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Old 08-24-2017, 01:23 PM   #31
jstiver09
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Re: reverse mechs... tell me why again?

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Originally Posted by Impaler Spearguns View Post
I am going to try out a couple of those rev roller mechs - mostly because I like the idea of the top screws making things easier. I have serious reservations about how much the sheer strength is on those screws - when put up against 3 tight bands but supposedly it works out- so wth - .
When you get those mechs in do a simple test. Cut recesses into a 2x4 and install one of those mechs properly secured with the 3 screws. Then screw it to a wall with the front of the mech pointing towards the floor. Figure out a way to fasten a rope to the mech and start hanging weights from it. Or tie a loop in the rope and stand on it, jump up and down, try your hardest to rip the mech out of the wood. Make sure you pull straight down though, don't pull out from the wall to ensure the force is equal to that of the bands loaded to the shaft. My guess is you couldn't rip it off no matter how hard you try. You greatly underestimate the holding power of those 3 screws pull by a 90 degree force. It is a very simple test to do.
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Old 08-24-2017, 01:43 PM   #32
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Re: reverse mechs... tell me why again?

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When you get those mechs in do a simple test. Cut recesses into a 2x4 and install one of those mechs properly secured with the 3 screws. Then screw it to a wall with the front of the mech pointing towards the floor. Figure out a way to fasten a rope to the mech and start hanging weights from it. Or tie a loop in the rope and stand on it, jump up and down, try your hardest to rip the mech out of the wood. Make sure you pull straight down though, don't pull out from the wall to ensure the force is equal to that of the bands loaded to the shaft. My guess is you couldn't rip it off no matter how hard you try. You greatly underestimate the holding power of those 3 screws pull by a 90 degree force. It is a very simple test to do.
It is important to make adequate hole in the wood to place mechanism. You are putting it from the top and band force is pulling to front. If the hole is adequate mechs housing will get stuck and you will just secure it with screws.
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Old 08-24-2017, 01:49 PM   #33
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Re: reverse mechs... tell me why again?

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I don't mind that.
That's a pretty reasonable angle, and works great on regular sized guns. Just becomes more difficult to get clean and easy with some designs, and I really enjoy playing with new lines and adding mass where it doesn't hurt hydrodynamics.

On this badboy, would have required a very sharp angle and might have been a pain to wrap if I had used a reverse mech with a small line release.
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Old 08-24-2017, 05:10 PM   #34
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Re: reverse mechs... tell me why again?

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That's a pretty reasonable angle, and works great on regular sized guns. Just becomes more difficult to get clean and easy with some designs, and I really enjoy playing with new lines and adding mass where it doesn't hurt hydrodynamics.
On this badboy, would have required a very sharp angle and might have been a pain to wrap if I had used a reverse mech with a small line release.
what mech you use on that aircraft carrier Grizz?
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Old 08-24-2017, 05:40 PM   #35
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Re: reverse mechs... tell me why again?

That thing is a Missile Launcher.
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Old 08-24-2017, 08:04 PM   #36
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Re: reverse mechs... tell me why again?

I'm using the Neptonics tuna mech and a custom made extra long line release. Took two tries and a lot of time to shape the line release, but with a little finesse I got it to the point where the line just glides right off. (the picture is obviously the starting point fo reference, the finished product is rounded and engineered and polished)

The body is actually pretty manageably once I rounded her edges and removed the excess. And the part that swings through the water is very narrow and hydrodynamic. I'll post some pictures in the build thread as soon as I can remember to take them.
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Old 08-28-2017, 06:35 PM   #37
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Re: reverse mechs... tell me why again?

Interesting thread
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Old 08-28-2017, 09:35 PM   #38
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Re: reverse mechs... tell me why again?

The last two Hunt shafts came with traditional long shaft tail, instead of the shorter optimised Abellan style tail, and whilst I'm cutting the tail down I figure it'd make sense to reduce the size of the mech slot cutout to more snugly fit my mechs [Ermes dbl roller]

Obviously the slot cutout is milled wide to fit all sorts of mechs - but as i am using only these roller mechs, makes sense to reduce the slot size to the point where its optimum for the roller to seat into, just enough wiggle room to make engaging the shaft easy

am i missing something here? is play in the shaft-sear seating necessary for other aspects of this trigger function?

pic attached if this makes no sense
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Old 08-29-2017, 04:21 AM   #39
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Re: reverse mechs... tell me why again?

