Sup /k/
Still haven't gotten my lathe hooked up.
Bought a cheap static phase converter for $250 or so from some stein/berg company made in USA. It looks pretty cheaply made and shitt, and it wouldn't pull the gigantic 7.5HP motor on the old Pratt & Whitney 16"x54" lathe.
Burnt it up trying to start it (my fault), bought a rotary phase converter (20 HP) and awaiting an electrician to hook it up so I don't electrocute myself accidentally (or worse, waste $1,300 worth of 3-phase equipment).
So my question is this, is there any use for milsurp worn out AK barrels? They're cheap enough I bought one just to look at, it's totally worn out of course, the rifling is still there, but the bore diameter would be too large and it would keyhole for sure. They also galled the shank around the chamber pressing it out.
Might be neat to find a good use for those.
My second question is, what brand of barrel blank should I look for in order to profile my own super special AK-74/AKM/AR-15 barrels? I would also like to learn to port the barrel blanks if possible, and any other frills like fluting one.
Looked in the American Gunsmithing Institute videos in the do/k/ument, didn't see any good learning material about profiling/porting/chambering barrel blanks.
If you have any good ideas I'd love to hear them, currently nojobs and this lathe is basically the love of my life right now.
tl;dr ?
What custom stuff would you do to rifle barrels and actions if you had some heavy machinery and time?
>>30073312
>American Gunsmithing Institute videos
They are trash, dont bother wasting your time.
>So my question is this, is there any use for milsurp worn out AK barrels?
You can use them for clubs, if you actually want to make use of them for something though learn how to find centerline on them and use them to learn to dovetail things.
>>30073361
What's hard about cutting dovetails?
I have a mill as well, just cut a square slot with an end-mill and use a dovetail cutter to cut the sides.
>>30073378
>What's hard about cutting dovetails?
Nothing, it is just a skill that is useful, same with finding centerline on a cylinder.
>I have a mill as well, just cut a square slot with an end-mill and use a dovetail cutter to cut the sides.
Yeah, I use a carbide endmill to hog out the middle then use the dovetail cutter to bring the sides to the right size, remember though all use of the dovetail cutter must be done only once, if you need multiple passes you will likely not reach the right final dimension.
>>30073361
>They are trash
Well they do have some good info on them, mostly little observations about the different firearms they cover. Being some old guys telling the story they also know some of the history about them.
I would take the info with a grain of salt after their AK riveting against the barrel stuff, but they're not completely worthless for sure.
>>30073389
>Nothing, it is just a skill that is useful, same with finding centerline on a cylinder.
Been watching youtube videos on this for a few days now, I think the best way to do it is either buy a purpose-made tool with a taper that fits up in the bore to indicate on, or find a small carbide rod (with a good tolerance) and make some brass cored rounds the right diameter to just slide in the bore and let me indicate parallel to bore.
I'm going to make a cat's head (spider I will fit into the 4-jaw) to hold the barrel for turning.
The lathe's head is too wide (42" or so) to fit the barrel completely through it and use a spider on the back end of it.
Here's a "cat's head": https://www.youtube.com/watch?v=2v0jO9URqFM
I can also turn long barrels completely between centers for profiling because 54" of bed.
>>30073423
>>30073389
>remember though all use of the dovetail cutter must be done only once, if you need multiple passes you will likely not reach the right final dimension.
How so? Not trying to be smug, just don't understand why you would lose your reference point if you need another pass.
>>30073423
>Been watching youtube videos on this for a few days now, I think the best way to do it is either buy a purpose-made tool with a taper that fits up in the bore to indicate on, or find a small carbide rod (with a good tolerance) and make some brass cored rounds the right diameter to just slide in the bore and let me indicate parallel to bore.
Or you could learn to find centerline on a cylinder and avoid unnecessary tooling and needless steps added your work.
>I can also turn long barrels completely between centers for profiling because 54" of bed.
They will sag/deflect if you dont support them.
>>30073441
The cutting of the sides of the dovetail must be done in one pass due to deflection of the endmill during the pass. This is why you need to hog out as much as possible before you use the dovetail cutter. Also it was just how I was taught, I figure if my teacher makes lazzaroni rifles he knows what he is talking about.
>>30073470
>Or you could learn to find centerline on a cylinder and avoid unnecessary tooling and needless steps added your work.
It's also a rifled cylinder, if you have a better technique that won't fuck it up I'm all ears.
Only thing I can think of would be to get an indicator with a long thin probe and try to indicate off the inside of the bore and ignore the jumps from the rifling. But that just seems silly. Please tell me a better method.
