Striped Threads

[mr meat]

was putting a bow together and I striped the hole in the rail closes to the trigger that holds the stock on! So how do I fix it, re tap with same size or go 1 size bigger and what size is 1 bigger

[tremps01]

Here what i do, I use an piece of an aluminium angle bar more thicker than the rail, re tap with same size and blocked it with 2 little block of rigid styrofoam front and rear to keep the al. angle in place I think it's 10/32 thread???

Marcel

[Normous]

Same as Marcel I tap a 3/16 to 1/4" thick aluminum bar and JB weld it inside the mainframe. I cut the aluminum as wide as the inner mainframe so that it cannot swivel.

[mr meat]

That had crossed my mind! Thanks guys

[IronNoggin]

Did much the same except with the bolt further out on the forearm of my Matrix 380.
Guess that will teach me for switching out triggers so much!

The answer I got here then was get a Helicoil kit.
I did, and it worked very VERY well.
In fact, I would be damn surprised if anyone could ever apply enough force to dislodge it ever.

http://www.helicoil.in/helicoil.htm

And now that kit never leaves my bow bag of goodies.
Never needed it again, but good insurance just in case...

Cheers,
Nog

[Tangle Eye]

I was gonna respond earlier and suggest the Helicoil kit but couldn’t remember the name of it. That thing is the bomb for repairing stripped threads. Check it out.

[Doe Master]

For thin walled applications these work good .
https://www.rivetsonline.com/rivet-nuts-threaded-inserts

[xcaliber]

For thin walled applications these work good .
https://www.rivetsonline.com/rivet-nuts-threaded-inserts

Some pretty good options here! Thanks.

[foofoo]

in the past ive tapped up a size. 12 -24 size. not sure why went with 10-32 with the stock screws. those finer threads to me are askin for stripping. the quiver mount holes down on the end use 10-24.

[Boo]

in the past ive tapped up a size. 12 -24 size. not sure why went with 10-32 with the stock screws. those finer threads to me are askin for stripping. the quiver mount holes down on the end use 10-24.

Fine threads give more thread contact and better leverage for the threads to hold. Fine threads also require less torque to hold parts together or hold more with less torque. That is why they are used on some car suspension parts and other critical parts like connecting rods. Your use of a larger fastener is a great idea but it would be much better with fine threads.

[Boo]

For thin walled applications these work good .
https://www.rivetsonline.com/rivet-nuts-threaded-inserts

Rivet nuts work really well. In the automotive business we use them to fasten things onto sheetmetal.

[foofoo]

closer threads make skip and tear out easier in soft metal. ive owned a boat load of older Horton crossbow with never a stripped bolt thread. the common thing is that they always used coarse threads. people like me sometimes honk down on stock bolts. the result is stripped threads. i dont understand why only a few inches down the rail Excal went with coarse threads for the quiver mount. popping the quiver on and off or yankin arrows out youd think would stress but ive never stripped a quiver mount hole.

[Boo]

Fine threads yield more threads in a given thickness of material. Conversely, the threads are narrower so more prone to stripping if over tightened. So maybe you're right that people are over tightening those fasteners. Another good quality of coarse threads is that it is more difficult to cross thread, another possibility.
When you said "closer threads make skip and tear out easier in soft metal." I think you're saying that it is easier to tap a coarse thread and have a better/smoother thread engagement surface, agreed on that. But if you look at how Excalibur make their threaded holes. They use roll or forming taps which are entirely cool. No flutes/cutting edges. They push material away with no tearing and a perfect thread.
BTW, when I was helping Trigger Tech with their final development, I probably had my stock off of my Exocet 200 60 to 70 times with no problems. Maybe being a mechanic by trade, I don't over torque or screw up enough to damage the threads in my mainframe. I used a T handle tool to limit the torque on the fasteners.

[xcaliber]

Don, you're right on about the fine threads, but most people don't live in the engineering world. I get a load of bunk from our Maintenance group when we choose fine threads. Although the really are much better, they don't seem to survive the wrecking crew! Yes, alignment is more important, and no long wrenches, or extenders are not needed.

[taz3]

A good practice to help prevent cross threading, is to turn the bolt counter clockwise while gent push into the threaded opening until you feel it click, then you can proceed to turn it clockwise. This allows the threads to seat correctly prior to threading parts together. It can be done with tools, but it is a "feel" thing that works best with your bare fingers.