First time posting, but I wanted to share my progress so far on my M16A1 603 retro build.

I started with a Tactical Machining 80% A2 lower in the white and CNC'd the buffer tube and pivot pin areas as best I could to match a 603 lower.  Hopefully the links work to the photo's showing the left and right side views of the lower after abrasive blasting.  My CNC mill spindle is limited to 1750 rpm so the 3D profiling took 90 minutes per side with pretty small step over to minimize sanding and blend out the machining marks.  I used a 1/8" ball nose end mill to perform the roughing followed by a 1/16" end mill with small step over to finish up the milling.

This should be the right side view:


This should be the left side view:


My plans are to engrave the left side with the proper engraving for a 603.  Please provide feedback on the "green" text as that is what will be engraved.  The serial number is not what I plan to engrave, as I plan to use a unique number and letter combination.  I have noticed that the serial numbers are not typically in a straight line, but are offset vertically but still properly spaced from each other, so I plan to replicate that.  The engraving as it stands looks like it will take about 60 minutes, again because of the slow spindle speed.

My planned engraving.


I think I've got the colt emblem to engrave pretty well. The photo below shows an early engraving of the emblem and I have made some changes / improvements since the photo was taken.


That's it for now.  Hope to get feedback so I can engrave the lower this weekend.  Followed by painting with Colt gray Duracoat.

Dave

This is all I have to say

Awesome Work!



Is that cambam? I'd love to have your engraving file for my next project

 

Looks great...........with one exception.  I hate to sound like a dick, but since you asked for feedback............on the pony.......back legs......you have the right rear leg "line" coming up the side of the body.....which is incorrect.  The right rear leg "line" should dead end on the horses belly.   The left rear leg will have the line curving up to form the "hip" on the body.
  If my explanation isn't clear I'll import your image and highlight the line/area I am referring to.

Yes, I'm using CamBam and I have no problem sharing the engraving files once I get them completed and verified with a proof engraving.

I asked for feedback, so no problem.  I also spotted the malformed leg on the colt.  Here is link to screen capture of the updated colt emblem engraving.

Awesome can't wait.

I could practice on scrap aluminum or wood for you if it would help.



 

Just noticed I'm missing the top of the globe between the pony's feet.  The images I have been using don't show enough detail in this area for me to determine if the top of the globe is there are not.  Can someone confirm if I need to add in this feature.

This receiver is different than yours, but maybe this will help


Original image found here http://jamesdjulia.com/wp-content/uploads/images/auctions/369/images/lrg/51800x4.jpg
Cropped:







 

Thats a better image than I've got.  I zoomed in on the original and I don't see the top of the globe, so that part looks correct.  I do see I may need to make a change to the pony's rear leg.  It looks like there is some kind of "knee" for lack of a better name on the pony.

Note the lack of the top of the globe and the pony's knee.


What I have CAD'd up now. Note lack of the top of the globe, but the pony's knee is different.  To me, my version looks better to the eye.  Question is should I modify to match the photo?

ddexd, I have to say that you have done some BEAUTIFUL WORK, with both re-profiling the 80% Lower to A1 Spec's, And with your Engraving.  I tip my hat to you.

ALSO Great First Post, and Welcome to the Forum.

You definitely set your starting bar very high.  Now all your future builds must continually increase that mark, because you don't want anyone to think your backsliding...LOL

As I've always said, it's just a little more to go first class.  So I'm trying to match the lower as best I can.  

I built up the CNC mill from a Sieg SX3 small mill from Grizzly tools.  The mill has been a lot of work just to get it to do the engraving you see.  I've forgotten how many times I've taken the mill apart to track down and resolve issues.  Then there has been this huge up hill climb to learn how to do CAD then parametric CAD, CamBam for CAM and now I'm learning Autodesk Fusion 360 which is an integrated package of parametric 3D CAD and CAM.  Eventually I plan to install a high speed 10k to 20k rpm spindle so engraving times can be sped up.

