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shalafi4
Feb 20, 2011

another medical bills avatar

Давайте строить винтовку.

Back up a few years. It's 2012 and myself and a buddy of mine decide that we want to build at least a pair of custom rifles.

Great!
Now what?

Our final conversation on deciding what to make went something like this.

Well... we defiantly want rifles, and preferably something we can have as a semi-auto. So we're limited to roughly AR and AK platform constraints.

We want something subsonic because suppressors are fun and things that make loud booms (while fun) tend to make groundhogs run.

300 whisper? na.. plus who knows which will get standardized...

Some giant necked up .308 to .45 caliber? it'll fit in an AR 10 and chuck huge chunks of lead? (yes we almost made a .45 raptor 3 years ago) ... looks at AR 10 receivers (at the time) YIKES nope too pricey.

hmmm... what can we do with similar AK rounds. (I had built my AK 74 the previous year)

Look up the dimensions of a 7.62x39 case... what can we do with it?

Then a lightbulb went off in the back of my head. The Russians already make a subsonic round based on a 7.62x39mm. A 9x39mm

And the project went from there.



We did some research and found that there was more than just necking the case up.



as a comparison here's a 7.62x39




Ok great! now we know what we want to make the rifles in! Also we can use existing 7.62x39 parts kits and receivers as the base to all of it. We got an Egyptian parts kit from apexgunparts that October, and were getting drawings started on reamer dimensions for the chamber.

Then Sandy Hook happened and the project got shelved.

Fast forward to February 2014. I'm staring at my tax return check wondering what I want to do with it. Plop down in my computer chair. What haven't I played in a while?... I haven't played Call of Pripyat in a while I'll load up a new game. Play for a while, pick up a VSS vintorez. ... *pause game*... looks at screen... look at check... F it I'm taking the project back off of the shelf!

I call up Pacific Tool and Gauge and start working with them to get a reamer designed.

The result, this as a framed posted in my office.



Also these.




After the reamers arrived I made a sizing die and then I realized this whole project would actually become a reality.


9x39 with a 286gr on the left. a Hornady 70gr 5.45x39 on the right.



What was next? getting designs for the whole front end rebuild of AK parts.

This is kind of a recap post that gets the project caught up to about a month ago. If there's anything you guys want more information on or additional photos of let me know and I'll see what I can do.

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Cyrano4747
Sep 25, 2006



YEESSSSSSSSS.

I have been waiting for this thread for far too long. I can't wait to see how it ends up.

SpartanIvy
May 18, 2007


Hair Elf

Rated 5 already

MohawkSatan
Dec 20, 2008

by Cyrano4747


Those engineering drawings

Serious question time(with only the ones off the top of my head):
What kind of steel are the reamers?
How much did they cost you?
Are they your own design?
Do you fireform the casings, or are they custom made?
Did the reamers really need to be within 0.0004, or was that a preference/accuracy thing?
Are you using them for machine reaming, or are they going to be used for hand reaming?
What kind of speeds and feeds do you run with them if they're machine reamers?
What kind of coolant/cutting oil are you using?
Why 9.3mm diameter bullets when the original was(reportedly) 9.25/9.26?
What kind of toolholders are you using for the reamers?
Can we see a setup?
What are you estimating chamber pressure to be like?
Did you do hoop calculations/pressure in cylinder calcs for the chamber and barrel, and if so, can we see them?
What's the twist on the rifling going to be, and how deep?
How did you calculate how much gas is going to be needed/used in the action?
Can I print off those engineering drawing you made for the reamer and frame them above wherever I'm working as a reminder that machining is the coolest loving trade?

EDIT: Do you think the same maths and work could make a 9x39mm Cz858 possible?

MohawkSatan fucked around with this message at 19:56 on Nov 24, 2015

Bummey
May 26, 2004

you are a filth wizard, friend only to the grumpig and the rattata


Neat

22 Eargesplitten
Oct 10, 2010

Certified Centrist Trash


MohawkSatan posted:

Why 9.3mm diameter bullets when the original was(reportedly) 9.25/9.26?
Do they even make commercially available 9.25mm bullets?

Are you going to need to custom-make the magazines? All of the authentic 9x39 magazines are straight rather than curved like a 7.62 or even 5.45 magazine.

Capn Beeb
Jun 29, 2003

Enter the woods, find a friend!


