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Gunsmithing Help for making stock on CNC machine

7magsavage

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Minuteman
Aug 9, 2012
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I have a friend who wants to make a custom stock for a friend. The stock is going on a Marlin model 336. Anyone able to help me point him in the right direction as to how to go about it?
Steve
 
It seems to me that a one off on a CNC for a kind of work your friend does not know how to do will end up costing a lot of money.
 
I know ZERO about CNC machines so I have no idea if what he is wanting to do is feasible or not. He is pretty slick working with wood and a really sharp guy. He had a friend of his approach him and ask him if he could make a new stock for the rifle and do some engraving work. I figured somewhere there has to be specs and demensions for just about anything??
 
honestly, i would just buy a replacement stock from Boyds and engrave that.........let someone else do the hard work for you, no need to go through the effort of carving and fitting it to the action if you can buy them already done.

all hed have to do is the engraving and refinishing.
 
honestly, i would just buy a replacement stock from Boyds and engrave that.........let someone else do the hard work for you, no need to go through the effort of carving and fitting it to the action if you can buy them already done.

all hed have to do is the engraving and refinishing.

That is a sensible suggestion.
 
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Been here, done it. Software, the right machine, experience...

That's how you do it. FWIW, it cost me roughly $42,000.00 to build this rifle. That total was parts and infrastructure.

https://www.facebook.com/snipershide...53284667747953

https://www.facebook.com/permalink.p...05264722901625

https://www.facebook.com/permalink.php?story_fbid=831937626900997&id=405264722901625


You can crack this nut several ways. Machined stocks on automated machinery is not new. Most use the digitize process. You Mount up a probe and bang around an existing stock so that you generate a point cloud of 3D positions in space. Import the data and G1 yourself to death. It'll get you there.

It's also gayer than buckets of dicks in my opinion. You leave so, so many options on the table doing it this way.

The better way imo is a 3D solid model of your part. You can get there a couple ways; Get on a CAD system and create it or take an existing stock and have it scanned into a mesh file that'll convert/import into a CAD system. I would advise a full parametric scan as it gives you some additional options.

The model has to be "water tight" for all this to work correctly. There's only a few companies I've found truly able to to this and it's not cheap: $4 to $5K is where the party starts.


Why all this crap?

Stand on a merry go round once. Get in the middle and you can buzz along and barely move. get on the outer rungs and it's a dear life situation with any kind of RPM applied. The same general rule applies with cutting tools. Digitized and duplicated stocks constrain the tool options. It's on center so it is gouging the part and creating a whole feck load of compression lines that will make you semi crazy later when you apply finish. It also handcuffs your tool size as the probe size drives the boat. It has to if your going to preserve the scale. (physical size of the part)

Get into a CAM package with surfacing tool paths and now you can drive the tool off axis so that you generate the SFM required to produce a clean finish. You can also change the size of tool for detail items such as a shadowline, grip transtions to the tang, etc...

It's ambitious and if your buddy is up to it, he'll have some very, very rewarding work once done. Just know it's a very intensive process and you better have a good understanding of machining strategy. Start out on laminated cedar blanks for proofing. It machines similar to walnut and costs cents on the dollar compared to good stuff.

Spindle rpm: You want a 15K spindle for this and you want a machine with a modern control that can read far ahead in the buffer. Dwell is poison.... Better have LOTS of memory storage as well. The stock we did the SHC rifle on had in total almost 750,000 blocks of code. If control memory is a concern, drip feeding or DNC is often the way to go. Get a computer that is solid if your using it to drive a machining center. Clear it of any horse shit software such as internet. Hell, rip the wireless card out of it and turn off any peripherals. Last thing you need is a girlfriend sending nude shots on the same terminal your using to try and communicate with a machine.

Last; One big ass coffee pot and an ashtray...lol. If he doesn't smoke, he likely will by the time he's done with this.


Good luck.

C.
 
Last edited:
I sincerely appreciate all of the replies.

To Mr. Dixon, I personally am very grateful for you to take the time for such a thorough response and explaining the details and challenges of this project. I feel certain that my friend will abandon the idea now, because he has no desire to become a rifle/rifle stock builder. He was trying to make a stock to help a friend out and likes to tinker. It would likely be the only gun stock that he would ever make. In my opinion it would not be worth it to continue the attempt. I'm certain that he will feel the same also.
Thank you again gentlemen.
Steve Norman
 
Us 'lil guys that do very limited stock making, still do it the way it was done 30 years ago- on manual duplicators. Still the most practical (and cost effective) way to do a one-off regardless, as Chad explained far more than I can comprehend the time/cost that must be expended before you can even cut with a CNC machine.

Easiest way to do this, is for your friend's friend, to locate a stock that's similar to what he wants- preferable, for the same action/rifle; makes it easier to get to the end zone. Then modify to the finished product. The "donor" stock can be (and should be) worthless to keep it simple- break out the sanders and bondo to create a Frankenstock. If you can't locate a cheap stock to use in creating the pattern stock, you can use any stock to then create a pattern stock from some cheap wood like Chad suggested (I just use Claro Walnut blanks with sapwood, cheap enuf).

Anyway- once you get a male pattern stock made- with or without inletting, send it off to be duplicated for the real deal. The stockmaker doing the duplicating can transfer over the inletting pattern from any stock made for that action if needed, but it's more work/$$.

This requires woodworking skills (and no computer), fairly labor intensive but not ridiculously so- and cost is proportionate to the amount of work done before sending it off to be duplicated.
Setting up and duplicating a stock that's ready to go is relatively inexpensive, and this remains the most cost-effective way to get a custom wood stock. They don't come off the machine ready to finish (fairly ugly when they come off the machine), typically they're cut oversize to allow for sanding/finishing- which again, is often done by the customer if they have the DIY skills.