Thank you, Mr. Tooley...

[tobnpr]

There was a thread running here recently where Dave showed a couple of tenon "collars" for measuring from face of go gauge to receiver ring when checking chamber depth. As soon as I saw it, I knew I had to have it- no more adding #'s and rocking depth gauges for me...

Found a Mit micrometer stem with .500 travel NOS on Fleabay for $25.
The spindle is way to small to work on the face of the gauge due to the center cut, so I turned a brass tip and drilled for a slip fit over the spindle and 20 under the 3/8" diameter of the stem. A little retaining compound, made sure it was square and let it set up.

Had some 6061, 1-1/2" round stock- turned it down, drilled and bored to fit over 1-1/16 tenon and a center hole for the stem.

Simple idea and works amazingly well- very repeatable as opposed to the rocking depth mike...
If you ain't got it- you need to make one. Only "downside" is I gotta think backwards, as the spindle is for an outside mike and not a depth mike.

https://imgur.com/5bMtXDE

https://imgur.com/bVDJGCY

 

[DaveTooley]

It's called subtraction.

 

[dnellans]

What are you guys doing for setting an effective zero? No one wants to keep track of the zero being at .273 (or other arbitrary).

on my current collars i made sure the ones i use regularly are all 1.000 to make the math easy working towards typical numbers in the .700-900 range.

are you making the fixed collar long then finishing it to length only after mounting and measuring a 1.000 guage block?

 

[hoz53]

There was a thread running here recently where Dave showed a couple of tenon "collars" for measuring from face of go gauge to receiver ring when checking chamber depth. As soon as I saw it, I knew I had to have it- no more adding #'s and rocking depth gauges for me...

Found a Mit micrometer stem with .500 travel NOS on Fleabay for $25.
The spindle is way to small to work on the face of the gauge due to the center cut, so I turned a brass tip and drilled for a slip fit over the spindle and 20 under the 3/8" diameter of the stem. A little retaining compound, made sure it was square and let it set up.

Had some 6061, 1-1/2" round stock- turned it down, drilled and bored to fit over 1-1/16 tenon and a center hole for the stem.

Simple idea and works amazingly well- very repeatable as opposed to the rocking depth mike...
If you ain't got it- you need to make one. Only "downside" is I gotta think backwards, as the spindle is for an outside mike and not a depth mike.

https://imgur.com/5bMtXDE

https://imgur.com/bVDJGCY

i remember seeing the ones Dave T posted the pic of. Nice job on yours. I take it you use it to measure protrusion of the HS gage? Id like to use one to measure shoulder to Breech Face. the disc would have to be big enough in dia. of coarse and id set it up so 0 is at the shoulder end of the collar. i want one —-thanks

 

[DaveTooley]

My 1" collar I zero on a surface Plate. That's flush with the end. You could use any ground flat piece. Ground recoil lug, ground HSS lathe bit etc. I get it as close as I can and then finish the zero the normal way like a micrometer by adjusting the rotating part. On the 2" version I use a 1" gage ball sitting inside an O-ring to keep it centered while adjusting the zero. On the 1" I screw it out past the 1" line and scribe lines with a razor knife in .025" increments. How far you can go depends on the who manufactured the thimble. On my Starrett I went out to over 1.200".

 

[tobnpr]

What are you guys doing for setting an effective zero?

Struggled a bit with this one when it came to facing the collar to length.
I ended up setting it 1.250 with the mike at max, so my range with this one is .750-1.250.

 

[DaveTooley]

i remember seeing the ones Dave T posted the pic of. Nice job on yours. I take it you use it to measure protrusion of the HS gage? Id like to use one to measure shoulder to Breech Face. the disc would have to be big enough in dia. of coarse and id set it up so 0 is at the shoulder end of the collar. i want one —-thanks

I use an appropriate angled disk for that. Height of the disk can vary as it's not critical. That way I don't need a dedicated setup. Place it on the counterbore then measure like measuring HS. For any given action I just record that number so I can duplicate it in the future. Measurement with the disk minus the recorded number = the depth the CB needs deepening.

 

[DaveTooley]

Struggled a bit with this one when it came to facing the collar to length.
I ended up setting it 1.250 with the mike at max, so my range with this one is .750-1.250.

I never tried to zero it that way. Easy to use a surface plate or something similar. I made the collars in one setup to keep everything parallel, perpendicular. Drill, ream, bore.

 

[DaveTooley]

This is what I use. Also pretty stable when using a depth mic.

 

[DaveTooley]

Doing a run of barrels now. My HS number is .948". It's not hard to get this close every time.

 

[hoz53]

I use an appropriate angled disk for that. Height of the disk can vary as it's not critical. That way I don't need a dedicated setup. Place it on the counterbore then measure like measuring HS. For any given action I just record that number so I can duplicate it in the future. Measurement with the disk minus the recorded number = the depth the CB needs deepening.

thats a good idea to measure counterbore depth- i will do that to — im also going to make a disc that staddles counterbore to measure shoulder to breech face the same way, inless i figure out something im missing and can think of a better way.
thanks much for your help

 

[ridgeway]

Here is the one I made...zero the mic on surface plate. Will read actual measurement from 0"-2" the same way you read an OD mic. The inserts are used to measure cone length. 25° and 30°.

 

[Dusty Stevens]

I must have gotten cut off from pics. I was going to show what i use. Think of ridgeways picture with a 1” ground ball bearing to fit any cone or no ball to use on a headspace gage. I have another one that fits the bat M as well. Just zero it on top of the ball on a surface plate and keep notes.

 

[xr650rRider]

Commercial version

PMA barrel micrometer

 

[GenePoole]

I'd like to see your pictures, Dusty. Here's mine for cone breech: