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Gunsmithing Indicating Rods, Ranging Rods and Grizzly Rods

Wheres-Waldo

Wheres-Waldo

Gunny Sergeant
Full Member
Minuteman
Nov 2, 2008
1,657
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First, Id like to pose the question, what is the difference between and indicating rod and a ranging rod? All the ones Ive used are cal specific, take bushing and are ~6" long....

Secondly, why would I ever need either of the two when I can use a Grizzly? For the purpose of dialing in the bore on a spider chuck, extra length = wider spacing between indicators = more resolution....
Not to mention, on a chambered barrel, 6" of ranging rod might hang out 1". Not nearly enough to indicate on.

Also, does anyone have a vendor that sells all 3 Grizzly Rods other than PTG?
 
And to further complicate your decision, why would you need any of those if you use a long reach test indicator?

Im not sure on specific terms which is which, but the indicator rods PTG sells are tapered with a removable bushing. The range rod I believe is non tapered but still takes the bushing, this one relies on having a well centered tailstock for indicating.

Only thing I use my indicator rods for anymore is clocking the bore curvature when threading the action on. And testing to see which pilot to use on the reamer.
 
The difference between the indicator rod and range rod is simply the angle of the taper and how soon it starts which limits how much of the rod goes into the barrel. I use indicator rods with great success and really can't see what issues people have with them. If your concern of repeat ability is a valid one simply leave the rod in and complete your tenon and shoulder etc. check indication pull rod and finish the counter bore and chamber. No biggie. I get great results doing that. I've double checked everything with dti and gtg.
 
Check, different taper on the two. Which tapers out to max diameter earlier?

Does anyone place much stock in the idea that, with regards to turning in a spider chuck that has both sets of adjusting bolts on the headstock (Look up Gre Tan or Viper Benchrest's spider chucks) the more indicating rod length you have to take TWO readings on... The better?

Im sure if you could put one in the chamber and one in the muzzle while dialing in, length would be a moot point. Our lathes headstock is so large that the muzzle doesn't hang out to take a reading on.
 
I have a viper fixture and use it. I generally chamber through my headstock though. I don't indicate anything on the end I'm not working on. It will do you zero good. Barrels are crooked plain and simple. If you try and indicate both ends at once you will simply be bending and stressing the hell out of the barrel to get it to cooperate. I look at barrel work much like bedding. You want it to be stress free so once you start cutting you're not relieving metal and making it go where it dosent want to go. The length of an indicating rod has been plenty for me to achieve coaxial alignment.
 
steelringer said:
How do you use a long reach on a bore that has lands and grooves?
Click to expand...

Read them - there is about .003 depth to the grooves, I will usually try to read on those since there is more area there, but every now and then I get a barrel with a bit of taper in the groove, or the grooves aren't uniform. I'll then either split the difference, or indicate off the lands ( the original bore diameter, before the grooves were cut ). I have also moved a bit, like 1/4" either way and usually the "funny" readings went away. Here's a short video for you, see it's not hard.




Waldo - take a look at the SSG Tru Bore system - here's a linky, Seems like that might work to retro fit to your big headstock lathe.

Straight Shot Gunsmithing

That's an ingenious solution there. I don't like having to use the rods on it, but you can always check it with the long reach DI.
 
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I use both the range and Grizzly rods.

The grizzly rods are smaller then the bore diameter and great if you want to dial in the last 2" of the bore, like Gritters does in his video.

The range rods (I use GTR) have a gradual taper and center themselves in the bore between the taper and the sized pilot. I like them for dialing in both ends of the barrel and finding top dead center if I am just dialing in the last two inches of the chamber end.

I also have a Brown and Sharpe long reach indicator that I rarely use to indicate. I think its great if you are dialing in a preexisting chamber to reset the shoulder or switch over to an improved cartridge.
 
Wheres-Waldo said:
Also, does anyone have a vendor that sells all 3 Grizzly Rods other than PTG?
Click to expand...

Manson lists them in his catalog. Normally his pilots are secured via an e-clip. This is a superior method to the little screw PTG uses, however, it is a pain in the ass to deal with.

Greg Tannel, GTR tooling, I think sells them as well.
 
