aluminium prechanged pneumatic progress

[urgle the danish cow]

so im obviously not any where near done with this but i will not be able to work on it over summer and will have to wait until fall.
total work hours: 29
ive had a couple of problems lately i was bringing the barrel down to fit in my .421875 inch hole and i was dry fitting it. well was looking like it was going to fit so i used scotch-brite on it to help fit at about 1200 rpm. BAD IDEA. the hardend steel barrel got very hot and when i inserted it into the action block the steel cooled down and fused to the aluminum. so after hours of working i built a poker and put it in a hydraulic press and had to put on about 1550 pounds of force to slide it out. turns out the barrel was at .4320 when it was out.
building the trigger was hard and was done with a hacksaw and wheel grinder.
the aluminum spring plug is held in with allen screws and the barre is held in with two cup tipped allen screws which really hold it in place.
the bolt needs to be redone bc its damaged and i want it to be aluminum.
this is .22 caliber with a 24 inch rifled crosman barrel. this is in fact based off of sir Howard Buckley's modern stock reservoir airgun and for his own rights i will not provide blueprints sorry.
now for pics sorry the trigger pics will not load for they are over the KB limit

[LovableAirGuns]

WOW good job man cant wait for the gun to be finisherd an also the rifling looks really cool

[Gippeto]

... i was bringing the barrel down to fit in my .421875 inch hole

Have a pic of the tool you used to measure to that degree?

The buckley rifle looks like a nice little project.... I'm sure you'll have fun with it.

[inonickname]

... i was bringing the barrel down to fit in my .421875 inch hole

Have a pic of the tool you used to measure to that degree?

The buckley rifle looks like a nice little project.... I'm sure you'll have fun with it.

I'll buy it.

[POLAND_SPUD]

... i was bringing the barrel down to fit in my .421875 inch hole

Have a pic of the tool you used to measure to that degree?

The buckley rifle looks like a nice little project.... I'm sure you'll have fun with it.

I'll buy it.

Yeah, blame the guy just because he converted from a true system of measurements into your outdated/retarded imperial system

[inonickname]

Have a pic of the tool you used to measure to that degree?

The buckley rifle looks like a nice little project.... I'm sure you'll have fun with it.

I'll buy it.

Yeah, blame the guy just because he converted from a true system of measurements into your outdated/retarded imperial system

God no I don't use that shit. Imperial should only be used to measure someone's height and the length of certain bodily parts.

[velocity3x]

.421875 inch hole ...
barrel was at .4320

How did you insert the barrel into the hole in the first place?? The barrel is .011" larger than the hole!

_________________
A government big enough to give you everything you want is big enough to take everything you have.

[Technician1002]

If you want to measure down to a few nm, may I recommend one of these?


http://www.nist.gov/mml/metallurgy/mml- ... scopes.cfm

As far as inserting it in the hole in the first place, the hole changes size with temperature.
http://sites.google.com/site/sed695b/pr ... -expansion
It was fit inside while still hot from the polishing, then it cooled.

In large ships and boats the tiller arm is installed onto the rudder post this way. The tiller arm has a hole too small for the post. It is expanded with heat and fitted onto the post and then cooled. This fit prevents the arm from working loose on the post in use. Sometimes the top of the post even needs cooled with liquid nitrogen or dry ice before the tiller arm will fit on the post.

[velocity3x]

As far as inserting it in the hole in the first place, the hole changes size with temperature.

Tech, Thanks for attempting to enlighten me but respectfully......no.

urgle said:

i was bringing the barrel down to fit in my .421875 inch hole and i was dry fitting it. well was looking like it was going to fit so i used scotch-brite on it to help fit at about 1200 rpm. BAD IDEA. the hardend steel barrel got very hot and when i inserted it into the action block the steel cooled down and fused to the aluminum. so after hours of working i built a poker and put it in a hydraulic press and had to put on about 1550 pounds of force to slide it out. turns out the barrel was at .4320 when it was out.

"the hardend steel barrel got very hot"...ergo the barrel expanded. The barrel expanded (not the bore).

"turns out the barrel was at .4320 when it was out."...Obviously in a cool(er), contracted state.

According to urgle's measurements....In the cool(er),contracted state, the barrel was 0.010" larger than the bore in which it was to fit. I'm sure with your machining experience, you realize that a press-fit of only 0.0005" is quite tight and requires the force of a press.

My guess is that the dry fit into the aluminum bore caused the bore to gall, making removal difficult at best. I think the measurements are wrong. IMO, to press in a barrel of + 0.010" isn't going to happen without a fully grown+++ press and Superman at the controls!

[urgle the danish cow]

As far as inserting it in the hole in the first place, the hole changes size with temperature.

Tech, Thanks for attempting to enlighten me but respectfully......no.

urgle said:

i was bringing the barrel down to fit in my .421875 inch hole and i was dry fitting it. well was looking like it was going to fit so i used scotch-brite on it to help fit at about 1200 rpm. BAD IDEA. the hardend steel barrel got very hot and when i inserted it into the action block the steel cooled down and fused to the aluminum. so after hours of working i built a poker and put it in a hydraulic press and had to put on about 1550 pounds of force to slide it out. turns out the barrel was at .4320 when it was out.

"the hardend steel barrel got very hot"...ergo the barrel expanded. The barrel expanded (not the bore).

"turns out the barrel was at .4320 when it was out."...Obviously in a cool(er), contracted state.

According to urgle's measurements....In the cool(er),contracted state, the barrel was 0.010" larger than the bore in which it was to fit. I'm sure with your machining experience, you realize that a press-fit of only 0.0005" is quite tight and requires the force of a press.

My guess is that the dry fit into the aluminum bore caused the bore to gall, making removal difficult at best. I think the measurements are wrong. IMO, to press in a barrel of + 0.010" isn't going to happen without a fully grown+++ press and Superman at the controls!

you are dead on with how it got in the barrel. i used a hydraulic press as i stated to get it out

[urgle the danish cow]

... i was bringing the barrel down to fit in my .421875 inch hole

Have a pic of the tool you used to measure to that degree?

The buckley rifle looks like a nice little project.... I'm sure you'll have fun with it.

you may also call it 27/64

[saefroch]

Sig Figs