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Old 05-04-2022, 06:56 PM   #46
Behslayer
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Re: Ermes Avatar speargun handle

What's the Diameter of the Roller in those drawings? I see it says 9mm?
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Old 05-04-2022, 07:12 PM   #47
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Re: Ermes Avatar speargun handle

A smaller "sear tooth" roller will give more ceiling room for the shaft tail to fit into, but will tend to pull up onto the front of the cupped recess in the sear lever arm. The mechanism will still work OK as the shaft trying to jump the "sear tooth" roller will load up on the sear box roof. As "seen" by the trigger mechanism the sear tooth is actually the front lip of the cupped recess.
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Old 05-05-2022, 12:54 AM   #48
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Re: Ermes Avatar speargun handle

All back rollers are 7mm diameter. You could get away with a 6.75mm roller if using american cut, but you really have to make sure that whatever tolerances are built in there don't add up and thus make a Euro cut shaft dangerous. With the standard DR trigger ... if the american cut shaft fits then it is safe to use without altering anything and you won't need the 6.75mm roller. The rollers are made of hardened 17-4 ph SS so if I were to make one in 6.75mm I would sacrifice an old 17-4PH shaft @ 6.75mm ... which are very easy to find. One shaft could easily provide 10's of back rollers and for a while those rollers were actually made out of 7mm 17-4ph shafts.
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Old 05-05-2022, 01:07 AM   #49
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Re: Ermes Avatar speargun handle

I think swapping shafts is asking for trouble, I have shafts for both and keep them separate. Whereas there was an attempt long ago to make eurogun shafts universal there was no such effort made with US shafts which can have different anti-rotation systems, e.g. a flat on top, flats on the sides and short vertical slots in the extreme tails.
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Old 05-05-2022, 03:35 AM   #50
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Re: Ermes Avatar speargun handle

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Originally Posted by popgun pete View Post
I think swapping shafts is asking for trouble, I have shafts for both and keep them separate. Whereas there was an attempt long ago to make eurogun shafts universal there was no such effort made with US shafts which can have different anti-rotation systems, e.g. a flat on top, flats on the sides and short vertical slots in the extreme tails.
Actually american cut shafts work perfectly well and maybe even better than euro shafts on a DR trigger. On the standard DR trigger there is just enough wiggle room where you can soak up the extra tolerance provided where it just is able to accept a Riffe american cut shaft with the default trigger... of course it is also able to use euro cut shafts as well. Albattar spearguns has been using some extremely heavy loads with Riffe american cut shafts for several years using this system with no problems. So I know for sure that it works if you build your gun to soak up the tolerances provided. In the computer simulation I really saw no problems at all ... if the american cut shaft fits and locks then it will shoot just fine. On some older Riffe american cut shaft you do have to shave off a little off the top of the trigger box (like .2mm) to allow the tang of the shaft to enter fully the trigger box ... and I actually caught that in the computer simulation ... but it is only a few seconds work with a small file. The new shafts seem to have a slightly more forward cut and enter without problems. All other american cut shaft I tried also enter with no problems. If I wanted to build a gun that uses both american and euro cut ... I would setup up my track and trigger height where the shaft is kissing the top of the trigger box ... this way it will shoot perfectly with american cut ... then in a pinch you could easily fit in a euro cut shaft ... with a slight drop in shaft stability maybe.

There is no doubt in my mind though that the entire speargun community would benefit from a new universal tang that uses some of the advantages of an american cut with some of the advantages of a euro cut. The DR Trigger would also be optimal for those shafts, but they would also work very well with normal triggers. In computer simulation modeling where I tested to failure ... the failure was always on the shaft tang. This obviously doesn't happen very often so is not really an issue as nobody gets close to these loads. But I have heard of carbon shafts breaking at the shaft tang as that area can corrode heavily and become weak.
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Old 05-05-2022, 03:53 PM   #51
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Re: Ermes Avatar speargun handle

If shafts are not properly locked in then guns can misfire, the problem is if someone pushes a shaft in and thinks it has been caught when it is not. Not all shafts have a flat on top of the tail. If you can afford to buy a new gun then you can afford to buy the correct shaft. Some people think of their gun as a black box, they don't think about the inner works.
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Old 05-06-2022, 10:07 PM   #52
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Re: Ermes Avatar speargun handle

that handle looks bloody great! finally a beefed-up DR mech pipegun, high grip, thumbrest, nice trigger reach, and long boss.

