Gunsmithing Blueprinting highlights.

[LRI]

Been awhile since I posted so what the hell. Folks get a kick out of watching actions being chewed on right?

Step one: tear down.

Pulling the old barrel off. Nothing too exciting. Just clamp the snot out of it and grunt that bugger off the receiver. Then strip the action to its base component, the receiver.

Setup. Here we clock the receiver, set the initial work height offset, and eventually indicate the action to the spindle bore axis.



clocking/height offset: The screw and gauge block just puts the action at the approximate height. Typically within .02" This is a very "flexible" location as the machine can easily adapt to wherever Remington felt like drilling a hole that day.

Having the screw against the jaw puts the action "pretty close" to the raceway being parallel to the "X" axis of the machine. We'll tune that up a bit here in a moment.

As the indicator shows "pretty close" isn't near close enough. Were out about .02" across the length of the setup gauge I made. Basically this thing is nothing more than two mill vise parallels soldered together at a right angle. I attached a magazine box spring with solder to apply pressure to ensure the vertical piece lays up against the receiver raceway. The objective here is to have the action clocked for positioning of the recoil lug and for customers running multiple action/barrel combinations. I've been able to ensure repeatability from barrel swap to barrel swap by having the thread clocking position (start position) in the same spot on the receiver.

Now were parallel to the X axis and the real fun can start; getting the receiver "straight up" with the spindle.

Mandrels. Lots of mandrels. . . These are hardened/ground units I made. they are in .001 increments as Remmy's tend to vary a bit due to wear and general manufacturing tolerances. It's pretty simple. Find one that just fits and call it good.

From here we can begin to adjust the fixture to manipulate the alignment. The four jack screws have large pads fitted into the base plate. The pads elevate the table and adjust to center the action. Just picture a 4 legged bar stool with adjustable feet. Basically the same principle.

 

[LRI]

Re: Blueprinting highlights.

We check the orientation in the X and Y axis until the indicator can move up/down with no movement on the bezel. Takes practice but after awhile you can do this pretty quickly.
The advantage here is the mandrel sticks out of the receiver pretty far. This distance greatly amplifies any deviation. When you get it right the accuracy is really, really good. It depends greatly on the accuracy of the mandrel so a lot of time and care was devoted when making these.

Once were "straight up" I move onto finding center. I do this last because jacking the base plate around moves the center location quite a bit. Only when the action is square should we find the center. An indicator swept across the OD makes pretty quick work of this. Just do each direction individually and keep splitting the indicated difference until the needle doesn't move as you sweep 360* around the mandrel.

Now we finalize the work height. Remington actions are set with a nominal distance of 1.150" from the receiver ring to the lug abutments. I preserve this distance so that tennons are consistent. I remove .005" from the lug abutment and work "up" towards the receiver ring in terms of how everything is qualified. This ensures minimal material removal and avoids detrimental cascading affects on primary extraction. The tool inserted in the receiver threads down till the bottom contacts the lug abutments. The tool is exactly 1.700" in height. I then run the tool to the gauge and touch off using a piece of .001" thick steel shim stock. If the machine displays 1.703" I know the receiver is sitting .002" higher than the previous one. (have to subtract the thickness of the shim stock) We then adjust the Z axis work offset by .002" (you always go in the same direction of the number. If for instance it was 1.697" I'd of adjusted by -.002")

Now I can start the program with total confidence that it'll run correctly. The only real variable here is the dimensional changes from the machine warming up. When a mill sits overnight the weight of the table will squeeze out the thin layer of oil on the ways. The spindle gets cold and shrinks a bit too. I resolve this with an environmentally controlled shop (to include the floor with radiant heat for winter time) and with a thorough warm up cycle first thing in the morning.

Ok, onto machining. In a moment I'll post a vid clip of the 1st operation:

 

[LRI]

Re: Blueprinting highlights.

Step one of machining is cleaning up the receiver ring. Just a quick skim pass over the surface in a clockwise rotation. I do this because the tool also rotates clockwise. Doing it this way avoids a nasty burr on the outside of the receiver. The burr on the inside is machined away later during chamfering of the ring's ID.

Now were boring the minor hole dimension in preparation for threading. The final op at the base of the lug abutments is also machined with this tool. One tool used for three critical operations greatly mitigates any tolerance stacking. In a lathe for instance it's common to use a facing tool to cut the receiver followed by a boring bar to cut the ID and lug abutments. Not a bad practice by any means. This is just about skinning the kitty with one knife instead of two.