I LIKE WHAT YOU GOT

GOOD JOB

shalafi4
Feb 20, 2011

another medical bills avatar

MohawkSatan posted:

Those engineering drawings

Serious question time(with only the ones off the top of my head):
What kind of steel are the reamers?
How much did they cost you?
Are they your own design?
Do you fireform the casings, or are they custom made?
Did the reamers really need to be within 0.0004, or was that a preference/accuracy thing?
Are you using them for machine reaming, or are they going to be used for hand reaming?
What kind of speeds and feeds do you run with them if they're machine reamers?
What kind of coolant/cutting oil are you using?
Why 9.3mm diameter bullets when the original was(reportedly) 9.25/9.26?
What kind of toolholders are you using for the reamers?
Can we see a setup?
What are you estimating chamber pressure to be like?
Did you do hoop calculations/pressure in cylinder calcs for the chamber and barrel, and if so, can we see them?
What's the twist on the rifling going to be, and how deep?
How did you calculate how much gas is going to be needed/used in the action?
Can I print off those engineering drawing you made for the reamer and frame them above wherever I'm working as a reminder that machining is the coolest loving trade?

EDIT: Do you think the same maths and work could make a 9x39mm Cz858 possible?

ok *cracks knuckles*

MohawkSatan posted:

What kind of steel are the reamers?
M42 High Speed Steel. PTG uses M42 because it generally will hold a sharper edge and is tougher than M2 (much more common HSS)

MohawkSatan posted:

How much did they cost you?
If I remember correctly they were only $130 each

MohawkSatan posted:

Are they your own design?
yes and no. They were done collaborating with Dave Kiff (THE reamer guy at PTG)

MohawkSatan posted:

Do you fireform the casings, or are they custom made?
Neither?
We don't have a functioning rifle yet. Those are 7.62x39 cases that are first sized into a straight walled case (even down through where the web starts), the upper 1/3 of the case is annealed, then the neck and shoulder are sized into shape. If you look really close there's a tiny wasp waist as an artifact to the forming process. That will be fireformed out the first time it's fired.

MohawkSatan posted:

Did the reamers really need to be within 0.0004, or was that a preference/accuracy thing?
YES.
That's actually PTG's "normal" reamer tolerance. they make higher precision ones as well. (and note it's +0.0004 not + or -)
They need to be like that because for example what happens if the .3929 neck measurement is a thousands or two undersized? Your case neck will be grabbed and you're going to be wearing your bolt.

MohawkSatan posted:

Are you using them for machine reaming, or are they going to be used for hand reaming?
A little of both?
the sizing die that I made from 4140 I machine reamed it *most* of the way then finished it by hand.

MohawkSatan posted:

What kind of speeds and feeds do you run with them if they're machine reamers?
If memory serves I was running it at 53RPM. The feed was VERY slow (hand feeding via a lathe tailstock)

MohawkSatan posted:

What kind of coolant/cutting oil are you using?
It's a chlorinated sulferized oil. Stinks but works great on steels

MohawkSatan posted:

Why 9.3mm diameter bullets when the original was(reportedly) 9.25/9.26?
I never actually had heard that?

*assumption time*
They're probably 9.3mm as that's a "relatively" common large game caliber in Europe. And on top of it 9.25mm comes out to 0.3642 inches and 9.3 comes out to 0.3661 inches. It's such a small difference that it wasn't worth us making custom bullet dies on top of everything else.

(comparatively that's very similar to the difference between a 9x19 bullet and one for a .38 spl or .357 mag.

MohawkSatan posted:

What kind of toolholders are you using for the reamers?
Currently they're being held between the work and a spring loaded live center in the tailstock. Rotationally it's being held in place by a pretty large tap wrench.

MohawkSatan posted:

Can we see a setup?
Patience :P I hadn't done a lot of documentation of the processes up until now so I didn't have a lot of the photos of what I had done. Once we get caught up to now it'll be photo central.

MohawkSatan posted:

What are you estimating chamber pressure to be like?
We're shooting for around 40~45ksi similar pressure to a 7.62x39mm

MohawkSatan posted:

Did you do hoop calculations/pressure in cylinder calcs for the chamber and barrel, and if so, can we see them?
nope... haven't done them because we don't know what the internal pressure will be exactly

MohawkSatan posted:

What's the twist on the rifling going to be, and how deep?

