Like asked in the heading, what is the advantage of a heavier hammer?
I guess it is for more consistent shot speed and / or better efficiency.
I guess it is for more consistent shot speed and / or better efficiency.
As I understand it from others, the spring normally stay the same.It will hit the valve harder opening a regulator set higher. Both the spring setting and the weight of the hammer affect how much of a blow the valve gets.
Look.
There´s a WAY more elegant, efficient and usable solution to that but it DOES take that either you or someone you know or if so a local machine shop does...
Have access to a lathe.
It works like this.
Hammer momentum in its own rights but this of course also means that there´s something to counter act that momentum. Pressure at the poppet, and in turn how mallable (read - soft) the actual seal is.
One of the main factors for closing force on the poppet is the poppet stem diameter. In turn, a smaller stem/spindle of course also = better flow beneath the valve seat.
So what i do these days, almost as sorts of a standard operational procedure, is to convert the valve housing to take a 2mm stem out of hardened steel.
In this case the stock poppet with a modified seal for an Aselkon, and next to it a 2mm jobbie on a PEEK seal. In the case of the Aselkons the diameter for the stock thing is on 3mm, and one might think "what difference does a mill do"... but it does.
In turn using PEEK for a seal can reduce opening force on the poppet by as much as 15%.
Many a pcp use a stem of even greater diameter, for even bigger winnings. A good source for 2mm material is what we call "silver steel" or.. drill rod.
Decent source.. regular bicycle spokes.
What i do is turn the "top hat" for the setup (the seal in other words) and then drill a 10mm deep on on 1.5mm diameter. Then i to the letter use brute force setting the stem on 2mm into that hole for an absolute MASSIVE press fit and indeed to this day i have to see one come apart.
I normally make the seal on a 15-16mm total as in that manner there´s enough material in there to hinder the 2mm rod from digging into the seal by any appreciable amount.
The new stem "bearing" part i just make out of brass, or actually bearing bronze in my case. Set the diameter i need for the outside vs what the valve body hands and then either thread or press fit using Loctite cylindrical.
Then the whole thing on the lathe setting it using a dial indicator for minimum runout.. and drill a 1.9mm dia hole. Then run a 2.000mm reamer through there and done deal..
PEEK however is a rather stiff material why i mainly use it for guns to see from say 140 bar up. Haven´t tried it, but i bet for lower reg pressure applications POM would be a better material choice as it´s softer.
Difference in power SPAN is not to be taken lightly! Let me tell you that much!
For higher "horsepower" applications this stunt can hand a good 30J, and that no laughing matter exactly. The beauty of it is that there´s no real downsides to this.
It basically just widens the span of the gun, and rather profoundly so.
Point in case (and many more like it) this 22cal Aselkon MX-10. Now sporting a 145cc plenum it slings 40 grain slugs just up against the speed of sound at will, for an easy cool 135J on the stock approx 550mm barrel.
Here a by me heavily modified 25cal Kral Puncher Breaker. Same deal. Can reach well beyond 140 at will.
..and so the story goes...
For the slugs I want more speed.I thought you wanted less speed, not more.
Yes, I should have mentioned that I did increase the reg pressure.Have you tried a higher regulator setting to verify the existing hammer and spring will not open the valve at the regulator setting you need?
Thanks for this. I will look into this at a later stage.Look.
There´s a WAY more elegant, efficient and usable solution to that but it DOES take that either you or someone you know or if so a local machine shop does...
Have access to a lathe.
It works like this.
Hammer momentum in its own rights but this of course also means that there´s something to counter act that momentum. Pressure at the poppet, and in turn how mallable (read - soft) the actual seal is.
One of the main factors for closing force on the poppet is the poppet stem diameter. In turn, a smaller stem/spindle of course also = better flow beneath the valve seat.
So what i do these days, almost as sorts of a standard operational procedure, is to convert the valve housing to take a 2mm stem out of hardened steel.
In this case the stock poppet with a modified seal for an Aselkon, and next to it a 2mm jobbie on a PEEK seal. In the case of the Aselkons the diameter for the stock thing is on 3mm, and one might think "what difference does a mill do"... but it does.
In turn using PEEK for a seal can reduce opening force on the poppet by as much as 15%.
Many a pcp use a stem of even greater diameter, for even bigger winnings. A good source for 2mm material is what we call "silver steel" or.. drill rod.
Decent source.. regular bicycle spokes.
What i do is turn the "top hat" for the setup (the seal in other words) and then drill a 10mm deep on on 1.5mm diameter. Then i to the letter use brute force setting the stem on 2mm into that hole for an absolute MASSIVE press fit and indeed to this day i have to see one come apart.
I normally make the seal on a 15-16mm total as in that manner there´s enough material in there to hinder the 2mm rod from digging into the seal by any appreciable amount.
The new stem "bearing" part i just make out of brass, or actually bearing bronze in my case. Set the diameter i need for the outside vs what the valve body hands and then either thread or press fit using Loctite cylindrical.
Then the whole thing on the lathe setting it using a dial indicator for minimum runout.. and drill a 1.9mm dia hole. Then run a 2.000mm reamer through there and done deal..
PEEK however is a rather stiff material why i mainly use it for guns to see from say 140 bar up. Haven´t tried it, but i bet for lower reg pressure applications POM would be a better material choice as it´s softer.
Difference in power SPAN is not to be taken lightly! Let me tell you that much!
For higher "horsepower" applications this stunt can hand a good 30J, and that no laughing matter exactly. The beauty of it is that there´s no real downsides to this.
It basically just widens the span of the gun, and rather profoundly so.
Point in case (and many more like it) this 22cal Aselkon MX-10. Now sporting a 145cc plenum it slings 40 grain slugs just up against the speed of sound at will, for an easy cool 135J on the stock approx 550mm barrel.
