Patch box release geometry

[Booneliane]

I’m fixing to install a patch box release on a rifle.

First time working with one of these.

TOW included instructions. By their diagram the geometry of all the pieces looks like this.

However, in my mind, shouldnt the push rod contact the spring lever as far away from the fulcrum point as possible for more leverage?

Like this?

That spring feels mighty stiff. And I feel a little more mechanical advantage over it would be a good thing.

 

[billraby]

There is a lot more metal on the spring than there needs to be. Cut down that thick part to the same thickness as the rest of the spring leaving only a triangle at the end in the original shape. Then you can cut the part that attaches to the lid a bit shorter and move the push rod higher up. I hope this makes sense.

 

[Vaino]

This type of Pbox release installs better if the button in the Bplate return is a separate item...I use a flat head screw w/ the slot filed off. ....this enables the button to be at a right angle to the return. The push rod then is just a straight piece of round stock which pushes against a screwed down catch spring which is made from .015 thick hardened spring steel. The catch is from a nail and is riveted to the lid. The rough sketch shows the details.....Fred

 

[Booneliane]

There is a lot more metal on the spring than there needs to be. Cut down that thick part to the same thickness as the rest of the spring leaving only a triangle at the end in the original shape. Then you can cut the part that attaches to the lid a bit shorter and move the push rod higher up. I hope this makes sense.

Perfect sense. Thank you.

 

[SqSlayer]

I recently completed this part of a build for the first time using the same components. I filed the thicker part of the spring down to about 0.030" thickness, width was left alone. The pushrod should contact the spring as far away from the spring mounting screw as possible without interfering with the latch/catch for best mechanical advantage.

 

[Ames]

Even looking at the drawings confuse me. Lets see a picture of the parts installed!

 

[SqSlayer]

Pushrod is coming up from the toeplate. Also check out Bill Raby's Lancaster build - Part 46 on youtube.

 

[Ames]

Nice! Thank you.

 

[Larry (Omaha)]

This type of Pbox release installs better if the button in the Bplate return is a separate item...I use a flat head screw w/ the slot filed off. ....this enables the button to be at a right angle to the return. The push rod then is just a straight piece of round stock which pushes against a screwed down catch spring which is made from .015 thick hardened spring steel. The catch is from a nail and is riveted to the lid. The rough sketch shows the details.....Fred

Fred,
My head is thicker than most humans, so help me out here. I installed this Track PB last April and yes the spring is waaaaaaay too stout. I trimmed the spring, and set up works just fine. What is the advantage of the FH screw?

 

[Vaino]

Fred,
My head is thicker than most humans, so help me out here. I installed this Track PB last April and yes the spring is waaaaaaay too stout. I trimmed the spring, and set up works just fine. What is the advantage of the FH screw?

I've found that it's easier to drill the pushrod hole if one doesn't start at the top of the Bplate return. The hole location for the FH screw which is perpendicular to the top flat of the Bplate is marked in the wood w/ a drill and the Bplate is removed to drill the hole for the pushrod. The flathead screw gives a little leeway if the pushrod hole is slightly mislocated.

Also, I prefer making many of the items in lieu of buying.....always have FH screws around the house, the pushrod is from a nail. I do buy the spring steel and heat treat it, and a RD head screw holds the catch spring down. The catch is riveted to the lid and is also from a nail. .....Fred