Author Topic: Bolt blues  (Read 247 times)

Alan

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Bolt blues
« on: May 07, 2018, 12:19:41 PM »
I categorically do not like adjustable detents on airguns. The idea is to have a detent to hold the bolt closed. But everyone I have seen slide along the bolt, then drop into a hole supposedly to keep the bolt from opening. Problem is, the bolt surface isn't recessed, which means the detent ball always presses against the bolt adding to the cocking effort. I can't speak for other, but I back off the detent so it doesn't drag. The result is, the bolt handle is a bit sloppy.

I've been trying to come up with an idea to secure the bolt handle without modifying the assembly. The attached photo is the solution, I hope as I haven't tried it in the field yet. If it works as well there, as it doesn't in the shop, I'll use epoxy instead of superglue.

By the way, the magnets grab the bolt stud, not the bolt handle.


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Alan

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sixshootertexan

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Re: Bolt blues
« Reply #1 on: May 08, 2018, 07:37:37 AM »
Nice. I planned on putting a detent on my rifle but not to keep it closed but rather to keep it open. It wants to close when I'm loading a pellet if I have the rifle pointed down.
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Alan

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Re: Bolt blues
« Reply #2 on: May 08, 2018, 01:47:53 PM »
Turns out, the magnets work well. However, I am going to replace them with the next larger sized magnets, just to add a bit more stickiness.
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Alan

I have an Omega compressor. If you're a fellow Guild member, and you pass through Roswell, NM, I'll fill your portable tank as a courtesy.

Gerard

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Re: Bolt blues
« Reply #3 on: May 08, 2018, 03:38:00 PM »
I haven't any air rifles where the bolt popping up is a problem, so no detents needed. Perhaps this is a thing with higher power airguns? Mine max out at 20fpe, that's my QB78D, and the bolt happily sits in the bottom of the slot under its own weight. But I do have a problem with bolts sliding forward while loading, muzzle-down, so all my air rifles have a magnet stuck to the back of the bolt. A bit tricky in a couple of cases getting the spacing just right, but a good neodymium magnet does the trick nicely, holding the bolt securely until I'm ready to push it forward.

For your specific application I'd probably use a fairly tiny magnet, but embed it in a steel block with a hole bored just the size of the magnet then epoxy it into the hole. A neodymium magnet with steel on all but the 'sticky' side (the one where you want it to stick to something) is hugely increased in power, the force lines being almost 100% redirected by the steel. This is called a 'focusing cup' by Lee Valley Tools and others, and they sell basic steel ones for many sizes of magnets there. But I've made them from scraps of mild steel for various jigs and things in the shop, just shaping a bit of steel to whatever will fit the space, get the angle right, whatever, then boring a hole to seat the magnet flush with the finished steel. You're bound to get a better grab on that bolt handle with the flat face of a magnet, and could probably get away with a 1/4" diameter by 1/8" thick one, or maybe even the 1/8" diameter version.
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