BEWARE FALSE PROPHETS (or indicators in this case)

adamsgt

adamsgt

Jerry Adams
When checking neck thickness as I started to prep new brass I used a fixture from Sinclair that used a dial indicator for measurement.


DSCN0061.jpg
As you can see the neck measured 10 thou. When I finally decided to do a check with a tube mic I got this


:DSCN0062.jpg


Measured 8 thou with this and a manual tube mic. Also got the same results when I inserted a .008 feeler gauge under the dial indicator tip. Appears that I've been more than little remiss in checking my measuring tools.At this point I wondering if the problem is with the dial indicator itself or how it reads when in the fixture. I'll have to do some more research on that.
 
I don'tt know much about the Baker brand of DI. Looks like that particular brand isn't very accurate..
I use sterritt.
 
Usually the digital instruments can be calibrated. Use a gage that you trust and that should solve your problem. There should be some instructions with your DI.

RCF
 
You can use a ball mike when setting a neck turner, but an outside mike measuring the neck over a seated bullet is the most sure way to know what you have.
 
adamsgt said:
When checking neck thickness as I started to prep new brass I used a fixture from Sinclair that used a dial indicator for measurement.


View attachment 12396
As you can see the neck measured 10 thou. When I finally decided to do a check with a tube mic I got this


:View attachment 12397


Measured 8 thou with this and a manual tube mic. Also got the same results when I inserted a .008 feeler gauge under the dial indicator tip. Appears that I've been more than little remiss in checking my measuring tools.At this point I wondering if the problem is with the dial indicator itself or how it reads when in the fixture. I'll have to do some more research on that.
Click to expand...

If the indicator measures the feeler gauge properly, then the indicator is not the problem. In the first picture, it looks like weight of the case could be levering the indicator tip upwards. Or if the rod supports the head of the case with a tip that goes through the flash hole, your necks could be non-coaxial with the case and cause the same problem. You could also have a donut at the neck/shoulder junction that the Sinclair rod is riding on, but the tube mike anvil is not.

Cheers,
Keith
 
Looks like an application error. :mad:
Both methods have their issues............
And .............I was told to do an avg. 3 sides out of 4 is good enough.
IE. .0081", .0081", .0081", .8000" is good enough. With a ball mic.
And there is an exception. But, you have to pay for that. Sorry no load data.
But, this is for a 6PPC tight neck.
 
mks said:
If the indicator measures the feeler gauge properly, then the indicator is not the problem. In the first picture, it looks like weight of the case could be levering the indicator tip upwards. Or if the rod supports the head of the case with a tip that goes through the flash hole, your necks could be non-coaxial with the case and cause the same problem. You could also have a donut at the neck/shoulder junction that the Sinclair rod is riding on, but the tube mike anvil is not.

Cheers,
Keith
Click to expand...

Keith, the indicator read 10 thou when I used an 8 thou feeler gauge. As far as the first picture, I used both hands to hold the camera so I didn't have a third available for the case. :p Actually it read 10 thou all round when I rotated the case 360 degrees. The case measured 8 thou around with the electronic mic and a mechanical tube mic. I've got one of those indicator stands with a granite base and I'm going to mount the indicator on that in the morning and see what it shows there. This could be a good learning experience in how to ensure the measurements you rely on are correct. Need to check the checkers. Thought just occurred to me that I probably don't have an adequate supply of standards to check the measuring instruments I use. Good deal, I haven't bought anything in a week or so. UPS man looks sad when he passes by my house.
 
adamsgt said:
Al, I didn't think we were supposed to discuss electing presidents.
Click to expand...

LOL ;)

Wasn't meaning to be rude BTW, in shorthand, "measuring is hard." I mostly use measuring tools for roughing and fitments for final gauging, I haven't used any sort of a neck mic for years because for ME most "measurements" under a thou or so are hard. When I do (attempt) to actually measure something under a thou I start by normalizing the instruments and some sort of a gage block. I often turn to my reamer bushings for this, or an assortment of pin gages. Measuring some bushings using two-three mics and several bushings or pins and writing everything down I can sometimes feel comfortable that I've got something "measured" to within a few tenths...... but when it comes to measuring necks I turn and load bullets, maybe even play with various neck tensions and come up with an overall dimension.

I don't even expect different methods to agree although I'm pleasantly surprised when they do :)

In this vein I've been impressed, nay blown away with the agreement I've found between PT&G reamer bushings and Deltronics pins. There actually ARE people who work in tenths.... repeatably.

But not me, not with cheap tools. And not without zeroing said tools prior to use.

al
 
Mike Bryant said:
You can use a ball mike when setting a neck turner, but an outside mike measuring the neck over a seated bullet is the most sure way to know what you have.
Click to expand...

That is the way I have always done my necks. Except, I do not own a Ball Mic. I rely on my outside mic with a seated bullet. When guys talk about turning there necks to X measurement it means nothing to me. I may ruin more pieces of brass on initial setup but it is just part of doing business.
 
CYanchycki said:
That is the way I have always done my necks. Except, I do not own a Ball Mic. I rely on my outside mic with a seated bullet. When guys talk about turning there necks to X measurement it means nothing to me. I may ruin more pieces of brass on initial setup but it is just part of doing business.
Click to expand...

OK, I'm trying to discern your process of getting the necks to the correct thickness without ever measuring the neck thickness directly.

Let's say you're shooting for a .261 OD for a .262 neck. So, you start with a neck turning tool, a piece of new brass and a bullet. You set the turner to take off an arbitrary amount of brass from the neck, expand the neck for the turner, turn the neck, size the neck for seating, seat the bullet and then measure the diameter. At this point you know how much has to come off the neck diameter for the desired neck size. Depending on how much you take off on the initial cut you may be able to get to the desired diameter with one more pass.

