Machining a Model 10 Aluminum Stock from Scratch

[holescreek]

I have been working on this project for a couple of weeks now posting in a build thread on a private builders forum. It occurred to me that since the victim is a Model 10 there's no better place to share the progress than here! Oh, I have a small CNC that I could use but the plan was to build this stock using only manual machinery because that's what most of the builders on the other board have access to.

Some back story:
I bought the .308 Model 10FCP-K early in 2008 thinking it was going to arrive with a McMillan stock as was pictured in the sale ad. Instead I got an "accustock" that was pretty pliable. I took the rifle out a couple of times and was disappointed with the accuracy results. In hindsight, 99.9% of the problem was me being ticked off about the stock switch and feeding the rifle nothing but mil surplus ammo. Fast forward 8 years and I bought my next new rifle, a Model 12FV which impressed me so much I pushed all other guns aside for a few months. There's a thread on it's stock here: http://www.savageshooters.com/showth...my-Model-12-FV

Since the model 12 got me reloading again I pulled the Model 10 out of the safe to give it a chance to redeem itself. I still have a long way to go to get it to shoot as well as the Model 12, my best groups are still .8~1" but aren't very repeatable.

Viewers invariably ask "how long does it take to make an aluminum stock?" and my answer is "I don't know" because I work on projects in my home shop and invariably get drawn from one thing to another, especially when people drop by. This time I decided I'd keep a daily log to track the hours. This worked in earnest for a few days before I started forgetting to write it down, then I started guessing on how long an operation took. Since I don't work off of a complete set of plans I tend to make changes on the fly then try to remember to update the drawing to match what I did. Yeah, right!

Anyway, on to the project.

As usual, my order of operations is to do the least amount of work on the part to allow me to get to an operation where the risk of scrapping the part is high. If There's a chance of trashing the part I want to get it over with before I have a lot of time invested. The next consideration is to choose setups in the best sequence to as to not machine a surface away that I will need to clamp on with a vise jaw later on.

I started out with an oversized block of 6061 aluminum and cut the length to a bit over 14". Rather than mill the extra length and width material away I chose to bandsaw it off so I could use the waste material to make other stuff with. The trade off is time and since I'm not getting paid it doesn't amount to much. I believe the bandsaw cut about .2"/minute. I stood my horizontal/vertical bandsaw up and used an accessory table. Adding a board over the still horizontal vise gave me a seat to sit down on for the long sessions. This would've been much faster if I'd bought a coarse raker blade for the bandsaw instead of using a worn out 12TPI blade.



After each saw cut was made I to put the block on the mill to square that side up.

After machining the sides and length I clamped it in the vise to cut the receiver channel straight across the top. The savage is just a round action so it's a simple fit. I use a 1" ball end mill to cut the channel.



Next step is to drill and ream .250" holes where the action screws will be (4.4" spacing on the short action Savage), these will be used for datum reference holes for all succeeding operations.

[holescreek]

After the datum holes I drilled the corner holes for the mag well with a long 7/32" drill bit then moved inward and plunged an extra long 3/8" carbide 2-flute endmill in to blend points in the corners.



Then used a long .75" 3 flute endmill to take out the material in the middle of the mag well.



Then I changed the setup to mount the receiver over parallels on my rotary table that has a 16" diameter sub plate mounted on it. so I could use the same 3/4" endmill to rough the side wall angles in. I believe this mag had 12d 18' angled sides.



Then finished them off with a long 3/8" 4 flute endmill.



Neither endmill would quite reach all the way through the block, I expected to have to flip the part on the rotary table to finish the cuts all the way through but was able to use a hand file to finish them off.

While I had the part clamped to the rotary table I went ahead and cut the FCG pocket since there are two angles in it that would require the rotab anyway. Since this was done over several days I made sure to recheck my zero location at the start of each day and anytime the rotary table was moved.



Here you can see the two angles where the receiver starts tapering down to the safety on the receiver.

[holescreek]

While I was at it I roughed the slot for the trigger in.





I forgot to machine a chamfer on the first step behind the rear action screw in the FCG cutout, it's needed to clear the accutrigger bar. I'll get that done in the vise.