*sigh*
so some math calculations we did we realized that a standard 9.3 barrel won't work... the twist rate is 1:12. Which will stablize a 285gr bullet down to (this is from memory so may not be 100% correct) about 1500fps?
Ideally we need a 1:9.5 but we're making the initial rifle as a 1:10 so we can buy an off the shelf barrel twist.

MohawkSatan posted:

How did you calculate how much gas is going to be needed/used in the action?
We actually didn't.

We're taking an existing design and the powder volume should be comparable.

MohawkSatan posted:

Can I print off those engineering drawing you made for the reamer and frame them above wherever I'm working as a reminder that machining is the coolest loving trade?

Go for it!

MohawkSatan posted:

EDIT: Do you think the same maths and work could make a 9x39mm Cz858 possible?
eeeee yes?
There's a technical fiddiculty that we've encountered that I haven't discussed yet. Magazines will be your enemy.

shalafi4
Feb 20, 2011

another medical bills avatar

Double post because

22 Eargesplitten posted:

Do they even make commercially available 9.25mm bullets?

Not to my knowledge?

22 Eargesplitten posted:



Are you going to need to custom-make the magazines? All of the authentic 9x39 magazines are straight rather than curved like a 7.62 or even 5.45 magazine.

*Have* to no actually... we found a very unexpected answer to it.

However we are because we want to have box magazines for it.

Applesnots
Oct 22, 2010

MERRY YOBMAS



Neato!

Bummey
May 26, 2004

you are a filth wizard, friend only to the grumpig and the rattata


Are you shoving this into an AK parts kit or attempting something cooler?

Force de Fappe
Nov 7, 2008



Pretty sure this counts as cultural appropriation.

And I like it.

Dead Reckoning
Sep 13, 2011


I don't know a lot about machining, but this is neat, and I'm looking forward to following it.

shalafi4
Feb 20, 2011

another medical bills avatar

Bummey posted:

Are you shoving this into an AK parts kit or attempting something cooler?

*mostly* the scope of hte project is to make an AK in 9x39

The part where a LOT of the machining comes in is anything that's attached to the barrel on an AK (rear sight block, gas block, front sight post) all have to be custom designed/made.

Bummey
May 26, 2004

you are a filth wizard, friend only to the grumpig and the rattata


shalafi4 posted:

*mostly* the scope of hte project is to make an AK in 9x39

The part where a LOT of the machining comes in is anything that's attached to the barrel on an AK (rear sight block, gas block, front sight post) all have to be custom designed/made.

Oh well. Not a home made VSS, but still cool.


Bummey fucked around with this message at 23:05 on Nov 24, 2015

TopherCStone
Feb 27, 2013

I am very important and deserve your attention


shalafi4 posted:

*mostly* the scope of hte project is to make an AK in 9x39

The part where a LOT of the machining comes in is anything that's attached to the barrel on an AK (rear sight block, gas block, front sight post) all have to be custom designed/made.

And the PBS-5 you now have to make, of course

shalafi4
Feb 20, 2011

another medical bills avatar

Bummey posted:

Oh well. Not a home made VSS, but still cool.

yet...



We want to get the bugs out of a working 9x39 load and the AK's built.

Then it's paperwork time

Bummey
May 26, 2004

you are a filth wizard, friend only to the grumpig and the rattata


shalafi4 posted:

yet...



We want to get the bugs out of a working 9x39 load and the AK's built.

Then it's paperwork time

record scratch

double take

excited look on face

New Concept Hole
Oct 10, 2012

東方動的


shalafi4 posted:

yet...



We want to get the bugs out of a working 9x39 load and the AK's built.

Then it's paperwork time

<--- irl

Action Jesus
Jun 18, 2002



aioli is just mayo
Aug 14, 2003

He has only forbidden to you dead animals, blood, the flesh of swine, and that which has been dedicated to other than Allah . But whoever is forced by necessity, neither desiring it nor transgressing its limit, there is no sin upon him. Indeed, Allah is Forgiving and Merciful


You're going to put a can on it, right? Let's not put the cart before the horse.

shalafi4
Feb 20, 2011

another medical bills avatar

Rigel posted:

You're going to put a can on it, right? Let's not put the cart before the horse.

Are you crazy? of course we are!

The Eyes Have It
Feb 9, 2008

Third Eye Sees All
...snookums

shalafi4 posted:

I haven't played Call of Pripyat in a while

Any time is Pripyat Time

Only registered members can see post attachments!

