Tuesday, 27 July 2021

Tool Tuesday - The Flexible Pick Up Tool

I can't say that this is a tool I use every day, but it's a super handy tool when needed. Squeezing the sprung plunger/handle arrangement and a small set of four spring steel jaws expand out of the other end. This allows you to grab, retrieve or otherwise manipulate small objects. Looking online most are advertising this with an image of it stuck down a sink plug hole, I can't say I've ever done that! However, I can say it has retrieved a lot of dropped parts/nuts/bolts from engine bays or quite often objects that have rolled down the back of a work surface. If you have any sort of hobby which involves fitting systems into tight tubes, as I do with rocketry, this is an excellent and useful tool. In rocketry you quite often have to thread a cord through a eye bolt placed inside the bottom of a 50cm long tube and this tool can really earn it's keep.  

They are a very affordable tool also, in fact mine still has the hardware shop price sticker on it of 99p, that's some years ago though, but a casual search online shows them as available for not masses more. Finally, they also are a fun tool that begs to be used by almost everyone who handles one, my children certainly have both played with it previously setting marble transferring challenges etc! They are quite sharp though, and certainly need to be handled with a little care and don't dream of grabbing someone else with them as they are surprisingly grippy/pinchy!


Wednesday, 21 July 2021

Opening a Tindie Store


After years of being a Tindie customer and a recent period writing content for the Tindie product blog I decided it was high time I set up a Tindie store. I've opened the store with a couple of rocket related products but I plan to keep adding random bits and bobs to it as I develop small items. 

First of the two products on there are my rocketry screw switches,  I started making and using these a few years ago but now having a few flights under their belt I am confident in the design. They have copper on both sides to which are soldered wires and the wires only become a circuit when you tighten the switch bolt. They are small and robust and on the product page you can see some photo's of them in different configurations/use. I'm selling them in 2 packs so you can set up 2 separate redundant systems in your rocket. 

The second product people may recognise! It's my Centre of Gravity and Centre of Pressure stickers that I used to sell via the Flame Trench shop. Sold in packs of 10 (5 of each design) they are super handy to mark your rocket airframe and make it easy for you to show the CG CP positions to an RSO!

Tuesday, 20 July 2021

Tool Tuesday - The Swann Morton Unitool

I need to reinvigorate my blogging rate and I've decided to start this weekly blog I'm calling #ToolTuesday. It's heavily inspired by my great friend @biglesp who for a long time has run the excellent #TuesdayTooling series over at his blog. Les focuses on software and microcontrollers on his Tuesday Tooling posts exploring tools and toolchains to get you up and running doing cool things across a variety of platforms. I've chatted with Les over the years that I should do a similar series but which looks at hardware tools useful in all kinds of making and tinkering and so here it is!

This first post is an odd starting point as I bought a stack of these Swann Morton Unitool multiblade craft knives recently as they are being withdrawn as a product. It's a shame as they are an excellent little tool. The three blades are larger than many of my smaller craft knives/scalpels and are excellent for all kinds of jobs. The very flat edged "D" blade is superb for cutting flat sheet items like balsa or cardboard and I use the angled "A" blade as a de-burring tool a lot as it can centre into small holes really well. The middle blade "B" is slightly odd in my opinion but as such falls into the "blade that gets used for heavy beater work" so I've abused that blade for all forms of carving and even wire stripping etc. 

The blades pivot and are retained with two thumb screws and they stay in place very well, which also leads to another reason I love the design, you can lock the blades away and close the device and the holes in the blades combined with the thumbscrews make it really secure. I've never had a blade come loose or open in my pocket. 

Finally, I love the look, when I was young and building plastic model kits the orange plastic handled single blade craft knives from Swann Morton where the only widely available choice and the Unitools styling reminds me of many happy hours tinkering! Hope you've enjoyed this first post, see you next week!

