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No, your analysis is incorrect. That force is the capture force that tends to counteract the moment force.

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That 40x pen scope is a great idea. Is that the one from Brownells? I have seen it many times. I don't know why I didn't think of that. I'm getting slow.
No, it's a "iGauging" scope. About $30. The graticule seems to be off by a thousandth or two, but that can be worked around, once you know the error. I think the error can possibly be adjusted out by moving the objective lens, which is threaded into position. The threaded adjustment is likely there for focusing purposes. The bottom end was cut at an angle to allow light to enter. The bottom tip seemed to be right at the focal point. So apparently you could just rest the bottom tip on the object, and it would be in focus. I am using it in a stand with a rack adjustment for focusing, so I turned the end down square. Also lets a lot more light in, which they need.

Anyway, it's perfectly usable for inspecting sear faces.

Have people been getting poor trigger jobs because the instructions that come with the various jigs assume sears have sharp points at the edge edge??

Also all the jigs I have seen bank the sear against a feature on the jig (the set screw). But what about the feature on the sear that banks against the jig. All these sear features only touch air. Why should a sear manufacturer hold one of these feature to +/- 0.001 or even +/- 0.005" . There is no inspection of these parts to see if ALL dimensions are within spec. If a manufacturer missed a dimension no one would know as the feature only touches air and thus the sear works fine. These sear features have a much shorter distance to sear center then the sear's flat. Thus an error on the sear feature magnifies the error in location of the 90 deg vertex.
I also saw those as potential problems. One has to rely on the fixture and sear dimensions being correct. With the Brownells fixture in its original form, I had to use a shim much larger than the .020" to get the face angle correct. A casual user would have no idea that the finished angle was wrong by simply following the instructions. Mine did appear to be out of spec. I checked it, but not everyone will. Rather than return or exchange it, I decided to use it as a base for my own fixture.

The erratic reading was likely slip-stick induced by the low stiffness of the spring in your pull gage. One pulls on the gage and the spring elongates. The elongation of the spring is such that its force matches then exceeds static friction. The object breaks free and now a lower dynamic friction occurs. At the instant the spring is still applying the force needed to exceed static friction. The force imbalance on the object has the object to accelerate. The object temporarily exceeds the velocity you are pulling the gage. The elongation of the spring drops, the spring's force drops, spring force now is below that for dynamic friction, the object stops moving, the cycle repeats.
Yes, and you can actually watch that happen. At some minimum speed that effect stops and the reading stabilizes. At different pull speeds, I'm not sure I see any difference in pull force. If there is any speed dependance, it's not proportional.

Signal averaging will definitely reduce noise. However it relies on a repetitive signal to average out the random noise. Thus your one shot measurement was likely difficult to get as it was non-repetitive.
The signal was not only tiny, it was also in the presence of extremely high voltages and magnetic fields (particle accelerators, commonly known as atom smashers). It was measuring the charge left in a detector when an atomic particle flew through it.

We could over-sample our one shot trigger pull but care is needed. The trigger is moving during the sampling and if not careful we could average out useful information. Also noise could be in-band and thus indistinguishable from actual signal. Sampling here acts as a low pass filter. We don't want to set the filter to low and loose signal. These are the issues that drive experimentalists mad.

If the noise is purely electronic I have found battery powering the sensors with good shielding and single point grounds cut it down a lot without resorting to electronic (or digital) filters or over-sampling.
It might be better to just sample as fast as reasonably possible, and then smooth the data afterward.


There is a new wild card. Can the hammer keep up with sear?

The sear can snap out from under the hammer hook at relatively high speed due to it's low mass. The hammer has a much greater torque on it, but is also a much larger mass. As the sear speed increases, the hammer hook tip force will decrease due to its inability to follow at full tension.

We are going to get a lot of caterwauling about crazy impractical engineers over this post....
No doubt.

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No, your analysis is incorrect. That force is the capture force that tends to counteract the moment force.

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Nope.

You first used the 1.31 lb force as resisting the sear motion into engagement (which I agree with in its direction).

You then use that same force as resisting the sear motion out of engagement.

It's the same force. How did the sign get flipped?

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Like Log I’m waiting for this to be a gunsmithing thread. I’m sure this discussion might benefit someone. I just haven’t figured out who that is yet.

