Wednesday, 20 May 2020

Thermal Insert Rig, modification of Dremel 220

Years ago I bought a Dremel 220 drill stand to help quicken the process of drilling PCB's, there is a lot online about the Dremel 220 already, and most of it is true.. whilst it can be a useful bit of kit if its all you have its wobbly and annoying and although you can get good results, you would be much better off with a small cheap drill press! That said mine has seen some use, often rigged as an extra hand holding the Dremel to use it as a small offhand grinder etc. Anyway, I've wanted to have a better option for pushing thermal insert nuts into 3d prints rather than just a soldering iron in hand and a pair or pliers. I have a plethora of the super budget Makerslife soldering irons (I reviewed them here!) and decided to have an attempt at converting one to fit onto the Dremel stand. 

At first I considered making some kind of adaptor that bolted into the existing mount for the Dremel and even got as fair as modelling the 18mm diameter 2mm pitch Dremel collar thread, but then realised that one bolt removed all the Dremel assembly from the main shaft and that it would be easier to have a soldering iron adaptor that just fitted straight onto the 16mm steel bar that acts as the sliding quill. 

I designed and 3d printed an adapter plate and realised I could unscrew the hot end from the handle of the soldering iron and I aimed to place the 3d printed adaptor in between the end of the element holder and the soldering iron's original handle. Having disassembled I realised I could pass the element and the wires through the adaptor and only needed to cut the ground wire and re solder it together and heat shrink it back together once assembled. 

The first attempted adaptor was too thin and flexed and also showed that, despite the plastic 3d printed adaptor being in the same position as the original handle, it was going to get to hot and begin to soften. I thickened the adaptor design and reprinted it with more infill. I then also reassembled the MKII version with some copper tape acting as a heat sink and also mounting the hot end using some over-size nuts and washers as standoffs to try and promote some cooling. It's worked and I whilst i can use it for a session to fit a few thermal inserts I think continuous use would probably cause the adaptor to soften eventually. I think the next iteration will be to use the adaptor as a drilling template to make a steel or aluminium one!

In testing it's been great, I could do with making some custom tips to mount on the end of the iron for different size inserts and as mentioned earlier probably remake the whole thing out of metal, however the inserts are going in well, and seem extremely strong!

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