So how can I verify my own work? Trued a 700

[Shawnba67]

So I finally decided to s*#t or get off the pot and lost my cherry trying a $389 Walmart 700 LA I picked up. I used a Manson .710 raceway reamer on it (also a first for me, I did check it for runout in v blocks and I've never seen a needle not move before! So it's pretty straight)
Set it up in lathe and spent nearly 2hr dialing in(double cats head setup. ). I'm fairly certain it dialed to less than .0002. I only have a .0005 indicator but the needle swing never left the hash mark on the dial face. (we are after the least movement possible more so than a particular number ) theN faced the action and lug abutments. You took nearly .0025 for cleanup. Then the threads got chased to .010 over they took .008 for a full cleanup i realize that I could have affected any of these run outs with a off center raceway bore job but at least now the ducks are in the same row!
SO THE REAL QUESTION how can I verify I did a good job? Just for my own growth and learning??? Thanks much for any help. Shawn

 

[Ggmac]

The only way I know of , have someone else verify ! Usually it was the instructor or other employee.
You could remove it and start all over again and if you come up with the same # s then you did good !

 

[WSnyder]

Turn a test tenon on a piece of stock using your trued action to fit the threads like you would when fitting a barrel. While the test tenon is still in the chuck thread the action on it. Insert the raceway reamer into the action and use an indicator on the reamer behind the action tang. The run-out will show you how well you did.

 

[DaveTooley]

Just to add something else to the learning process. Start with a very close fitting thread fit for the first test. Leave your setup and don't disengage any gears. Run the action up hand tight, check the run out, reduce the pitch diameter enough so that there is some play in the thread fit. In fact make it on the loose side. Check the run out again.

 

[Alex Wheeler]

You also need to check lug contact with a stripped bolt. After you true the bolt of course. You can either use layout blue on the back of the lugs and make sure it wipe both lugs clean. Or you can center up a stripped bolt in the reciever, push it up towards the top of the action with pressure on the bolt face. You are looking for the bolt to center itself in the rear bridge. Thats how I check mine. If you put pressure on the bolt face and the bolt wants to always be in contact with the top or bottom of the action you have an issue.

 

[Shawnba67]

Thanks very much guys. Some good food for thought. I'm
Hoping I'm on the right path, by double checking myself to be sure I'm doing at least the best of my current ability.

 

[jkohler]

I just trued a 700 yesterday. It was a new stainless receiver. I must of won the lottery with it as it was the truest out of the box that I've personally seen which isn't a plethora by any means The front ring was out .0005 threads where out .004 lug abutments I just took a .001 off. Bolt face was right on and the lugs was right on. I did check my work and verified that I didn't make a mess of it.

 

[butchlambert]

I just trued a 700 yesterday. It was a new stainless receiver. I must of won the lottery with it as it was the truest out of the box that I've personally seen which isn't a plethora by any means The front ring was out .0005 threads where out .004 lug abutments I just took a .001 off. Bolt face was right on and the lugs was right on. I did check my work and verified that I didn't make a mess of it.

Most of the newer CNC actions are like that. If the OP will listen to Dave and Alex he will be doing the right thing.

 

[gunsandgunsmithing]

It's a basic understanding in machining that the test fixture must be at least as accurate as the tolerance..and really twice as accurate! So, if you have a lathe that is CAPABLE, and indicate the part in to .0002", AND and you're able to hold that tolerance during machining...KUDOS! You have a good machine and technique...excellent really, and should be able to produce excellent work. Now, to check said work in the same machine, you have .0000 tolerance for any discrepancy between the setup used to machine and the setup to check it. ZERO! So, what if you dialed the work piece in to .0002" and then did it again when checking it...what is the potential run out...not including any machine run out nor tool deflection? I hope you can see my point. The test equipment should be at least twice as accurate as the tolerance.

 

[jkohler]

Most of the newer CNC actions are like that. If the OP will listen to Dave and Alex he will be doing the right thing.

Now if they could only get the bolt handle in the right place.

 

[Rich S]

I'm new at this also. Just trued my second action yesterday. Although not addressing your original question, below is what I did to help ensure a good set up throughout the machining:

• During set up I make sure the reamer/mandrel can freely move in the bolt races. I found it is very easy to to distort the receiver while indicating it in. To indicate mine I used the Manson reamer. I turned it around and put a wrap of tape on the flutes to protect them and prevent the flutes from being in the bolt race.
• After the action was indicated in and reamer/mandrel removed I reach in with an indicator to verify run out on the front bolt raceway just past the lug abutments. A standard indicator reaches this area.
• I true up the front ring 1st. After it is cut check with an indicator and it should be "0" run out.
  