Now were threading! The trick here is how does a guy time the tool to the existing thread? Its pretty simple actually. Remington doesn't care where the start/stop position of its thread is. There's no reason to as it has no bearing on anything. So the challenge becomes setting the tool properly so that it picks up the existing thread and continues it. With a lathe its a matter of running the machine till the ID threading tool is in the bore. Then stop and adjust the tool position with the carriage till it falls into the root of the thread. Essentially were doing the same thing. Only we do it a bit differently and (hopefully) more accurately because the tool can't really be out of position the way an ID threading tool can be. (meaning the tip of the tool is exactly square to the bore and not cockeyed. This can easily be done with a lathe since the tool post can be rotated to any position wheres a mill can't)

Basically I just picked a position in the threading cycle where the Y axis is at the zero position. The tool runs to this Z height and stops. I then hand jog the tool in the X axis and monkey with the Z until the tip of the tool falls into the crest of the thread. Note the difference in Z height position and adjust the TOOL LENGTH offset instead of the WORK HEIGHT offset. Tool lenght is indiviual to each tool used. Work Height adjusts EVERY tool used in the program.

It's now sit back and let her rip time.

Here is a vid clip showing the highlights of everything.



This is a good opportunity to illustrate something. Its often a heated topic of debate on exactly how necessary this practice is. Are the actions "really that bad" and will it improve the way the rifle shoots?

Look at the photos carefully. If you notice the endmill only cleaned up a portion of the receiver ring and only one lug abutment. This action was out quite a bit. Exactly how much I'm not sure as I didn't take the time to measure it, but the tools don't lie. I'll shift the Z offset slightly and run the part over to clean everything up. The point is the actions are mass produced and there are variances.

I often reduce this to a drag racing analogy. If we go pro stock we need around 1350hp to be competitive. The guy who stays up all night tinkering might find an extra 25hp by massaging and fiddling with parts. That 25hp isn't much for the amount of effort invested, but when your up against others with the same engine displacement, total weight, and skill it means your going to beat him so long as you cut a good light and have the tune correct. In a situation like this those 25 little extra ponies means a great deal.

Blueprinting falls into the same category. It takes a great barrel fitted by someone who understands accurate gunmaking to get to the intial 1350hp. The remaining 25 are divided between action tuning, bedding, ammunition, trigger, scopes, etc.

So it largely boils down to level of commitment. If you take shooting serious and want to KNOW beyond a doubt when you make a mistake (off call) then blueprinting should be a part of your build specification as its one less thing to second guess yourself about. If you just want a minute of pie plate rifle then your money may be better spent elsewhere. It may very well be a minute of angle gun, but every once in awhile your going to have a kicker that pokes a hole in left field for no apparent reason. The blueprinting along with everything else will make most of that go away. That's what the extra 25hp gets you.


Thanks fer lookin.

 

[223ai]

Re: Blueprinting highlights.

Chad,

I love seeing these threads, it's very interesting to read through. Please keep it up.

Sent you an email earlier today...

Best,
JP

 

[LRI]

Re: Blueprinting highlights.

Before:

After:

 

[Kitsap]

Re: Blueprinting highlights.

Chad,

You are just plain twisted....

And you have become very good with both the still camera and the video.

Thank you for taking the time to document and share.

 

[jbell]

Re: Blueprinting highlights.

Chad, as always great post. I really liked the video, it and the pics are as attention to detail as your gun puttin together. Thank you for sharing with us.

 

[northern50]

Re: Blueprinting highlights.

Very nice, love these posts. And I liked the Days of Thunder intro to your movie. That's some fine editing to boot!

 

[McLarenross]

Re: Blueprinting highlights.

Ill tell you what. Ive been watching your posts now for as long as Ive been visiting this site and I can say without a doubt I will be sending you my rifle to get its new tube when the time comes. You really have a whole nother level of understanding of both machining and gunsmithing and your work defiantly benefits from it.

 

[Clark]

Re: Blueprinting highlights.

Ever wonder why Remington put glue on the barrel threads?
Were they getting galling?

 

[03psd]

Re: Blueprinting highlights.

