Bullet Comparators

[Popsbengo]

Been busy in the workshop:   Bullet comparators for 6.5,  .308,  .338.   I use a dial indicator with 10mm flat probe.  I've got a granite table so I just set up on there.

Blued steel (looks so much nicer than stainless),  copied the hole dimensions (for the bearing surfaces) from some borrowed comparators  - easy to get the right reamers from Tracy Tools.

Probably cost me more than the three items from Brownells but it kept me quite for a morning..

 

 

 

[terryh]

Nice 😎 and using the granite slab and a dial gauge is a lot quicker than in Vernier callipers.

Keep thinking of something along those for sorting 22rf rim thickness?

T

 

ps concur Tracy tools are rather useful

[Popsbengo]

2 minutes ago, terryh said:

Nice 😎 and using the granite slab and a dial gauge is a lot quicker than in Vernier callipers.

Keep thinking of something along those for sorting 22rf rim thickness?

T

I missed it on the picture but the dial indicator has a lift lever so it's pretty easy to lift without upsetting any settings.  I use a slip gauge to check 'zero' hasn't inadvertently moved on the gauge now and again.  

Hope it was worth the effort and I see some results down range 😁

[terryh]

.... you'll be building a Juenke machine next 😱😉

[meles meles]

Hmmm, we'd like to see him build a Junkers 87...  😁

[Popsbengo]

Juenke machine 🤔

Had to Google the obscure reference.  Can't say I'm impressed with the design;  Heath-Robinson-esk

What do Badgers know of hairyplanes?   My Mum was a WAAF Engine Fitter on RR Merlins during WW2,  and her son was responsible for knocking down the Merlin & Griffin testbeds at RR Crewe ! (deliberately I must add).

[meles meles]

34 minutes ago, Popsbengo said:

What do Badgers know of hairyplanes?  

You may have tried to airbrush us out of your 'istory, oomans, but the Badger Expeditionary Airforce saved your bacon at D Day. Badgers are excellent dogfighters and if you look at pictures of D day air ops you'll see lots of aircraft with black and white insignia painted on the wings and fuselage. That was us keeping the Nazis at bay for you. We still watch your backs.

 

 

[Elwood]

Nice, I did pretty much the same thing only I purchased all the components, I really wanted the lift arm but couldn't find anything to fit onto my dial indicator. 

My one gripe with the comparators is if the bullet isn't sitting completely central it throws  the measurement out, I would like to see higher sides on them.

Mine largely sits dormant now as I load for to many calibers.

[Popsbengo]

2 hours ago, terryh said:

.... you'll be building a Juenke machine next 😱😉

You peeked my interest with the "Juenke" machine.  In my educated opinion this is a load of baloney  - it took me less than 30 sec to see the wiring diagram (BulletInspector.com call it an electrical diagram) was wrong:  The +12V. is going to the anode of a diode in series.  Doh !  Nothing gonna work there dude.   There's an on-board 12V regulator that aint' going to regulate anything with a 12V supply.   Not designed by an electronics engineer or even a competent hobbyist I suspect.

 It's complete bullshert.  It's no wonder they offer no guarantee or money back!!

The nearest I can guess what the thing is supposed to be doing is some sort of balanced bridge circuit that is nulled out for a mass of metal (bullet) and when that mass is disturbed it swings the meter.  What those disturbances are are open to speculation.  There have been blind tests done with deliberately bad bullets and plain rods -  well demonstrated that it's baloney.

[terryh]

PbG,

Never actually seen or know anyone who's used on, it just stuck in my mind of something seen along the way with folks sorting bullets.

T

[Popsbengo]

1 hour ago, Elwood said:

My one gripe with the comparators is if the bullet isn't sitting completely central it throws  the measurement out, I would like to see higher sides on them.

Yes it's a problem but I have made clearance rings to align the bullets perfectly upright.  Like a donut that sits on top of the gauge block and squares up the bullet along the major diameter.

I would have liked to make it all in one but my tooling doesn't allow.

[terryh]

PbG,

Are irregular meplats an issue by using, what appears to b a 'flat', on the nose of the dial gauge ?

T

[Elwood]

57 minutes ago, terryh said:

PbG,

Are irregular meplats an issue by using, what appears to b a 'flat', on the nose of the dial gauge ?

T

terry I know you're going to see your error the minute I post this, but the meplats are inside the comparator, the flat nose makes contact with the base of the bullet.

I honestly think this probably the best way to measure bullets base to ogive and the lift arm gives it great  consistency combined with ease of use and speed.

[Popsbengo]

1 minute ago, Elwood said:

terry I know you're going to see your error the minute I post this, but the meplats are inside the comparator, the flat nose makes contact with the base of the bullet.

I honestly think this probably the best way to measure bullets base to ogive and the lift arm gives it great  consistency combined with ease of use and speed.

yep, spot on.  measures the bearing surface to the tail.  As the tails are slightly variable in form the flat helps take the high point each time,  not necessarily the best solution but better than a single point varying on placement of the bullet under the gauge.

[terryh]

my bad, should have looked rather than 'think' what I saw! apologies 😯