Gunsmithing PTG Dual Pilot Range Rods

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SSC

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Mar 4, 2008
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La Grange, TX
www.scoutsupplycompany.com
#1
Anybody try them yet? that is a lot of coin for a bushing rod?

Deep-10-inch-Muzzle-Brake-&-Chamber-Range-Rod-resize.png

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">These Range Rods have an OAL of 10" and 2 bushings for maximum stability. These rods are caliber specific and are great for dialing in Muzzle Brakes & Unchambered (Virgin) barrels.

14 cal - $325.00
17, 19 & 20 cal - $225.00
22 cal to 6.5mm - $199.00
7mm (284 cal) to 38 cal - $175.00
40 cal to 50 cal - $125.00
</div></div>
 
#6
Re: PTG Dual Pilot Range Rods

I like the concept and when you think about tw cost they aren't too much more if you don't already have an indicator rod and a range rod for all the different calibers. I do like how on these it would matter the state of tw crown or if the barrel was not cut off at 90*

Would like to know more about 308Nate's rods.
 
#7
Re: PTG Dual Pilot Range Rods

I would bet that most smiths wouldent be able to take advantage of the added accuracy anyways.

Hell all the standard bushing range rods I have dialed me to within .0001 TIR if I didnt fart while turning the headstock. How much closer, or better yet, what is to be gained from indicating any closer. I would bet most lathes, mine included, out there have .0005 + to start with.

There is a point of deminishing returns
 
#8
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">One Interapid long stem indicator works in every barrel. This makes no sense to me with all the tolerances that stack up.</div></div>

Those are .0005" grads, right? Does anyone make a .0001" long stem?
 
#9
Re: PTG Dual Pilot Range Rods

It is a .0005" indicator. I don't know of a .0001" long stem indicator. Not hard to get to 2-3 tenths TIR. I don't run bushing any tighter than that anyway. I would rather be a few tenths loose than a tenth tight.
 
#10
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">One Interapid long stem indicator works in every barrel. This makes no sense to me with all the tolerances that stack up. </div></div>

This.

Agree 100% on tolerance stacking and bushing fit...not to mention, the rods don't pick up the bore exactly where it counts, necessarily. The indicator does - as long as you stick it where it counts.
 
#11
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rprecision</div><div class="ubbcode-body">I would bet the most smiths wouldent be able to take advantage of the added accuracy anyways.

Hell all the standard bushing range rods I have dialed me to within .0001 TIR if I didnt fart while turning the headstock. How much closer, or better yet, what is to be gained from indicating any closer. I would bet most lathes, mine included, out there have .0005 + to start with.

There is a point of deminishing returns </div></div>

My thoughts exactly.

Regards, Paul.
 
#12
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rprecision</div><div class="ubbcode-body">I would bet the most smiths wouldent be able to take advantage of the added accuracy anyways.

Hell all the standard bushing range rods I have dialed me to within .0001 TIR if I didnt fart while turning the headstock. How much closer, or better yet, what is to be gained from indicating any closer. I would bet most lathes, mine included, out there have .0005 + to start with.

There is a point of deminishing returns </div></div>

are you checking the bore directly with a dti or are you assuming because you read near zero tir on the a range rod, the bore is just as dead nuts? i've gone away from tapered range rods because i have found them to be unrepeatable. sure, i built very accurate rifles using them but i think the grizzly rods and a fitted bushing give better, more repeatable results. if i dial the rod into zero tir, the bore still has less than a tenth of runout when direct reading it.
 
#13
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rprecision</div><div class="ubbcode-body">I would bet the most smiths wouldent be able to take advantage of the added accuracy anyways.

Hell all the standard bushing range rods I have dialed me to within .0001 TIR if I didnt fart while turning the headstock. How much closer, or better yet, what is to be gained from indicating any closer. I would bet most lathes, mine included, out there have .0005 + to start with.

There is a point of deminishing returns </div></div>

are you checking the bore directly with a dti or are you assuming because you read near zero tir on the a range rod, the bore is just as dead nuts? i've gone away from tapered range rods because i have found them to be unrepeatable. sure, i built very accurate rifles using them but i think the grizzly rods and a fitted bushing give better, more repeatable results. if i dial the rod into zero tir, the bore still has less than a tenth of runout when direct reading it.


</div></div>

I take my readings direct from the range rods.

As a side note I have expirenced the same inconsistancies that you speak of. Although at the most it has changed is .001 on the high side .0003 on the low. I found that machining the crown to 90 degrees after getting it within .005" and then throwing the range rod back in made pretty much resolved it. In my mind the taper was trying to locate on a inconcentric surface.