>>30073470
>They will sag/deflect if you dont support them.
Lathe came with a steady rest (three of them), they're plenty big, the biggest will accomodate a round piece 14"+ in diameter or so, which mostly worries me that someone tried to turn something that big on my lathe.
The smallest of the three should work for supporting a barrel sized piece, if not I'll be off to the used machinery/tooling store.
I would like to find a follow rest for a Pratt & Whitney 16"x54" model C if you happen to know of any.
>>30073470
Okay, makes sense. I don't think they would size a cutter expecting some deflection though.
>>30073534
We are talking about finding centerline on the outside of a cylinder, the rifling wont come into play here. This is for the express purpose of drilling and tapping and cutting dovetails.
Thats good that you have steady rests, I wasnt sure if you did. Then never mind about what I said earlier. I dont know where to get any but I suggest finding machinist groups on facebook and the like, they can help you out.
Well remember, when it comes to dovetails the only factors that matter are dept and maintaining the correct angles on the sides. If you do it in one pass deflection of the cutter wont matter as you wont add to the error, if however you have to try multiple times the changes of your part sliding out of the dovetail are very high.
>>30073470
Also, do you know anything about porting a barrel blank?
Any special requirements? like will it matter if I cut through into a piece of the rifling?
>>30073568
Oh, I see what you mean. Didn't know you were still talking about cutting dovetails. I was talking about work parallel to the bore.
Hmm, I bet a center finder like this one would help with that: http://www.amazon.com/Grizzly-H2940-Round-Center-Finder/dp/B0000DD4BS?ie=UTF8&keywords=center%20finder&qid=1464292898&ref_=sr_1_8&sr=8-8
I have one similar, haven't used it yet though.
>>30073568
To add to that, when we are cutting dovetails in barrels the hardness will change based on depth which will also impact how long the dovetail cutter lasts in total usage. If you are cutting dovetails in a good 1911 slide you would be lucky to get three passes from one cutter before it is worthless either due to it being burnt out or its dimensions are off due to how hard of a material it is cutting.
>>30073602
neat, didn't even think of that.
I cut these serrations into the slide of my 1911 (not very deep ofc). Cocked the head of the mill 45 degrees and set a depth of cut and moved over 10 or 15 thousandths each pass with a square end mill.
I didn't notice any excessive wear and tear on the end-mill, but it's a Sarco slide.
>>30073599
>Also, do you know anything about porting a barrel blank?
Some, I just plunge cut with a carbide endmill and then hone out anything that gets galled on the inside. I would imagine it would matter but I dont really know how to avoid it save through the use of a lot of math and a dividing head.
I have never used that product, I have used http://www.amazon.com/Mitutoyo-050103-Center-Finder-Diameter/dp/B002SG7PPM/ref=pd_bxgy_469_2?ie=UTF8&refRID=1WZ73JWC4ESZ8FNCJ4WK before and it works well.
>>30073620
I only use solid carbide endmills when working on 1911s and even then I dislike it due to how hard the nice ones get.
>>30073646
I have that exact same center/edge finder, I have used one from a different company quite a lot too.
I never realized 1911 slides would be that hardened, I did use a brand new end-mill for the slide serrations though.
Any idea what kind of steel they use?
>>30073696
>Any idea what kind of steel they use?
No idea, I just know that each one I have cut on that has a worth of over 1k has been terribly hard to the point of where I gave us using HSS endmills on them and now only use solid carbide.
>>30073720
One more question, is there any advantage to grinding a barrel shank after machining?
Like one made for a press fit, like an AK barrel shank.
I figure since it's pressed into the trunnion and then pinned, if the surface finish was better it wouldn't wobble around quite as much during firing, and be more accurate?
Oh, and green mountain 5.45x39 and 7.62x39 barrel blanks are only like $45, are they worth it? They aren't chrome lined.
>>30073755
The better of a surface finish you can get on something the better it will be in general. It looks better, it extends the life of the part and if you need to press it into something or do an interference fit it will work better. I am not sure about accuracy in the case as it would be hard to pin down what is causing you grief in any form on an AK type of weapon due to how they are designed.
I honestly dont know anything about AK barrel blanks as I make custom bolt action rifles.
>>30073784
Do you have any grinding equipment for your line of work?
>>30073798
Yeah I have many pedestal grinders to grind lathe tool bits, scrapers for stock work and polishing things. I also have a surface grinder that I mostly use for recoil lugs.
>>30073814
Do you think there would be any improvement if you had a toolpost grinder for grinding locking lugs and bolt faces after truing them up?
>>30073833
Maybe but a surface grinder works just fine.
