Open-source 3D model for rifle chassis

[sa-shooter]

Good day all

I have a buddy that has access to CNC equipment and got me wondering about machining up a chassis.

Does anyone know if there are any/where to find open-source 3d models of chassis designs online? I have very limited experience with Fusion 360 but something of this magnitude is way out of my skill set. I thought it could be a fun project in the event that i can get my hands on a workable model.

Side note: The intended rifle for this project is a CZ455 rimfire.

Any advice/guidance would be greatly appreciated!

 

[Mr.BR]

Anything you find on the net is questionable,you can possibly find some on Grabcad, wouldn't put any trust in design being to specs in the critical areas. So you are better of drawing a new one from scratch, design can be kept simple.

 

[jcmullis2]

It would be nice if you could use a 3d scanner or something to take the bs out of it.

 

[Gtar]

Pretty much any model you will find to download will be an STL made by someone who never had to machine what they modelled. Most models on Grabcad and Thingiverse are STL's more suited to 3D printing. Get some calipers and take some dimensions and then do some fusion 360 tutorials, it's actually pretty powerful software for the price and there is an endless supply of tutorials for both the CAD and CAM portions of it.

A 3D printer will save you bins full of metal chips while you design and test different designs and interfaces. I've machined up quite a few stocks and the machining at the end of it is the easy part, it's the design and prototyping that's the time consuming part. With the price of the KRG/MDT stocks now, you definitely wouldn't be doing this to save money! It is interesting and rewarding though when you can shoot something that you've designed and made. These were all done in Fusion 360:

 

[Terry Cross]

Good day all

I have a buddy that has access to CNC equipment and got me wondering about machining up a chassis.

Any advice/guidance would be greatly appreciated!

Just your fixtures alone would likely make it impractical.

Most components of any length would not be made by simply clamping a block of aluminum in a Kurt.

./

 

[...]

Just your fixtures alone would likely make it impractical.

Most components of any length would not be made by simply clamping a block of aluminum in a Kurt.

./

honestly its not as involved as it sounds.

a buddy of mine machined up a chassis for his anschutz with nothing more than a mill-drill and a kurt.....out of stainless no less.

its not going to be the fanciest chassis in the world, but all it really takes is time.

 

[iceng]

As someone who's company is building chassis curently..

Good luck. Not an easy task. Many iterations, variations, compatibility, etc..

 

[GunmanBlue]

As someone who's company is building chassis curently..

Good luck. Not an easy task. Many iterations, variations, compatibility, etc..

How's the purple beast coming along?

 

[jcmullis2]

Unless you have the right equipment and the knowledge to operate it the end product will be lacking or amateurish.

 

[THEIS]

Hi,

Guarantee that you can purchase (easily) 5 of every chassis on the market right now cheaper than actually producing your own IF you count your time.

If you are one of those people that think your time is free then you will still be in the "red", lol..........

Sincerely,
Theis

 

[jcmullis2]

Even the guys with the skills and equipment buy their chassis’s or stocks. Threading and chambering barrels is one thing and designing and milling complex parts is another. Just my $0.02.

 

[iceng]

@GunmanBlue Really well actually. I won't let slip that we may be taking pre-orders soon for a release in rem, tikka and Howa. If only PRS went ahead in Buchan we would have launched it then... Then NT also had an issue so didn't go.. ugh.

"Soon".

 

[The D]

Tagging in, I love the idea

Op, don’t get discouraged. Just know that a project like this is going to take a minimum 4x longer than you anticipate. Keep at it and please update with your progress

 

[iceng]

Tagging in, I love the idea

Op, don’t get discouraged. Just know that a project like this is going to take a minimum 4x longer than you anticipate. Keep at it and please update with your progress

4x ? Wow, your optimistic.

It goes like this.

1: work out what sort of market you want to fulfil, or what sort of product you want (hunting, rimfire, ELR, PRS, whatever).

2: market research to determine if the product you propose is viable. "Is there a hole to fill".

3: cost evaluation as a result of point 2. Development time, prototype time, lead time to market, etc.

4: start making prototypes within a budget. You don't exactly make a "full bells and whistles" as a first run (usually). 3d printing is awesome here. As is half size, if possible. Gives you a good scale of things, what will work, what won't, things you have already found before running a machine.

