• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

Ball micrometer

Richard Coody

Ok guys i am about ready in my evolution as a handloader to step into the neck turning arena. All my rifles are no neck turn but i want to uniform my necks. Just a skim turn but i want it consistent for a whole lot of brass.

If it makes any difference the rifle is a 6BR and i use all lapua brass.

I have the PMA neck turner and just because i want it i am going get a benchrite case lathe.

I have a sinclair neck checker but my understanding is that to really check neck thickness i need a ball micrometer. I usually avoid digital devices but with my old.eyes they are a lot easier to read. Anyway advice on this tool would be greatly appreciated.
 
I use the Mitutoyo 115-313 and it works for me. Someone sells this same micrometer except it has a tapered spindle. I bought mine new, but since have seen some for sale on this forum. Do you have experience measuring to 0.0001"? Takes some touch.

You will find this information useful. http://www.6mmbr.com/casenecktools.html
 
Last edited:
jepp2 said:
I use the Mitutoyo 115-313 and it works for me. Someone sells this same micrometer except it has a turned ball shaft, don't recall who. I bought mine new, but since have seen some for sale on this forum. Do you have experience measuring to 0.0001"? Takes some touch.
Click to expand...

Yeah i have been thinking about that. Until recently i thought .001 was a pretty ridiculous measurement. I would think that you have to be very careful about consistent pressure to come close to .0001. Expect it to take some practice. That is why i was thinking digital but i don't like digital.

Thinking about this one.

http://kmshooting.com/mitutoyo-micrometer.html
 
The ball mic with 60˚ option is a K&M product. I got mine used and, after years of using the "standard" one, I really like it. If you are not schooled in using/reading the mic it is going to take a bit to figure out (at least it did for me).
When you neck-turn, especially for no-turn necks, there are things other that also must be addressed. When neck thickness is thinner the overall neck tension is going to need revisited. In other words, if you are using a .267 bushing (example only) and turn the necks to a consistent .012 then you'll likely need a .266 or even .265 bushing. At least that is what I have found.
Another point I would make. If you are brand new to the game you should practice to refine your technique on OLD brass that is past its prime. You will need to, IMO, practice a while before you'll get what you really desire.
Good luck!
 
Richard Coody said:
I would think that you have to be very careful about consistent pressure to come close to .0001. Expect it to take some practice. That is why i was thinking digital but i don't like digital.
Click to expand...

The fact it is digital doesn't increase the accuracy (unless you consider reading the scale to be accuracy). It is vitally important you use the clutch release to limit how much you tighten. That will give consistent readings. If you grab the barrel and wrench down - so to speak, you will not get accurate readings.
 
jepp2 said:
The fact it is digital doesn't increase the accuracy (unless you consider reading the scale to be accuracy). It is vitally important you use the clutch release to limit how much you tighten. That will give consistent readings. If you grab the barrel and wrench down - so to speak, you will not get accurate readings.
Click to expand...

So what you are telling me the tool has a tension built in that will give that consistent pressure for a consistent reading.
 
shoot4fun said:
The ball mic with 60˚ option is a K&M product. I got mine used and, after years of using the "standard" one, I really like it. If you are not schooled in using/reading the mic it is going to take a bit to figure out (at least it did for me).
When you neck-turn, especially for no-turn necks, there are things other that also must be addressed. When neck thickness is thinner the overall neck tension is going to need revisited. In other words, if you are using a .267 bushing (example only) and turn the necks to a consistent .012 then you'll likely need a .266 or even .265 bushing. At least that is what I have found.
Another point I would make. If you are brand new to the game you should practice to refine your technique on OLD brass that is past its prime. You will need to, IMO, practice a while before you'll get what you really desire.
Good luck!
Click to expand...

Oh yeah

I know this will be a new learning experience. I have been avoiding going down this path for some years but my shooting and reloading have evolved to the stage that it is time.

I will be in no hurry. Have about 50 cases that will be sacrificed in this learning experience. This is an experiment to see if i can improve.my groups another tenth.
 
Richard Coody said:
So what you are telling me the tool has a tension built in that will give that consistent pressure for a consistent reading.
Click to expand...

Most micrometers will have a ratcheting 'clutch' on the end of the barrel but it is not for getting measurements/ensuring the same pressure. Repeatable, accurate measurements are obtained by getting a very consistent touch when closing the micrometer on the workpiece. Practice, practice, practice. Suburban Tool has some good videos on proper care/feeding/use of gauging equipment including micrometers.
 