I am still learning here, I am far from a expert. I always find it interesting how other folks spin things up, I usually learn something or see it in a way I didnt see before.
 
#14
Re: PTG Dual Pilot Range Rods

I know a lot of people are going to disagree with me and that's fine. I've been building match winning record setting rifles for over 25 years. I'd say at least 20+ years using a long stem indicator on the breech end and nothing more than a snug fitting bushing on the muzzle to indicate on. My rifles have set over 35 world records based purely on accuracy. I can appreciate the Gritters method but I have never seen the need to explore an alternative setup.

There are so many factors that affect the concentricity of the chamber. Bore straightness is one, they do wonder around a bit, some more than others and mostly on the breech end. Here's an example of one issue that has to be considered. Look at the relationship/location of the bushing on the reamer. I have never heard one word of discussion about that. Some speak of tenths like they can accually work to those tolerances. It doesn't happen but in this case tenths can show up in the finished chamber. The distance between the bushing and the throat of a reamer can have an affect on chamber concentricity. Crooked bore and a bushing that is way out in front means misalignmant. Example. I have one reamer, a magnum on a 2.5" case, that was ground on a blank for a 2.850" case length. I don't use that one much but I have never gotten what I call a perfectly concentric chamber. The reason, crooked barrels and a bushing that is located way out in front that's trying to follow the bore. All the rifles shot just fine but that reamer and the chambers are not quit right. That is just one of the factors that affecting chamber concentricity.

There many ways to skin this cat and get acceptable results but I view rods as a crutch that can introduce errors and remove the most important piece of equipment from the process. Your brain and applying basic machining techniques to this very very simple task. In 2011 and 2012 I've chambered over 500 barrels using this technique with no problems.

Get yourself a simple 3X jewelers loupe with a 3 1/2" focal length. About $20-$30. No need for a borescope. After you chamber a barrel patch it out clean, hold it up to a light and focus on the freebore in the chamber. It will in all likelyhood be an enlightening experience. There should be a concentric shadow as the freebore transitions to the rifling. Very easy to pick up just a few tenths misalignment.
 
#15
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">
Get yourself a simple 3X jewelers loupe with a 3 1/2" focal length. About $20-$30. No need for a borescope. After you chamber a barrel patch it out clean, hold it up to a light and focus on the freebore in the chamber. It will in all likelyhood be an enlightening experience. There should be a concentric shadow as the freebore transitions to the rifling. Very easy to pick up just a few tenths misalignment. </div></div>

That's a great idea.

I had been wondering why it seemed to be more difficult to get my WSM reamer to cut a good chamber than my 308 based reamers. I hadn't thought about how far forward the pilot was sitting on the thing, I guess they just make 1 size of magnum blank and grind everything from there. I cut a 284 this weekend just by single-point pre-boring the hole and not using any bushing at all and it came out great, I think I'm going to take a piece of cut-off and go retry that WSM reamer using that method.
 
#16
Re: PTG Dual Pilot Range Rods

Out of curiosity, when indicating directly off the bore how much trouble is it trying to get the bottom of the groove or the top of the lands (whichever you're indicating off of) to line up properly with one of the chuck's adjustment axis? It seems like with a 5 groove you'd always be off at one point or another.
 
#17
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body"> There should be a concentric shadow as the freebore transitions to the rifling. Very easy to pick up just a few tenths misalignment. </div></div>

in the right light, this is something i can see with the naked eye. i have seen new chambers from very well known builders where that transition is heavy on one side of the bore and none 180* out. with the way i am doing it lately, all of mine i can just see a rch of a transition 360* around the bore.
 
#18
Re: PTG Dual Pilot Range Rods

Ratbert

You develop a technique with the 5 groove barrels. You're working in two planes and there will be two screws, maybe inboard and outboard that line up close enough. It's not difficult at all. The three groove barrels can be a bit challenging but it's just work, not rocket science.

One more thing be careful using a short piece of barrel in a chuck. Aligment issues with the bore. You may not get valid results.

300sniper

If everything is right you don't need a bushing as everything is selfcentering. I won't say how much under the bore dimension I use on my bushings but they don't fit very closely. I'm serious when I say you can see a tenth or two misalignment. You can pick up on a lot things in regards to the bore and grooves. Particulary in buttoned barrels. Not knocking them as I've used hundreds of them. You see some strange shapes at times.