5: feedback. Get reliable people to give feedback. And honest feedback. Not to shit on your idea. But often things like "I do night shooting, can I run a super long pic rail without hitting that thing there ?" Or "I'm a hunter, where's the sling points ?". Even "it's too heavy for fclass, you need to get it under X kg to make it viable, also need weight out of here and put here to work for us".

6: refine your next prototype with info you have, also remember the costing of things. You don't want to make 10+ trial prototype as your budget will be dead, and you don't want to rush to market an incomplete job. It's a REALLY fine line. Often why many parts never see the light of day. The bean counters shut the project off as it cost too much to develop.

7: retail price point (partly point 2.5). If you made 4 prototypes, and you want $10 profit on each item, you expect a 100 product life cycle, and your retail point is $100. Do some math.. you need to produce the product for about 50% of retail, roughly. Factor in packaging, marketing (stickers, sponsorship, give away, etc) plus rework on parts (say a machine breaks a cutter, so you have a dead part, or someone paints the part the wrong colour, etc) and RMA Warr. Don't forget hardware you buy, like screws, or grips, or recoil pads.

The first chassis that imaginary company retails for $1000, is probably a $10k chassis. They need to sell 500 before they even break even, let alone start paying development costs or suppliers.

 

[Gtar]

4x ? Wow, your optimistic.

It goes like this.

1: work out what sort of market you want to fulfil, or what sort of product you want (hunting, rimfire, ELR, PRS, whatever).

2: market research to determine if the product you propose is viable. "Is there a hole to fill".

3: cost evaluation as a result of point 2. Development time, prototype time, lead time to market, etc.

4: start making prototypes within a budget. You don't exactly make a "full bells and whistles" as a first run (usually). 3d printing is awesome here. As is half size, if possible. Gives you a good scale of things, what will work, what won't, things you have already found before running a machine.

5: feedback. Get reliable people to give feedback. And honest feedback. Not to shit on your idea. But often things like "I do night shooting, can I run a super long pic rail without hitting that thing there ?" Or "I'm a hunter, where's the sling points ?". Even "it's too heavy for fclass, you need to get it under X kg to make it viable, also need weight out of here and put here to work for us".

6: refine your next prototype with info you have, also remember the costing of things. You don't want to make 10+ trial prototype as your budget will be dead, and you don't want to rush to market an incomplete job. It's a REALLY fine line. Often why many parts never see the light of day. The bean counters shut the project off as it cost too much to develop.

7: retail price point (partly point 2.5). If you made 4 prototypes, and you want $10 profit on each item, you expect a 100 product life cycle, and your retail point is $100. Do some math.. you need to produce the product for about 50% of retail, roughly. Factor in packaging, marketing (stickers, sponsorship, give away, etc) plus rework on parts (say a machine breaks a cutter, so you have a dead part, or someone paints the part the wrong colour, etc) and RMA Warr. Don't forget hardware you buy, like screws, or grips, or recoil pads.

The first chassis that imaginary company retails for $1000, is probably a $10k chassis. They need to sell 500 before they even break even, let alone start paying development costs or suppliers.

Point 5 is very valid for the F-class stock I posted the photo of above. I was given the maximum weight so weighed all the parts up and modelled the stock and the software had it come in about 100 grams underweight. When it was 90% machined I checked the rules and the weight had to include the bipod. There was a lot of retrospective pocketing involved but it came out around 20 grams under the limit. I think I made about $10 an hour by the time it was all wrapped up . It was an interesting project though.

 

[The D]

4x ? Wow, your optimistic.

It goes like this.

1: work out what sort of market you want to fulfil, or what sort of product you want (hunting, rimfire, ELR, PRS, whatever).

2: market research to determine if the product you propose is viable. "Is there a hole to fill".

3: cost evaluation as a result of point 2. Development time, prototype time, lead time to market, etc.

4: start making prototypes within a budget. You don't exactly make a "full bells and whistles" as a first run (usually). 3d printing is awesome here. As is half size, if possible. Gives you a good scale of things, what will work, what won't, things you have already found before running a machine.

5: feedback. Get reliable people to give feedback. And honest feedback. Not to shit on your idea. But often things like "I do night shooting, can I run a super long pic rail without hitting that thing there ?" Or "I'm a hunter, where's the sling points ?". Even "it's too heavy for fclass, you need to get it under X kg to make it viable, also need weight out of here and put here to work for us".

6: refine your next prototype with info you have, also remember the costing of things. You don't want to make 10+ trial prototype as your budget will be dead, and you don't want to rush to market an incomplete job. It's a REALLY fine line. Often why many parts never see the light of day. The bean counters shut the project off as it cost too much to develop.