• I cut the lug abutments next
• Then I recheck run out of the front raceway and front ring
• Next I cut the threads
• Before breaking it down, I recheck run out of the front face and bolt race.

Anyone using the lathe while reaming the bolt race with a Manson reamer? I did this with the second action I did. It was a bit of a pain but did give a better surface finish than I got reaming by hand. I basically indicated in the receiver, held the tap handle by hand and used the tail stock as a pusher. I could get through the rear bolt race with this set up. Then had to flip the receiver around. I ran the lathe in reverse and use the tail stock as a stop while puling pressure on the reamer. I ran 35 rpm and used a slow feed.

Rich

 

[Alex Wheeler]

Cant say Im a huge fan of reaming. Up front there is very little raceway left in front of the feed ramp. Its so easy for the reamer to push off the top of the raceway and just cut the bottom. It definitely can be done, just be aware of that.

 

[Shawnba67]

Ok so in the sake of learning I will own up a rookie F up. Couple of months ago I replaced the spindle drive belts on my lathe. I apparently didn't get the bearing preload adjustment locked down well enough. During my checking of this job I found I had .0025 spindle runout. So at this point I don't know whether to scream or cry. So I fix the preload issue verify the machine is holding .0002 or soon a cut. It's old Sheldon lathe I can't see expecting much more than that . Any way cut a new threaded 1.072 "tennon" and screwed the receiver onto it. Stuck the Manson reamer into the receiver from the rear and took a reading 12-7/16" back from the front ring I have .024 runout. So I have no idea what a factory one might be but I'm hoping I haven't made mine worse than the average Walmart 700.
Ive already taken .004(probly was only .003) . Is there enough meat to try it again? Or is it what it is at this point? Any advice is appreciated.

 

[Rich S]

Based on your measurement of 24 mils TIR 12' from the front ring, the centerline is out 12 mils at that location. The front ring should have about 1 mil runout if it is all from the front ring being out of square. The threads being off center could factor in as well. I don't have experience to know what is acceptable. If it were mine I'd indicate it back in and measure runout of the front ring and threads. That will verify how much of a clean up cut is needed.

 

[boltman223]

Based on your measurement of 24 mils TIR 12' from the front ring, the centerline is out 12 mils at that location. The front ring should have about 1 mil runout if it is all from the front ring being out of square. The threads being off center could factor in as well. I don't have experience to know what is acceptable. If it were mine I'd indicate it back in and measure runout of the front ring and threads. That will verify how much of a clean up cut is needed.

24 mills equals 944 thousandths. That's a lot of runout! And 12 feet is a long ways away.

 

[DaveTooley]

Ok so in the sake of learning I will own up a rookie F up. Couple of months ago I replaced the spindle drive belts on my lathe. I apparently didn't get the bearing preload adjustment locked down well enough. During my checking of this job I found I had .0025 spindle runout. So at this point I don't know whether to scream or cry. So I fix the preload issue verify the machine is holding .0002 or soon a cut. It's old Sheldon lathe I can't see expecting much more than that . Any way cut a new threaded 1.072 "tennon" and screwed the receiver onto it. Stuck the Manson reamer into the receiver from the rear and took a reading 12-7/16" back from the front ring I have .024 runout. So I have no idea what a factory one might be but I'm hoping I haven't made mine worse than the average Walmart 700.
Ive already taken .004(probly was only .003) . Is there enough meat to try it again? Or is it what it is at this point? Any advice is appreciated.

Give me a call and we can talk about where you are and how you got there and maybe a path forward.
704-864-7525 shop

 

[Rich S]

24 mills equals 944 thousandths. That's a lot of runout! And 12 feet is a long ways away.

Sorry for the confusion. I've worked with machines and millwrights for the last 25+ years and a 0.001 inch is often called a mil. Typo on the 12' should have been 12". Actual calc is closer to 0.0013". Basic trig or similar to calcs used to calculated shims to correct angular alignment on machinery couplings.

Sounds like he has the right person to talk to. Hope all goes well.
Rich

 

[PWS]

Got laid off this winter so this thread has been timely in that, I too, just spent the last two weeks attempting to improve the accuracy of a stainless Ruger Hawkeye in .223. Got lots of time but not much money or tooling so making do with what's on hand.

First thing I did was turn an indicating mandrel out of an old barrel per Bill Hambly-Clark Jr's book. Then, I took WSnyder and Dave Tooleys' advice above and turned, threaded, and left in the chuck a test tenon, at first as large as I could force the action on, then reduced by .001" in three steps.