A Wizard of Goatse
Dec 14, 2014



what's your estimated timeline on getting a gun that can shoot these right now? Do you have your own machine shop, and just farmed out the reamers for the tooling metallurgy, or are you making the drafts and having someone else make all the actual parts?

SpartanIV posted:

Rated 5 already

A Wizard of Goatse fucked around with this message at 07:04 on Nov 25, 2015

Somebody Awful
Nov 27, 2011

BORN TO DIE
HAIG IS A FUCK
Kill Em All 1917
I am trench man
410,757,864,530 SHELLS FIRED




Bummey posted:

Oh well. Not a home made VSS, but still cool.

There's an order to these things. OTs-12 Tiss -> OTs-14 Groza -> VSS.

Roundboy
Oct 21, 2008


I am following this because I love the fiddly machining bits.

shalafi4
Feb 20, 2011

another medical bills avatar

Mister Sinewave posted:

Any time is Pripyat Time

Not enough Vodka present



A Wizard of Goatse posted:

what's your estimated timeline on getting a gun that can shoot these right now? Do you have your own machine shop, and just farmed out the reamers for the tooling metallurgy, or are you making the drafts and having someone else make all the actual parts?

Currently it's late winter/early spring....ish? The biggest time wait right now will be the barrels. I've been scrambling around quite a bit at work and haven't gotten a hold of the one company that actually makes 1:10 twist 9.3 barrels off the shelf.

I currently run my own machine shop at a university. So I can do a good portion of the work myself. (just can't bring/work on receivers here) I also have a couple basement machine shops that I have limited but reliable access to for any receiver work.

I farmed out the reamers for a few reasons. I had never designed one so I had no idea which part needs to be 0.0005" and which can be + - accuracy of eyeball. It's always best to just ask the people who do this sort of thing for their living. Also I don't have a single piece of equipment that reliably hold the + 0.0004" tolerances needed on a round object. (let alone the equipment to check the compound tapers needed)




The drafts have been done for the parts I need to machine. I'm hoping to get a post out detailing that process either today or over the weekend. I'm definatly making all of these parts.
(yes everyone will get to see a different glimpse into the land of the black magic voodoo elves on the other side of the requisition button. Well... other than lathespin.gif he's already familiar with elf land.)

Sperglord Actual posted:

There's an order to these things. OTs-12 Tiss -> OTs-14 Groza -> VSS.


Pfft bullpups, bullpups, we don't need no stinking bullpups!

Actually it would be fun to design and build but right now it's not in the plans.

Teaser time for those who want to see chips/setups




shalafi4 fucked around with this message at 15:02 on Nov 25, 2015

Bummey
May 26, 2004

you are a filth wizard, friend only to the grumpig and the rattata


I haven't been as excited for a thread since nonentity and his oil barrel o' fun.

Kthulhu5000
Jul 25, 2006

by R. Guyovich


I am totally down with this. Even if it's not a 100% pure recreation of what Izhmash or whomever makes,, more variety in the AK realm is always cool as poo poo.

hazardousmouse
Dec 17, 2010

That ain't a noodle, chirpy!



As someone who has none of the skills or materials needed for this, godspeed. Shine on you crazy star!
Or.

MohawkSatan
Dec 20, 2008

by Cyrano4747


shalafi4 posted:

YES.
That's actually PTG's "normal" reamer tolerance. they make higher precision ones as well. (and note it's +0.0004 not + or -)
They need to be like that because for example what happens if the .3929 neck measurement is a thousands or two undersized? Your case neck will be grabbed and you're going to be wearing your bolt.

I did note the one-way tolerance. Undersizing would obviously have catastrophic effects.

quote:

If memory serves I was running it at 53RPM. The feed was VERY slow (hand feeding via a lathe tailstock)

Is there any particular reason for running at such a low RPM, or do chamber reamers not follow the general reamer rule of half speed, double feed? My rough apprentice math says it should be around 440 RPM if you've got a 4140 barrel at around 200-250 BHN(using the quick formula of [CS*4]/D).

I'd have more questions, but it's 4:37am, and my attempts at roughly calculating barrel wall thickness(assuming a 50% safety margin in case of proof loads) are going horribly wrong for some reason. Next info dumb you give us, I'm sure I'll have something.

shalafi4
Feb 20, 2011

another medical bills avatar

MohawkSatan posted:

I did note the one-way tolerance. Undersizing would obviously have catastrophic effects.