Here a by me heavily modified 25cal Kral Puncher Breaker. Same deal. Can reach well beyond 140 at will.
..and so the story goes...
For the slugs I want more speed.
Yes, I should have mentioned that I did increase the reg pressure.
With the higher pressure a 34gr slug will increase in speed for each turn in on the spring until the spring is turned in at it's maximum, only then it stops increasing at about 850fps. I don't see any plateau where the speed is leveling out. The speed I want to reach is 950 - 980fps.
The reason I don't want to tackle such a project now is that it is more detail work and I don't want to modify the original parts. I will rather get another valve body to modify or make one if I can, and keep the original as it is. After all the modifications I did, I still have all the original parts I can return if required.Look.
There´s a WAY more elegant, efficient and usable solution to that but it DOES take that either you or someone you know or if so a local machine shop does...
Have access to a lathe.
It works like this.
Hammer momentum in its own rights but this of course also means that there´s something to counter act that momentum. Pressure at the poppet, and in turn how mallable (read - soft) the actual seal is.
One of the main factors for closing force on the poppet is the poppet stem diameter. In turn, a smaller stem/spindle of course also = better flow beneath the valve seat.
So what i do these days, almost as sorts of a standard operational procedure, is to convert the valve housing to take a 2mm stem out of hardened steel.
In this case the stock poppet with a modified seal for an Aselkon, and next to it a 2mm jobbie on a PEEK seal. In the case of the Aselkons the diameter for the stock thing is on 3mm, and one might think "what difference does a mill do"... but it does.
In turn using PEEK for a seal can reduce opening force on the poppet by as much as 15%.
Many a pcp use a stem of even greater diameter, for even bigger winnings. A good source for 2mm material is what we call "silver steel" or.. drill rod.
Decent source.. regular bicycle spokes.
What i do is turn the "top hat" for the setup (the seal in other words) and then drill a 10mm deep on on 1.5mm diameter. Then i to the letter use brute force setting the stem on 2mm into that hole for an absolute MASSIVE press fit and indeed to this day i have to see one come apart.
I normally make the seal on a 15-16mm total as in that manner there´s enough material in there to hinder the 2mm rod from digging into the seal by any appreciable amount.
The new stem "bearing" part i just make out of brass, or actually bearing bronze in my case. Set the diameter i need for the outside vs what the valve body hands and then either thread or press fit using Loctite cylindrical.
Then the whole thing on the lathe setting it using a dial indicator for minimum runout.. and drill a 1.9mm dia hole. Then run a 2.000mm reamer through there and done deal..
PEEK however is a rather stiff material why i mainly use it for guns to see from say 140 bar up. Haven´t tried it, but i bet for lower reg pressure applications POM would be a better material choice as it´s softer.
Difference in power SPAN is not to be taken lightly! Let me tell you that much!
For higher "horsepower" applications this stunt can hand a good 30J, and that no laughing matter exactly. The beauty of it is that there´s no real downsides to this.
It basically just widens the span of the gun, and rather profoundly so.
Point in case (and many more like it) this 22cal Aselkon MX-10. Now sporting a 145cc plenum it slings 40 grain slugs just up against the speed of sound at will, for an easy cool 135J on the stock approx 550mm barrel.
Here a by me heavily modified 25cal Kral Puncher Breaker. Same deal. Can reach well beyond 140 at will.
..and so the story goes...
I will make a new hammer as soon as I get back home and have some time to do it. I think this is what it needs.It allows you to run a much higher reg pressure as the heavier hammer will open the higher pressure. Thus you can shoot higher velocities and heavier projectiles. I would say please use your gun stock and see what its capable of first. Diving head first into heavier hammers and slug power kits can really cause headaches if you don’t know what you are doing.
Yeah Matt, i hear you.Fwiw I use peek on poppets that see as little as 25 lbs holding force personally, and in other applications as low as 100 lbs. It boils down to surface quality and sealing margins more than holding force on the poppet, in my experience.
I am not a fan of 2mm stem bores personally, it loosens the 'tuning window' which means its more sensitive to variation in hammer strike...I have all the math to support this if you would like me to go deeper, just ask.
I personally wouldn't go less than 2.5mm on a stem bore for most pcp's, for the average user... while the stem diameter that sits within the throat can go down to 2mm no issue, imo to improve flow and reduce the required throat diameter to support porting forward of it.
~3mm stems are fairly standard in pcp's for a reason, to provide more consistent closing force that is less sensitive to hammer strike variability, and for end-user tunability. Meaning, smaller stems within the bore take a lot less shift in hammer spring pre-load to shift fps, this is not always a good thing....Sure they take less hammer strike, but there are better ways to skin this cat...
Such as a pilot valve or balance valve, both of which will have their own caveats, but by far and large, out perform the simple reduction of stem bore and consequent stem diameter when it comes to reduced hammer strike requirements...because they reduce the holding force, not the closing force (the latter, greatly effects tunability, the former, does not).
This..coming from a user who currently has 1mm stem diameter present in my throat, that still relies on a 3mm stem within the bore for consistent closing force.
2mm stem bores absolutely work and are one approach, heck, you can go down to 1.5mm and with HSS drill rod you'll likely never snap the sucker unless your holding force on the valve approaches and exceeds 180 lbs. Which, touching on that, you should be weary reducing stem diameters without knowing their limitations based on the force acting on it, from holding force in a closed state, to closing force in an open state. But again, it's not the best approach or manufacturers would all be doing this long, long ago...
Not to deter anyone from doing such mods, heck, have at it, but be warned of all the above.
-Matt
One flipside to extremely heavy hammers is first up that the internals are rarely dimensioned to take that sort of pounding.I will make a new hammer as soon as I get back home and have some time to do it. I think this is what it needs.