Saturday, 19 June 2021

Chonk Rocket! Build and First Flight

Pre Covid I was mentoring a school team towards taking part in a UK rocketry competition and I'd bought a few bits and pieces on their behalf. Some estes BT80 body tubes, a matching nosecone and some F36 cti motors. Of course Covid scuppered the team and I had these bits sat here looking at me, so I decided to build something. I'd never really designed and built something for the upper end of mid power, I have models that I've designed up to D on 24mm diameter motors and then the bigger HPR stuff. I also realised that a simple reasonably wide airframe mid power rocket is an excellent test vehicle for testing DIY parachute designs and getting a bit of data.

"Chonk" Is quite a straightforward build in essence, I CNC'd some centering rings and CNC'd the through the wall fins. I decided to put a fine layer of fibreglass on the rings but I haven't glassed the fins. I find through wall fins make a very strong fin can and as such I felt with everything stuck to the 29mm phenolic motor mount tube that it was all going to hold together.  Despite being a simple single deploy airframe I wanted to get flight data, where possible, to make it a decent test platform so I performed extensive butchery  modification to the off the shelf NC80b nosecone. 

I used the bandsaw to take off the base of the nosecone and then installed a 2mm threaded rod by pouring around 10mm depth of laminating epoxy into the nosecone tip. I left a nut on the threaded rod in the epoxy to act as a decent anchor. I also CNC'd a plywood ring to sit in the lip of the shoulder and receive the closing bulkhead and later I added a couple of M2 nuts and bolts to further hold the bulkhead and NC all together. I then made a bulkhead with a simple soft retainer and reinforced the bulkhead with fibreglass and a wooden centre washer. Inside the bulkhead I installed some uprights around the threaded bar area and installed 2 altimeters, a perfectflite Alt15 and an Eggtimer Quark the latter of which I had wired up to an openlog board for it to write flight data to an SD card. 

To arm the altimeters I used the CNC screw switches which I designed and built quite some time ago, they worked flawlessly and maintained continuity throughout the flight. As the nosecone is quite heavy it's gets some decent loads/forces on ejection and deployment so it was a good test. A couple more test flights with this design and I might be tempted to make a few and stick them on tindie to sell.  

Chonk flew last weekend in great conditions at Midland Rocketry Club and I'd made a 60cm 10 gore annular chute to fly in it. Chonk was probably slightly over chuted but a very steady and stable descent was made and I do like how people watching react to the annular chutes as they aren't a common sight at UK rocketry events yet! I reduced the delay to 7 seconds, but definitely it was a little late (even better test for the screwswitches!) and if I fly in this configuration again I'd take the ejection delay down to 6 seconds. 

One of the best things that happened at the event was a fantastic rocketeer and accomplished modeller Pete turned up with a downscale micro version of "Chonk"! He'd seen me making Chonk on twitter and decided to make one using a micromaxx 6mm motor! Such good fun and his Micro Chonk flew very well! 

Tuesday, 25 May 2021

M-Sure 150mm Digital Caliper

A while ago I was sent a set of Moore and Wright Dial Calipers for review for Hackspace Magazine. The company that sent them over was Machine DRO who I'd bought off previously (an excellent digital height gauge still in regular use). I remember at the time one of the members of staff saying that they were working on an in house range of measuring and metrology kit. I spotted the other week that their in house M-Sure range had been launched and quite fancied the look of the digital calipers, my current cheapo set (one in a long line of cheap digital sets) having just died!  Priced at £28 I ordered a set of the 150mm. 
Dispatched quickly they soon arrived well packed with the calipers themselves in the case inside a plastic bag with some protection waxed paper in between the precision ground jaws. A desiccant bag also was added to make sure their was no moisture. Also in the case is a small plastic tool for opening the battery cover, although it's fair to say a coin would do the job if this went missing. I couldn't spot a CR2032 inside the case and was about to start muttering and wading through my draws to find one but I then realised the battery was in the rest of the packaging along with a instruction manual should you need it!

I was pleased to see a small O ring seal in the battery compartment, but do be warned that this isn't fixed in place and sits rather loosely in the groove so can fall out when the cover is removed. The display had a clear plastic film over it but once removed the display is clear and crisp and the refresh rate is very fast, certainly faster than the cheaper calipers I have used. Note in the picture below that there is a seal over the USB connector. If I were to make one of two small complaints it's that the left hand side of this cover sticks up where there is a plug that retains this seal when the USB slot is uncovered. Whilst none of the seals claim to be waterproof it was a bit annoying that the addition of a seal had in fact created a little area for chips/dust/moisture ingress into the case. 