Is there any particular reason for running at such a low RPM, or do chamber reamers not follow the general reamer rule of half speed, double feed? My rough apprentice math says it should be around 440 RPM if you've got a 4140 barrel at around 200-250 BHN(using the quick formula of [CS*4]/D).

I'd have more questions, but it's 4:37am, and my attempts at roughly calculating barrel wall thickness(assuming a 50% safety margin in case of proof loads) are going horribly wrong for some reason. Next info dumb you give us, I'm sure I'll have something.

The short version is they have a LOT more active contact surface than a traditional reamer.

normal reamers if you're cutting a straight hole the only part engaging is the front lead in chamfer and possibly the first 1/4 of the side walls are actually cutting (probably less than this if it is sharp)

A chamber reamer the ENTIRE cutter is engaged AND cutting


Edit: imagine the RPM on a pretty intricate lathe form tool compared to a single point tool... similar idea

shalafi4 fucked around with this message at 17:56 on Nov 26, 2015

MohawkSatan
Dec 20, 2008

by Cyrano4747


shalafi4 posted:

The short version is they have a LOT more active contact surface than a traditional reamer.

normal reamers if you're cutting a straight hole the only part engaging is the front lead in chamfer and possibly the first 1/4 of the side walls are actually cutting (probably less than this if it is sharp)

A chamber reamer the ENTIRE cutter is engaged AND cutting


Edit: imagine the RPM on a pretty intricate lathe form tool compared to a single point tool... similar idea

Okay, I was figuring it was something like that. In that case, is there a formula for figuring it out, or is it an approximate guess based on experience or experimentation?

shalafi4
Feb 20, 2011

another medical bills avatar

MohawkSatan posted:

Okay, I was figuring it was something like that. In that case, is there a formula for figuring it out, or is it an approximate guess based on experience or experimentation?

If there's a specific formula I'm not aware of it? Just from experience reamers that have any real kind of profile to them I try to run around 100 rpm for a 0.5" ish reamer

bulletsponge13
Apr 28, 2010


This is an awesome thread and a completely amazing project. Shine on you crazy machinist!

shalafi4
Feb 20, 2011

another medical bills avatar

Batshit crazy idea: $16 (beer)

Super awesome tech drawings: $30

Shiny weird shaped precision cutty thingies: $275

Realizing the black hole of the project has opened up: priceless


So... to recap we have a plan, reamers, go/ no-go gauges, and a sizing die made.



Not pictured is the sizing die. I'll get some photos of it once I'm back home. For an expanded ball/decapping pin I ordered an RCBS spare parts stem with .366 sizer.

here's where the project started spreading out in the scope of it.

We knew that we are using AK actions.

For those who are not familiar with them down to every nut and bolt enjoy. (I'll be referring to this drawing for a while)



Take a couple minutes to really look at it. Specifically everything that touches the barrel and the gas system.

There's a lot there... take another look.

OK, First thing to note on for our project. Nearly everything is pinned onto the barrel. The only one that is labeled on the drawing is the Barrel pin. However you can see 5 other pins if you look closely.

1 on the rear sight base
2 on the gas block
2 on the front sight post

So these will need to be completely redesigned.


Alright so we need to remake at least 3 part for our mutant AK.

Time to sit down and start designing.

There are pretty drat near an infinite number of ways to go about designing parts.

Many are better than others but here is a glimpse into the crazy process that I go through.

What does each part do?

Rear sight: Holds the rear sight. Helps guide the gas piston during cycling. (Possibly help hold the hand guard? )

Gas block: Ports and directs vent gas to the gas piston. Fully supports the Gas piston when at rest.

Front sight: Holds the front sight. (in some AK designs also holds the threads for any muzzle device)

Are there any hard restrictions ?

To me hard restrictions include:

New parts having to fit into other non modifiable parts. Fixed existing lengths.

Basically dimensions that can't or shouldn't be changed.



OK for all of you who just skim through these pages and like to armchair general it's

QUIZ TIME

How many hard restrictions/constraints are there for the parts I've been talking about? Remember that we are making a new barrel the MUST have a larger OD than the existing one.

I'll answer general questions but not ones that directly answer any of the constraints.