Really looking forward to trying this out, after having wasted $$ and considerable time on Pathos D1 mods [lesson there being if you wanna use em with twin hot small ID bands and heavier shafts, you HAVE to carbon wrap the handle to limit all the flexing going on in that skinny plastic handle and sloppy O-ringed boss], I miss having a really long-range pipegun.

not being a fan of having all those euro ‘accessories’ hanging off my gun, I’d probably fill that bracket slot with reinf epoxy. defs grind off that bloody safety lever, but hell, this looks great!

muzzle looks nice too, just add decent generic carbon pipe for a really versatile sharpshooter. 140 x 7.5 shaft with twin 14.1mm small ID primelines at 380%, pipe trimmed so flopper just a few mm outside the muzzle. lookin good
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Old 05-06-2022, 10:10 PM   #53
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Re: Ermes Avatar speargun handle

Quote:
Originally Posted by spearq8 View Post
Actually american cut shafts work perfectly well and maybe even better than euro shafts on a DR trigger. On the standard DR trigger there is just enough wiggle room where you can soak up the extra tolerance provided where it just is able to accept a Riffe american cut shaft with the default trigger... of course it is also able to use euro cut shafts as well. Albattar spearguns has been using some extremely heavy loads with Riffe american cut shafts for several years using this system with no problems. So I know for sure that it works if you build your gun to soak up the tolerances provided. In the computer simulation I really saw no problems at all ... if the american cut shaft fits and locks then it will shoot just fine. On some older Riffe american cut shaft you do have to shave off a little off the top of the trigger box (like .2mm) to allow the tang of the shaft to enter fully the trigger box ... and I actually caught that in the computer simulation ... but it is only a few seconds work with a small file. The new shafts seem to have a slightly more forward cut and enter without problems. All other american cut shaft I tried also enter with no problems. If I wanted to build a gun that uses both american and euro cut ... I would setup up my track and trigger height where the shaft is kissing the top of the trigger box ... this way it will shoot perfectly with american cut ... then in a pinch you could easily fit in a euro cut shaft ... with a slight drop in shaft stability maybe.

There is no doubt in my mind though that the entire speargun community would benefit from a new universal tang that uses some of the advantages of an american cut with some of the advantages of a euro cut. The DR Trigger would also be optimal for those shafts, but they would also work very well with normal triggers. In computer simulation modeling where I tested to failure ... the failure was always on the shaft tang. This obviously doesn't happen very often so is not really an issue as nobody gets close to these loads. But I have heard of carbon shafts breaking at the shaft tang as that area can corrode heavily and become weak.
Thanks Pete, Majd, Jon, all for input on this, great to learn more about the mechanics and engineering behind these DR mechs!

After years of testing various versions of Mario’s DR mechs on wood guns of all sizes and pipeguns, I’ve found that if you want consistent accuracy at distance it’s critical to keep clearance btwn mech roof and shaft tail -as measured with shaft on track just outside the mech - to an absolute minimum. More than 0.5mm clearance, or not enough - shaft tail contacts mech roof when inserting - and accuracy suffers.

When aligning Ermes DR ‘Wings’ mechs on my wood guns I put two 0.6mm flat SS washers under each of the three threads. If i want to change down to 7.5mm shaft I just remove one washer from each thread, thus maintaining that optimal clearance btwn mech roof and shaft tail. If i need to change up to 8.5mm shaft, i just add a third washer on each thread.

Regards the shaft notch-sear roller interface, although the Hunt ‘Bleu’ and Salvimar ‘Atlantis’ shafts I use work perfectly well in these mechs, I always trim off the last 25mm of shaft tail and cut my own much shorter-radius notch to fit the sear roller perfectly. Easy job with just hacksaw, round file & caliper, and achieves perfectly snug fit with zero slop. Also provides an extra inch of bandstretch, without going too short and jeopardising shaft stability. Ends up being a shade longer in the tail than Abellan-spec shafts.

