Printing Pinion Gears for the mini lathe.

I managed to strip one of the pinion gears on the mini lathe a while ago and I was surprised that I couldn't find a 3D model of them to print, particularly as I'd seen a lot of gear wheel sets for the mini lathe on thingiverse and elsewhere (I think this is an indicator that perhaps other people aren't as idiotic as me and don't strip their pinion gears)!

 Today I set about sorting it with some 3d printed replacements. I used the involute gear tools in the "Part Design" workbench of FreeCAD which I am using more and more as my go to CAD environment. It's a pretty easy tool to use so long as you know the "module" of your gear which can be worked out as it is the pitch circle diameter divided by the number of teeth. Counting up the teeth on the old stripped gears showed they were a 25 tooth and a 20 tooth and the overall diameter was close enough to make me feel that the pitch diameter was going to be the number of teeth in mm giving a module of 1. I'd read online that the mini lathe gears all ran at 20 degree pressure angle. A quick bit of calliper work on the hole diameter and we were ready to CAD!

The results are great, printed in PLA at 35% infill I've been running the gearbox for a couple of hours and all seems well. I've printed up a few spares and chucked them in the box of gears. As I couldn't find this set of gears online anywhere I've put it up on thingiverse as a project so hopefully it's of use to others. You can find the files and the print settings here. 

10 minute make, Filament reel stand!

So whenever I swap to use a big reel of filament (2.3kg ones) I always end up concocting an elaborate balancing of stuff to hold it on! I've been known to have 2 piles of books with a piece of threaded bar balanced across them before now. The other day I was about to scrap some small stands I'd made that could hold a 25mm dowel between them I'd originally made as a jig to help fibreglass onto a tube. I quickly realised with a larger base and a shorter piece of dowel it would fulfill my filament holding needs. I just use a slightly undersize "o" ring on the dowel to stop the reel from drifting along and off the stand. Perfect!

Hackspace Magazine Issue 32, Opensource MTV robot!

Normally when each months Hackspace Magazine comes out I update this "keeping track of my articles" post, do a few tweets and move on. This months magazine has a project I put together that feels worthy of a little blog post all of its own though! I was asked to write a tutorial using a cheap tracked robot chassis kit (just the wheels, chassis, motors and tracks around £20-25 online) on how to build a budget robot. I decided to go a bit further than just cutting a couple of boards to mount stuff to and came up with an entire modular system built up on the cheap chassis from 3d printed parts. Whilst this particular robot is referred to in our house as "red one" the whole modular robot project is called "MTV" short for Modular Tracked Vehicle. All the modules feature M4 holes on 10mm centres so that modules can be mounted in lots of places and it can all be reconfigurable perfect for adding experiments and other doohickies too! I did all the 3d work in FreeCAD so that it is made with opensource and free tools and also all the files are published in a project repo on gitlab. I'm not going to give you the link though, you have to go download the (excellent imho) magazine, read the articles and find the link there! Check out hackspace issue 32 here.  I'd love to see others tinkering on this so do feel free to join in, merge requests are open on the repository and do get in touch if you build one!

Follow Up - Thermal Insert Tool Rig MKII

A few weeks ago I posted about converting a Dremel workstation and adding a 3d printed part and a hacked soldering iron to make a thermal insert tool. It was great and through a combination of some spacers and some copper tape as insulation it would resist the heat for a short session of inserting. However, I wasn't satisfied with it for longer sessions of use and so I decided to remake the mount out of a block of EN1A steel I had in the scrap pile. Rather nicely Hackaday picked up on that original post here.

I used the 3d printed part as a quick drill guide as it didn't need masses of accuracy and it sped up the conversion a lot. I also decided to do away with the soldering iron handle as it didn't really need it.  The last job I did was to modify one of the soldering iron tips by cutting a few mm off the end of the point. This meant that when fitting smaller thermal inserts the tip would fit inside the insert and self centre and could apply pressure without either poking through the underside of the insert or marking the plastic outside of the insert. It works very well and I may well may some different tips for different sizes.
Whilst the Dremel workstation inherently are a bit wonky and flexible (I'm thinking of a new experiment to try and make it a little better and some other mods, I'll post at some point) it's been great to use and the height adjustments it offers are great and it can accommodate a good range of work pieces such as this "MTV" robot... which I need to do a blogpost relating to in its own right!