7: retail price point (partly point 2.5). If you made 4 prototypes, and you want $10 profit on each item, you expect a 100 product life cycle, and your retail point is $100. Do some math.. you need to produce the product for about 50% of retail, roughly. Factor in packaging, marketing (stickers, sponsorship, give away, etc) plus rework on parts (say a machine breaks a cutter, so you have a dead part, or someone paints the part the wrong colour, etc) and RMA Warr. Don't forget hardware you buy, like screws, or grips, or recoil pads.

The first chassis that imaginary company retails for $1000, is probably a $10k chassis. They need to sell 500 before they even break even, let alone start paying development costs or suppliers.

He’s not trying to sell anything, this sounds like a pet project.

 

[GunmanBlue]

@GunmanBlue Really well actually. I won't let slip that we may be taking pre-orders soon for a release in rem, tikka and Howa. If only PRS went ahead in Buchan we would have launched it then... Then NT also had an issue so didn't go.. ugh.

"Soon".

Great to hear! Certainly missed Mildura and Buchan. I wasn't going to Darwin unfortunately.

Keep it up. More Aussie made stuff is great news.

 

[lariat]

GTAR, Theis and Iceng are laying down truth. Theis has been down this road and knows his shit, GTAR and Iceng I have no previous knowledge of but their experience mirrors my own.

Is it impossible? Nope. I’ll actually be one of the guys that encourage you to take the leap. You only live once. Seriously. And the machining skills will be much better at the end.

GTAR’s 3D printing methodology is solid. I would say to back it up further with doing the first model in wood using what you have programmed up. Cheaper than new aluminum and thinking it’s going to be right the first time. Just a suggestion.

 

[CerebralDistortion]

I've seen a couple of "one offs" made by people with free access and availability to equipment and some of them were really well made.

However, having a 3d-printer and SolidWorks my TRG forend is still a year plus in the works.
Mainly because I have very little free time.

For this to work (OP's question) you need to know you software. And taking someone else's .stl and milling something out of aluminium really is probably a very expensive way to fail.

So go for it!

 

[Gtar]

GTAR, Theis and Iceng are laying down truth. Theis has been down this road and knows his shit, GTAR and Iceng I have no previous knowledge of but their experience mirrors my own.

Is it impossible? Nope. I’ll actually be one of the guys that encourage you to take the leap. You only live once. Seriously. And the machining skills will be much better at the end.

GTAR’s 3D printing methodology is solid. I would say to back it up further with doing the first model in wood using what you have programmed up. Cheaper than new aluminum and thinking it’s going to be right the first time. Just a suggestion.

The 3D printing makes it easy to get something in your hands and see if it's going to do what you expect it to when you're drawing it. I've been playing around with the stock below and have printed most of it at least once and come up with a pile of revisions I am going to make before I start machining anything.

If you're going to give it to someone to machine, you really need a proper 3D model rather than an STL. If you were going to carve it out of wood on a router or print it, the STL is fine but I won't work from one because they're difficult to edit and have no real datums to work from.

I've got my own CNC mill but it's still a lot of time and material to produce something that's not quite what you wanted. A decent printer isn't a huge investment and there's a multitude of other things you can produce that make it very useful even if you never get a stock done. Learning the CAD to make your models is a skill well worth working on. If only they were as simple to machine and finish as they are to render!

 

[THEIS]

Hi,

In regards to the first 2 images.

Have you ran dynamic simulations in regards to recoil with them?

If not you may want to do that before you spend money and time with the rear buttstock interface as it sits IMO way too low for proper recoil motion.

Can you please advise as to what made you put it at the bottom, other than it only place to put it to not look exactly like Xylo rear buttstock interface?

Sincerely,
Theis

 

[sa-shooter]

Thanks for all the replies. To clarify, I do not intend to make a business out of this, it is simply a one-off project. I have a friend that already has a machine shop with CNC equipment making other production level items, so the machining capability is not a problem.

As for pricing, I am not based in the US and after doing a costing, not counting my time, making a one-off chassis for myself would cost less than 1/8th of buying something like an MDT. At the cost of only the material and perhaps a few milling bits, I can't really see a down side.

The idea here is to hopefully find a model and make the necessary changes, yes the main issue is the inletting and may require a few runs on a 3D printer to work out the details before running it out of metal. Fortunately the action is made of round stock so I am considering a "V" cut in the chassis and then mill out the necessary cavities for the trigger, magazine shroud/ mag port and the action holes. Similar to the AI chassis.