 
#19
Re: PTG Dual Pilot Range Rods

It is hard to imagine being able to look at a bore/chamber and see imperfections by eye, but having looked at thousands of barrels of 3 years in QC, it will happen.
Most people pick them up and do a 'yep, looks good.' They have no idea that they are looking at anything other than a 'spirally hole.'
In time, off centeredness is quickly visible, and any other irregularities, the trick is knowing what is truly problemtatic and what is annoying to OCD. The problem now is picking up a factory gun, or even many customs and finding one that is acceptable.
It is interesting to read everyone's experience and techniques, and compare it to my own. As with most of gunsmithing it is impossible to say which techniques are right when so many produce results.
 
#20
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">I know a lot of people are going to disagree with me and that's fine. I've been building match winning record setting rifles for over 25 years. I'd say at least 20+ years using a long stem indicator on the breech end and nothing more than a snug fitting bushing on the muzzle to indicate on. My rifles have set over 35 world records based purely on accuracy. I can appreciate the Gritters method but I have never seen the need to explore an alternative setup.

There are so many factors that affect the concentricity of the chamber. Bore straightness is one, they do wonder around a bit, some more than others and mostly on the breech end. Here's an example of one issue that has to be considered. Look at the relationship/location of the bushing on the reamer. I have never heard one word of discussion about that. Some speak of tenths like they can accually work to those tolerances. It doesn't happen but in this case tenths can show up in the finished chamber. The distance between the bushing and the throat of a reamer can have an affect on chamber concentricity. Crooked bore and a bushing that is way out in front means misalignmant. Example. I have one reamer, a magnum on a 2.5" case, that was ground on a blank for a 2.850" case length. I don't use that one much but I have never gotten what I call a perfectly concentric chamber. The reason, crooked barrels and a bushing that is located way out in front that's trying to follow the bore. All the rifles shot just fine but that reamer and the chambers are not quit right. That is just one of the factors that affecting chamber concentricity.

There many ways to skin this cat and get acceptable results but I view rods as a crutch that can introduce errors and remove the most important piece of equipment from the process. Your brain and applying basic machining techniques to this very very simple task. In 2011 and 2012 I've chambered over 500 barrels using this technique with no problems.

Get yourself a simple 3X jewelers loupe with a 3 1/2" focal length. About $20-$30. No need for a borescope. After you chamber a barrel patch it out clean, hold it up to a light and focus on the freebore in the chamber. It will in all likelyhood be an enlightening experience. There should be a concentric shadow as the freebore transitions to the rifling. Very easy to pick up just a few tenths misalignment. </div></div>

Dave are you indicating at a single point or two?
 
#21
Re: PTG Dual Pilot Range Rods

Single point on the breech, the throat and then the muzzle. I did the math one time and figured out the possible misalignment of the bearing surface of a 65 gr. 6MM benchrest bullet in a barrel chambered in 6PPC with I think .003" runout in the barrel over a chamber length of 1.5". The measurement started out like this .00000 something. In other words we can't measure it and we can't load ammo that good. I trust a direct read from an indicator VS this thingy with a bushing on the end wedged into the barrel. It works for me. As always your mileage may vary.
 
#22
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">Single point on the breech, the throat and then the muzzle. I did the math one time and figured out the possible misalignment of the bearing surface of a 65 gr. 6MM benchrest bullet in a barrel chambered in 6PPC with I think .003" runout in the barrel over a chamber length of 1.5". The measurement started out like this .00000 something. In other words we can't measure it and we can't load ammo that good. I trust a direct read from an indicator VS this thingy with a bushing on the end wedged into the barrel. It works for me. As always your mileage may vary. </div></div>

Thanks Dave are you dialing straight off the bore and if so any tricks with the bouncing especially on small calibers.
 
#23
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">I know a lot of people are going to disagree with me and that's fine. I've been building match winning record setting rifles for over 25 years. I'd say at least 20+ years using a long stem indicator on the breech end and nothing more than a snug fitting bushing on the muzzle to indicate on. My rifles have set over 35 world records based purely on accuracy. I can appreciate the Gritters method but I have never seen the need to explore an alternative setup.

There are so many factors that affect the concentricity of the chamber. Bore straightness is one, they do wonder around a bit, some more than others and mostly on the breech end. Here's an example of one issue that has to be considered. Look at the relationship/location of the bushing on the reamer. I have never heard one word of discussion about that. Some speak of tenths like they can accually work to those tolerances. It doesn't happen but in this case tenths can show up in the finished chamber. The distance between the bushing and the throat of a reamer can have an affect on chamber concentricity. Crooked bore and a bushing that is way out in front means misalignmant. Example. I have one reamer, a magnum on a 2.5" case, that was ground on a blank for a 2.850" case length. I don't use that one much but I have never gotten what I call a perfectly concentric chamber. The reason, crooked barrels and a bushing that is located way out in front that's trying to follow the bore. All the rifles shot just fine but that reamer and the chambers are not quit right. That is just one of the factors that affecting chamber concentricity.

