GTA
Support Equipment For PCP/HPA/CO2 and springers ,rams => 3D printing and files => Topic started by: WobblyHand on August 22, 2020, 06:52:35 PM
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So finally managed to get my hands on a 1389-010 forearm. Many thanks to Hack21. It would be nice if this forearm could be scanned. I'm probably not the only person who has wanted get one of these 3D printed. Anyone have a 3D scanner? Could you scan this for me?
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If you don't get an answer, you might try photogrammetry (which I have not done). Since that forearm is smooth without a lot of detail it might be a good candidate.
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I beleave treeburnerct has access to a 3d scanner.
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Contacted Access 3D Services https://access3dservices.com/3d-scanning/ (https://access3dservices.com/3d-scanning/) for a quote. Have no idea what this would cost. Will find out in a bit.
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If you are unable to find someone to scan it for you I would look into a old kinect sensor and the software to use it. They are pretty cheap. Plus it will allow you to do any future projects.
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It seems I may need to look into a kinect sensor. I've read about them before, but wasn't sure they could get fine features. (Fit related.) Did not get an official response from my RFQ, so back to square one. I did contact treeburnerct, and got a response, but have received nothing from the actual RFQ. Perhaps my answers were such that the RFQ was perceived as a non-serious inquiry. Or some issue with AG NLA parts. Maybe, it takes time to get to the RFQ because they are busy. To be fair, it's been less than 2 weeks, so I'll give it more time.
Photogrammetry looks like another whole rabbit hole. A lot of the open source software is powerful, but requires a lot of time to master. Seeing some of the video demos clearly demonstrates to me there is a whole lot of tweaking and "inside" knowledge, which I don't have at the moment.
Since I've fallen into multiple holes already this year, don't need another project/past time! Heck, I'm busy with my few airguns and learning how to machine to support my air gun habit.
Would have been nice to get it scanned. For now, its installed on my 1322. It fits my hand a little better than the wooden fatty although the designs are practically identical. Have to say my walnut, stained and TruOiled, fatty forearm is a lot prettier. But the plastic is more practical.
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Ive drawn and printed a version of that forearm (I have a 2289...)
Im not convicned that PLA will be strong enough, or even ABS or nylon. I do think you could reinforce the holes and get better life out of it, but Im skeptical
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Well Dan, that doesn't sound encouraging. Are there any printable materials that would work ok? Is the problem the stress due to the 6-32 grub screws? Could you put in inserts in that help out there?
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Maybe some sort of fiber reinforced would be good if straight ABS and PETG cannot handle the loads, but the cost of materials negate just buying a injection molded part. I have not printed nylon myself so I cannot say what I think it could handle I would have to see the part to know what it could handle 3D printed as an exact.
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Dan, show me that fore end.
Maybe it could be printed again around a piece of aluminum.
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hahahaha Ok, should have said: I think the layer lines — no matter the orientation at print time, is gonna be the weak area.
Wobbly, Insanity, I think the matierials are strong enough, IF they were cast, but every layer line is a potential fail point IMO
Mark, I’ll have to admit, my lack of engireering skills keeps me from seeing a way to offload the stresses from the plastic to some kinda insert, or any way to spread the load on the materials. PM your email and Ill send you the .stl
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At the risk of exposing my total ignorance, where do you think the stress points are? I was naively thinking they'd predominantly be at the holes that attach the part to the pump arm. I was thinking if that hole was made larger in diameter, say a 1/4" or so, then one could make an insert that was threaded externally to fix to the plastic part, and internally for the grub screw. This piece could be made of steel or brass. Wouldn't the larger diameter of the insert spread out the load? Or is the issue something else?
Be gentle, I know nothing about 3D printed parts!
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From what I see outside of SLA printing this would last a little while but will fail no matter the steps taken to prevent it. If it were a static foregrip then Bob's your uncle but pumping generates a lot of load on pivot points and with layers in 3d printing it is not a question of if it will fail but when.
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So for those not skilled in the art, you are saying the layers may de-laminate due to the stresses due to pumping over time? And this is a limitation of this technology?
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Insanity, yes thats whast Im thinking
Wobbly, yes to both.
Some test prints in various orientations to move the layer lines in other directions Id think would be worth a test or 3.
FWIW, I’d LOVE to rpoven wrong :)
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I print Ruger 22/45 frames from cf nylon. I think it is the best all around for these types of apps.
If made to fit against a pump arm, the screws to basically hold it from falling off, the stress should all be in compression.
Wood has been used for years as pump handles without issue. It is weak in tension perpendicular to grain, similar to 3D print.
The heat resistance of the cf nylon is the biggest selling point for me.
Dave