[holescreek]

I got enough done to get the action sitting in the receiver. I cut the slot for the recoil lug and chamfered the FCG step to clear the accutrigger sear before cutting the finger hole for the trigger.

I used the tapered edge of a long #3 centerdrill for the FCG chamfer, they aren't just for spotting holes you know. :-)



After drilling two holes through with a 3/8" drill bit I used a 1" drill bit for one end (hole) of the trigger guard and plunged a 1" endmill through the other one. The holes were too close together to use the 1" drill bit on both of them. After drilling to 1" I used a boring bar to open both holes to 1 1/8".



The action fits very tightly in the block (without screws), I can pick the receiver up and it takes the block with it. No bedding necessary on this stock!

[holescreek]

If I remember correctly I was up to 12.5 hours in the shop to get to this point. Problem is it's hard to say how much of that time was actually machining and how much was drawing/getting dimensions off the computer.

Next I started on one side of the trigger guard/grip cuts. I started by boring a 1.5" hole for hand clearance behind the pistol grip.



Then milled the steps for the guard and grip thicknesses:



Next I switched to a 1/2" EM and cut the step for the AR pistol grip then flipped the block over and duplicated the steps on the other side so that I ended up with a 3/8" wide section for the AR grip, 5/8" wide area for the grip surround and 1/2" wide trigger guard.



Then I cut off much of the excess on the band saw so I could finish up the grip section later.

[holescreek]

The next two photos are out of order. After I cut off the excess I set it up in the vise and cut the edges of the AR grip mount to size. I put the block on a 30 degree angle block in the vise to cut the grip relief.



Then I place an AR grip over the mount and use a transfer punch to locate the screw hole. You can see the punch mark in the photo above.



With the block still sitting 30 degrees from the table I use an edge finder to center up my Y axis on the mount then use a wiggler to pick up the center punch mark from the transfer punch to set my X axis. Then it's just a simple drill and tap for the screw hole.



At this point I still need to decide what the final shape/contour in front of the magazine is going to be. Until then I won't know what I will be able to clamp on to cut the angled sides above the pistol grip.

[holescreek]

I put some layout dye inside the channel at the rear then set the action in place and traced around it just for visual reference while I was milling away to my print dimensions. At my age I need all the visual references I can get. I milled the top of the rear stub down to size then set the stock up at 13 degrees and milled the taper on top of the block to match the receiver. Afterwards I cleaned the chips away and set the receiver back into the stock to see how well it matched up.



Next I plunge cut (actually chopped) the blend radii on each side of the stock behind the grip where the stub will blend to a taper on the sides of the stock. I chopped the radii in instead of milling with the side of the cutter in order to eliminate the chatter from cutter vibration. Most of the radius will be machined away later on but chatter is a ***** to get smoothed out by hand.



Once the radii were complete I side milled the stub width to size, which in my case it 1.33" wide.



Then I flipped the receiver over and cut the underside to thickness (1.13") and finished the length.

[holescreek]

This rifle will have a folding stock using a hinge I made in a different build thread.

[holescreek]

Next I did the end work and set my 12" angle plate and trammed it parallel to the Y axis. I used a pair of cant-twist clamps to hold the stock and and edge finder to pick up my location.





I machined both ends, the stub end got drilled and tapped for the hinge and the fore end got a couple of holes for the extension rods I've been using. I thought about doing something different with the fore end on this one but after a couple of days gave up and used what has been working well for me the way I shoot.

[holescreek]

Then set up to cut the bolt handle relief:

[holescreek]

I set the action in the receiver to try to figure out what I want the final shape to be.



Then set it up to start removing material below the mag well and expose the trigger guard and machined the cutout for the mag catch. As mentioned before, I really need to be careful to not remove critical stock too soon. I have a catch-22 going on where I'd like to fit a mag catch but can't do that until I remove material (at an angle) to clear the mag but I need that material to clamp on for finishing operations.