There many ways to skin this cat and get acceptable results but I view rods as a crutch that can introduce errors and remove the most important piece of equipment from the process. Your brain and applying basic machining techniques to this very very simple task. In 2011 and 2012 I've chambered over 500 barrels using this technique with no problems.

Get yourself a simple 3X jewelers loupe with a 3 1/2" focal length. About $20-$30. No need for a borescope. After you chamber a barrel patch it out clean, hold it up to a light and focus on the freebore in the chamber. It will in all likelyhood be an enlightening experience. There should be a concentric shadow as the freebore transitions to the rifling. Very easy to pick up just a few tenths misalignment. </div></div>

Ok I will fully admit my ignorance here! I am confused and or in way over my head

When I think of getting a barrel true in a lathe for preparation for threading, chambering, etc, I think of it this way. I work through the headstock. I select a range rod with close fitting bushing and slowly work each end of the barrel, indicating of said range rod, to as little total indicated run out as I can get. Sometimes I can get it pretty dam good to say within .0003 or so using a .0001 dial indicator. From there I am off and running. I do one end at a time and complete all the machining in two operations (chamber then flip and crown + thread). I have a fairly used lathe but tolerances are ok, not some tool room deal but it works. I have every bit of .0005” change between a warmed up headstock and cold. I indicate on a hot one.

Here is my confusion. If you’re indicating on the bore directly with an indicator I am guessing its something like this:

http://www.grainger.com/Grainger/MAHRFEDERAL-INC-Dial-Test-Indicator-5RHF1

Since the indicator will bounce up and down on each land and groove how do you ever know where you end up? Are you just looking for a consistent measurement land to groove all the way around and therefore because each measurement is consistent the theory is the bore is running consistent.

OR

Are you measuring on a single land or grove at a time by measuring the lateral movement as you run the indicator all the way in and all the way back out?

I understand that a bore may change throughout the barrel. And I like the idea of chasing this change for a more consistent / concentric chamber.

I am very fascinated by this process but am completely lost

Thanks
 
#24
Re: PTG Dual Pilot Range Rods

indicatechamber.jpg


This how I do it. That's an Interapid # 74.111965 with a 2.675" long stem. I work on the top of the lands just like you do with a rod and bushing. I'll accept the slight amount misalignment/ runout in the bore as a given on every barrel knowing 1. I can measure the amount if I want to, need to. 2.I can't see it in the finished chamber and 3. It won't affect accuracy if I do a thorough job of managing all the factors that go into a precision chamber. I will say there have been a few barrels over the years that had to be handled in a more elaborate manor because of just how crooked the barrel was in the first few inches. You may or may not have to bore the roughed in hole.

Rods of whatever description haven't been around that long. Before some used gage pins. Some tenth indicators reaching in as far as they could. That's what I did for years until getting the Interapid. Then life got easier.
 
#26
Re: PTG Dual Pilot Range Rods

These are intruiging to me. I never liked tapered range rods because there were too many variables, and it took just as much set up time to get comfortable with them as it did to just indicate in two places near the throat. My main complaint with the tapered rod was that the contact points spanned a good chunk of barrel and if that wasn't straight, as Mr. Tooley stated above, you couldn't even luck into a yaw free entry with that setup.
These dual pilot versions however, seem like they have some merit. The contact points span a shorter section in the critical area and the rod diameter is less than bore diameter so it would seem effective in reducing the effects of a less than straight bore. Stacked tolerances are an issue but assuming .0004 stacked at 1" between contact points we are looking at roughly .0014 max runout at the first indicated point assuming worst case conditions (Based on something like a 30BR). 14 tenths seems like a lot but when you think about the margin for error created by your indicator button bouncing over lands it's probably closer than one would think. At worst I would think it could get you very very close with a shorter setup time. Having two simultanious indicating points while setting up the cat head seems like it would speed things up greatly.

Has anyone tried one yet?
 
#27
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">One Interapid long stem indicator works in every barrel. This makes no sense to me with all the tolerances that stack up. </div></div>


Stop making sense David. Your scaring the kids.
 
#28
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">.... After you chamber a barrel patch it out clean, hold it up to a light and focus on the freebore in the chamber. It will in all likelyhood be an enlightening experience. There should be a concentric shadow as the freebore transitions to the rifling. Very easy to pick up just a few tenths misalignment. </div></div>

This is the test I use to evaluate the chamber work any time I have one done. I've had work done by some well known builders and it is very interesting what you see.
 