It is pretty amazing how much manufacturer difference the tolerance is with the back slot in both euro and american cut ... so for trigger design that can really be a PIA. Best would be one standard slot size and all trigger manufacturers design for it. I think more ciritical is height of trigger seating. You just don't want the shaft to be wedged up in the mech ... and be much higher than the track. When you fire the gun the shaft will have to jump down onto the track ... which causes shaft instability and loss of velocity and accuracy. That is why I prefer the leaf triggers over pinned triggers. You can absolutely dial in the shaft to track tolerance so that the shaft comes out as stable as possible by simply adding or removing tiny washers.
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Old 08-29-2017, 06:53 AM   #40
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Re: reverse mechs... tell me why again?

" Best would be one standard slot size and all trigger manufacturers design for it."

All shaft makers would prefer this too. When you make a shaft to fit one trigger the action, pull and release is great. The problem is it won't fit another manufactures trigger mech and or won't perform smoothly. So from a shaft makers point of view it is better to make a shaft that will fit and work in several mechs and not just one. It won't be perfect but it will work. This keeps the shaft cost down across the different mechs.
Shafts are a lot like bullets for guns. A standard caliber bullet will work in a standard caliber gun. The speargun makers are making triggers for shafts that have not been made yet which is ridiculous and a possible liability down the road.
Kinda like making a gun that shoots a .224 bullet instead of a .223 bullet.
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Old 08-29-2017, 07:36 AM   #41
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Re: reverse mechs... tell me why again?

Kavachi, I'm not sure about Euro mechs, but atleast with Square notch mechs you do want the littlest amount of play. This allows the mech to fully engage. If you place a shaft into a mech you can feel it engage and click. then pull it forward a little and feel the play. If there is no play, it's easier for a shaft to have partially engaged be resting on friction. Load 1-2 bands and out it goes. That extra little play allows the sear to find it's place at the deepest point of the shaft. my take on it atleast.
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Old 08-29-2017, 10:23 AM   #42
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Re: reverse mechs... tell me why again?

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Originally Posted by Red Tide View Post
" Best would be one standard slot size and all trigger manufacturers design for it."

All shaft makers would prefer this too. When you make a shaft to fit one trigger the action, pull and release is great. The problem is it won't fit another manufactures trigger mech and or won't perform smoothly. So from a shaft makers point of view it is better to make a shaft that will fit and work in several mechs and not just one. It won't be perfect but it will work. This keeps the shaft cost down across the different mechs.
Shafts are a lot like bullets for guns. A standard caliber bullet will work in a standard caliber gun. The speargun makers are making triggers for shafts that have not been made yet which is ridiculous and a possible liability down the road.
Kinda like making a gun that shoots a .224 bullet instead of a .223 bullet.

I think the back roller system patented by Mario is really a genius idea. I remember when I first saw it ... I was really surprised that I had never seen it before and very few people had even used it. The back roller is free floating and so it will accomadate any shaft notch so long the shaft can enter the mech ... as it is not fixed and thus will move around until it finally gets the correct wedge. Hell ... even a square notched shaft worked really well in testing and in my 3D computer simulations. I was a little worried that with american mech the two sharp edges of the notch might damage the actual roller (or at least scratch it) but in testing this turned out to not be an issue and trigger passed safety testing at super high loads with american notched shafts. Again ... this was not by design but rather a side benefit thing that just worked well due to how the trigger functions.
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Old 08-29-2017, 04:47 PM   #43
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Re: reverse mechs... tell me why again?

