Rifle Stock on a Rotary Axis.

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Imagineering
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Rifle Stock on a Rotary Axis.

Post by Imagineering »

Has anyone yet created a Target Rifle Stock using a Rotary Axis for the whole Job?

A Friend would like a Stock carved from an existing STL File. I have created two-sided ToolPaths using the Dowel Index Method, but would like to see if a Rotary Strategy is possible.
Attached are images of the two-sided version.

The disadvantage of utilising the two-sided Strategy, is that a Fixture and extra ToolPaths are required for the Action and Barrel recess, (not shown here).
Left Side.jpg
Right Side.jpg

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Re: Rifle Stock on a Rotary Axis.

Post by larrybadgett »

The disadvantage of utilising the two-sided Strategy, is that a Fixture and extra ToolPaths are required for the Action and Barrel recess, (not shown here).
Can't you do this first as a three sided ?
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Re: Rifle Stock on a Rotary Axis.

Post by Imagineering »

larrybadgett wrote:
The disadvantage of utilising the two-sided Strategy, is that a Fixture and extra ToolPaths are required for the Action and Barrel recess, (not shown here).
Can't you do this first as a three sided ?
I could do it three sided, but I have a Rotary Axis and I'm looking for a Strategy, or suggestions how to do it that way.

.

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Re: Rifle Stock on a Rotary Axis.

Post by kilrabit »

Aspire will not cut past the center line of the object, this will make your design very difficult to machine in a rotational manner.




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Re: Rifle Stock on a Rotary Axis.

Post by IslaWW »

I have not created the stock per se, but have created a rotary fixture to cut them. Make sure that your 4th axis has its big girl panties on!

Cutting a blank that size from hardwood to the required depths takes a lot of force and a lot of Z clearance. During testing we also found out that due to twisting over the length during cutting both ends had to be fixture held. This required a fixturing plate at both ends with 20:1 reduction connected by a drive shaft that was propelled by a 2500 ozin stepper with 4000 line encoder.

The proof of concept was toolpathed with Aspire, but a full 4 axis machining program was used for production. (reasons above)
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Re: Rifle Stock on a Rotary Axis.

Post by davemartin88 »

If you were wanting to try something like this on a one off type of project on a machine that isn't industrial strength, could you add some kind of physical support while the blank is being carved? I'm thinking something like a couple of wooden blocks clamped to the frame of the rotary and the blank once in position. They would be removed and reinstalled after the first side was cut and the blank flipped. Silly thought?

I've had good but not perfect success with the indexed dowel method for two sided carving but might be interesting to see the result on my rotary. Most likely, any error that is doubled when doing two sided machinery might get even worse when adding another axis, maybe I'm talking myself out of this, lol.

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Re: Rifle Stock on a Rotary Axis.

Post by dealguy11 »

I've used blocking for rotary indexing before, and it is helpful. However, be aware that it is easy to introduce positional errors this way - if you jam the blocking in tight enough to dampen vibration, then you may inadvertently push the part up a little bit, or cause it to rotate a slight amount. This will be visible in the final part.

Another thing to consider in trying to do this on a rotary setup is that the rotary equipment has to be set up very precisely in order for it to index properly without indexing errors where the 2 halves come together. The rotary needs to be parallel to the movement of the machine in both the long axis and in Z, and the tools has to be centered very precisely over the centerline of the part. Any errors are doubled on the resulting part.

Bottom line is that this part would be easier to make with three-sided machining on the table. I'm very much a rotary proponent, but the rotaries on most of the machines I've seen are not stout and precise enough for this kind of work. Also, as has been pointed out above, Aspire will not allow you to do a full 3d model of a rotary part where the centerline is exposed so you're pretty much stuck with indexing it in Aspire unless you resort to some trickery which I'm still working out - not sure even that would allow for this part.
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Re: Rifle Stock on a Rotary Axis.

Post by ohiococonut »

The toughest part is going to be the actual inletting for the action. If you were going to make more than one you might be further ahead to buy or build a stock duplicator. There are a few out there to get design ideas from or you can just buy one.

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Re: Rifle Stock on a Rotary Axis.

Post by Imagineering »

Thanks for the replies Guys, but I'm not thinking of a Rotary just to flip it around to machine 3 separate sides. I can do that as 3 separate 3d Toolpaths with the standard XYZ Axis.
I was looking for ideas on the possibility of using the Rotary Axis to continuously machine the whole Stock. I'm now aware that Aspire can't machine past the Centre-Line, so this strategy may not be an option. I have 300mm Z to play around within.

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Re: Rifle Stock on a Rotary Axis.

Post by larrybadgett »

In my experience, the accurate boring of a hole all the way through the stock for attachment is by far the hard part! :)
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Re: Rifle Stock on a Rotary Axis.

Post by Leo »

Imagineering wrote:Thanks for the replies Guys, but I'm not thinking of a Rotary just to flip it around to machine 3 separate sides. I can do that as 3 separate 3d Toolpaths with the standard XYZ Axis.
I was looking for ideas on the possibility of using the Rotary Axis to continuously machine the whole Stock. I'm now aware that Aspire can't machine past the Centre-Line, so this strategy may not be an option. I have 300mm Z to play around within.
Aspire is a great product for it's intended use. There is not much out there that is better. There is a significant amount of cool stuff beyond it's intended use, but there are limitations.

One thing that Aspire is not, is a full 3D CAM software. There are no strategies to do a full 3D project in Aspire.

With that said, there ARE creative ways to use Aspire plus some more creative strategies to compile several Aspire programs into one file.

I would personally approach a gun stock as a 4 sided operation. When I worked at Winchester I am pretty sure it was done in a 4 sided operation also and not on a rotary. I know they did a lot of sanding after machining.

Another possibility is to try to unwrap the STL and create a wrapped file. THAT, would be a full 3D cutting profile, but it would be severely inefficient and I think quite inaccurate.

The pocket for the receiver really need to be accurately milled. That would be better done as a 2D toolpath, as well as the pocket under the receiver. I would build a fixture to hold the stock accurately for the receiver pocket. I would cut and sand the outside toolpath first.

The outside toolpath can be 3D and 2 sided, but again, it does not need rotary.

You may be itching to find a cool thing to make on the rotary, but perhaps there is something more suited than a rifle stock.
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Re: Rifle Stock on a Rotary Axis.

Post by rscrawford »

I have tried unwrapping and wrapping .stl files to get them into Aspire for rotary indexer work, and it has never turned out accurate enough.

I don't think this is a good job for Aspire index cuts anyway. You could do some with it, but then you'd want to do 2D cuts for the pockets anyway.

RhinoCAM (or MADCam) would be a good program for this (the 4 axis version). It has a lot more toolpath options for the 4th axis.
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Re: Rifle Stock on a Rotary Axis.

Post by Imagineering »

Thanks Guys.

What I'll probably end up trying is;

First Toolpath - top of Stock including Barrel and Receiver Cutouts.
Second ToolPath - one Side as per Pic at start of thread.
Third Toolpath - the other Side as per the other Pic at start of thread.

.

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Re: Rifle Stock on a Rotary Axis.

Post by Leo »

Sounds like a plan.

Except I think you should do the receiver and barrel cuts last, so that you can align the stock and get the receiver and barrel cuts dead center.
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