Richard Coody said:
So what you are telling me the tool has a tension built in that will give that consistent pressure for a consistent reading.
Click to expand...

Absolutely. But consistent rotation speed will allow the torque clutch to work the most accurately and give the most repeatable results. On the K&M unit you are looking at, it is the small knob on the end of the barrel (away from the ball). It is all in the touch you use.

Forum member rardoin was kind enough to share with me information that corrects my suggested use of the torque clutch on a micrometer. I appreciate that information and will share it here: Jepp, I respectfully disagree with using the safety clutch as a method for getting consistent pressure for precision readings. The force it takes to 'ratchet' the clutch is not nearly as consistent as developing a fine feel when rotating the barrel to get a reading. Although it may seem insignificant, the frame of a micrometer will undergo elastic deformation even at the pressure applied by the clutch. When taking measurements to be accurate within a few 0.0001" or when closing on a malleable material such as cartridge brass it will have an affect on measurements. I was taught many years back by a master machinist and tool and die maker (my brother in law) on how to get proper measurements with all types of measuring and gauging equipment and if you play with your mic a bit and try the touch method and compare it to using the safety clutch you will see the difference. I reference the Suburban Tool site which has some great demonstrations on using a micrometer.
 
Last edited:
Richard, you've gotten good advise above, but I would offer a couple of tips. 1.Buy you a good solid base to mount your ball mic into.
2. Rig up a stop on the spindle, so you are measuring at the same point on the neck each time. 3. Practice your measuring and take your time. Turning is not rocket science, but it does have a learning curve. Best of luck to you.
 
Willie said:
Richard, you've gotten good advise above, but I would offer a couple of tips. 1.Buy you a good solid base to mount your ball mic into.
2. Rig up a stop on the spindle, so you are measuring at the same point on the neck each time. 3. Practice your measuring and take your time. Turning is not rocket science, but it does have a learning curve. Best of luck to you.
Click to expand...

Both are in my plan. Holland makes a stand that is resonably priced. The stands by the micrometer manufacturers cost as much as the tool. Any recommendations?

I have look at several ideas on a block. Thinking plastic tubing might work better than taping on a block. What are your thoughts?
 
Panavice 201s work decent enough for holding a ball mic. And are adjustable.

https://www.amazon.com/dp/B000B61D22/?tag=accuratescom-20

One thing I've learned turning necks, is always run the cutter down the length of the neck twice. The first time gets the "meat" off, and if you run it down a second time, it makes them very close to uniform. Originally I turned them for my 6br, and had inconsistencies. It wasn't until last week when I did 150 cases for my dasher, that I started running the cutter down a second time, and the uniformity was substantially better. (No adjustment on the cutter, just run it down a second pass).

I used a friends lathe, and a forster cutter, since the shiny k&m one I bought requires a different expander mandrel than I think literally everyone else.
 
Lots of good advice here.

When I was working for a living, we generated some data on the accuracy various folks achieved with micrometers. The machinists did measurably better than the engineers, who did slightly better than non-technical types. The point is - there is a benefit to practice. Like most things, it's a learnable skill and not one folks are born with.

Last night I prepped a bunch of 6 ppc necks, and re-learned that the resulting thickness varies with depth of cut. With the same setting on the cutter, necks will be thinner if you take a lot off. Keep this in mind as you zero in on your final dimension. If you are ooching in on the final thickness a tenth or so at a time, then think, a-hah! that's the setting, then grab the next piece of brass that needs 0.0005 or more taken off, it's going to wind up thin.

For the most part, I've used K&M tools and the modified micrometer I got from them.
 
I have the following to be of value regarding a tube mic support:
1) a number of good functional mic stands on amazon for not a lot of money
2) No 3 rubber stopper with a hole in the center works well with a bit of trimming (see attached photo)

best regards
dan
 

Attachments

  • tubemic2.jpg
    tubemic2.jpg
    965.2 KB · Views: 50
Richard Coody said:
Both are in my plan. Holland makes a stand that is resonably priced. The stands by the micrometer manufacturers cost as much as the tool. Any recommendations?

I have look at several ideas on a block. Thinking plastic tubing might work better than taping on a block. What are your thoughts?
Click to expand...
I have a small bench vise that has a pair of plastic jaws. I mount my ball mic in the jaws and have both hands free to measure. Not very elegant but gets the job done and the vise is handy for doing small jobs like trigger work etc. ....... Just a thought.
 
You must log in or register to reply here.

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Classified Ads

Forum statistics

Threads
165,584
Messages
2,198,537
Members
78,983
Latest member
Len6163

Share This Page

Back
Top