Brownells BRN-180 Build Part 3: Custom wood grip
Brownells BRN-180 Build
Part 3: Custom Wood Grip (Drilling holes)
I sat down at my bench and inspected my progress on the custom wood grip. I test fitted it to the BRN-180 lower receiver and noticed the smallest of gaps between the grip and the receiver. But desiring it to have an even tighter finished fit, I took the gip back over to the drill press to give it one more very small pass with the end mill bit.
As you can see in the above photo, I got my wish, as the gaps were now negligible. Unfortunately, when I went to make the final pass with the drill press, I had adjusted the height of the bed but mistakenly forgot to lock the bed in place. So when I started to make the final minute pass the end mill grabbed the wood and really screwed the whole piece up.
It messed up the whole interior of the piece which made the fitment of the grip loose on the lower receiver.
But the worst part about it was it took a small chunk of wood out of the right side, DIRECTLY where I would need to drill out for the safety selector spring. That was the damage which required me to . . . start completely over.
I used the original to cut the rough dimensions with the chop saw.
I again measured and sketched out the needed dimensions, using the magpul grip as a template.
I then went about milling out the center of the grip and this time I decided I could achieve a better fit in the end if hand sanded the forward edge.
After having redone everything, the wood grip V2 was looking really good and was now ready to have some holes drilled.
Using the Magpul grip as a template, I observed the safety selector spring/detent hole sat very very close to the inner edge of the grip. I was concerned about drilling this hole because I was worried about the prospect of blowing through the edge of the wood. 
I decided to use the scrap grip piece as a test subject and drilled a hole close to the edge.
After drilling my test hole, I measured it in comparison to the Magpul grip and although I was close to the edge, I was not close enough. 
I continued to use the scraped grip and drilled three additional test holes.
I was pleased to see the walnut tolerated the drill bit very well. Even the closest hole had no blow through or issues. Having built my confidence on the scrap piece, I was ready for the nail biting part; drilling the new/final grip. After doing a lot of brainstorming on how to find the exact point where I needed to drill I came up with a method which worked really well.
I found a small nail which had the right diameter and used a pair of linemans pliers to cut it to the proper length, and then used my bench grinder to knock down the sharp part. 
I then inserted the nail with the pointed side of the nail facing upward so the tip was protruding slightly above the surface of the lower.
I then pushed the grip into place and onto the nail point. After I removed the grip, it left a perfect little pin prick where I needed to drill. I double checked with the micrometer and the mark was spot on!
Using my mark, I drilled the safety selector detent spring. I used some masking tape to measure/mark off the proper depth.
I purchased a CMMG lower parts kit, and removed the safety selector spring and detent and tested everything out.
I just held everything together and used a flathead screwdriver to make sure the detent was under proper spring pressure, and it was! Next up was to drill out the hole for the grip screw.
I learned the 7/32 roll pin punch fit perfectly in the lower receiver grip threads with zero play which gave me a way to pinpoint the exact location of where I needed to drill the grip screw hole.
After walking the punch with a small hammer it left a perfect indentation where I needed to drill. A 1/4" drill bit was the perfect diameter needed for the grip screw. I got lucky and had an extra long 1/4" drill bit which was needed to go all the way through the grip. 
After getting the grip leveled, I used the cross vise to get the drill bit perfectly positioned and drilled the hole all the way through the grip.
I initially bought a Sons of Liberty Gun Works grip screw but after discussing it with my Dad, we both reasoned it would be better to use a much longer grip screw as the more wood left in-between the head of the screw and the lower receiver. 
I bought this stainless steel 1/4"x28x3" screw and it was perfect.
I used the head of the screw to draw some lines where I was going to mill it out.
I then threaded the bolt into the lower receiver and held it up to the grip to help determine the depth I needed to cut in to the grip for the head of the bolt.
I decided to use the endmill to cut out a square hole in the bottom of the gip. The square/blunt face of the bit would make for a flat surface for the grip bolt to mate up to.
Do determine the proper angle for the end mill bit, I inserted the 1/4" drill bit back into the bottom of the grip and then secured the bit into the chuck of the drill press. I then raised the bed until I was able to secure the grip into the cross vice. I then lowered the bed down and removed the 1/4" bit, leaving the grip at the perfect angle.
I then used the cross vice and end mill bit to carve out a square hole to the exact needed depth.
The square hole turned out absolutely perfect and looks very clean.
The hole and new grip screw mounted up to the BRN-180 lower receiver perfectly.
Well it took me two attempts, but I am thrilled with the progress I made on the custom grip. All of the scary/precise holes and angles have now been cut and drilled. Next up, carving this to shape!
If you want one of these awesome Brownells BRN-180 lower receivers, click the following link and hook yourself up!
If you want to watch a video version of this blog post, head over to my YouTube channel at the following link:
Remember, Faith Kills Fear!
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