1. TIGHT threads - Holy Smokes!!! While threading the receiver on the stub, it "coned" around the spindle axis approximately .060". I did twist the mandrel within the bolt race and it indicated .0015 runout so although the mandrel isn't very precise, it's not the source of that much error. Runout did not change as receiver was drawn up to the test tenon shoulder hand tight.

2. Threads -0.002" diameter - not much better! Same .060" cone while turning onto the threads but this time runout dropped to .035" when receiver was torqued up hand tight to shoulder.

3. Threads at -0.004"dia. Same .060" cone but .030" when torqued.

4. Threads at -0.006"dia. Same as #3.

So I did some simple trig ratios (similar to what IhuntIL is doing) and given a thread length of .700" and point of indication on mandrel of 10" beyond, the factory threads appear to run out +/-.0021 over the .700" length. (x/.7tenon length=.030runout/10")

Since runout was more than halved with the looser threads, I'm guessing that the action went from indexing on the threads to indexing on the face. Since runout never went less than .030", more "ratio-nating" leads me to believe the receiver face is at least .0008" off square. (0.55"half diameter of receiver ring/x=.015runout/10").

 

[PWS]

So the above test didn't take two weeks but the trials and tribulations in attempting to improve the receiver alignment did.

Spent a few days installing sleeves to take up bolt slop (per Hambly-Clark's and Jim Boatright's information) and made a bushing and lap to lap the bolt face.

Spent two days building an action jig from a 3" dia x 1/4" wall DOM tubing threaded into a spare back plate. First stubbed toe was locking the mandrel into the receiver by distorting it with the jack screws. Once that was taken into account, another day was used up dialing in the action, taking it out, retrying, etc. Finally figured out that holding the outside end of the mandrel on the appropriately positioned tail stock center allowed me to rough in the action with the jack screw ring by the headstock and thus pre-centering the other screw ring.

Spent about a week to figure out my little late model 8X18 SouthBend bench lathe isn't accurate enough to get anywhere near .0002" runout, let alone .001", at the end of the mandrel sticking out from the jig, nor heavy or rigid enough to do this work. I thought I had the mandrel running within the .0007" typical of my lathe and went ahead and touched up the lug seats, threads, and face. The two attempts with the jig on two more test tenons show a net improvement of about 15% less runout ("about" because my indicators don't show consistent and repeatable runout). So....

I turned a mandrel between centers and left it setup on the lathe on which to mount the receiver with bosses at the bridge and lug seats and a .450" diameter x 6" length from within the receiver ring to the tail stock. This allowed me just enough space to get my toolpost and a HSS tool bit slender enough to touch up the threads along the narrow section of the mandrel. One (of the few) advantages of the small lathe is being able to hand crank the spindle and keep an eye on work at the other end of the bed so none of the chasing was done under power. (And yes, I did snap one tool...)

Spent the last few days on this and finally saw significant reduction in runout such that the receiver now cones approximately 0.020"TIR as it is being spun on the threads and the indicating mandrel shows .002" of runout when the receiver is hand torqued up to the face. This is with threads that are very slightly loose (.0005"dia?) leading me to believe that the threads now run out +/- .0007 and the receiver face is as close to perpendicular as the system allows. (x runout/.7"tenon = .01"/10"mandrel).

In case anybody is wondering, the last test tenon and barrel fit at 1.010" major diameter so I wasn't hogging too much material from the receiver.

As a side note, I don't know that a stainless Ruger is the best action to use for a first attempt. The front action screw hole is drilled through the threads and I'm also convinced that the receiver has hard spots in it. It took three hours of hand cranking to clean up most of the hillbilly dykem (sharpie ink dabbed on with a Q-tip) and I had to resharpen my tool twice. Three specks of porosity also showed up in the cleanup cut I took off the receiver face.

I cut the tenon off the barrel and set it back and got everything put back together this afternoon. Hopefully I'll get to the range Friday to see if this makes a difference. The rifle averaged right at or just over 1moa for five - five shot groups at 100 for the 1500 rounds it's seen.

Anyway, a general thanks to all for the inspiration and information!

Mike in Kodiak

 

[GenePoole]

As a side note, I don't know that a stainless Ruger is the best action to use for a first attempt. The front action screw hole is drilled through the threads and I'm also convinced that the receiver has hard spots in it. It took three hours of hand cranking to clean up most of the hillbilly dykem (sharpie ink dabbed on with a Q-tip) and I had to resharpen my tool twice. Three specks of porosity also showed up in the cleanup cut I took off the receiver face.

If I'm not mistaken, the Ruger Hawkeye actions are investment cast. This would be consistent with your observations of porosity and hard spots.