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| |-+  Kel-Tec RFB, RDB, M-43 (Moderator: Ronmar)
| | |-+  Wanted to show off my 3D printed RDB handguard
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Author Topic: Wanted to show off my 3D printed RDB handguard  (Read 2895 times)
pat_bcr
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« on: August 09, 2019, 01:31:43 PM »

Hey all,

 I just started getting into the RDB, and while I like the gun, I hate the stock handguard. I had a 2D sketch turned into a model and then a prototype printed to test the proof of concept.

 I like the slimmer lines of this handguard but there are definite areas to change and improve. I'll update when I can, but this is just a hobby project for me at the moment.


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BullPop
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« Reply #1 on: August 10, 2019, 01:21:59 PM »

nice

magpul slots?

hot barrel an issue?
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BellatorInvictus
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« Reply #2 on: August 10, 2019, 06:40:10 PM »

Looks nice and clean. What material? What printing process?
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pat_bcr
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« Reply #3 on: August 12, 2019, 01:30:48 PM »

Yes, they're MLOK slots. I definitely need to do some tweaking to the layout but it's a huge improvement to the original handguard. I wanted to see if I could design a lightweight, low profile MLOK version that wasn't as 'tall' as the Lucky Irishman or the KelTec MLOK version.

 This was an FDM print and I think it's just ABS plastic. I didn't ask the printer lol. I don't think it'd stand up to major heat loads in its current format unless I change some materials or alter the way it locks into the gas block. Ideally, I'd like to get the final version made out of Aluminum but that's very expensive.
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waffenmeister
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« Reply #4 on: August 12, 2019, 03:23:30 PM »

Did you test with 100+ rounds in 1 hour? Can you share STLs?
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pat_bcr
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« Reply #5 on: August 12, 2019, 07:53:32 PM »

I haven't put any rounds through it just yet, but I wouldn't expect much in this iteration. The one advantage is that it's secured to the gas block using an aluminum spacer that runs where the original push pin used to be. Two screws are used on opposite sides to clamp down onto the gas block.

 I'm hesitant to release an STL just because I'm considering getting the design made up in aluminum and I don't want to potentially complicate any future business arrangements. If I change my mind and decide not to go the manufacturing route, I'll be happy to share it publicly.
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waffenmeister
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« Reply #6 on: August 13, 2019, 08:32:56 AM »

Aluminium is the past century. Aim to composite materials like carbon fiber
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pat_bcr
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« Reply #7 on: August 13, 2019, 01:10:07 PM »

I don't disagree with you, and I was thinking of doing a second print after making my design changes in carbon-fiber reinforce nylon.

However, I am poor and only have so much coin to throw at a passion project, so I'll be lucky if I ever get one made out of aluminum at this rate lol
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Sputnik90
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« Reply #8 on: September 05, 2019, 12:16:41 PM »

 
Looks very nice!

I can confirm that carbon-fiber-reinforced nylon is the way to go for home printing of firearm accessories.  The carbon fiber keeps the parts warpage low, and the nylon has decent engineering properties even in the Z-direction, which is where most FDM prints and materials will fail.

I might be able to print one for you if that's your bottleneck.  I already have a Lucky Irishman aluminum guard, so I'm not much interested in disassembling it to test for you.
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mig1nc
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« Reply #9 on: October 13, 2019, 12:20:11 PM »

Have you thought about making a top cover for the front, with a gap to adjust the gas regulator kind of like the gap on the Sig MCX?
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pat_bcr
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« Reply #10 on: October 22, 2019, 05:41:51 PM »

I actually had, yeah. I've kind of put this project on the back burner, because I don't have a ton of 3d design skill (or time, or money) to work on improving the design, even though I think it has potential. I think once the official Kel-Tec MLOK aluminum handguard comes out, there's going to be very little demand for my design. I've tried to find a manufacturer to team up with and get an aluminum version made, but I haven't had any luck.

I also thought about making a version that would use an extended picatinny rail. Picture a two-piece aluminum handguard, incorporating a replacement scope rail that would extend to the lock nut on the 17" barrel version, with appropriate cutouts for the charging handle and gas adjustment knob. It'd attach to an aluminum handguard similar to my design, but with a top cover to meet and interface with the extended rail. Just another concept I was tinkering with.
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mig1nc
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« Reply #11 on: October 22, 2019, 06:31:47 PM »

Man, that sounds pretty cool.

I hope you can still make it. If it's good enough, people will still buy it over the factory one.
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LeeMajors
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« Reply #12 on: January 11, 2020, 07:24:38 PM »

Good clean design.

I will mention that we prototype in both Carbon Fiber and Kevlar reinforced 3D printing and while it's good for solid objects, it's not very good for things that don't have at least 1/4" thickness.  The problem is that you can't run the CF or Kevlar long strands along the printed model to add the rigidity without a minimum wall thickness. 

I just did our RFB handguard prototype and due to the 1/8" wall thickness the only thing he could use was Onyx (crushed CF mixed with the plastic) and while it's rigid enough to mount, it's easily bent/broken.

However, there are other manufacturing processes that could be utilized (extrusion is the main go-to for this type of piece) in 6061 for probably about $60 each not including how you plan to mount it (mounting stays). 

Innovation is good.  Good luck to you!
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mig1nc
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« Reply #13 on: May 07, 2020, 08:13:05 AM »

Old thread now, but seeing the RDB Defender photos out, I like this design a little better as it is less offset than the Kel-Tec one. Which just looks weird with the barrel not in the center and makes the grip fatter than it needs to be IMHO.
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pat_bcr
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« Reply #14 on: June 11, 2020, 02:46:47 PM »

Thanks for the supportive comments and interest. Unfortunately with everything going on, money is even tighter than before and I can't put any more time or funds into refining this project, although I would love to.

 I gave up trying to modify the design to integrate some reinforcements and changes, mostly because my skill at using the software was hitting a wall, and I didn't have the time to teach myself how to use it and get better. If anyone is interested in the .stl or .step files to play with it, feel free to PM me and I'll be happy to share it. I'd love to see if someone can improve and adapt the design into something more robust and usable.

 I ended up doing a bit of 'bubba' work and built up the front of the handguard to where it should have been in the first place. I don't know why I thought that thinning out the forward handguard was a good idea but it looked cool in my head. I used JB Weld to build up the areas until they matched the height of the rest of the handguard. It held up well initially, but as soon as I installed any MLOK accessories into the slots, even rubber rail covers, the force over time cracked the handguard. Maybe an internally stiffened handguard, printed from a tougher material might be able to hold up, but realistically I think it would be better suited to injection moulding, which is obviously cost-prohibitive for an individual.

 Either that, or have it made from aluminum. I've wondered about buying a cheap AR-15 aluminum MLOK handguard and using a Dremel to make it fit with the RDB, but that's another project for another time.



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