Last edited by kavachi; 05-07-2022 at 12:24 AM.
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Old 05-06-2022, 10:42 PM   #54
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Re: Ermes Avatar speargun handle

All the cassette based eurogun trigger mechanisms have one common trait and that is the shaft tail goes into an opening where the only controlling factor is the sear box ceiling and the top of the sear tooth. To that you can add the guide track if the shaft actually sits in it. In the early euroguns based on clamshell alloy handles the spear tail sat between a floor and a roof with clearance at the sides except for the shaft stop lugs right at the rear of the spear. That is why those guns had a rectangular mouth on the sear box. The curved sear tooth was to stop pulling the trigger driving the shaft backwards against the band pull because the original mechanism was a variation on the type used in spring guns. By way of contrast US spearguns sat their spear tails in a tunnel, so the shaft tail was imprisoned in a socket. The square cut tail notch originates from single-piece triggers, the only way such triggers will work. If the spear tail can deflect or wander around in the sear box that is why you can have inaccuracy, but you will only notice it on longer shots. Most fish used to be shot at around 10 to 12 feet from the muzzle, so early guns usually delivered the goods, you just had to work your way in to bring the fish into range, or rely on its curiosity to bring about its undoing.
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Old 05-07-2022, 12:09 AM   #55
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Re: Ermes Avatar speargun handle

Avatar handle looking veerrrry nice on Urta's carbon cuttle

https://www.instagram.com/p/CYXCjcgshGD/
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Old 05-07-2022, 12:29 AM   #56
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Re: Ermes Avatar speargun handle

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Originally Posted by kavachi View Post
Avatar handle looking veerrrry nice on Urta's carbon cuttle
https://www.instagram.com/p/CYXCjcgshGD/
Hell, if that cuttle properly floats an 8mm shaft, might be my dream prefab gun
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Old 05-07-2022, 01:04 AM   #57
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Re: Ermes Avatar speargun handle

Here is a 26.5 mm barrel.
https://www.nautilusspearfishing.com...fiber-barrels/
China seems to be into producing carbon barrels, possibly even the one above. /www.alibaba.com/product-detail/26-5mm-spearfishing-barrel-tube-carbon_62262487321.html

Last edited by popgun pete; 05-07-2022 at 05:25 PM. Reason: more info
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Old 05-08-2022, 01:14 AM   #58
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Re: Ermes Avatar speargun handle

Quote:
Originally Posted by Behslayer View Post
What's the Diameter of the Roller in those drawings? I see it says 9mm?
The 9mm is the depth of cut taken by the software to get a cross sectional analysis of active parts. This gives you a good picture of how everything will interact together.
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Old 05-08-2022, 01:20 AM   #59
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Re: Ermes Avatar speargun handle

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Originally Posted by kavachi View Post
Hell, if that cuttle properly floats an 8mm shaft, might be my dream prefab gun

With 8mm shaft ... for sure a carbon fiber pipe is very useful in absorbing the extra weight of the shaft. The Cuttlefish shape adds more lift as there is more air space. There are quite a few Cuttlefish tubes made of CF out there and if you follow ermessub instagram page you will see quite a few guns setup with that. If using the Pathos CF pipe and muzzle ... there are some lead coins in the muzzle of the Pathos guns which can be removed and will make an 8mm shaft possible and still keep the gun from being a sinker.
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Old 05-08-2022, 02:16 PM   #60
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Re: Ermes Avatar speargun handle

Quote:
Originally Posted by popgun pete View Post
Here is a 26.5 mm barrel.
https://www.nautilusspearfishing.com...fiber-barrels/
China seems to be into producing carbon barrels, possibly even the one above. /www.alibaba.com/product-detail/26-5mm-spearfishing-barrel-tube-carbon_62262487321.html
thanks Pete!!
am using Nautilus’s cuttle and carbon pipes, they’re nice stiff, straight, well-finished product

For me though these typical cuttle barrels just don’t swing that much easier than plain carbon pipe [which is still not particularly slippery]. Nor do they fully float my 8mm dbl offset flopper shafts

the Soriatec cuttle in that pic with Ermes handle is more flattened, with a nice concave deck, and the cuttle profile extends further towards the ends than the generic cuttle barrels. I’d like to buy extra long barrel and chop the round pipe section off each end to get the slipperiest possible profile and max float for the heavy shaft, but their longest barrel only 115 overall, so that aint gonna work for a 130 bandstretch gun.

https://www.instagram.com/p/CbimOm6jY5K/

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