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Side feed hop unit

Posted: Sun May 26, 2019 7:04 pm
by Lord Elpus
On a project, that I’m collecting parts for, I’m going to need a side feeding hop unit, now I could go down the 3D printer road, but those who have wandered down this long journey, know how long it takes, and even then it may not work!
So I thought I’d have a go at making a prototype that works before getting involved with the plastic printer.
Took an AK 47 hop unit cut the feed pipe off with the help of mr dremel and his little circular saw attachment, and moved it round to the side. Not knowing how this was going to turn out, but at least might give me some idea on sizing up. Milled out new inlet hole, wired in position using bolt locking wire ( motorcycle racing days) set about plastic welding it together with a soldering iron and using cable ties as welding rods ( another motorcycle repair trick, used on broken plastic fairings) then used a metal bond epoxy to cover and strengthen it up.
It’s come out quite good, forgot to take pics of stages in the process, but will be doing another if this one works on trials.

Re: Side feed hop unit

Posted: Sat Jun 01, 2019 7:40 pm
by dadio
For the pre viva and agm sten's I made I did the reverse , I cut the adjuster off and stuck it back on at 90° then milled new flats on the side of the barrel so it was rotated 90° as well ,my thought was that the adjuster was under less stress than the feed tube and it meant I didn't need as much precision but I was and still am using it not just getting the right measurements . I did try to turn and mill out hop units but never got it right , not enough precision on my part ,3d printing is the way forward for sure with this stuff , the mp40 ones I've made I print at 45° to the bed so no internal support is needed , I added a couple of easy cut of parts to hold it to the bed at the right angle .

Re: Side feed hop unit

Posted: Sun Jun 02, 2019 7:26 pm
by Lord Elpus
I did think about just turning it on it’s side and do a “ tdc “ type of hop adjustment, and for the barrel placement, to sleeve over the hop on the clip part drill and tap the sleeve to clamp the barrel, much the same as airsoft pro do some of their replacement hops.
I just wanted to see how it would work out this way, and have something to give to my printer man, but this works! I’m in the process of ripping out the side of an AK 47 frame to accommodate this as I’ll be using AK mags on the project. Of course the amended feed tube will have to be supported much as they are anyway in the AK.
I may yet have to have a longer feed tube to do the job on the project, I want to get this to work first before building it all then finding out I can’t make it work properly,......plus I might have the only side mounted mag AK 47!

Re: Side feed hop unit

Posted: Sun Jun 02, 2019 7:58 pm
by dadio
Don't tell the Russians ! Its not an FG42 being planned by any chance ?

Re: Side feed hop unit

Posted: Thu Jun 13, 2019 8:05 pm
by Lord Elpus
Not an FG 42, a Johnson 1941 LMG, going to attempt two at once, hence the reason for side feed hop unit. Nearly done on conversion to the test bed AK, so until I get a result from making a working prototype, I won’t start the project guns.

Re: Side feed hop unit

Posted: Thu Jun 13, 2019 10:42 pm
by dadio
That's a new one on me , were they ever used in WW2 ? I like the odd ones , always fancied making a Leningrad Gun myself. Looks like a fun project , the mag looks to go in horizontal but below the barrel level, an interesting challenge , I'm sure your testing will work out well :good:

Re: Side feed hop unit

Posted: Sat Jun 15, 2019 8:17 am
by Lord Elpus
Yes, the mag being lower, is one of the reasons to make a working prototype, if I can make a straight line one, I can make one slightly longer with maybe a 30 degree angle to it. I was thinking of using mini gun para 249 hop unit to start with and adding a tube, I have two of these, but I have more old AK47 ones to experiment on!