Custom Carbon Fiber Handguard

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So, I'm usually shopping for deals - but some things never go on sale. On one of my rifles, I spent a little over $150 on a 12" carbon fiber handguard. It's great and I like it - but it's freaking expensive for something I don't bolt much to other than a flashlight and a bipod.

After building my wife's AR-15 - I realized that I really liked the way her Krinkov brake works and I really like the look of her 16.5" handguard (picture attached). My new Krinkov brake (1 5/16" OD) is on the way already - but before I install it, I need to have my new handguard worked out.



This is the brake


So the closest I can get to that using carbon fiber is 15" and it's nearly $200.

I got to thinking about it, and realized that there isn't any reason for me not to do it myself. It's not like there are many parts.

I ordered this barrel nut from Mentium. 1.4" diameter (35.56mm)
mentium-usa.com/products/steel-barrel-nut-slim-handguard

And I ordered this 500mm (19.6") x 40mm/od x 36mm/id carbon fiber tube on eBay. 1/2mm clearance should be nice and tight on the barrel nut - and 2mm thick should be nice and strong (and light)


Stay tuned. When the parts arrive - I'll figure out barrel nut alignment, hole placement, exact cutoff length and spend some quality time making sure things are aligned.

Yes, I'm stupid...I frequently have dreams that solve problems I run into during the workday. Sometimes, I solve problems I didn't know about - it's neat.

Last night, I had 2 dreams. One was completely unrelated - and the other pointed out that I didn't take into account the gas tube. Yes, my nifty plan to make a CF handguard was dashed by a dream.

No matter - I still plan on making it, I just have to figure out the new CF diameters and determine what dimension my spacers must be.

Anyone need a 40mm OD CF tube?

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So, the tube I should have ordered is this one:



I'm using cad to design my spacers. This is actually working out well, because I think I've designed something very unique.

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Looks like the cheaper - but more tool-like Sunex crows foot 1 3/16" is too wide for the Mentium barrel nut

So, I've ordered the Mentium crows foot... Kinda pissed - but what can I do? I heard that Snap-on makes one that's thin enough - but at this point I think I'll stop wasting money on things that might work.

So, before I run off and order what I believe to be the correct diameter CF tube - I'm going to be taking more precise measurements on the barrel nut, as well as identifying the thread pattern and making some preliminary mounting hardware.

The 24 barrel nut threaded mounting holes are in 2 rows with each consecutive hole being 30 degrees apart.

I think I'll take some aluminum bar stock and drill it to accommodate 2 screws on the barrel nut (counter sunk) and thread 3 (in between) to screw through the carbon fiber tube. I think 6 of these bars should do nicely - and will leave a gap for the gas tube.

Pictures and measurements coming soon.

1ST MEASUREMENT TIME!

OK, the barrel nut arrived today - so I can take my first measurement. it's true diameter is 1.38in/35.05mm (as opposed to the 35.56mm number given by the mfg) - so a half mm off, nothing that's going to hurt the project. My pre-made CF tubing options are limited. For the most part, I can get 1.5mm thickness or 2mm thickness, and once you arrive at 40mm OD, everything above that is in 10mm increments. I measured the OD of the CF handguard I already have and it's just shy of 50mm, so I know that size will accommodate the gas tube. That's what I ordered 50mm OD x 46mm ID.

That leaves me with an 11mm gap to fill. Distributed, I need 5.5mm spacers between the barrel nut and the handguard. That thin, I'm concerned about tapping the aluminum spacer. 5mm isn't really much, so I'm thinking the screws will pass through the spacer into the barrel nut tapped holes. Not sure how I'll get them in place though.

I wish I had a lathe

I'm going to have leftover CF tube. I may cut it into strips and glue them in place - then drill my mounting holes through the triple-thick CF tube....