MikeeBooshay said:
Read them - there is about .003 depth to the grooves, I will usually try to read on those since there is more area there, but every now and then I get a barrel with a bit of taper in the groove, or the grooves aren't uniform. I'll then either split the difference, or indicate off the lands ( the original bore diameter, before the grooves were cut ). I have also moved a bit, like 1/4" either way and usually the "funny" readings went away. Here's a short video for you, see it's not hard.




Waldo - take a look at the SSG Tru Bore system - here's a linky, Seems like that might work to retro fit to your big headstock lathe.

Straight Shot Gunsmithing

That's an ingenious solution there. I don't like having to use the rods. on it, but you can always check it with the long reach DI.
Click to expand...

How do you make sure that the muzzle end is running true. I know with rods you measure close to the barrel and towards the end of the rod. Ive been toying the idea around about picking up a lathe for some hobby work. So im trying to weigh options etc. I like the SSG true bore setup.
 
steelringer said:
How do you make sure that the muzzle end is running true. I know with rods you measure close to the barrel and towards the end of the rod. Ive been toying the idea around about picking up a lathe for some hobby work. So im trying to weigh options etc. I like the SSG true bore setup.
Click to expand...

If you're doing a chamber, you don't care where the muzzle is and if you're threading a muzzle, you don't care where the breech is. The bullet is going to use that last 2 inches or so before the muzzle to determine its path once it leaves the barrel. The breech could be at 90 degrees to the muzzle (See most recent MythBusters). Conversely, when chambering, you want the bullet to enter the freebore perfectly parallel concentric and you don't need to be at all concerned with where the muzzle is.
 
Gene Poole said:
If you're doing a chamber, you don't care where the muzzle is and if you're threading a muzzle, you don't care where the breech is. The bullet is going to use that last 2 inches or so before the muzzle to determine its path once it leaves the barrel. The breech could be at 90 degrees to the muzzle (See most recent MythBusters). Conversely, when chambering, you want the bullet to enter the freebore perfectly parallel concentric and you don't need to be at all concerned with where the muzzle is.
Click to expand...
Guess thats what im getting at, making sure your concentric when chambering. Guessing the wording i used was incorrect. Where the rod is allows you to make sure its running true not so much caring about the muzzle end.
 
steelringer said:
How do you make sure that the muzzle end is running true. I know with rods you measure close to the barrel and towards the end of the rod. Ive been toying the idea around about picking up a lathe for some hobby work. So im trying to weigh options etc. I like the SSG true bore setup.
Click to expand...

I usually true up the muzzle end also, using the same method, with a spider there, with the breech end "not very tight" in the chuck. After I get the muzzle end as close as I can, then I snug up the breech. The breech is held in a Set-Tru chuck, and I true that next. I finish by rechecking the muzzle. If it moved much, I re-true it, then true the breech again. Using the Set-Tru, it doesn't take long. I do try to get the pointer on the DI close to where the neck is going to end up. If I have any questions about whether it is a good setup or not, I just check a couple places along the chamber, usually it is good.

Last few batches of barrels I have gotten, it has been a real pleasure to slap one in the Set-Tru, snug it up, and see that minimal changes are needed to zero it. Someone is doing a much better job of running OD to bore these days. Sure makes life easier!
 
Oddly enough, Grizzly's site only has rods 2 & 3 that I could find. Already have plenty of bushings. Grizzly's don't taper though? That doesn't sound good
 
Wheres-Waldo said:
Grizzly's don't taper though? That doesn't sound good
Click to expand...

They don't need to taper. I find they work well, very well. I initially setup using one and then double check the lands with my long reach Interapid DTI and it almost never needs any additional fine-tuning. Using a close fitting bushing I find it easier to dial in with it vs. direct reading.
 
Got on the phone with THE VIPER (Great guy by the way) at the shop yesterday and have one of his chucks inbound. Also trying to get a set of Grizzly rods in the shop to play around with.

I appreciate the advice guys
 
Matt, talking to a good friend (gunsmith)about the range rods the other day. He said, and I'm sure you've heard this before, that he could never get the same measurement twice or at least not consistently. I can shoot you his number if you want...
 
I've reinserted my rods after indication many
times and have never had a problem getting repeat. Not really sure what the issue is with others.

waldo, bob is a great guy and will hand you the shirt off his back. Viper fixture is good to go. Use mine constantly.
 
I'm sure 95% of repeatability in indicating will come from rigidity in your set-up and a knats ass fit between your bushing and bore.

Ofcourse if you leave your rod in the bore while you're turning, you remove the variable of error and inconsistency in range rod set-up between indicating before and after.
 