This project is still in its infancy, probing whether its worth the hassle. But if all goes well and I do find/or end up making my own model I shall post it here.

 

[Gtar]

Hi,

In regards to the first 2 images.

Have you ran dynamic simulations in regards to recoil with them?

If not you may want to do that before you spend money and time with the rear buttstock interface as it sits IMO way too low for proper recoil motion.

Can you please advise as to what made you put it at the bottom, other than it only place to put it to not look exactly like Xylo rear buttstock interface?

Sincerely,
Theis

To be honest, it's one of a bunch of different styles to try and get away from an AR15 grip. Everything I've made to this point uses one and I wanted to get away from it. The thought behind the low mount was to make it easy to make in 2 pieces and join under the grip so there's no fasteners showing and no real square edges. My mill has 800mm of x travel so I can't machine it all in one go without an extra couple of setups.

I haven't done any simulations at all, it's one of those time-wasters at night instead of watching TV. I've got no plans of making it as a product, I was in business for myself for 20 years and I'm not interested in doing it again. My job gives me 7 days off a fortnight so this is just a hobby now.

I love the look of the timber grips on the Xylo stock, the whole thing is a real piece of functional industrial art in my opinion.

Here's another version with a "brace" at the top but the "thumbhole" ended up a little low to be really practical or comfortable.

 

[BullGear]

I have a son who works for a company who does a LOT of work for the aerospace industry. I've asked if he could mill a chassis for me. He said they could except for the time it would take. They have a ton of the right equipment and he said he could do it after hours. I've often thought about taking him on on the idea, but he's swamped with real work and he doesn't have time to build the model for the machinery.

Maybe one day, but not right now.

 

[serevince]

Randomly found this thread today.

Some awesome info from industry peeps and talented machinists alike in here.

I am neither of those. I did design my own .22 chassis though. 2016-17, there weren't many .22 chassis, and I wanted one. Not too hard if it only needs to fit one gun, and make 1 person happy.

Savage FV-SR. Takes AR stuff obviously. I made another rail to work with full size AR hand guards, but I liked it better with the small diameter hand guard. Runs perfectly. Kids gun now, and it still putting smiles on faces!

 

[epeet]

I made a TC Contender forend because I wanted one with a rail, in a certain length, and there was absolutely no option out there on the market. It has worked perfectly, but I bet I had about twenty revisions before the final one - easy to do on a 3d printer, maybe harder on CNC. Remington 700 dimensions are pretty easy to run down. It would be pretty simple to design something that took an A2 or M4 buttstock, a little more involved if you want it to be a full chassis (and you need much bigger chunks of aluminum). Chassis prices are what they are because quality design is tough and the machining a few feet of aluminum is out of reach for a bunch of folks. It would be great to see more options out there, especially if it brings the overall prices down.

 

[iceng]

Been working on this for almost 2.5 years. Someone ran a comp model for tikka at PRS australia on the weekend.

 

[TwentyFiveTwenty]

The 3D printing makes it easy to get something in your hands and see if it's going to do what you expect it to when you're drawing it. I've been playing around with the stock below and have printed most of it at least once and come up with a pile of revisions I am going to make before I start machining anything.

If you're going to give it to someone to machine, you really need a proper 3D model rather than an STL. If you were going to carve it out of wood on a router or print it, the STL is fine but I won't work from one because they're difficult to edit and have no real datums to work from.

I've got my own CNC mill but it's still a lot of time and material to produce something that's not quite what you wanted. A decent printer isn't a huge investment and there's a multitude of other things you can produce that make it very useful even if you never get a stock done. Learning the CAD to make your models is a skill well worth working on. If only they were as simple to machine and finish as they are to render!

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I love stocks that come off the bottom - been doing builds like that for decades. It’s ludicrously uninformed to think that you’ll need to run simulations to see how it manages recoil.

Provided you can draw a straight line from center muzzle to center breech thru to shoulder pad it doesn’t really matter if there isn’t always material along the way. Thats how kinetic energy works.

Will there be a couple of femto seconds where that energy uses the buttstock-to-handle joint as a fulcrum? Yes. But provided that is a sufficiently stiff joint, thats femto seconds. Then everything gets absorbed by the shooters mass.

You should be able to watch your rounds hit through the scope without needing to re-aquire the target.