Answers to be posted on the next main update.

https://www.youtube.com/watch?v=gjVmeKWOsEU

shalafi4 fucked around with this message at 15:55 on Nov 30, 2015

Bummey
May 26, 2004

you are a filth wizard, friend only to the grumpig and the rattata


ilu

MohawkSatan
Dec 20, 2008

by Cyrano4747


Quick look(I'm not an AK person, seeing as they're basically illegal in Canada) says the parts that you are going to HAVE to make or change are the gas block, front sight ,handguard retainer bits, and of course the barrel. Gas block, handguard retainer, and front sight sizing are dependant on barrel size, and as you're adding about 1.7mm of bore size, the barrel walls obviously aren't going to remain the same size. Increased barrel size might also mean a need for a increased front trunion size, which would mean modifications to the receiver, but that might be avoidable depending on the amount of spare space in the trunion that can be bored out. Odds are your fixed constraints are the major operating parts(bolt assembly, gas piston, FCG,) and most likely the receiver itself, unless you're also gonna homebrew an oddball AK receiver.

shalafi4
Feb 20, 2011

another medical bills avatar

Boo

For the record you guys are no fun.


The answer is 5



I also apologize for this one it's going to be more a wall o'text than usual. I'm going to try to walk through the whole designing process.




So our restrictions are.


Diameter of the front trunion.

The 9x39 round is so close in dimensions to a 7.62x39 that we don't need to modify/make a new trunnion.



Length of the gas piston.

We need that to set where our new gas block will be positioned on the barrel



Diameter of the gas piston.

If we make our gas block too small, bad news. If it's too large we'll probably bleed too much gas around the piston and it may not cycle.



Centerline distance from the bore of the barrel to the center of the gas piston.

If that's off a little bit the bolt carrier will tilt as it cycles. Not normally an issue with an AK but it *can* cause premature wear on the receiver.



Barrel can't be too thin

This one is a little more nebulous. Intuitively it makes sense but there is not a specific "The answer is this specific number" type of problem to solve.
(well without pretty massive amount of computer modeling and a crapton of equipment and time that I don't have)



So we have our constraints. Now what?

We have 4 hard constraints and a "squishy" one.

I started with the "squishy" one since everything attaches onto the barrel I figured determining it's outer diameter would probably be a good start.

This one I pretty much solved empirically rather than in CAD or by experience. Ideally I wanted to try and keep the attachment pieces under 1" thick to help save on stock costs but I wouldn't know until I had a barrel diameter determined.

I'm sure I looked like a doofus walking around Cabela's one day. I went around with a set of calipers and measured every 9.3x57 or 9.3x62 mauser I could find.
They were all hunting rifles so the barrel profiles were pretty thin.

Most came out around 5/8" give or take. so I figured that .650" would be an absolute MINIMUM outer diameter.

So now I have a lower limit to my "squishy" tolerance. Time to figure out the maximum.

Again, ideally I wanted to make the front and rear sights and gas block out of 1" bar stock. I figured if we were making them out of steel a minimum dimension of around 1/16" around the barrel should be strong enough (assuming there's some extra bulk around where the pins go)

So assuming that the "max" barrel OD would be about 0.875 (1" - 0.625*2)

Ok so we have a barrel OD range of about 0.650" ~ 0.875"


Time to pull in one of the hard constraints to check and see if it would work.

Will the trunion bore size cause any issues with a barrel that big? *checks a couple trunions* NOPE! we're good The couple AK trunions I have are 0.917" YYYEEEEEYYYY I should be able to make my parts out of 1" stock!


I go back to talk with my friend who essentially is the customer for the 2nd one of these. We both want to make a fairly heavy barreled version at least for our prototype.

So 0.875 is the "max" we could go... I want to give myself some wiggle room in case the bar stock is undersized so I figured make it 0.866. Yes it'll be chunky but having a quarter inch thick barrel I KNOW that I'm well into the safety zone on pressures. (and don't have to go through the calculations on them in detail)


To wrap up, we know our constraints and have a rough barrel design hammered out (I dont' have a CAD model of it) Basically it's 0.917" for the trunion segment and then rolls down to 0.866" OD the entire length of the barrel.

Next up the first really fiddly bit and wrapping up the rest of those constraints.




As always feel free to ask questions on anything. The worst that'll happen is I'll give you a stupid answer

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DJExile
Jun 27, 2007



I don't have a lot to add but this is genuinely one of the best threads I've seen in years and I'm really interested to see how it all comes out.

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