Side view:

[holescreek]

I need to remove a bunch of material off the sides to slim the receiver down and remove weight. While I still have material to clamp on I cut the 9 degree wrist transitions on each side, then finished the overall widths.





My plan called for a 3" radius in front of the mag well and I didn't want to have to bore it all out. My DRO has a few canned features I rarely use but tonight was an exception. It has a radius feature that lets me choose between internal and external radii, input the radius size, cutter diameter, and how much of a step over I want and it computes the positions in X&Y I need to move to to plunge cut the radius so in a mere 55+ position moves I was able to rough in the 3" radius before going back and finishing it with a boring bar.

[holescreek]

Side work is done, I removed as much excess material as was practical and got to try something new.



The "new" thing was to mount an 1/8" radius cutter in a boring head to put a radius on a 1" mill cut. It worked better at a very low speed, in fact it was just as easy to rotate the spindle by hand with the adjustment wrench while feeding it out.

[holescreek]

Got the mag angle cut and was able to check mag function. I had to push the mag up an additional .13" to get the height I needed but after that it functioned flawlessly.





Oh yeah, I have 25 hours in the receiver up to this point.

[hafejd30]

Looks awesome!!!!!!

[jpx2rk]

Wow, nice looking results.

[holescreek]

Thanks!

I got the mag catch made yesterday and the palm rest target grip fitted today. My model 10 currently has a bottom bolt release and I need to change it to a top release for this receiver. I bought a top release sear from Brownells for around $12 but will need to modify it to fit. I'd rather not mill a clearance cut on the side of my receiver but if it came down to it, I could, but then I'd need to refinish the receiver. I believe I read where someone just bent the lever portion out a bit to clear the receiver and it worked fine.

That's where I'm at on this project at the moment, I'll update the thread as the project lumbers along.

[holescreek]

After getting it together with the receiver I didn't like the feel of where my index finger laid along the receiver to reach the trigger so I spent a couple of hours very delicately chopping aluminum to raise the internal opening of the trigger guard 1/8". Of course that also moves all the blend radii too. Since I already cut the taper along the bottom of the receiver to clear the mag well all I had left to clamp on was the exposed 1/8" ledge on each side of the receiver.

[holescreek]

Got the bottom release sear changed out yesterday, unbelievably easy!

Old sear:



New sear:



It works fine but the lever sticks up alot further than my other rifle with an original top release. I suspect that it's because this sear is generic for several models. If it bothers me after some time goes by I'll make some changes to drop the exposed lever a bit lower.

[handirifle]

I think it looks like a piece of junk and you should recycle it. I will PM you my address, since I know where a good recycle yard is. Keep churning out recyclable metals.

[holescreek]

Just adding pics of parts made throughout the last week. I have around 3 hours in the cheek rest adapter and maybe an hour in the threaded tubing insert and plug. I always make a removable plug for the end of the tube in case I want to add weight to the tubing later on.



I got the tube silver soldered onto the folding stock adapter and the end plug and then made an adjustable cheek rest.



I'm going to try something different with the butt attachment just to stick to my no CNC rule. My current plan is to drop another piece of buffer tube about 3" below the top tube and have the butt plate attach to it. Right now my hangup is figuring out how to lock it down so it's still adjustable for LOP. It's down to either using multiple set screws or a pair of cross pins with ball detents that I can pop out to slide the butt plate front to rear independent of the cheek piece. The only reason for dropping the tube down so far is to provide a surface for the rear bag to hold up. I may take some experimenting to come up with the right solution.

[handirifle]

You're a lot like me, in that you like to do a lot of things yourself. The difference, is mine usually LOOK home made! I cannot imagine a CNC turning out anything that could look any better. Nice work.

[holescreek]

Getting closer:



I assembled everything to get a good look at what might be needed. I've still got a couple small parts to make before I start on the finish :

[holescreek]

I got the last of the parts done then put it all back together for a test shoot, hopefully soon.







As usual, slapping color onto it is the hardest decision of all. Gotta see what color of paint I have left in the garage.

[Tim300wsm]

That is one he'll of a project you got there. I would be proud to say I built this if I were you. What is the overall weight of the the rifle?