeCAD. Clicking the nosecone tool icon should launch a nosecone parameter dialogue in the combo view window on the left of the screen. Scrolling down you can click “Lookup” to launch the exact same database of components as you just launched in openrocket. You can scroll to the same nosecone and select it and it will appear as an object in the live preview and also as an object in the combo view. If you wanted to simply 3D print this you can select the object in the combo view window and then click “File-Export” to export the nosecone ready for printing. You can pretty much do this without learning any more about FreeCAD and Openrocket if you wanted too, but, if we learn a few more skills, we can do some other really simple yet useful rocketry tasks.


Another simple example perhaps of use is imagining we want to build an upscale version of a rocket with a scaled up nosecone. If we select a nosecone from the database in FreeCAD we can then jump over to the Draft Workbench. With the nosecone selected we can now click the “Scale” tool icon. As a tip to help you find tools, if you hover over any icon in FreeCAD it will say the name and a small description of the tool and I describe the tools with the names these rollover descriptions use. In the scale dialogue click the “enter point” button and in the next dialogue make sure that both the “Uniform Scaling” and the “Create Clone” buttons are selected. Then change any one of the X Y or Z axis scale amounts to the scale you require, so for example if you want to double the size of the nosecone change one value to “2”. The other values should change automatically and then when you click OK an upscaled (or downscaled) version of your nosecone will appear as an object.


Finally, for this example, if you know a little about using FreeCAD you can easily add geometry to parts you create on the rocket workbench. In the image I’ve simply brought a cloned nosecone part into the Part Design workbench and then added some features to make an attachment point for a recovery system. If you are interested in developing your FreeCAD skills my free to download tutorial book FreeCAD for Makers is available from the Raspberry Pi Press here.

This is only the tip of the iceberg in terms of what what FreeCAD and Openrocket are capable of. The Rocket workbench is amazing in terms of what it can automatically generate parts wise. Nosecones, transitions, tubes rings, rail buttons, rail guides and more; there is a really impressive fin can generator as well as some pretty high end fin flutter analysis tools. The real beauty is that you can simply transfer dimensions and data over from a design you have worked on in Openrocket. Having rebuilt it quickly in FreeCAD there are so many options available, as an example I can simply select a centring ring in the FreeCAD design and take that part to the Path workbench and create toolpaths to then cut the rings on my CNC router. I can export all manner of files for parts for laser cutting or other processes. It’s a really good tool to learn some skills on if you are a rocket fanatic!

Monday 2 October 2023

Ballooning at Liverpool Makefest and Lessons Learnt.


So this could win the award for the most overdue blogpost ever. Back in summer I attended Liverpool Makefest as a maker and showed off lots of flying stuff under the title "Concretedogs Flight Lab", which coincidentally is also the title of book of projects I've been not finishing for a long time! One of the activities I showed and told at Makefest was my DIY Hot Air Balloons.

I originally wrote about these ideas back in Hackspace Magazine Issue 61 where I talk about their construction. As most councils have quite rightly banned the use of fire filled disposable balloons the approach here is to heat the balloons to perform shorter hop like flights and, when indoors, use a light kite line as a tether.

Previously I'd heated the balloons having an assistant hold them up and I fill them from the base with a single electric heat gun. But in an attempt to create more lift for this event I made a chimney from a meter length of vitreous enamel pipe into which fed 2 electric heat guns. It definitely makes more lift but I think the concept could be improved a lot. One of the issues is that the air is constantly moving and being pumped into and out of the balloon. It would be better to have less movement of the hot air and more heating! One possible solution would be to have a series of baffles in the chimney so that it creates more heat and less airflow. The other option I'm still really keen to try on a calm day outdoors is using a camping stove in the base of the chimney to get a high temperature whilst not creating a moving column of air.

The other challenges are the tether, there is of course the challenge of keeping the tether light and as altitude increases the weight of the tether becomes more apparent. Another problem I had at Liverpool was that if the tether snagged (usually on me!) this would cause a jerk in the line and often, especially when the balloon was quite high with a lot of tether weight, the balloon canopy would tear. I'm planning to run some experiments with a small length of really lightweight thin shockcord/elastic at the balloon end to try and mitigate this problem.

Wrapping up, this activity was great, loads of people mentioned that they wanted to try it and lots of people were entertained by the site of the balloons. It really is a lot of fun for a couple of quids worth of materials!

Monday 4 September 2023

Starting HEMA Longsword, Indoor Training Sword Project on Printables

I've recently started training in HEMA (Historical European Martial Arts) with a focus on German longsword. I live in a small house with quite low ceilings so swinging a meter plus synthetic trainer around won't work. I'd been using a length of 25mm dowel but you have no edge orientation, ie which side of the sword is which, or crossguard orientation so wanted to improve it.

I've modelled a simple small crossguard and a pommel in FreeCAD and printed them out. I glued the crossguard sections out in petg and have glued them into position to give me a similar length handle to my synthetic trainer. The pommel is glued on first to make sure its exactly lined up and then a screw was inserted into the printed and countersunk hole to make sure it definitely stays in place.  The slight challenge with a piece of 25mm dowel is that it obviously isn't balanced in the correct position or weigh anything like a synthetic trainer or a steel federschwert. So to partially rectify this I've drilled (off centre of course!) a long hole into the tip of the dowel and poured in glue and added lead weights. Whilst this doesn't make it as heavy as a steel it does correct the balance point to around 6 cm in front of the guard. 