His name is bob pastor. The Viper
ptg carries his fixture as well as other products. I highly
recommend his high sulfur cutting fluid. It's called vipers venom and is really good stuff.
 
Wheres-Waldo said:
I'm sure 95% of repeatability in indicating will come from rigidity in your set-up and a knats ass fit between your bushing and bore.

Ofcourse if you leave your rod in the bore while you're turning, you remove the variable of error and inconsistency in range rod set-up between indicating before and after.
Click to expand...


The think the criticism about repeatability comes from the accuracy of the indicators used and the lathe bearings. All of my .0001" indicators say they are accurate to within .0002". Over 2" of the chamber end you can theoretically be .0004" out. Keep in mind I am not a machinist- they love to argue about this stuff.

Ive dialed in barrels to .0001", indicated top dead center, taken the barrel completely out and repeated it. I noticed top dead center moved slightly indicating that things weren't as repeatable as I had hoped. Could be my lathe, could be my indicators, could be I am the only one who has tried it a bunch... I don't know. (I also have had great results with Shilen barrels so maybe I am weird.)

At this point I will indicate both ends, just the chamber end and mark top dead center, or chamber between centers depending on what I am doing. Sometimes I use a fixed GTR reamer holder, sometimes I use a floating. I've gotten great results from each method. Out of the 20 builds I've done, worst gun I ever built shot .75 MOA with factory ammo and I've made a bunch that shoot .1-.200s with handloads. I think the quality of the barrel matters more, sure you could mess something up, but I really think its up to the barrel maker.

FYI- I only build my own guns, I'm not doing this for a living.
 
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chipsfan said:
Ive dialed in barrels to .0001", indicated top dead center, taken the barrel completely out and repeated it. I noticed top dead center moved slightly indicating that things weren't as repeatable as I had hoped.
Click to expand...

When attempting to make measurements of that precision, it doesn't take more than a few degrees change in temperature to completely foul up any chance of repeatability. That's why claims of such precision are basically fallacy except under the most controlled conditions.

One of the standards for repeatability and reliability (R&R) that I used on a project several years ago involved making a series of measurements (10, if I recall correctly) with a particular setup, calculating the standard deviation of the results, and then multiplying by a constant (5.15, I believe - and yes, that is not the usual 6x multiplier associated with "six sigma"). The result was an approximation of what precision could be expected from the setup over a much larger sample of measurements. I can guaran-fuckin'-tee that the tools and setups used by almost every gunsmith would fail to yield the claimed precision if subjected to such studies.
 
E. Bryant said:
When attempting to make measurements of that precision, it doesn't take more than a few degrees change in temperature to completely foul up any chance of repeatability. That's why claims of such precision are basically fallacy except under the most controlled conditions.

One of the standards for repeatability and reliability (R&R) that I used on a project several years ago involved making a series of measurements (10, if I recall correctly) with a particular setup, calculating the standard deviation of the results, and then multiplying by a constant (5.15, I believe - and yes, that is not the usual 6x multiplier associated with "six sigma"). The result was an approximation of what precision could be expected from the setup over a much larger sample of measurements. I can guaran-fuckin'-tee that the tools and setups used by almost every gunsmith would fail to yield the claimed precision if subjected to such studies.
Click to expand...

Thanks, I thought I was losing my mind. I have a science background which is why I tried to check the repeatability.

I've actually tried it 3 and 4 times in a row and couldn't get it the same. I've had better repeatability by dialing the ends with range rods for what its worth.
 
Killswitch Engage said:
His name is bob pastor. The Viper
ptg carries his fixture as well as other products. I highly
recommend his high sulfur cutting fluid. It's called vipers venom and is really good stuff.
Click to expand...

I'll second the Viper's Venom. Great all-around cutting fluid.

Chambering:
img_20140223_161228.jpg



Threading:
img_20140222_155345.jpg



Parting:
img_20140224_195632.jpg



Crowning:
img_20140224_201743.jpg
 
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As others have said earlier in the thread - my preference is to indicate internally off of the rifleing (over a good span @ the throat & Chamber) rather than dialing off a protruding rod.