But I'm seeing light at the end of the tunnel.  Just need to get the pony leg figured out, run a test engraving then onto engraving the lower.  I hope to get a test run on the engraving done tonight.  I'll post a photo of the results for comment.

Thanks for everyone for the praise and feedback.  Feedback is greatly appreciated.

Nice!!!

One thing with cambam you may find useful is its ability to profile from an image. So lets say you had a perfect image of the logo and you painted it black and white in photoshop. Cambam could use the grayscale image to get tool paths.



I took the image you posted and got this 3D relief in about 3min. It didn't come out perfect but you get the idea





 

Well it kind of came out ok I guess.  I ran the code a couple times on scrap and it looked good.  But of course when I ran the engraving on the lower it appears some backlash has creeped into my Y-axis.  You can see the text slopes up as you read it left to right.  Bummer, but I can always make another one.



Next is the job of applying Colt gray Duracoat.  I havn't used Duracoat before so that will also be a new learning, probably next weekend.

Here is the test piece, which looks a lot better, but I can see the backlash in the SEMI engraving.

Hey, some rifles made it out of the factory with rollmarks skewed like that. I'd keep it as is and roll on. Gives it some character

Seriously though, this is awesome.

Awesome, can't wait to do my upcoming 607 this way. Are you going to anodize it xm grey? Whose doing the work?

For this one I was just going to spray it with Duracoat Colt Gray.  

I do have everything to do type II anodizing myself, but I don't have the gray dye.

Could you do a wooden lower on your equipment?  That's beautiful work.  

Wood would be no different than aluminum other than the cutting speed would need to be higher.  Think how fast a wood router turns 20,000 rpm.  My setup would be painfully slow to do in wood with my spindle speed limited to 1,750 rpm.  There are cheep, about $100, high speed spindles for sale on ebay and Amazon that I have considered bolting on to my mill to increase engraving performance.  It took an hour to engrave the pony and text on the lower because I was limited to less than 1-inch per minute of feed speed across the part.

My feeds and speeds calculator tells me I can travel incrementally faster speeds with a faster spindle.  These speeds and feeds are specific to the cutter type and the material being cut.  In this case 7075 material and MDF.

rpm          7075 feed "/min           MDF feed "/min
 1,750      0.96                            2.34
10,000      3.42                            13.35
18,000      7.65                            24.03  <-- hit a torque and tool stickout limit for the small tool.  Basically feed it any faster and it will snap off.

So a higher speed spindle pays off in permitting faster feed rates and shorter cycle times on the mill.  Helps when you have to run tests and they take 1-hour and find you need to make an adjustment then run another test for an hour.  Like shampoo, rinse and repeat.

So can I mill wood, the answer is yes but painfully slow and to mill out a lower from a solid block of MDF while possible would take an eternity at 1750 rpm spindle speed.

ddexd, I think it looks great !  Yes, there is a little bunching, but I've seen Colt's that weren't perfect before.

BUT, If your not happy with it, I'm OK with the idea of you sending it to me (for safe keeping, of course). LOL

Really Nice Work you did there.  I can't wait to see your next project.

Well I manage to track down the issue on the mill.  I kind of feel foolish to admit it, but I had the gib screws on the Y-axis too tight.  This was introducing extra backlash as the lead screw loaded up on torque.  So I used my Wheeler's FAT Wrench to set the torque on each of the gib screws and I think we have a winner.  I ran a test on a piece of scrap 6061 aluminum.  I had the cutter set too low so it over engraved the text a little, but the text is in a straight line.  Even put a straight edge on each line and as far as I can tell everything is straight.  Too bad I've already engraved the lower.  Guess I have an excuse to do another one, I'm sure the wife will understand.

Here's a picture of the text.

Great work! I'd leave the lower receiver as is. As mentioned earlier, the text on the originals wasn't perfectly aligned. Where in LA are you? Not many ARFcom people in my area.

86HMMWV: Thanks for the feedback.  I'm located New Orleans.

You know I just realized he was from LA too lol.



 

I was just down there a few weeks ago (brother's wedding). I'm from Northeast LA.

I noticed that both of you guys are.