Range rod

[johnnymac]

Hello everyone,
I've chambered a few barrels and have used a range rod to dial in the barrel each time. I'm getting ready to build a 6BR. When I insert the range rod in the barrel I only have about 2 inches sticking out of the barrel. This seems shorter than the other times I've used range rods. Is this enough to dial in the barrel?

Thanks
John

 

[Grimstod]

That does sound to short but it can't be to long either or you will get tool deflection from just your indicating rods as the press on it. Anyone els have thoughts?

 

[jscandale]

I guess it all depends on what setup you are using on the lathe. If you are using spiders on both sides of the spindle, all you need is a half inch sticking out because you will want to indicate as close to the bore as possible. If you are using a TBAS or a truing sleeve with 8 jack bolts, you will certainly benifit from a longer rod since all of the indicating will be done on the inboard side of the spindle.

I have some rods from JGS and some from PTG and all of the PTG rods are quite a bit longer.

JS

 

[jkohler]

Not being a smart donkey but have you checked to see if the range rod is the right size. That sure sounds Pretty short to me.

 

[johnnymac]

Yes, the rod is the correct size. I have a grizzly g0709 lathe with a 4 jaw chuck and a spider on the outboard side. I normally dial in my barrels for chambering by inserting the rod in the chamber end and putting indicators on two points on the range rod(one close to the bore and one out on the end). I just wasn't sure if only having about 2 inches would be enough....

Thanks for all the replies so far.

 

[jkohler]

Johnnymac
You could always just get it close with the rod then go in and verify off the lands and groves there self.

 

[dakor]

Put a bigger bushing on the range rod. What size bushing are you using now?

 

[johnnymac]

correct me if im wrong but using a bigger bushing wouldn't change anything right? The taper on the rod is what causes the rod to get tight and stop, not the bushings. I'm new to this so maybe i'm missing something.

 

[jscandale]

Yes, the rod is the correct size. I have a grizzly g0709 lathe with a 4 jaw chuck and a spider on the outboard side. I normally dial in my barrels for chambering by inserting the rod in the chamber end and putting indicators on two points on the range rod(one close to the bore and one out on the end). I just wasn't sure if only having about 2 inches would be enough....

Thanks for all the replies so far.

Johnny,

While your method is certainly effective, if you have a mounting point on the outboard side of the headstock for another indicator, it sure makes the job a bit easier. Also, you'll only need a minimal amount of the rod sticking out of the bore to indicate right close to the contact point.

JS

 

[Erik Cortina]

Yes, the rod is the correct size. I have a grizzly g0709 lathe with a 4 jaw chuck and a spider on the outboard side. I normally dial in my barrels for chambering by inserting the rod in the chamber end and putting indicators on two points on the range rod(one close to the bore and one out on the end). I just wasn't sure if only having about 2 inches would be enough....

Thanks for all the replies so far.

Johnny,

While your method is certainly effective, if you have a mounting point on the outboard side of the headstock for another indicator, it sure makes the job a bit easier. Also, you'll only need a minimal amount of the rod sticking out of the bore to indicate right close to the contact point.

JS

You could just use an indicator directly on the bore, no need for a rod.

 

[Preacher]

correct me if im wrong but using a bigger bushing wouldn't change anything right? The taper on the rod is what causes the rod to get tight and stop, not the bushings. I'm new to this so maybe i'm missing something.

If the bushing is not a nice slip fit you will get wrong readings.
If the bushing is loose you will not get a true reading, even if the tapered end is in place.
Use a indicator in the bore and be done with it...

 

[dakor]

You want your bushing to fit correctly as stated above. As for indicating in the bore with a DTI I was going to switch to this until I talked to 3 different top end DTI makers and they told me their product would not read correctly with a long stem on it. I talked to two technicians at Mitutoyo and both said if I used a longer stem I would get in accurate readings. So my .0001 indicator could be off substantially and might not even read down to .001 let alone .0001. I will stick with the rods.

 

[jkohler]

Dakor check out a Interapid 312b-15 test indacator. It has a long nice long Stylus point on it.

 

[Erik Cortina]

They also make indicators that read down to .00005".

Dakor, have you tried indicating the bore with a rod, then face the barrel, and then put rod back in and check again? I'm curious if you would get the same readings?

 

[338 Mollett]

Is this a new barrel or are you setting back an old one ?

 

[dakor]

I did look at that Interapid and if it was a .0001 instead of a .0005 I might give it a try. I have had good luck with rods and there are other smiths out there using them with good results including the gentleman that taught me. I have checked after facing and I have not seen much if any change. I think the big misconception is that a guy takes the rod out and taps it back in and complains about a different reading or runs to small of a bushing. The reason for this is they are not getting it the exact depth where it was the first reading or the bushing is to small. Bores are not straight so if your rod is deeper or shallower than the first reading it more than likely will differ by some degree. The other thing I like about the rod is with most of the cartridges out there I am getting a reading at or ahead of where the throat will be because that is where the bushing is sitting and I don' t have to pre bore to get a reading up in that area like you would with a 2 inch DTI.

 

[jkohler]

Dakor even with the indacator being .0005 the lines are far apart you can see any movement. The contact point is 2.750 long also. I also use a mitutoyo pocket test indacator. But with that one you do have to drill to reach up in the throat area.

 

[dakor]

I am sure I will give it a try with a DTI at some point to down the road so that is good to know.

 

[The Viper]

Hello everyone,
I've chambered a few barrels and have used a range rod to dial in the barrel each time. I'm getting ready to build a 6BR. When I insert the range rod in the barrel I only have about 2 inches sticking out of the barrel. This seems shorter than the other times I've used range rods. Is this enough to dial in the barrel?

Thanks
John

Hi John,

The reason your range rod is not locking up until the last two inches is that your bore is slightly larger than nominal size. Just use one indicator and move it from close to the bore and then all the way out to the end, during the indicating process. It will work just fine.