gunstocks?

[JMC Design & Fabrication]

Probably already know the answer to this but going to ask it anyway. New to cnc and have been working with my bot for about a month, and love it by the way, but was wondering if it's possible to cut designs in gunstocks. I know the machine can't work from different Z axis zeros but didn't know if I was overlooking anything.

[coryatjohn]

Typically, 3D objects such as gunstocks are cut using an indexer, which is like a lathe only computer controlled.

[gundog]

I think the hardest part would be modeling it. Do you have Aspire? If you could model the gun stock profile I think you could put a carved design on it. Maybe a probe to get the profile then put your design in. This is work I have not attempted but I think with the right software and patience it could be done.

Mike

[bleeth]

The simple answer is yes you can. You need to scan or probe the stock to get your base model into your design software and then apply/model your carving.

If you're doing something fairly small like a logo you may be able to create the curve you are going to cut it on by careful measurement.

[Nate Zellmer]

I’ve been working on a pet project involving gun stock machining on a custom tool setup. The tool is designed primarily for indexer use but retains some Y movement for both 3+1 and 4 axis machining.

I used a scaled profile photo, some calipers, and a tape measure to create the model in Aspire. Once the photo was placed and scaled, I created vectors, then component shapes. Finally these components were blended to create the final model. This method is a bit time consuming, but is a very good learning exercise for Aspire, and subsequent models will go faster. Probing uses machine time instead of your modeling time. It’s a very good option if you want an exact copy of a stock.

I used a 3 plus 1 technique for machining this stock. This uses the indexer to turn the stock to each of the 3 planes for machining rather than continuously turning the part as a wrapped job would. The blank is made of scrap ¾ glued up and shaped to common commercial stock blank dimensions.

I’ll be doing a final stock in laminate with a full write-up soon. This trial gave some significant lessons. Rigidity of the part can be an issue. Next time I’ll cut the barrel and receiver portions first. Additionally ensuring the square of the tool and position of the zero positions are very critical. Small errors can double when machining 2 or more faces.

[Tom Bachman]

That's pretty freaking cool, Nate.

[myxpykalix]

Nate,
I would be very interested in learning how to do this adequately translating the instructions using my program. I saw your picture and what i think you need is "Thin stock support".
Check out my version of that, being an old skate from one of the grandkids.
I have since modified it to have springs on the base to put upward stability on the part since you lose that support if you cut away alot of material.

What i'm interested in is seeing how your part is finished cutting and how you have your waste material holding it, and how you cut the toolpaths for barrel placement.
When do you think you might have your instructions? Looks good!:D

[Nate Zellmer]

Hi Jack,

That support looks great! I'll probably change up the order a bit. so that there's a little more material around when I machine the barrel and receiver. Also, the laminate is significantly stiffer than scrap ply. Right now we're waiting for another gear head to evaluate. This one is alleged to have lower backlash. I'll believe it when I see it.