Trigger Assembly Screws

[snowhunter]

My scope mount started moving so I read on the forum to tighten the trigger assembly. I understood the post to say only tighten the front screw with blue loctite and leave the back screw alone. I just read another post saying to tighten both screws. I am very new to this sport and need your help. Thanks

[Doe Master]

A dab of blue Loctite on both screws and then snug them up .

[xcaliber]

Snug is the key word. Let them dry for more than 24 hours in an atmosphere of 50 degree temps F or higher. All 4!

[Arrowflinger]

Snug is the key word. Let them dry for more than 24 hours in an atmosphere of 50 degree teSmps F or higher. All 4!

. 4 trigger screws? scope screws?

[xcaliber]

Yes! There are several posts about upgrading screw's. I have some extra aluminum screw's that are better than stock, but the Titanium set is a better option. There are several posts about them, but if you want some of the leftover aluminum screw's, just let me know.

[snowhunter]

Thanks for the replies about the trigger screws. It was mentioned to tighten all 4 screws. I see the two screws in front and back of the trigger, where are the other two screws located? Thanks

[chilly_willy]

I use the pink Loctite works just as good as the blue Loctite. It's used for 1/4.20 thread size and smaller.

[Normous]

Thanks for the replies about the trigger screws. It was mentioned to tighten all 4 screws. I see the two screws in front and back of the trigger, where are the other two screws located? Thanks

If you remove the two stock to mainframe screws you will see two screws holding the trigger unit to the mainframe. Access from underneath.

[Boo]

No offence guys but the word snug can be misleading and relative.
In order for a fastener to keep something tightened, the fastener has to do some stretching. It is that elasticity of the fastener that keeps the parts together and I don't see a snug bolt (snug in my mind) holding anything on a crossbow.
I tighten the scope mount screws enough so that I hear a snap when they are loosened. To install the screws, I use a long T handle. I know the screw is tight enough when the handle of the T handle twists 90 degrees. Remember that if the screws come loose repetitively, you will distort the threads in the trigger unit and eventually, those threads will strip. I tighten the snot out of them and have never had them come loose. Normally, I do not use loctite on anything with the exception of limb and riser fasteners.

Once you understand the physics on how and why fasteners work, you'll realize snug is not good enough.
To give you guys an analogy, when we were building race engines at the shop where I did my apprenticeship, we used forged Carrillo connecting arms. They did not come with torque specs. They came with torquing instructions. The instructions told us to measure the length of the connecting arm bolts at rest. The bolts were correctly torqued when the bolt reached a specified increase in length. That meant that the bolt was stretched enough to hold the 2 bearing halves together and run in an engine to 7,000 rpm+.

[Normous]

To add slightly to Boo's post I suggest restraint when tightening the stock to mainframe screws since the mainframe wall thickness does not provide enough 'snotable" thread depth.

[Boo]

To add slightly to Boo's post I suggest restraint when tightening the stock to mainframe screws since the mainframe wall thickness does not provide enough 'snotable" thread depth.

Agreed! Thank you Norm!

[xcaliber]

Yep, we used a tool called a Huck Gun, rivets basically that torqued until they snapped at the score line, tough to get out too. We didn't use them on Crossbows with shallow threaded holes, apples and oranges really.

[xcaliber]

Maximum recommended torque is 65 inch pounds, that would be installed into steel with 1.25 x the bolt diameter deep into threaded portion. What is the recommended torque from Excalibur Crossbows? Certainly someone from up North has privy to this information. The heads of the screws strip rather easily, probably sacrificial to the mount. I replaced all my screws, and snugged them up with Locktite, no issues.

[Normous]

I found the below information:

[/b]

We actually don't have a torque spec for the shoulder bolt, it just needs to be tightened to the shoulder. The limb bolt torque spec is 20.5 ft/lb.

I think sometimes torques specs get people in trouble if their torque wrench is not calibrated which most aren't. In production we have special power wrenches set to a number but not a specific torque value. Bill always said to tighten them the best you can with a standard allen wrench and that should do it. This as always worked for me.

Peter

[xcaliber]

Most folks keep wrenching after it clicks too, thanks for the information. After I got better screws my fear was washing out the threads.