When i saw this, I thought "£40 for a 3d printer?  Including UPS shipping? This is too good to be true!"

Though thinking about it a bit more, I couldn't think of any way they could get away with the money.  Aliexpress offers full buyer protection if you buy through alipay, and money is held in escrow.  So I bought a couple to see what the dealio is. If it does arrive and its shit, just the motors would cost more then £40 to buy, and I can definitely reuse them.  I figured going into this paranoid, I might just about be able to figure it out before they run away with my money.

This morning, I got shipping confirmation, with a china post shipping code. "Wow, maybe its not a scam?" I thought. Then I received this message:

hi. friend. Because you choose courier suspended. We send you the goods by China Post Air Parcel. Give you cause delays receive the package, so we give you $15 in compensation. You may submit disputes. A partial refund of $15 agreement. We give you a refund in a timely manner. Thank you

Ok, yeah, thats a bit odd.  This is the penny dropping.

The way AliExpress works, you can open a dispute on any order for either the full, or part of the purchase price.  If the seller agrees, the refund is paid out to you right away.  But if I open a dispute for the shipping, maybe I lose the ability to open a dispute for the remainder if the item doesn't arrive? The FAQs were unclear, so I set off to AliExpress customer support:

If I open a dispute for a partial refund (for the shipping), can I then open another dispute later if the item does not arrive

No, if the dispute has been agreed the seller with partial refund, the remaining payment will be release to the seller automatically

With this, I highly suggest to please ask a full refund instead.

So there it is.  Beautiful in its simplicity.  You ask for a dispute for the shipping charges, get your £8 shipping back, and lose the ability to claim back your £32 for the rest the item when it doesnt arrive.  Since I have 40 days of purchase protection remaining, I'm going to hold off claiming a full refund for a couple of weeks, and I'll update here if I turn out to be wrong and something does arrive!

Update!

Another message is being sent to those of us who have ignored the first message, or replied that the refund is not necessary:

Friends. Goods are in transit. Do not worry. We give you a refund of compensation today. Tomorrow no longer compensate, please submit the dispute in a timely manner, thank you

Ahh, a time limit! Best get the refund quick, otherwise they wont offer it anymore! I've received this second message, as have others. I'm guessing it wont be long until aliexpress close their account, so they've gotta try and get as much cash out asap.

Update!

Just got an email from aliexpress:

Your order --REDACTED-- has been frozen due to suspicious seller activity.

We have suspended this seller’s account because we detected unsafe trading activities. All of your pending orders with this seller have been frozen for your security.

We have asked this supplier to provide supporting evidence, such as shipping documents and qualification certificates. If the supplier is unable to provide the evidence or if the evidence is insufficient, we will close the order and process the refund for you within 5 business days (In case of certain circumstance, the processing period may be extended).

We apologize for this inconvenience. At AliExpress we are committed to ensuring you enjoy a safe shopping experience. We will continue striving to improve. Your understanding and cooperation are highly appreciated, if you have any question or suggestion, please click here

Your understanding and cooperation are highly appreciated.

Sincerely,

AliExpress Trade Security Department

I'm fairly unsurprised by this, hopefully the refund will be forthcoming fairly quickly.

Final Update

Your Order No:-REDACTED- has been closed because the supplier did not provide necessary evidence. The payment will be refunded to you within 7-10 working days.

AliExpress strives to continuously improve our trading environment. Thank you for your understanding and continued support.

Sincerely,

AliExpress Trade  Security Department

And its over. This experience has massively reaffirmed my confidence in aliexpress' customer services and payment systems. Other sales websites should take notice!

I spent some time earlier in the week getting the bandsaw at Hackspace Manchester working, so now its cutting again!  The main problem with the bandsaw is cutting straight, as it was an ebay purchase it diddnt come with a fence, so there was nothing to run the cut material against.  This model of bandsaw hasnt been made in around 30 years, so trying to buy a new one will be impossible, and ebay is too much hard work.

Though we do have a 3d printer... and a workshop.  Idea!

Step one was to have a look at the bandsaw.  It has a channel running along the front , so I took some measurements to see what I was working with.

So, i had the measurements, it was time to take to my CAD software and design something to fit in the channel.  My choice for this is OpenSCAD.  I used it to first create the shape of the channel, then to carve this shape out of a block.

I extruded this to a few mm wide, then printed it to test.  There was a bit of tweaking needed to get it to fit exactly, so i ended up doing 4 iterations with the sizes tweaked slightly.

Once i had one that fitted, i printed it out extruded to 20mm to check it would fit and slide correctly.

It did, so i moved onto designing the actual fence.  Step one was to cut some aluminium extrusion to size, and measure it.  A month or so ago I had managed to womble a nice straight piece of 16mm x 16mm  3.2mm thick L channel, which was pretty much the perfect size.  I cut this to size, and modelled it in openscad.

The actual cad modelling took a couple of hours of tweaking, but i the above picture shows the basic steps.

First off i extruded my clamp to 50mm wide, and added a wedge to the side of it.  50mm gives enough width for it to sit in the runner, and counteract twisting force from the back of the fence being pushed on.  The wedge is to give support to the top part of the L channel.

Second, I added two captive nuts and holes for M5 bolts.  Mainly because we have a massive bag of M5 hex-head bolts that are perfect for printed thumbscrews. Theoretically i could have threaded into the ABS directly, but i felt this wouldnt last, so embedding a nut seemed like the best option.

Third, i carved out the hole for the L channel.  This leaves a bit of an odd shaped unsupported piece, which may be weak. Because this piece will be in the channel, i decided to leave it, as it'll make measuring up on the built-in ruler more accurate.

Lastly, i added some pilot holes for attaching the aluminium to the 3d printed part.  i decided to use 3mm x 12mm self tapping screws for this, because i had them on hand, and they can be countersunk fairly easily.

I test-assembled the whole thing in the vice, it fitted nicely in the channel, so it was ready for connecting together.  I marked, center punched, drilled and countersunk the holes for the 3 screws that hold the whole thing together.  Add some screws and we're sorted!

Of course, i had to do a test cut at this point, so some of the scrap acrylic pile was chopped into little strips.

Woohoo, it worked!  All it needed to be complete is some knobs.  So i headed over to thingiverse to find a knob that'll fit nicely over an m5 nut... and found nothing useful.  No worries, i just OpenSCADdded one up.

So there it is, a useful thing i've made on the 3d printer that wasnt a part for a 3d printer!

Source files (stl, openscad) are available on My GitHub