Maybe an astrophysicist who builds 1911’s on the weekends? All I’m saying is the average person who builds 1911’s as a hobby or profession isn’t getting anything they can really apply practically. And I’ve always felt that is the true nature of this subforum. The practical application of gunsmithing
 

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Like Log I’m waiting for this to be a gunsmithing thread. I’m sure this discussion might benefit someone. I just haven’t figured out who that is yet.

Maybe an astrophysicist who builds 1911’s on the weekends? All I’m saying is the average person who builds 1911’s as a hobby or profession isn’t getting anything they can really apply practically. And I’ve always felt that is the true nature of this subforum. The practical application of gunsmithing
I think the quest for understanding was lost in the math long ago. The hobbyists and pro’s utilize an understanding of the mechanism to perform the operations for desired results.

I dropped out of an engineering program in college because the act of engineering was lost in the math. I got more application of engineering in the engineering physics class than I did in the engineering classes. Working on a unique camshaft and valve train oiling problem with a high performance car I was building put me in touch with one of the cam company’s engineers. Called a couple other high tech places. Found the problem myself. The cam companies substituting Chevy small block mechanical lifter doesn’t work in a Pontiac. Just because the diameter, length and seat location are thr same doesn’t mean the lifters didn’t cause oil bleed. The oiling cuts were grossly different. As a matter of fact, it eventually could have knocked the lifter bosses out of an expensively machined block.

I called the cam company about it, told them what we found. That conversation went like this thread. They were right in their mind. I found the proper lifters from McKellar Engineering. The reports in the car magazines soon afterward started reporting on Pontiac lifter bosses being broken out of the blocks because the bottom of those Chevy oiling grooves eventually dropped below the bottom of the lifter bore on the small base circle high performance cams. The next trip up the cam pushed the lifter and the block boss up. Result..scrap metal. I imagine the cam company wrote. few checks.

Sorry about the babble but it applies here. A lack of utilizing the understanding of the mechanism was lost in the “but the math indicated...”.
 

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If it breaks like glass at 3 to 4 pounds ,that's what I like my finger to feel it doesn't care about the math. All this stuff that's been thought for years and years about the let off being a surprise is garbage I want to know and control the let off. Your finger tells your brain what it feels your brain tells your finger what to do.
 

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Engineers, can't live with them, or without them, one thinks the secondary is needed to resist the half cock from hitting the sear, and when his trigger hesitates uses ultra grease to fix. And the other purposely cuts the sear at 87º which causes a hesitation and increase in pull to get a "safe" #5 1/2 trigger. Makes one wonder, What!

Reminds me of talking to a Kimber engineer about their use of the S80 9mm firing pin stop in all calibers regardless they don't have an S80 or benefit from the extra notch that has caused all kinds of problems of stuck slides and broken push rods, deaf ears. Slide on the left S70 45acp, on the right we have the engineers choice of an S80 9mm/38sup firing pin stop. You can clearly see a scratch mark on the left of the right side slide where the push rod is in direct line with the square hole just waiting to cause trouble when assembling the slide to frame. The engineer denied it was a problem. lol

611941


LOG
 
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You would have lost your ghat damn mind talking to Sig engineers. 🤣🤣

Sig engineers wondering why every classic line gun is shooting super low. They make the recommended fix of crushing the front of the slide in a 1 ton press to change lock up angle.

All it would have taken was 5 seconds with the print and a dial caliper and I would have told them that every dovetail was shallow and there was way too much gap making the sight artificially taller than it should be.

I did what they said. “Fixed” literally thousands of guns that way. But it was at that exact moment I realized Sig wasn’t the place for me. I applied to Colt’s Custom Shop around then. 🤣
 

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Ok, putting numbers aside, let me see if I understand this:

In the absence of friction, with just a sear and a tensioned hammer, the hammer will pull the sear inward?

In other words, if I were to pull the sear out slightly, it would snap back in?

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Here’s a question for the group. Is talking about how the components work outside of its design function even worth discussing?

How do the parts function without the sear spring? What difference does it make since it operates with a spring?

Discuss.
 

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No, but it would stand still at the point it was forced too, and the point, of a sear snapping out due to the fact we do have enough friction for the force to be built up to a point of release. If the hammer hooks slide down the face of the sear primary, and they can, the trigger force could then be released and the hammer would not fall, nor would the sear reset itself, unless the hammer was cocked back to allow it too. You can force this to happen with an overcut thumb safety. However if when watching the sear and pulling the trigger as I have described at least twice in this thread and the sear cannot be seen to move it will have a crisp trigger, if you can see it you could then also relax after a force was applied and the sear would hold the hammer in the position it was moved too, not a crisp trigger.