Now you adjust the turner to take off more brass, pull the bullet, expand the neck if necessary, turn the neck some more, size the neck for seating, seat the bullet and measure. If you get close enough on the second pass the next iteration should get you to where you want to go.

At this point the turning tool is set to cut the final diameter. However, as the Lapua .220 brass is about .015 thick and you'll be want to get into the .008-.010 range you'll be taking off approx .007 total from the neck thickness. I know my K&M protested some when I got near removing .004 at one pass so this means you'll need at least two passes. This means you'll probably need a second tool to do the first cut seeing as you already have one set for the final cut.

Now this process may be nothing like what you actually do, but it's what I could come up with to turn the necks without measuring the neck thickness directly but only measuring with seated bullets. So if what I outlined is complete BS then could you provide a more detailed explanation of how you get to the desired results without measuring the neck thickness? I certainly agree with you and Mike that the final proof is measuring with the seated bullet.
 
Jerry that is what I do. Except I do not use the same piece of brass to get to the final diameter.

This is my process.


Expand neck
Trim to 1.500"
Chamfer inside of neck mouths
Debur flash holes
Slip a expanded case over the cutter mandrel
Adjust cutter till just making contact
Remove brass
Adjust cutter down. Those that have a K&M turner know it has a crude scale on it. Turn the cutter down to what I think it should be making sure to not go further than I want.
Cut the neck
Remove any traces of cuttings and oil
Size then seat bullet
Measure outside diameter.

If not enough, set that case aside and repeat with a fresh case except I turn the cutter lower before turning.

Like I said, I use more cases to get where I want. In reality once the cutter is set it should never need readjusting. I do not sweat it if from turning session to turning session that they are bang on at say 3 thou total clearance. I just make sure that I turn 25 cases in a sitting and they fall within close tolerances.

A ball mic is just something that I fealt I have no real need to spend money on when an outside mic is more useful to me for otehr applications.

JMO but I am no Hall of Famer.
 
I use a pumpkin tool for my ppc and make one cut only. On my 30BR I do it with one cut using Jerry Stiller's neck turner. I don't get beat by my brass.
 
CYanchycki said:
Jerry that is what I do. Except I do not use the same piece of brass to get to the final diameter.

This is my process.


Expand neck
Trim to 1.500"
Chamfer inside of neck mouths
Debur flash holes
Slip a expanded case over the cutter mandrel
Adjust cutter till just making contact
Remove brass
Adjust cutter down. Those that have a K&M turner know it has a crude scale on it. Turn the cutter down to what I think it should be making sure to not go further than I want.
Cut the neck
Remove any traces of cuttings and oil
Size then seat bullet
Measure outside diameter.

If not enough, set that case aside and repeat with a fresh case except I turn the cutter lower before turning.

Like I said, I use more cases to get where I want. In reality once the cutter is set it should never need readjusting. I do not sweat it if from turning session to turning session that they are bang on at say 3 thou total clearance. I just make sure that I turn 25 cases in a sitting and they fall within close tolerances.

A ball mic is just something that I fealt I have no real need to spend money on when an outside mic is more useful to me for otehr applications.

JMO but I am no Hall of Famer.
Click to expand...

OK, I understand what you're doing. You don't explicitly say so but your response implies that you use one tool to take it all off on one pass once you've got it where you want it. Is this correct? What tool do you use for turning the necks? I talked to K&M two days ago and the guy said that 4 thou was about the most I should try to take in one pass, hence two tools. Maybe that was just a sales pitch. I have the carbide cutters in the mail from K&M maybe they'll allow me to take more off at once and maybe a higher rpm.

I think I'm beginning to understand why I'm being drawn to benchrest shooting, I'm a gadget junkie. :eek:
 
Yes I cut in 1 pass. I am shooting a .269 neck thus 1 tool is all I need to get the neck diameter I need.

I use my cordless 2 speed Ridgid drill on the slow setting. I make the cut in from mouth to shoulder at maybe half speed and a slow movement in. When it reaches the stop, I speed the drill up and slowly retract the case to the mouth. I then go in and out one final time.

I hold the tool in one hand and the cordless in the other. I have something about holding either in a vise. I let my hands and wrist be the shock absorber. Maybe when I get older I may not be able to do it but for now...............
 
CYanchycki said:
Yes I cut in 1 pass. I am shooting a .269 neck thus 1 tool is all I need to get the neck diameter I need.

I use my cordless 2 speed Ridgid drill on the slow setting. I make the cut in from mouth to shoulder at maybe half speed and a slow movement in. When it reaches the stop, I speed the drill up and slowly retract the case to the mouth. I then go in and out one final time.

I hold the tool in one hand and the cordless in the other. I have something about holding either in a vise. I let my hands and wrist be the shock absorber. Maybe when I get older I may not be able to do it but for now...............
Click to expand...

OK,the .269 neck explains a lot. The light and heavy guns I'm shooting now are ones I bought used and have .262 necks. The barrels still have some life left and I'll go to a .269 neck when I rebarrel. I have three Kreiger gain twist barrels sitting on a shelf and a PTG 6Beggs reamer with a .269 neck alongside. Probably do the rebarrel this coming winter.

Was afraid that with the indicator issues I had cut the necks too thin. I had been shooting for .0085 and ended up around .008. Then I watched the first Jack Neary video and he recommended a .0081. So I may have lucked out. This will be interesting.
 
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