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Originally Posted by Behslayer View Post
Kavachi, I'm not sure about Euro mechs, but atleast with Square notch mechs you do want the littlest amount of play. This allows the mech to fully engage. If you place a shaft into a mech you can feel it engage and click. then pull it forward a little and feel the play. If there is no play, it's easier for a shaft to have partially engaged be resting on friction. Load 1-2 bands and out it goes. That extra little play allows the sear to find it's place at the deepest point of the shaft. my take on it atleast.
thanks Jon. yes - working out just how much play in the shaft-sear[roller] seating is needed so you have enough wiggle room to confirm it's properly engaged, rather than shoving it in and then having it slide out when you load the first band.....as that curious bull mahi casually swims away!

Majd, I understand that ensuring there is absolutely minimal clearance between mech roof and shaft tail - to minimise any vertical movement as mech releases the shaft - is the critical factor. And that the back roller design engages securely regardless of notch shape and size.

Was really just speculating as to whether all that unused notch space may possibly have any other detrimental effect on shaft stability on release. And with the above in hand, I see that as long as shaft tail is in contact with mech roof and in line with track the shaft should go where its told

good to be able to ramble on a bit and work these things out. thanks y'all
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Old 08-30-2017, 08:29 AM   #44
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Re: reverse mechs... tell me why again?

so, the roller mech works like all other euro mechs? what i mean is- does it hold the spear by wedging spear like a sandwich between the roof of the mech and the sear?
unlike the square notch setup -( that I always heard was much stronger btw) that just holds the spear - without using the mech housing

with this euro setup - you NEED leaves because - how else is the the spear going to be basically scraping the top of the mech as it enters- if it doesn't - then it WILL lift when sear engages - by very definition- it HAS to- in order to smash the spear up against the roof. With a setup like that - you have 2 rollers making the whole spear exit smooth on the bottom of things - but what about that spear scraping its way out of the mech housing?

no wonder you dont like et guns or pinned mechs - they wont work at all with this new mech.

Sounds like it needs to have a pair of rollers on the top of the spear too ?

Seems like with the spear sandwiched in there - it will Have to lift a little when sear engages? right ?

majd - you are describing a setup where the lift is minimalized - but you speak as if its negated altogether.
that may be true on one brand of spear within one batch - but you can expect - over the life of the gun - there could be many brands of spears used and some of them are certainly not going to fit with the tolerances you describe- either some of them are gong to be too big and just strike the mech housing on top - or be smaller - and have a gap between the spear and "roof" as it enters mech - which will allow (better yet - force ) lift.

That may be ok wth a rear handle setup - but I bet if you had a pushrod on one of those - it would be far more likely to do that half cock thing .

Also - the difference in spear companies' tang height is the biggest problem for me all the time - even within the same brand - i see dramatic differences - between batches. The last batch of spears - I got from my guy - were so much taller at the sear height - that they all collided with the mech housings and wouldn't even enter the mech.
I thought I had mounted and pinned the mech height wrong - but when i used my riffe spear to check it - I had room to spare- so I ended up filing and grinding the flat spots on the spears to get them to fit.
If I had been using euro mech that sandwiches the spear -'i'm not sure I could have pulled that off- maybe? idk?

I'm not being critical - so much as wondering what you thought about these factors - or how you dealt with them.

also - popgun pete made a point earlier about different radius sizes in roller / spear interfaces put pressure in differnt angles - depending on the size of the arc on the spear or the size of the roller - it will either push down more - or less - as it locks in. with different spears having different size rounded spots on them - make them push against your roller at different angles - this seems to be a fact - my question is - does it make the spear exit smoother or worse depending on size of round cutout for spear "radius"
I know they vary greatly - on some brands - especially riffe - they make the cutout much larger - to allow them to work for square notch shafts.
but on (for instance) omer shafts - the cutout curve (eliptical - not radius actually- right?) is much smaller and only fits euro mechs.

It sounds like - in order to get full performance with a roller sear - you need to stick to one brand of spear - and it needs to be a company that has ridiculously good standards in their tangs and slots. Not sure if that company exists - except riffe - but they still put the sharkfins 4"back on the euro spears - wasting that precious band stretch
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Old 08-30-2017, 08:58 AM   #45
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Re: reverse mechs... tell me why again?

