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.