#30
Re: PTG Dual Pilot Range Rods

For the sake of discussion, let me see if I can put it another way...
If using a long stem indicator and indicating at the throat only, one could cut a chamber in a 6mm barrel a full 3 degrees off axis and the TIR at the elipse would measure 0.00032562". You could have a really screwed up chamber but everything would still look right on the indicator.
 
#31
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrm850</div><div class="ubbcode-body">For the sake of discussion, let me see if I can put it another way...
If using a long stem indicator and indicating at the throat only, one could cut a chamber in a 6mm barrel a full 3 degrees off axis and the TIR at the elipse would measure 0.00032562". You could have a really screwed up chamber but everything would still look right on the indicator.
</div></div>

So indicate at the throat depth and then move to the breech using only the carriage in a straight Z movement. Ditch the "wonder rod" as its been proven not to repeat, develop a tolerance stack, and just generally suck a fat egg.
 
#32
Re: PTG Dual Pilot Range Rods

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

So indicate at the throat depth and then move to the breech using only the carriage in a straight Z movement. Ditch the "wonder rod" as its been proven not to repeat, develop a tolerance stack, and just generally suck a fat egg. </div></div>

That is similar to my current method (If you could call it current), only I indicate in two places closer to the throat. Ideally I like to indicate right at the leade and an inch in front if I can. I used a .0005 Mitutoyo with 2.625" reach so I could only do that on short cartridges like a ppc or BR. My theory is that I am only concerned with perfect axial alignment from the neck through one bullet bearing surface length. I realize I lose resolution by having the measuring points that close together but I feel like it is a good comprimise between resolution and dealing with runout back at the breech.
The wonder rod, unlike a traditional or tapered range rod, avoids the breech runout issue and it appears to be much easier to focus the setup on what I consider the critical spot in the bore. Even the interapid indicator with more reach than mine will be hard pressed to do this on full length cartridge.
Re: repeatability- That is what I am trying to find out. We know the tapered range rods have issues, but I have yet to hear about any real world reviews of this double pilot design. Are they inheriting their reputation from previous iterations or do they suffer the same limitations?
I'm not questioning anyone's methods at all. God knows Dave Tooley is a master at his craft and you appear to be one also. I'm not nearly as experienced as either of you, but I've cut somewhere around a hundred chambers and have migrated from through the headstock to between centers and back to through the headstock using a method very similar to what you guys use. The latter method definitely produced the best accuracy of the rifles I built so I know it works but it still won't stop me from being curious and asking questions. I'm pretty sure none of y'all got where you are by blindly following the status quo.
smile.gif
 
#33
Re: PTG Dual Pilot Range Rods

Status quo. There is no such things. I've been doing this a long time. The first 5 years I was sponge, the next 5 I sorted out what I had absorbed those first 5 years. That's when I got dangerous. I thought I had learned it all and even worse <span style="font-weight: bold">I knew better than all those other hacks out there</span>. That lasted 5 years.
The last 10 years I've known what's important and what's not. That makes work so much easier. I'm still learning and trying new things. Many customer are test mules and they don't know it as it takes years of feed back to arrive at a informed opinion. No radical changes just gently massaging designs and processes. Chambering is the easy part or it should be.
 
#34
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">One Interapid long stem indicator works in every barrel. This makes no sense to me with all the tolerances that stack up. </div></div>

I watched Don Geraci build a few guns and when i saw how he set them up and chambered them all i could do was think "you have to be kidding me" it was just way to simple , one long stem intrepid and three saw set tru chuck , had a barrel dialed in in a third the time it would have taken me. After watching him chamber and thread then fit it to an action that simply had the lugs lapped i though their was no way it was gonna shoot , two days later when the glue set in the stock i was back up their to watch him shoot it and was again amazed at the accuracy.

He swears that the accuracy in 99% in the barrel and quality of the chamber and i have to admit that its hard to argue with decades of success , same goes for you Mr Tooley.
 
#35
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dave Tooley</div><div class="ubbcode-body">Status quo. There is no such things. I've been doing this a long time. The first 5 years I was sponge, the next 5 I sorted out what I had absorbed those first 5 years. That's when I got dangerous. I thought I had learned it all and even worse <span style="font-weight: bold">I knew better than all those other hacks out there</span>. That lasted 5 years.
The last 10 years I've known what's important and what's not. That makes work so much easier. I'm still learning and trying new things. Many customer are test mules and they don't know it as it takes years of feed back to arrive at a informed opinion. No radical changes just gently massaging designs and processes. Chambering is the easy part or it should be. </div></div>

smile.gif
I'm in the dangerous stage. You guys have 5 more years of my obnoxious theories and questions.