I dont even understand half of the technical stuff you did, but i do know it makes sense and can do nothing but improve accuracy. great video and still. I cant help but peer over at my 3 factory 700s and think of them as dirty un-sat factory misfits in definite need of a thorough tightening up!

 

[CS223]

Re: Blueprinting highlights.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">

Basically I just picked a position in the threading cycle where the Y axis is at the zero position. The tool runs to this Z height and stops. I then hand jog the tool in the X axis and monkey with the Z until the tip of the tool falls into the crest of the thread. Note the difference in Z height position and adjust the TOOL LENGTH offset instead of the WORK HEIGHT offset. Tool lenght is indiviual to each tool used. Work Height adjusts EVERY tool used in the program.
</div></div>

Chad, technical question. If I understand you correctly (semantics) You're eyeballing the threadmill to the crest of the thread. (It would be difficult to eyeball it to the root.) The crest is typically P/4 in the case of the Rem. thread, the crest should be about .016" wide. That's a lot of wiggle room, esp. on a machine that jogs in tenth increments. I haven't done the math so opening up the thread to 1.085" as you do might allow the thread to clean up within the amount of 'eyeball' tolerance.

Have you considered or tried making a close tolerance plug, something akin to what you use to qualify the lug abutments, perhaps with a 1/2 cross section and then threading it into the receiver with the flat oriented in X. Then move the threading tool engagement in -X at Y=0, jockey Z until the threading tool meets in the root of the plug thread. Being that you're looking at the cutting face of the threading tool and the flat face of the plug cross section (tool on the RH side of the plug), you could, with a little back light, see pretty much dead nuts thread engagement, and there's added benefit the root being P/8. You'd have to add .5P plus the Z correction to your H offset if my reasoning is correct.

Would making the process this elaborate amount to picking fly poop out of pepper given the rest of the process?

 

[LRI]

Re: Blueprinting highlights.

I align the tool to the root of the thread. So long as my eyeballs keep werkin ok it does a killer job. LED flashlights and a magnifying glass is a powerful tool!


I did fuss with a "thread mill setup jig" awhile back. Basically I took the same plug to qualify off of the lugs and put a witness mark on it to show clock position. Problem was the math and trusting it. By eyeballin I know exactly where that tool is. With the jig "it should be right" is what my gut often said. I pussed out and went back to the visual way because I don't want to have to call a cst and explain that I ruined his action. A healthy human eyeball can pick up about a .002" deviation. The 1.085 thread is big enough so that a little error gets washed away when machining so its been werkin ok.
Great question.

 

[Bryan27]

Re: Blueprinting highlights.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CS223</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">

Basically I just picked a position in the threading cycle where the Y axis is at the zero position. The tool runs to this Z height and stops. I then hand jog the tool in the X axis and monkey with the Z until the tip of the tool falls into the crest of the thread. Note the difference in Z height position and adjust the TOOL LENGTH offset instead of the WORK HEIGHT offset. Tool lenght is indiviual to each tool used. Work Height adjusts EVERY tool used in the program.
</div></div>

Chad, technical question. If I understand you correctly (semantics) You're eyeballing the threadmill to the crest of the thread. (It would be difficult to eyeball it to the root.) The crest is typically P/4 in the case of the Rem. thread, the crest should be about .016" wide. That's a lot of wiggle room, esp. on a machine that jogs in tenth increments. I haven't done the math so opening up the thread to 1.085" as you do might allow the thread to clean up within the amount of 'eyeball' tolerance.

Have you considered or tried making a close tolerance plug, something akin to what you use to qualify the lug abutments, perhaps with a 1/2 cross section and then threading it into the receiver with the flat oriented in X. Then move the threading tool engagement in -X at Y=0, jockey Z until the threading tool meets in the root of the plug thread. Being that you're looking at the cutting face of the threading tool and the flat face of the plug cross section (tool on the RH side of the plug), you could, with a little back light, see pretty much dead nuts thread engagement, and there's added benefit the root being P/8. You'd have to add .5P plus the Z correction to your H offset if my reasoning is correct.

Would making the process this elaborate amount to picking fly poop out of pepper given the rest of the process? </div></div>

I wish I had the technical knowledge to know what you just said!

 

[redirt78]

Re: Blueprinting highlights.

Nice to see some of the process that goes into making an accurate rifle.

 

[LRI]

Re: Blueprinting highlights.