You have stated that your 87º whose primary center is the shortest distance to the sear pin center does indeed has a hesitation, not unlike a 2 stage trigger as the escape edge is higher than the center. This is an example of a sear that can be seen moving when the trigger is pulled and will stay at the at the first hesitation point if the force on the trigger is relaxed. Of what value do you claim this has. A #5-#7 trigger is easy if desired without having a built in hesitation point.

So this is kind of the point of frustration, zero friction isn't going to happen, and nothing has been said if it is also in a zero gravity condition, or if the pistol in this questionable condition is pointing upwards or downwards, or ? So it is a nonsensical statement to begin with. If it was relevant how far would a bullet travel if the barrel and bullet didn't have any friction, and if at the same time wasn't any friction between the soles of your shoes and you were standing on a slight decline, I'm sure it could be calculated, but its relevance isn't even of any interest.

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No, but it would stand still at the point it was forced too, and the point, of a sear snapping out due to the fact we do have enough friction for the force to be built up to a point of release. If the hammer hooks slide down the face of the sear primary, and they can, the trigger force could then be released and the hammer would not fall, nor would the sear reset itself, unless the hammer was cocked back to allow it too. You can force this to happen with an overcut thumb safety. However if when watching the sear and pulling the trigger as I have described at least twice in this thread and the sear cannot be seen to move it will have a crisp trigger, if you can see it you could then also relax after a force was applied and the sear would hold the hammer in the position it was moved too, not a crisp trigger.

You have stated that your 87º whose primary center is the shortest distance to the sear pin center does indeed has a hesitation, not unlike a 2 stage trigger as the escape edge is higher than the center. This is an example of a sear that can be seen moving when the trigger is pulled and will stay at the at the first hesitation point if the force on the trigger is relaxed. Of what value do you claim this has. A #5-#7 trigger is easy if desired without having a built in hesitation point.

So this is kind of the point of frustration, zero friction isn't going to happen, and nothing has been said if it is also in a zero gravity condition, or if the pistol in this questionable condition is pointing upwards or downwards, or ? So it is a nonsensical statement to begin with. If it was relevant how far would a bullet travel if the barrel and bullet didn't have any friction, and if at the same there wasn't any friction between the soles of your shoes and you were standing on a slight decline, I'm sure it could be calculated, but its relevance isn't even of any interest.

LOG
It's not nonsensical at all.

I am trying to see if I understand the non frictional forces. The lack of friction might be hypothetical, but the remaining forces are not.

There is either a net force inward or there isn't.

My question has a definite answer.

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Here’s a question for the group. Is talking about how the components work outside of its design function even worth discussing?

How do the parts function without the sear spring? What difference does it make since it operates with a spring?

Discuss.
This is something I'm sure others have done long ago, but had never heard of it when I was contemplating trigger work and the balance of the contributing aspects of the trigger force required. And I mentioned it here years ago, NE will remember when I first suggested this to him and another member Russ.

The force required to drop the hammer without the sear spring is simply a way to determine this component of the trigger systems requirement. I thought, okay we have the center disconnector leaf, and we have the left sear leaf and can pretty accurately weigh each, but what about the force required to drop the hammer, as the third component. And found that it was certainly easy to determine, cock the hammer push the sear into place push the disconnector up, I hold 1911 upside down with the slide against the bench top as I pull the trigger with the trigger gauge. A number that is then identified, plus the center and left leaf is the total weight of the trigger pull. As I have said previously I found that the center leaf does need, or requires in most circumstances to be at least 16oz. and also found the sear leaf can be as light as the leaf will allow and always apply tension throughout its range of functional motion, so I check it with the sear in the half cock which is the deepest and requires the sear spring leaf to have enough tension to hold the sear fully in the notch, I check this with a scribe point to tickle the leaf in this position to verify it does indeed have some tension, comes in about 6-8.oz. So If you did not know what the trigger force required to drop the hammer without the sear spring was and you had set the 2 leaf's as you had maybe done before, but this time the pull was much higher or lower than expected, knowing this third component would bring understanding to your effort.

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It's not nonsensical at all.

I am trying to see if I understand the non frictional forces. The lack of friction might be hypothetical, but the remaining forces are not.