Here is an extra long contact point I've turned up for my Centricator (wtf is that? old school Deckel device for centreing/indicating).
A few have been advocating the use of long reach "Interapid" DTI's for this purpose, but when I looked into acquiring one of these I simply couldn't justify that kind of expense at this time. Then I remembered that I had this gadget and went about investigating how it could be adapted for the purpose.
Spherical contact point is 3.00mm dia.
I tapered it to be quite slender for access purposes inside of .300" mainly and I'd imagine it should have no problems even down as small as .220" (we shall see).
There's been no perceivable deflection under reasonable indicating operating/indicating load so all good in that regard.

The Centricator for Lathe use is mounted either in the tailstock or in the MT tool holder of the Dixon QC tool post


3k18.jpg


d6bb.jpg


yhx1.jpg


63ao.jpg


he6j.jpg
 
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E. Bryant said:
When attempting to make measurements of that precision, it doesn't take more than a few degrees change in temperature to completely foul up any chance of repeatability. That's why claims of such precision are basically fallacy except under the most controlled conditions.

One of the standards for repeatability and reliability (R&R) that I used on a project several years ago involved making a series of measurements (10, if I recall correctly) with a particular setup, calculating the standard deviation of the results, and then multiplying by a constant (5.15, I believe - and yes, that is not the usual 6x multiplier associated with "six sigma"). The result was an approximation of what precision could be expected from the setup over a much larger sample of measurements. I can guaran-fuckin'-tee that the tools and setups used by almost every gunsmith would fail to yield the claimed precision if subjected to such studies.
Click to expand...

Aint one single doubt in my mind about this. Guys love to claim .0001 and shit but reality tells a whole different story.
 
Killswitch Engage said:
Aint one single doubt in my mind about this. Guys love to claim .0001 and shit but reality tells a whole different story.
Click to expand...
I have no doubt that smiths dial their actions and barrels into this degree because I've watched several do it but like you said 3-4 deg change in temp will cause that to move WAY more than than a couple tenths. If you dial in a barrel and go eat and come back it is not gonna be dialed in the same.
 
I've dialed in barrels many times to no movement on a .0005 short stem indicator. That doesn't mean the machine can cut
to .00000 in fact I don't believe there is one that does. Finally, that tight of tolerance doesn't really mean shit in the world of accurate firearms. Is there anyone building ammunition to .00000 run out and charges to within .01 gr. nope ain't gonna happen. But you can say we can eliminate all the variables possible and if that makes you sleep better at night go for it. We are chasing a ghost when it comes to tolerances that tight and accuracy. I've seen barrels chucked up with shit for indication and reamed and shot groups consistently in the .2-.3 range. Any one on a tactical rifle forum shooting a weapon for money or work need better then that?
 
RE: temperature and tolerance.

We are looking at alignment of a round bore into another round bore inside of a cylinder. If that bore to bore alignment is zero at 70 degrees, how much will the alignment change at 120 degrees? At 20 degrees?

I'm no ME but my hunch says while dimensions will change, that alignment will stay the same. We're measuring indicated runout, not a physical dimension.
 
JJones75 said:
I have no doubt that smiths dial their actions and barrels into this degree because I've watched several do it but like you said 3-4 deg change in temp will cause that to move WAY more than than a couple tenths. If you dial in a barrel and go eat and come back it is not gonna be dialed in the same.
Click to expand...


The indicator may not read at the same place but the TIR will be the same.
 
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It's not the dimensions of the bore changing that worry me - it's the "stacking" of every single dimension in the entire setup changing due to a couple degree temp swing in whatever environment happens to occur in one's shop. I doubt very much that it has even a whiff of effect on the real-world accuracy of a firearm, but I also strongly suspect (once again, without actual data to back me up) that all this talk of precision way down in the low tenths range is some combination of placebo and Pygmalion effects.

I've yet to see a good metrology lab that is set up in a drafty polebarn, but then again I'm no expert in these matters. I did spend a small portion of my career working with a gentleman in quality engineering who'd spent some number of years measuring roller bearings for automotive wheel hubs, and from that I got an appreciation for the difficulty of repeatable measurements when the decimal point is way over on the left side. I'm not expecting a inquiry from Timken any time soon, let's just put it that way.

Please understand that I am in no way trying to suggest that we not attempt to achieve the utmost precision when performing barreling work, but rather that we (or at least *I*) should not fool ourselves (myself) into claiming a level of precision that is simply not reproducible under typical gunsmithing conditions.
 
I've dialed in barrels just about every way possible. Lately, I've taken to using indicator and range rods with tight fitting pilots.