One of the good things about age is perspective. I started just a couple of years after you did. You are at the top of the game and I now design injection molded toy guns. Thats a pretty good sign that I didn't have all of the answers like I thought I did. I think the experimenting was more fascinating to me than actually making a living. Now that it's just a hobby I get to embrace that side.
I appreciate the conversation and hope that my catching up isn't beating the dead horse too much around here.
 
#37
Re: PTG Dual Pilot Range Rods

One critical aspect to chambering:

Your brain is a dangerous thing. Learn when to turn it off.

Examples:

A guy has a $250,000.00 cnc cutter grinder that's made thousands of reamers for the industry. Don't get the bright idea that your smarter than the tool and go to work on it with an Arkansas stone. Relief, rake, and cutter geometry is a science. The formats can be traced back to reference materials like the Machinery Handbook. They are there for a reason.

"Feeling up" the reamer. So many insist on the practice of laying their hand on a reamer as their eyes roll into the back of the head in some bizarre Zen like Radan Mortal Combat manuever. (FINISH HIM!) The idea being if the tool chatters they can back out before damage is done.

Here's a reality check. If the tool chatters, your too late. Go back to the dojo and watch some more Bruce Leroy till you can shoot lightening bolts from your finger tips.

Any top level smith on this site put their finger on a turning tool? Threading insert? How bout a drill?

If the answer is yes, my next question is how many fingers do you still have?

Work holding and tool rigidity is machining 101. Ignoring it or becoming a black belt doesn't magically make it disappear.

Stick to fundamentals and you'll win, win, win far more often than you fail.

I'm off to torment young children that dare to mooch candy from my porch. muhahahahahahahahah!

Happy Halloween germs.

C.
 
#38
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">One critical aspect to chambering:

Your brain is a dangerous thing. Learn when to turn it off.
</div></div>
haha, reminds me of an Eddie Murphy skit. "The mind is a terrible thing..."

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">
"Feeling up" the reamer. So many insist on the practice of laying their hand on a reamer as their eyes roll into the back of the head in some bizarre Zen like Radan Mortal Combat manuever. (FINISH HIM!) The idea being if the tool chatters they can back out before damage is done...
</div></div>

Do you use a floating reamer holder or a rigid setup? How do you manage your chip load? Do you cnc, use the carriage feed, or use the tailstock?
 
#39
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrm850</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">One critical aspect to chambering:

Your brain is a dangerous thing. Learn when to turn it off.
</div></div>
haha, reminds me of an Eddie Murphy skit. "The mind is a terrible thing..."

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">
"Feeling up" the reamer. So many insist on the practice of laying their hand on a reamer as their eyes roll into the back of the head in some bizarre Zen like Radan Mortal Combat manuever. (FINISH HIM!) The idea being if the tool chatters they can back out before damage is done...
</div></div>

Do you use a floating reamer holder or a rigid setup? How do you manage your chip load? Do you cnc, use the carriage feed, or use the tailstock?
</div></div>

Rigid tool/work holding all the way!

It's a cnc setup using a simple G82 canned peck cycle. I wrote a special macro to slow down the rapid rate so that the reamer doesn't retract/return at the 1000ipm rapid rate that it normally would. All this means is the tool pulls back/enters slower than normal, but the feed rate is still the same. Simple M300/M301 to turn it on/off. The peck cycle cuts an incremental amount, retracts, rapids back to +.01" from where it last stopped, and feeds into the material again.

My principle reason for doing this is that I use a high pressure feed for the lubrication through the barrel. Jamming a pilot in the bore causes an alarming spike in hydraulic pressure. It's hard on the pump/filters, etc. A slower entry allows the pressure relief valve to operate better.

The cartridge type dictates the peck depth. Small calibers don't have the chip gullet clearance that a 30-378WBY would so you have to be more conservative. The full retract combined with a high pressure muzzle flush means it clears the gullets very efficiently upon retraction.

This is why I don't use a straight linear plunge. With HSS reamers you just can't get the fluid transfer around the pilot to do this. I wish you could. I've considered gun drilling the reamer from the back side and putting cross holes in the chip gullets and flushing from the backside as well as the front. David Kiff and I experimented with this years ago when I was at Dakota. It worked (awesome), but we had other problems. (Machine related) It broke a few tools and I just gave up on it due to the expense of burning up reamers.

The other reason is even though the reamer is on center, it could (has in the past prior to writing the macro) caught an edge at the should/body junction and rattled down the chamber as it tries to center. A slower entry avoids this.

My view on this is simple. If a guy walked through the door and wanted a hole reamed to a specific size in my mill I'd grab the appropriate reamer, chuck it up in a tool holder, find center, and cram it through the bore. I wouldn't be using a floating holder in my mill, so why use one in a lathe? If we devote the time to position a barrel the way were supposed to we know the bore is on the same tangent as the tail stock/carriage. So why a floating holder unless something in the machine is off?