In use the calipers are a very nice experience, the movement is smooth all the way up the scale and is still pleasant up towards the 150mm end. Again I have had calipers that get either floppy and loose or grindingly stiff at the far end of the scale so these are excellent in that respect. 

Under the USB seal is a Micro B USB connector. Data output is common across some of the M-Sure range which includes Digital Micrometers, Dial Test Indicators, Height Gauges, Bore gauges and more. There are some generic "linear gauges" I have my eye on as a potential DRO system for a small milling machine. I haven't tried the data output function on these calipers yet but I'll feedback when I have. Note that some other instruments in the M-Sure range need an additional add on USB interface to enable data capture and there are also extra remote displays available for some devices in the M-Sure range. 

My second small complaint, that really shouldn't detract from an otherwise excellent set of calipers, is that they have some marks and staining presumably from the manufacturing process, most noticeable on my set is a stain under where the PCB sits when the calipers are closed. This is not an issue for me at all, they will be filthy after some time on my desk, in my bag and in the shed, but it's important to mention. The aren't advertised as clean room specified but just in case someone buys them and opens them in their high end metrology lab!

My two little niggles aside these are an excellent buy at a great price. I've always had good customer service from Machine DRO and they were a pleasure to work with a while ago writing up the Hackspace article. 

Thursday, 13 May 2021

Vinyl Cut your own Perseverance Rover Fiducial Markers.


Image Credit NASA/JPL Caltech

I've been doing some writing recently that had me looking a lot at pictures of the Perseverance Rover currently carrying out fantastic science on Mars. Whilst writing on this other project I got mildy obsessed with the appearance of some of the fiducial markers that are on the rover's body panels. These markers are used by either machine vision systems or by analysts back on earth to check dimensions and distances and to calibrate sensors accordingly. 

I decided I wanted to make some of my own, they's look cool on a rocket and could be used as a roll pattern, but equally they just look cool on my toolboxes etc! They are a simple design that I put together in Inkscape and I've uploaded the project files to Thingiverse. If you have access to a vinyl cutter then these are pretty straightforward to cut and layup. 

Tuesday, 6 April 2021

Repairing the best worst extractor lamp!

Not sure if this is a blogpost or just a cautionary tale, but anyway DON'T BUY THIS SOLDERING EXTRACTOR LAMP! With that said... here is my tale. I wanted a small solder extractor and I saw these extractors built into a angled lamp, running off USB power they peaked my interest and I handed over £40 for one online.  On arrival I unpacked it and put it into use, it was OK, not the strongest extractor by any standards but my solder area is under a Velux window and it has enough of a draw to move the solder fumes away from me and out of the window. On the cable to the USB plug it had a controller with 4 momentary press buttons on it, you could switch between 3 "colours" of LED lamp, all shades of white, one a "cool white" one "warm white" and one that was a combination of both. You could ramp up and down the light level in steps, but I always had them on full power. It also had a fan control to set the "power", this was always on full and you could tell that when the fan was on it was starved of current a little as the light would dim. If you turned the lamp off the fan would speed up! 
Anyway, the control system lasted about 2 weeks! I came to it one day and it had failed, I couldn't turn the lamp on and although I could run the fan I couldn't adjust it and randomly an LED in the controller was stuck on. I did really like it though, I liked being able to clamp it to my workbench and drag the lamp and extractor really close to work so I decided to try and fix it.

Pulling the controller apart and a bit of probing with a multi meter I realised that basically the control system made or broke the negative power rail and when the microcontroller was operational was probably PWM'ing the power to each circuit. I realised that I could quite simply wire in a switch for the fan and for the two LED light rings. I wasn't bothered about having both the LED lamps on at the same time. So a quick bit of soldering and then a small 3D print and I have a simple but working "controller" back on the lamp. I reattached the USB cable as I have lots of USB outlets and also it's nice that it can run off a battery pack if and when we get back to maker events or rocketry in fields!