Question for machinists

[Lucky Shooter]

I think I've gone about 3/3 stir crazy and have started a small job for fun.

I'm using a micrometer head to make a tenon length/headspace gage
and have some questions about fitting the head to the measuring surface.

I'd like to avoid pressing the parts together and to avoid putting in a set screw.
Would like to be able to lightly tap the parts together.

In polishing out the hole for the micrometer head, what should the relative
sizes be for tapping them together ?

I looked at Machinery's Handbook and don't think I saw the light.

Will appreciate any replies.

A. Weldy

 

[Dessert]

I think I've gone about 3/3 stir crazy and have started a small job for fun.

I'm using a micrometer head to make a tenon length/headspace gage
and have some questions about fitting the head to the measuring surface.

I'd like to avoid pressing the parts together and to avoid putting in a set screw.
Would like to be able to lightly tap the parts together.

In polishing out the hole for the micrometer head, what should the relative
sizes be for tapping them together ?

I looked at Machinery's Handbook and don't think I saw the light.

Will appreciate any replies.

A. Weldy

I’ve made several chamber gauges, and use dial indicators. easy/peasy.

 

[jkohler]

Why are you against putting in a set screw if I may ask.

 

[Dessert]

I drill the hole to a slip fit then use J-B weld. Sorry I didn’t post this with my above post.

 

[WayneShaw]

Set screw with 1 or 2 lead shots down the hole to push against the micrometer.

 

[Toolbreaker]

I like using split collars for gage mounting, but a set screw with lead shot like Wayne stated would work just fine. Just don't honk down on the set screw.

 

[jackieschmidt]

Why not just use a sleeve that is longer than the tenon and a set of depth mic’s?
I assume you are wanting this tool to measure things such as headspace and cone depth.

 

[jkohler]

I used set screws on this one with no binding in the head.

 

[DaveTooley]

I've got 4 different ones with tenth thimbles. All used set screws. Calibrate with a surface plate or gage ball. Very easy. Don't over think this.
I used a bit of Loctite along with screws.

 

[DaveTooley]

Why not just use a sleeve that is longer than the tenon and a set of depth mic’s?
I assume you are wanting this tool to measure things such as headspace and cone depth.

Sometimes simple arithmetic can be challenging.

 

[Bamban]

Butch Lambert gifted me this indicator. It was set up for bolt guns. I replaced the sleeve for the AR15 0.8125 tenon . When I initially set the gauge to read headspace, I adjusted where the readout was clamped to read 0.200x for the standard 13/16x16 tpi x.620 tenon, so when doing barrels for the longer 13/16x20 tpi x 0.920 tenon, it reads 0.500x. I used a real GI M16 bolt to set up and BAT Machine barrel extension.

The indicator is held to the sleeve by 3 set screws bearing on pieces of heavy duty weed eater string.




For the bolt guns, I just made some sleeves and used a depth mic, like how Jackie does.

 

[Lucky Shooter]

I'll wind up using a set screw.

Just don't want to damage the head putting it together or later by taking it apart.

I learned about the use of sleeves some years ago
when Jackie and other guys on BRC helped a few
beginners get started---don't know where they found the patience.

Simple arithmetic is just that----simple. This doesn't preclude the possibility of mistakes when
standing over a lathe---can be embarrassing.

Thanks for the replies.

A. Weldy

 

[DaveTooley]

This what I use. I have 4 made up for different diameter threads and different HS numbers. You can use a 1" thimble and get to over 1.175" by scribing a line at .025" intervals after you get past 1.000" And you can repeat measurements to within a few tenths.
Measure small cut small
https://www.ebay.com/itm/Mitutoyo-1...594011?hash=item3b3401a71b:g:lE4AAOSwT~xdEiRi

 

[Ggmac]

I think I've gone about 3/3 stir crazy and have started a small job for fun.

I'm using a micrometer head to make a tenon length/headspace gage
and have some questions about fitting the head to the measuring surface.

I'd like to avoid pressing the parts together and to avoid putting in a set screw.
Would like to be able to lightly tap the parts together.

In polishing out the hole for the micrometer head, what should the relative
sizes be for tapping them together ?

I looked at Machinery's Handbook and don't think I saw the light.

Will appreciate any replies.

A. Weldy

Y you could use an o-ring or two on the external piece of the internal slider piece .

 

[The Pumpkin]

I like using split collars for gage mounting, but a set screw with lead shot like Wayne stated would work just fine. Just don't honk down on the set screw.

View attachment 1190327

What's the torque setting on a HONK down? D

 

[DaveTooley]

Here's one I've never seen before
https://www.ebay.com/itm/MITUTOYO-M...306948?hash=item1cee6e8dc4:g:9rMAAOSwE25e-nj1.

 

[Danny1788]

Here’s the one I made. Super cheap. Easy to use and repeatable measurements. I mainly do rem700 type tenons so I don’t normally need anything longer then 1” of travel.

 

[Danny1788]

For those wondering, once I have my tendon threaded and timed. Before I cut my counter bore. I put my gage on the tenon and zero on the breech. Then I have my zero.. from my action measurements I know exactly what to set the headspace at. I bought all the parts on amazon and machined the aluminum collar. Took about 30min and used a set screw with no loktite or anything. The flat anvil was a premade part and works perfect

 

[hoz53]

For those wondering, once I have my tendon threaded and timed. Before I cut my counter bore. I put my gage on the tenon and zero on the breech. Then I have my zero.. from my action measurements I know exactly what to set the headspace at. I bought all the parts on amazon and machined the aluminum collar. Took about 30min and used a set screw with no loktite or anything. The flat anvil was a premade part and works perfect

so you calculate protrusion of head space gauge and use that?

 

[marazzi59]

If I understood your question I would be looking for a .001" difference between the two parts. If thats to tight then break out the sand paper and slowly work one part to a nice slip fit and then maybe use a epoxy or loctite or super glue to help hold it together