Sorry. Reading my original post I see the confusion. When I said "crest" imeant the root of the female thread which would be the crest of the barrel tennon. Just backwards thinkin.

 

[300sniper]

Re: Blueprinting highlights.

great work and thread as always chad!

i still have not sacked up and tried truing a receiver vertically on the cnc. i think i may internal thread a couple tubes on the lathe and use them for program testing, practice picking up an existing thread, and confidence building before i risk destroying a receiver.

 

[CS223]

Re: Blueprinting highlights.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body">great work and thread as always chad!

i still have not sacked up and tried truing a receiver vertically on the cnc. i think i may internal thread a couple tubes on the lathe and use them for program testing, practice picking up an existing thread, and confidence building before i risk destroying a receiver. </div></div>

Just hold a piece of Delrin in the vise with a v-block, thread mill it to the 1" spec. Loosen it, rotate it and then try to pick up the thread. That way, if you're off, you don't risk trashing an expensive thread mill. (Even if you're using an insert style like Chads, the inserts aren't cheap). If you're off by just a little bit, you can see your error in the fine cuttings.

Chad: Thanks for the clarification on the crest/root, that's what I meant by 'semantics'.

 

[netranger6]

Re: Blueprinting highlights.

great stuff, thanks for taking the time to post it up.

 

[69icarus]

Re: Blueprinting highlights.

These are incredible to view! For us Jackwagons that "dont know what we dont know" it brings a new perspective to understanding accuracy and what all comes into play. thanks!

 

[Csf45]

Re: Blueprinting highlights.

beautiful!

 

[CS223]

Re: Blueprinting highlights.

Another question for you Chad. I was thinking (I'm bad about that) about your process where you align the receiver raceway parallel to the X axis. In doing so, you are ensuring the pinned lug bottom remains parallel to the raceway. I assume the action will always be bedded to the stock after the machine work. The observation I have, again fly poop from pepper, is that when the action is set in the stock on the pillars & tightened, the action screws are going to align the receiver (rotated axially) in relation to the pillars (ideally with the screws centered in the pillars) which will result in the pinned lug and raceway possibly being canted ever so slightly in relation to the action screw axis. Not an issue with new bedding, not an issue with a factory stock, possibly an issue with an existing bedded stock. Any particular reason not to use the axis of the action screws for reference
for the lug pinning instead of the raceway? What am I missing?

 

[300sniper]

Re: Blueprinting highlights.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CS223</div><div class="ubbcode-body">Another question for you Chad. I was thinking (I'm bad about that) about your process where you align the receiver raceway parallel to the X axis. In doing so, you are ensuring the pinned lug bottom remains parallel to the raceway. I assume the action will always be bedded to the stock after the machine work. The observation I have, again fly poop from pepper, is that when the action is set in the stock on the pillars & tightened, the action screws are going to align the receiver (rotated axially) in relation to the pillars (ideally with the screws centered in the pillars) which will result in the pinned lug and raceway possibly being canted ever so slightly in relation to the action screw axis. Not an issue with new bedding, not an issue with a factory stock, possibly an issue with an existing bedded stock. Any particular reason not to use the axis of the action screws for reference
for the lug pinning instead of the raceway? What am I missing? </div></div>

you think along the same lines as i do. if the raceway is canted slightly, but the action screws are and scope screws are 180* apart (6 o-clock and 12 o-clock) and the lug is aligned to them, i personally don't see the issue. i choose the action screw location as my 6 o-clock.

 

[LRI]

Re: Blueprinting highlights.

You guys don't tape the recoil lug during bedding?

You should be if your not.

I checked this on a variety of actions when I first started doing this. Meaning squareness of the hole to the raceway. While they aren't perfect usually they are very, very close. A threaded hole (especially one with such little thread engagement) is a poor choice to datum off of. The raceways are perty dern good as its a qualifying feature on the receiver.

So far it's not caused any issues with anyone. I've done well over 100 of these now.

Ok, back to taping the lug. Assume its out by say .005" The tape I use is .02" thick. So even if it is out (and for sake of argument we'll assume it is) the only portion of the lug contacting the stock is the backside where recoil is transmitted. The sides and bottom are in space once assembled. .005" still leaves .015" of clearance so no issue.

I doubt seriously the lug on a factory M700 is always perfect when using those awful tools to grab the lug with the guard screw. First your assuming the hole is straight, the screw is a qualified slip fit in the tool, and that the tool itself is perfectly symmetrical/square to the receiver. Nevermind the shear load on the screw as the action is snugged up. As much as I loath the things the proof is in the pudding. Plenty of hard hitting M700's built just this way. That being said I KNOW some of those are out of whack. At least with me its a consistent "out of whack" if it even is.

Make sense?

I think the pinned lug located off the raceway is pretty safe.

Great question!

C.

 

[300sniper]

Re: Blueprinting highlights.

if you were to snug up then torque a receiver into a vee block type chassis, what is the natural bdc going to follow? the receiver screws or the raceway? since my receiver wrench that i made uses a screw to locate half of square to the front receiver screw hole. i set my lug parallel to it.

to be fair, i have never measured how far off the raceway is compared to the receiver screw holes. judging by what you found, in reality, it's probably a moot point.

 

[CS223]

Re: Blueprinting highlights.

Makes sense to me, the question was more theoretical. The lever arm of your parallel raceway jig basically amplifies the error resolution. The amount of cant is much smaller at the lug and within the range of the space afforded by taping the lug. To indicate off the screw, a bushing would have to be made & held by a screw at least as long as half of your parallel (guessing it's a 6" parallel) to get the same resolution.

I am by no means challenging your skill and expertise, just trying to wrap my head around it all. I appreciate all the time you & others take posting and explaining techniques & especially the hows & whys. This information isn't found in any books.

 

[LRI]

Re: Blueprinting highlights.

FWIW Greg Young, Owner of Southern Precision Rifles in Naples FL, has me run a batch of new in the box M700's from Brownells for his inventory.

7 are in process as we speak and should be completed by close of business today.

The half dozen I ran this morning all cleaned up really well so they should make for a great way to start a custom build.

He goes by "Bugholes" here on the Hide.

C.

 

[maccrazy2]

Re: Blueprinting highlights.

Chad. What do you charge to blueprint a 700 action and pin the recoil lug?

 

[brunop]

Re: Blueprinting highlights.

Looking for this, too. Asked in a different thread of yours.

 

[Head-Shot]

Re: Blueprinting highlights.

Chad, I have the same question as maccrazy2. I am doing a Remington 700 build on the new MDT Tac 21 platform and trying to make the rifle rather precise. I will be doing an overall review of the weapon soon. The build (everything but blueprinting) will be done in 2-3 weeks. If the rifle stays within the budget I want to get it blueprinted as well.

 

[LRI]

Re: Blueprinting highlights.

$200 for the labor, $55 for a new lug.

Lugs are pinned to the receiver and are .3125 (5/16) thick.

Get em coming cause right now as we speak I'm running another batch through the mill, then its onto barreling and whatnot.

Much better to run them in batches as it's almost half a day to set up ol girl to run these.

I have the programming/setup for barreling these receivers all turn key as well. $200 for a std contour and $250 for fluted.
Includes, thread, chamber, H/S, crown, spin polish, and CNC engraving the cartridge.

Crown offer options: STD 11* tgt or the 11* recessed hunter style. your choice, no affect on price.

Brakes: $125 for installation. Threaded muzzles for cans: $75.00 and threads are measured to split the tolerance right down the middle of a class 2A thread (what most companies seem to use for muzzle cans)

Hope this helped.

C.

 

[cattle buyer]

Re: Blueprinting highlights.

Thanks for taking the time to post this stuff. Do u do pre 64 mod 70 ? Ive got an 06 that I want to retube into 25-06.

 

[LRI]

Re: Blueprinting highlights.

yesser

CRF Winny Medium Tac Build, 300WM

 

[cattle buyer]

Re: Blueprinting highlights.

great. thanks Im stuck on mod 70's and everyone does not want to work em. I have a post 64 supergrade boss 300 win mag I want turned into .264 mag. folks laugh at the boss but Ive had 3 that were super shooters. went to ur website will be in touch. v best

 

[LRI]

Re: Blueprinting highlights.

Its one of my favorite actions.

Be glad to help.

C.

 

[Head-Shot]

Re: Blueprinting highlights.

Thanks for the information, Chad. I appreciate it. I might have some work for you in the near future. I've got your contact info but it might be a month or two. Keep up the great work.