There is either a net force inward or there isn't.

My question has a definite answer.

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So does, if there wasn't any friction between the bullet and the barrel bore, what would be the bullets velocity? This could be calculated and sure you could, but would it be relevant in any way to gunsmithing, except to verify to those who wanted to know something that is an antidote at best.

A slingshot under those conditions would be a better choice.

In regards to the sear and hammer question, I implore you to play a little with the sear and hammer on a fixture such as pictured, or on the side of the frame with test pins designed for this purpose and satisfy for yourself just how the sear and hammer interact. Can you do it without friction, no, I don't believe you can, but you can develop an opinion based on the experience as to whether it is stable, or not stable. That's relevant, and has an answer,

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So does, if there wasn't any friction between the bullet and the barrel bore, what would be the bullets velocity? This could be calculated and sure you could, but would it be relevant in any way to gunsmithing, except to verify to those who wanted to know something that is an antidote at best.

A slingshot under those conditions would be a better choice.

In regards to the sear and hammer question, I implore you to play a little with the sear and hammer on a fixture such as pictured, or on the side of the frame with test pins designed for this purpose and satisfy for yourself just how the sear and hammer interact. Can you do it without friction, no, I don't believe you can, but you can develop an opinion based on the experience as to whether it is stable, or not stable. That's relevant, and has an answer,

LOG
I have a fixture that I made for use on a microscope stage, and have made lots of observations of the engagement.

I have also manually staged sears at various points of engagement, and it was stable at all points.

My question hasn't been answered though.

Is there a net force pulling the sear inward?
And in the absence of friction would it therefore snap back in if pulled out slightly?

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I have a fixture that I made for use on a microscope stage, and have made lots of observations of the engagement.

I have also manually staged sears at various points of engagement, and it was stable at all points.

My question hasn't been answered though.

Is there a net force pulling the sear inward?
And in the absence of friction would it therefore snap back in if pulled out slightly?

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Of course not, get real, the landing spot of the hammer hook tips is higher so snapping back would only happen if the sear was improperly cut, you know this and have done this. Why ask an irrelevant question whose answer is obvious? Of course if the sear spring was present and the hammer were pulled back a little it would, wouldn't it?

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Of course not, get real, the landing spot of the hammer hook tips is higher so snapping back would only happen if the sear was improperly cut, you know this and have done this. Why ask an irrelevant question whose answer is obvious? Of course if the sear spring was present and the hammer were pulled back a little it would, wouldn't it?

LOG
Thank you. And you're right, I know all that.

There is apparently differing beliefs about whether there is a force pulling the sear into engagement. It would be good if it was resolved.

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Thank you. And you're right, I know all that.

There is apparently differing beliefs about whether there is a force pulling the sear into engagement. It would be good if it was resolved.
I do believe there can be a proclivity by the hammer hook tips to snug up the sear, if you will, but actually hold it, I do not believe so, the sear holds the hammer in the cocked position and if the sear is as it should be the spot the hooks land on is higher, how much depends on how much engagement.

The way the hammer hook tips contact the sear primary I believe makes a big difference relative to the hook face (which I know doesn't touch) but where they are relative to the hammer pivot makes a difference which can be shown in example. I gave some of these examples early in the thread. For instance if the hook plane is dead center to the hammer pivot in position, its going to follow at light weights, and why the Para hammer is not a candidate for less than three.

Hammers whose hook plane bisect the center to the edge of the hole, or slightly closer to the hole edge, work quite well. You can explain this I believe by the relative position of the hook tips as they get further from the center the hook tip moves differently relative to the sear. I have never drawn this out nor analyzed it past my experience of this difference in geometry, I quoted an old thread in this thread from 2010 I believe when I brought this up and was confirmed by other very experienced pistol smiths we have been blessed to have here and whose experience was shared. I hate to quote them, but Geo. Smith of EGW has confirmed this as well.

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Rather than edit to add, we must /should remember that the sear is indeed held in place by the hammer hooks force bearing on the sear, if it were not then the trigger pull would be very easy, but it is the contact of the hammer hooks bearing on the sear primary under the force of the mainspring that must be overcome to release the hammer. and yes of course friction certainly comes into play, and most importantly is the detail the 90º sear provides, and that of course is a clean break once the initial force is applied that the hammer hook tips now have clearance to escape into the glory it was promised. Bang. ;)

LOG
 
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