Quote:
Originally Posted by Impaler Spearguns View Post
so, the roller mech works like all other euro mechs? what i mean is- does it hold the spear by wedging spear like a sandwich between the roof of the mech and the sear?
unlike the square notch setup -( that I always heard was much stronger btw) that just holds the spear - without using the mech housing

with this euro setup - you NEED leaves because - how else is the the spear going to be basically scraping the top of the mech as it enters- if it doesn't - then it WILL lift when sear engages - by very definition- it HAS to- in order to smash the spear up against the roof. With a setup like that - you have 2 rollers making the whole spear exit smooth on the bottom of things - but what about that spear scraping its way out of the mech housing?

no wonder you dont like et guns or pinned mechs - they wont work at all with this new mech.

Sounds like it needs to have a pair of rollers on the top of the spear too ?

Seems like with the spear sandwiched in there - it will Have to lift a little when sear engages? right ?

majd - you are describing a setup where the lift is minimalized - but you speak as if its negated altogether.
that may be true on one brand of spear within one batch - but you can expect - over the life of the gun - there could be many brands of spears used and some of them are certainly not going to fit with the tolerances you describe- either some of them are gong to be too big and just strike the mech housing on top - or be smaller - and have a gap between the spear and "roof" as it enters mech - which will allow (better yet - force ) lift.

That may be ok wth a rear handle setup - but I bet if you had a pushrod on one of those - it would be far more likely to do that half cock thing .

Also - the difference in spear companies' tang height is the biggest problem for me all the time - even within the same brand - i see dramatic differences - between batches. The last batch of spears - I got from my guy - were so much taller at the sear height - that they all collided with the mech housings and wouldn't even enter the mech.
I thought I had mounted and pinned the mech height wrong - but when i used my riffe spear to check it - I had room to spare- so I ended up filing and grinding the flat spots on the spears to get them to fit.
If I had been using euro mech that sandwiches the spear -'i'm not sure I could have pulled that off- maybe? idk?

I'm not being critical - so much as wondering what you thought about these factors - or how you dealt with them.

also - popgun pete made a point earlier about different radius sizes in roller / spear interfaces put pressure in differnt angles - depending on the size of the arc on the spear or the size of the roller - it will either push down more - or less - as it locks in. with different spears having different size rounded spots on them - make them push against your roller at different angles - this seems to be a fact - my question is - does it make the spear exit smoother or worse depending on size of round cutout for spear "radius"
I know they vary greatly - on some brands - especially riffe - they make the cutout much larger - to allow them to work for square notch shafts.
but on (for instance) omer shafts - the cutout curve (eliptical - not radius actually- right?) is much smaller and only fits euro mechs.

It sounds like - in order to get full performance with a roller sear - you need to stick to one brand of spear - and it needs to be a company that has ridiculously good standards in their tangs and slots. Not sure if that company exists - except riffe - but they still put the sharkfins 4"back on the euro spears - wasting that precious band stretch

Look ... I could go on about every single detail of how we went about designing this trigger, but not sure it would make any sense to many people and would probably need about 20 pages. You are mixing up what I am saying about triggers ... the issue of having the trigger installed correctly has nothing to do with the trigger design ... it is just my recommendation on how to get improved performance from a trigger regardless of whether it is an american cut or euro. American cut and euro cut are pretty much identical in how they function. One has a square cut and one has a curved cut ... functionally they work the same. I don't know where you got that american cut triggers don't depend on top of trigger box top to ensure the trigger doesn't slip off ... I don't recall ever seeing an american trigger with a hollowed out top. Sure I have seen those Indo or Malay home made primitive spearguns which are like that ... but that is certainly not a trigger that you consider safe. You could say that an american square notch is inherently more secure as the shaft would have to go up a 90 degree curve rather than say a 40 degree curve. But thinking that you don't need the top of the mech is just crazy. I actually have bought a gun with an american trigger that was set too high, and remember that with a certain american cut shaft ... that shaft would slip off the shaft sear and shoot by itself when I loaded it. So trust me ... you need correct trigger depth for your speargun design to be safe ... but the fine tuning I mention is going one step further to actually improve performance and accuracy. This has nothing to do with a triggers design.
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