There lies the answer.

Machining 101:

Setup is everything. This includes work holding (fixturing the part to be machinined) and tool rigidity. Look at the mass in a Aloris tool post/carriage on a quality engine lathe, any cnc lathe turret, or a cnc mill spindle column, etc. There's a reason for that. Mass means stuff doesn't want to move inappropriately.

That mass goes a long way towards making accurate parts. Holding a reamer with a tap wrench/pair of vice grips and playing Bruce Lee violates the fundamental rule. You may get away with it a few times (and I too did this for a long time back when I started out) but the odds of failure outshine the success. It will bite you and in more ways than one. Someday that reamer is going to bite and spin. If its between your fingers those flutes are going to turn your skin to hamburger. It'll peel you like an onion in a split second. Keeping your digits out of the way means you go home with all 10 of them.

A lathe is the 2nd most dangerous machine in a shop. 2nd only to a surface grinder because when a wheel lets go, its literally like standing next to a road side bomb in downtown Baghdad. A mill may bite you and take a finger. A lathe will take your entire arm before you even realize you had an accident. Never forget this.

Hope this helps.

C.
 
#40
Re: PTG Dual Pilot Range Rods

Chad, I love reading and seeing the pictures of your setup, makes so much sense and I can completely agree with what you are saying. Now that said I do have a question on how you feel about a Manson Floating Reamer holder? It allows the reamer to center itself on the spindle and it doesn't require holding a tap wrench or vise grips. Granted it isn't as rigid as a non-floating method, but does this better answer your concerns?

Thanks,

Dave
 
#41
Re: PTG Dual Pilot Range Rods

There's a lot of ways to peel the skin off this cat. I don't profess to know the best way. I just know the best way for me.

I've never used a floating reamer holder from anyone. Dave Kiff has been on my ass for years (in a good natured way) to try a floating tool holder. I've always declined his offer because I don't see the need. What I made works best for me.

There's a ton of talented gun plumbers out there using the full gamut of processes. I'm merely offering what I've been able to make work. I'm one of a very few shops using cnc stuff for actual gun work. Many make parts on automated machines, very few build rifles on them. It necessitates going in a different direction at times in order to try and maximize what a cnc is capable of: <span style="font-style: italic"> time compression </span>.
 
#42
Re: PTG Dual Pilot Range Rods

Sounds like a great setup Chad. It's hard to match the surface finish and accuracy of a cnc with a manual, but for those of us that don't have a TL-1 we have to adapt.

I've used the Zen method and a floating tool holder. Without having a programmed feed speed, I feel like it is important to have some feedback which the Zen method provides. There is a bit of a disconnect with the floating holder and it can get kind of scary looking at it in some barrels if you don't single point a partial first. Neither method is ideal to me and the situation at the time kind of dictates which way I go. If the spindle runout is good and the lathe trams well, I like to drive the reamer directly on a dead center with a tap handle. If I can take a light cut and see chips evenly distibuted in the flutes then I go with it. I've never had any problems with chatter using either method except for one pesky 7stw reamer I had. One of the major drawbacks with both of these methods is keeping reamer alignment until the bushing enters the bore.

The safety issue is a big concern. I've always used the old fashioned 60rpm spindle method so there is some time to get clear if it gets away from me, but I wouldn't think of trying it at some of the speeds I see that are en vogue today.

I would be curious to know what the most popular method is for those who use a manual lathe? What did Ackley, Neider, and McMillan do?
 
#43
Re: PTG Dual Pilot Range Rods

This topic interests me a lot. I am relatively new at the chambering game, but not as new at the machining parts of it. I have had the benefit of a couple good tutors, from the BR world, as well as the knowledge of the group here, especially Mr Dixon and 300sniper, who always seems to find a new ways to skin cats!

One of things most us learned pretty early, was not to trust worn ways, or tailstocks not perfectly centered. I think perhaps, even without thinking it thru, that this is why there are a lot of reamers being held by hand. That, and for most, it is a method that works for a lot of people. There are however, a certain perverted segment out there, that thinks there must be a better way.

Without a doubt, Chad is right on with his point about work-holding. It applies to tool-holding in every other way we approach machine work, except chambering, and this is where we need to get better. IF you don't want chatter, or tool marks, what do you do? Check speeds and feeds, and make the setup stiffer, right? Remove things that add uncertainty ( where this thread started) and measure directly, not indirectly.

