Saturday, January 01, 2011

This Week's Project: Weight Loss Program for Miniguns

Chalk up another item on the list of "things I'd prefer not to ever redo but ended up doing anyways".

I had an opportunity to try out building something with the new revised minigun schematics I posted a while back. Seems that there's some errors that needed to be corrected with those schematics, in terms of a few dimensions being wrong. As posted, they either require longer support arms on the handle mount bracket (sheet 2), or a shorter profile on the outer barrel support (sheet 1). A modification of 2mm more on the handles or 2mm less on the outer barrel support (actually that needs to be dimensioned in general) will fix the problems. Oh well. None of you actually are using my plans anyways, so you're not affected.

Since this build used the newer schematics and improved building methods, I have officially designated this model as the "production" model. I've taken the opportunity to try out different build methods to lighten up the minigun as much as possible. Also, I've forgotten how I built it in the first place, so I had to.

The main differences in the production model and the prototype involve the larger, more liberal use of Magic cards. The whole handle bracket for the prototype was purely 110lb cardstock, whereas I've taken the opportunity to experiment with hollowed assemblies for the lower bracket. The ammo chute, power control module and bottom pipe mount were built the same way with Magic cards. The piping itself was done properly, at the elbow. I achieved a cleaner bend by notching sections of tube evenly to form a gentler curve than the atrocious abrupt elbow on the prototype model.

The drum is the biggest change. I made the drum as thin as possible knowing that a wall thickness of 1mm is sufficient for the mildly cosmetic nature of the shape, and that I was going to reinforce the middle and ends with a three card layer circle plug. There's now a taper from the aluminum section to the start of the black region, a task not feasible back then in the era of manual sanding. Having a Dremel allows for greater opportunities! The end caps on the prototype may have been constructed from a back of a art sketch pad due to the supreme rigidity. That material is also significantly heavier than Magic cards.

The minigun barrel spindle assembly was built with purely 110lb cardstock this time. I think I may have used a plastic tube in the prototype to reduce friction. That may also have been a big factor in the weight reduction.

 The rest of the build was the same as the last. Except I had no idea how I pulled off making the rear handle bracket without a Dremel. Or in general. I ended up shearing off a section in the middle and needed to reinforce it with a paper clip rod. I'll call that "planned strategic structural enhancement".

I noticed a long way though that I undersized the minigun barrels from 6.35mm to 5mm. I don't really care and I don't think anyone else does either. It looks OK as is. Makes painting the barrel assembly easier.

Here's the completed production model Sasha, Serial Number 0002 (assigned one, as though I'll be making more, but you never know). The Mini MS stand I bought a while back finally found a good purpose. Just the right height to display this monstrosity.

The build took around a week (with copious breaks in between part fabrication), and definitely was made easier with pre-existing plans. However, I had some quality issues with the large drum that resulted in a warped outer surface. That entire drum needed to be scrapped and redone, costing a day's worth of work. It's not particularly an annoying project to do, but it's not pleasant either. I did achieve a noticeable weight reduction, but not enough to allow the minigun to be properly wielded by the Heavy.

As for the fate of Prototype S/N 0001, it shall remain in possession of The Vortex as no smart person would want the flawed model (and I actually like the older one better for some reason). S/N 0002 shall be used as barter for rare and exotic trade goods.

1 comment:

stock trading said...

The project is great and good.