It works really well and whilst it definitely is not as good as getting outside with a full length trainer or steel it is excellent for indoor wet weather sessions or for sticking in a bag for use in a hotel room etc! I've put both the STL and the FreeCAD project files up on Printables here


Sunday 20 August 2023

Cheap Wireless Earpick (eeeurgh) makes Reasonable Inspection Camera


I'd seen a couple of examples of people buying these little "earpick" cameras and using them as electronics inspection cameras. I then saw the NE3 earpick camera for just £6.99 delivered so thought it was worth a go. I DEFINITELY DO NOT recommend these as an item you should stick in your ear... in general I believe the best advice is that nothing should be put in your ears unless under the direction of a medical practitioner. Anyway, the £6.99 device arrived, it's pen sized, has a single button, a metal tube/probe and came with some soft silicon attachments for digging around in your ear. Curiously mine also arrived with an extra small leather pouch outside of the main box with some steel implements inside it.. again.. these aren't going anywhere near my ears, but I may yet think of a use for them!

When you turn the device on with a long press of the button the camera end of the probe illuminates with a decent amount of light. The device broadcasts it's own SSID and you need to download a slightly spurious, but functional,  Android app from a QR code in the manual. In the app you select the wireless network and then you get a live image (with very little latency I was surprised to see) on your device. You can then click to take a photo or long press to create a video clip. 

It's not  super high resolution and is distinctly SD in it's flavour, but it's probably more than enough for inspection situations when you are out and about and away from anything better. I could certainly imagine using it to poke into little gaps and holes in enclosures and perhaps for peaking into rocket airframes. For £6.99 it's a steal. 

FWIW The device charges via USB C and theres a small cable included. Other models and other people have found that if they USB similar devices to a laptop that they can get these to appear as web cams. I haven't been able to get this to be detected on any of my linux boxes, but I'll keep tinkering and feedback. 

Just to finish off here is a tiny video clip from the device. 

Monday 24 July 2023

Makerspace Arran

I'm really lucky that over the years I've got to visit and work out of loads of makerspaces, hackerspaces, fablabs and others. Mostly in the UK but a few notable overseas ones also. I can't say that this one is overseas, well apart from you need to get a ferry to visit Makerspace Arran on the fantastic and beautiful Isle of Arran. 

In fact, if memory serves this is only my second ever Scottish makerspace, my first being the sadly missed Maklab in Glasgow which I was lucky to visit and hot desk from a few times over the years. I was really interested to have a quick look at Makerspace Arran as it's in a similarly remote and rural position as some of the Ffiws makerspaces I've been involved with here in North Wales. It was only a flying visit but it was lovely to see a few of the projects I'd spotted on Makerspace Arran's social media in the flesh. The space is actually on two levels with the ground floor being a shop. The location of the shop is right at the start of a very popular walking trail up Goat Fell which is the highest summit on the Isle of Arran. Also at the foot of the path around the makerspace are a garden centre, a pub (which does great chips) a microbrewery and a leather workers workshop and shop. There's a stack of parking and a lot of tourist footfall in the area. 

The shop sells stuff that has either been made in house or has been made on the island and has a great range of gift items that are really nicely curated and relevant to the location. There are no "kiss me quick hats" or other generic stuff, everything is made here, and has links to Arran. It's really impressive. There's lots of stock of tee shirts commemorating your walk up Goat Fell and small lasercut medals as a reminder of your successful ascent. They've researched some of the traditional historical games that would have been played on the island in times gone by and reproduced them using the laser cutter. They are also up for helping out other producers and makers. 

There were some lovely cast epoxy broaches and necklaces where the epoxy has been cast into the shape of Arran itself and Mark told me about how they had used the 3D printers to help create objects to then create silicon moulds from to help the maker increase production and accuracy. One fantastic project is the lasercut Liberator 1 LB30A kit which has a sad connection to Arran in that one crashed into Mullach Buidhe in 1941. The lasercut kit is created in 1.5mm plywood and has interestingly used as a source an old book of air plane silhouettes which was created in wartime as a guide for civilians to identify aircraft. 

They aren't all about the profit though, the small makerspace located above the shop is beginning to look at running workshops for anyone to book into. There's currently an exploration to see if there is enough interest in workshops around scale modelling using kits. I did offer to run a FreeCAD workshop up in the space whilst we were visiting but sadly, due to some makerspace members being off the island that week it wasn't to be! Ah well maybe next time!

Tuesday 9 May 2023

Hipster PDA Stencils, My First Printables Upload.


Long time readers (and my what a wonderful select bunch you are!) will recall I've been pretty obsessed with Index Cards and the idea of the Hipster PDA for a long time. Over the years I've designed, tinkered with and scavenged all manner of HPDA systems ranging from the classic binder clip and card, through to unconscious making of HPDA boards and even a nice Living Hinge Lasercut Design over on thingiverse. I've also recently started keeping an offline calendar, this is for a few reasons, one is at both my gym and where I train martial arts I have no signal/connectivity (yes rural mountain N Wales still offers some pockets of no 4G!) but I still need to check dates for sessions and exams and such. Some true disciples of the HPDA path go as far as buying printers that will directly print to 3*5" card blanks, but I wanted to take a leaf from the "journaling" community and create some stencils. 

So there's 3 stencils so far, a simple tick list, a universal calendar and a slightly odd mind map one! I've also been meaning to move over to Printables as a site to share my occasional small designs and so thought these might make a good first upload. Do feel free to check them out, download and print