If it wasn't a rifle, and after all, we "know" what is best there, how would we do this? Maybe the lathe is the tool we have used, and we need to look at using a jig bore grinder? I used one back in the 70's for some very precise parts, much tighter tolerances than you'd expect for a barrel.

Maybe an EDM? Grind or turn an electrode and plunge it? Fit it with an insulating pilot. Or cut the throat after the chamber, no reason it has to be done at the same time, it has always just been done that way.

Single point CNC a chamber? I think I remember seeing a thread on that somewhere.

This discussion is probably better done on a BR type board, but..... a lot of guys there are stuck, doing it the way they always have, and defending it. I really like the exchange of ideas here, and so.... Please, your thoughts, gents.
 
#44
Re: PTG Dual Pilot Range Rods

I tell ya what I'd love to try.

Picture a piloted tool with a single flute, a chip gullet, and a mass of material revolving around say 300* to support it. Put the single flute on a helix so that it's not a linear "bite" into the steel. Shape the tool so that the 300* of contact surface has waves that'll burnish the interior and then add through coolant holes that evacuate the gullet from the back side.

Essentially you'd have a combination of cutter and plain bearing very similar in principle to how a crankshaft is supported in an engine using pressurized lubrication.

I've struggled with the idea that all 5,6,8 whatever flutes are generating equal chip load. I realize they must, but it just seems odd in my little squirrel cage.

One thing I've noticed in my setup. I know chambers are on size by one little quirk that used to scare the piss out of me till I realized what was happening. When the tool retracts, it'll compress the springs that keep it against the dead center. Then the tool literally "pops" out of the chamber and back onto its register. I was always terrified of it breaking till I realized there's only ONE way this happens; The tool is exactly on center and it's forming a mirror image of itself in the the chamber walls. If it were cutting cockeyed it would produce a bore thats larger than the tool, there'd be no "stiction" in the tool with the chamber.

I've come to expect/demand "the pop" when chambering.

Great post! I agree that this stuff is far more interesting to chat about so long as feelings don't get hurt and the ego stays on semi auto instead of 3x burst.
smile.gif


C.
 
#45
Re: PTG Dual Pilot Range Rods

Thanks for providing the great reading, folks!

My next chambering will utilize the tool post instead of the tail stock, with my floating reamer holder clamped in a boring bar tool holder via a simple adapter. I'm hoping that this is quicker and smoother, considering that my 16x40 TOS has a tailstock that is the opposite of quick and smooth (it does, however, have the mass of which Chad spoke of above). It will also allow for use of the carriage feed mechanism. I'm not quite sure why I feel the need to continue using the floating holder, considering that I've bored out receivers using a solidly-held chucking reamer without any second thoughts.

And FWIW, I don't hold tools with my hands anywhere near a lathe, having pushed my luck one too many times with a table saw. Having fingers reattached and reconstructed was no fun, and I do not wish to repeat the experience with larger body parts.
 
#46
Re: PTG Dual Pilot Range Rods

Chad, have you seen the latest EDM hole popping machines? Sinking a small ( .010 to .125 ) hole, thru inconel anywhere from a half inch to several inches..... in 30 seconds. The electrolyte runs BLACK with the smut from the process, at several gpm, thru the hollow electrode. I used to have a cool video of a 5 axis hole popper, making holes in a set of turbine vanes, dozens of holes, in minutes.

Compared to that, locating a chamber within a couple tenths, ought to be pretty easy. And no need for reamers anymore, just cut an electrode on the lathe.
 
#47
Re: PTG Dual Pilot Range Rods

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mikee Booshay</div><div class="ubbcode-body">Chad, have you seen the latest EDM hole popping machines? Sinking a small ( .010 to .125 ) hole, thru inconel anywhere from a half inch to several inches..... in 30 seconds. The electrolyte runs BLACK with the smut from the process, at several gpm, thru the hollow electrode. I used to have a cool video of a 5 axis hole popper, making holes in a set of turbine vanes, dozens of holes, in minutes.

Compared to that, locating a chamber within a couple tenths, ought to be pretty easy. And no need for reamers anymore, just cut an electrode on the lathe. </div></div>

What kind of surface finish can you get with the newer machines at those speeds?
 
#48
Re: PTG Dual Pilot Range Rods

Using a sinker has been tried. it certainly works, but there's no real gain in performance over a conventional form tool. Then there's the issue of having to make the electrodes and dealing with the erosion.

It'd be cool though.
smile.gif
 
#49
Re: PTG Dual Pilot Range Rods

With EDM, chambers and cartridges would no longer be constrained to having round cross-sections. Think of the marketing possibilities! I totally look forward to the internet arguments about the virtues of hexagonal vs. pentagon cross-sections.
 
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