Finally, below is a picture of an insert, It's great to be able to get these in well without marking the surrounding plastic and they work incredibly well and if put into the correct size/tolerance hole they are much much tougher than tapping into a 3d print.

£12 HDMI-USB Video capture card on Ubuntu (cheap portable Rpi Monitor!)

A while back I was ardently reading @biglesp post on a HDMI-USB capture card that he had been tinkering with and using as a way to have a super minimal setup for a raspberry pi without needing a monitor for it. At the time I think the Mirabox cpature cards he was looking at were over £100 and it was to rich for my tastes!

Then last week my fellow flame trench buddy @Ascii211 posted about a $10 usb capture card he had been playing with. Having tracked one down on Ebay in the UK for £12 I thought it was worth the punt to see if it would play nice with Ubuntu.

I rigged it up today with a raspberry pi4 (4gb) as an input and plugged it into the trusty (badly in need of a reinstall) Thinkpad x220 running Ubuntu 18.04. A quick check of dmesg seemed to indicate that it had been recognised etc.

I noticed in the terrible instructions with it it mentioned VLC as a potential bit of software for capturing, after tinkering around in VLC for a few minutes I couldn't get it to work at all. However... I'd used "gucview" as a camera capture application before so opened that to see if it played nice. Short answer... yep it does. Video preview and capture at 1080p at 30fps was pretty happy, theres a slight lag in the video feed but nothing that isn't workable. I'm keen to checkout how it does with camera input and I keep meaning to play with OBS (open broadcaster software) so I'll update after tinkering a bit more.

Baffle designs and their use in High Power Rocketry

Just uploaded this video looking at the baffle designs and their usage in a couple of rocket designs including the type that's used in the opensource ODR rocket. I also discuss why and when baffles make sense to use for either recovery fire protection or for strong recovery system mount points.

New Video for the Ffiws Makerspace project now live! Getting started with FreeCAD

Really missing my in real life work in the Ffiws makerspace, and certainly missing all the brilliant users who used to put me through my paces asking for help and guidance. It's a pleasure then to get asked to make the odd bit of content for the Ffiws team to share during lockdown. Here is the latest, a getting started with the brilliant, cross platform, free and opensource FreeCAD software. 

TS 100 Soldering iron review

I've procrastinated over buying one of these for probably a year as I have read lots of good things about both this one, the TS100 and it's sibling the TS80 but I could never quite decide which one I wanted. I knew that either where reported to be excellent soldering irons but I couldn't decide if I wanted one that I could use with some kind of USB C power pack for mobile use or one that I could use with a LiPo battery. The LiPo option clouded further by the fact that with the TS100 most people used  a 4 cell or larger LiPo and the largest ones I have is are my collection of 3 cell 2200 mah ones I use in the quadcopters. I somewhere had the idea that these wouldn't supply enough voltage. My mind was only made up when I read that the TS100 will work with a 3 cell absolutely fine, albeit with the caveat it will take a little longer to heat up. As it happens it will heat up to 300 degrees on a 3s LiPo in around 15 seconds... So for the odd quick repair in the field it's certainly useable. 

I bought my TS100 with the 'I' tip which is a fine point suitable for SMD work. I tend to use a fine tip for most work with other irons but I may well pick up a larger chisel tip at some point for this iron. The 'I' tip supplied is great, tinned easily and is super precise. Indoors at the workbench I use  a 19 volt Toshiba laptop power supply and it will heat to 300-400 degrees in seconds. It's astonishingly quick. I haven't upgraded the firmware as yet (all manner of custom firmwares are available) but already I can operate and change the temperature using the 2 buttons with one hand whilst usually holding whatever I am trying to solder with the other!

The tips are fitted using a pair of small allen bolts to retain them and the TS100 was supplied with the correct size allen key. The supplied cardboard box with fitted foam meant the TS100 arrived very well protected but the tip isn't inserted when in the box so the box isn't a long term storage or transportation solution. I'll have to make something at some point, or indeed, download one of the myriad of cases the community have designed for this iron to 3d print. 

I probably have around 5 hours of time in soldering a wide variety of stuff with this in the last 2 weeks and I have to say can't find much at all to be critical of with this iron!