I can dial runout down to a couple ten thousandths, pull the rod, reinsert it, and it will show essentially the same runout. I can't imagine needing more.

Recently helped a good friend and hunting partner put together a 338 Norma. He called a couple weeks ago to tell me he had just finished putting five shots on a softball sized rock at 750 yds without using a rear bag. Works for me.

Not working professionally allows me the luxury of saying that dialing barrels in to absolute perfection really doesn't appear to be necessary.
 
E. Bryant said:
It's not the dimensions of the bore changing that worry me - it's the "stacking" of every single dimension in the entire setup changing due to a couple degree temp swing in whatever environment happens to occur in one's shop.
Click to expand...

That's where I am- again- not being a ME, machinist, or professional builder....
 
300, thanks for those videos. I wrote this yesterday but figured it would cause too much of a stir but with your videos backing us up I will risk it.
I own a set of range rods but rarely use them for dialing in a barrel. I use them to measure holes and things. The end of new barrels are bell shaped from lapping and there is no way to get an accurate indication of what the bore is doing at the throat and 2" ahead with a range rod. I don't consider what the bore is doing at the chamber because it's all being cut away to bring it into alignment where it matters the most. The throat and 2"ahead. What do you do with a barrel the range rod will fall through? The new Remington 770 barrels are way oversize as are a lot of AR barrels. A Grizzly rod supported in the tail stock drill chuck over a lubricated rubber o-ring with very light pressure allows us to get an accurate read where we need it. Then add in the barrel bore distortions from fluting or very light profiles. The diameters change but the bores are usually round. I can detect all these variations with our inspection processes. Until I get an .0001” indicator with a 6" long stylus I will have to keep fiddling with the Grizzly rods on the chamber end.

I use a brand new 2200 pound, high precision lathe that has never had anything heavier than a barrel in it and it's not used for anything but light gunwork. As 300 has demonstrated by video the machines are capable of cutting and holding .0000” alignment. Obviously holding .0000" is not the end all in accurate rifles but it's something I insist on if for no other reason than I can. I live in an area that doesn't suffer extremes in temperature and our shop heat keeps it consistent day to day. I use Starrett .0001" indicators and constantly check them against each other. When neither moves then it's time to cut. With the Grizzly rods I can recheck during and after in the exact same places I originally dialed into. This was how I discovered that excess muzzle brake torque constricts the end of the bore. I was triple checking the alignment after fitting a brake and the bushing wouldn't fit unless I loosened the brake a little.

I run an open shop and let customers come and see the indicators running dead still for themselves. I block out 8 hours to fit a rifle barrel. The better barrels don't take that long but the iffy ones can. One of the ones mentioned in this thread are so bad it makes it impossible for us to fit. Our customers appreciate what we do but I'm sometimes criticized by other smiths for taking so long. One world reknown guy that lives near here. I use a lot of his parts, lugs, levels, some of his fixtures and tooling. He keeps reminding me, “we are not building diesel injectors here.” He may not be, but I try.
 
E. Bryant said:
It's not the dimensions of the bore changing that worry me - it's the "stacking" of every single dimension in the entire setup changing due to a couple degree temp swing in whatever environment happens to occur in one's shop.
Click to expand...

The barrel is a one piece cylinder. If the chamber to bore runout is dead nuts at one temperature, it is going to be dead nuts at any temperature. The setup does not matter as long as you get the alignment you are after. Once that chamber is cut, the alignment isn't going to change.
 
E. Bryant said:
But the headstock in which that barrel is spinning is certainly not a single simple piece of geometry.
Click to expand...


The rotating mass is symmetrical. The height/location may change with the casting temp but the center of the rotating spindle is still going to be the center of the spindle.


I don't have the time to do it (wish I did as I get off of this sort of thing :D) but I challenge anyone with the cheapest hobby bench top to a HLV to a large turning center to bore a hole with a fine, light pass then measure the TIR. Without changing the setup, check the TIR again with a 10-20 degree temp difference. I am certain you will see a dimension and location change but the TIR will be the same.
 
MDSpencer said:
Why do you guys like the Range Rods? Have you thought about the Breach face, of the barrel not even square from the center line of the barrel?
Click to expand...

That's the point. Line up the bore to the spindle (with a range rod, grizzly rod, or direct DTI) and when you cut the breech face and tenon, it will all be perpendicular/parallel to the bore axis.
 
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