Short R9 guide fitted in spring and a top hat with LONG guide in spring

[nced]

Noticing that when my R9 springs take a "bend" it's at the unguided end of the spring. Well, I just made a two piece guide and when each end of the guide is butted together it fills the inside length of the piston. Actually, the top half of the guide is simply a top hat with a really long tight fitting "guide stem". Here is a pic.........

You can see, that both ends of the spring guided and have a Delrin thrust washer between the spring end and base flange. By the way, the spring isn't bent, the "bent image" is simply due to the wide angle camera lens. LOL

Anywhoo.....both halves of the guide are tightly fitted to the spring and with my test shots there was no twang or vibration at all! I did some chrony and accuracy testing and this scheme worked out well (so far). Here is one of my 100 bull targets with 1/4" bulls that I shot in two separate days. The first 50 bulls were shot when my .177 R9 was shooting CPLs at 805fps using an old 34 coil spring with .120 wire wound with a .540 ID. All shots are done upstairs at 18 yards hunter class field target style (sitting on a bucket resting the gun on cross sticks) and both sessions were shot the same way. The second 50 shot session was shot today the same way however I made up a new spring kit based on a new 34 coil spring with .120 wire wound with a .540 ID. I had the new spring hidden in a parts drawer from years ago and it wasn't even set yet! I spaced up the new spring to shoot CPLs at 880 fps so the cocking was stiffer than before, however the shot cycle was really nice. Here's a scan of the target shot in two sessions..........

Anywhoo.....I've read and believed that my .177 R9 would be less "hold sensitive" at 11.5 fpe than at 13.5fpe, and perhaps it is, however I can't tell MUCH difference with my shooting at only 18 yards, if ANY!

[ptpalpha]

Hi Ed,
A couple questions:
Do you notice any difference in the cocking or shot cycle between the original guide set-up and the new 2-pc?
Changing springs too makes comparing the a bit harder, I know, just wondering if you think the 2-pc gave you an advantage beyond preventing spring bend.
Also, you mentioned the delrin washers, but I see your guides are black.  Nylon?
Another great idea, by the way.  When are you going to put all these things together and write a book?  (not joking....the more I read about DIY things for tuning/improving airguns it seems your name is always there.  Thanks for the help, Ed.  I'll be first in line when you publish!)

[nced]

Hi Ed,
A couple questions:
Do you notice any difference in the cocking or shot cycle between the original guide set-up and the new 2-pc?
Changing springs too makes comparing the a bit harder, I know, just wondering if you think the 2-pc gave you an advantage beyond preventing spring bend.
Also, you mentioned the delrin washers, but I see your guides are black.  Nylon?
Another great idea, by the way.  When are you going to put all these things together and write a book?  (not joking....the more I read about DIY things for tuning/improving airguns it seems your name is always there.  Thanks for the help, Ed.  I'll be first in line when you publish!)

Do you notice any difference in the cocking or shot cycle between the original guide set-up and the new 2-pc?
Well, as you mentioned, a different spring makes direct comparing unlikely, however the cocking and shot cycle is just a SMOOTH as the single fitted guide so far. Since the two piece spring guide has more contact with the spring and is tight fitting I'm guessing that the max velocity is also affected, but after shooting a couple hundred shots with the arrangement the CPL velocity has settled at about 860fps. This does make me wonder if I can get a twangless shot cycle by using a "not so tight" guide to spring fit. With the two piece guide I suppose that there could be an issue if the spring broke "in the middle" since the rear guide section doesn't engage the end of the latch rod before cocking. To date I haven't seen a spring break "in the middle" so perhaps this isn't an issue. Here is a pic of my most recent "spring break"...........

As you can see, the spring broke near the top where the "spring squirm" is greatest.

Also, you mentioned the delrin washers, but I see your guides are black.  Nylon?
The guides are cut from a piece of BLACK Delrin rod I had in the parts bin. The washers are made of WHITE Delrin that I normally use. Personally I think that the WHITE Delrin is better for a guide.
I've also made guides from molly filled 6/6 nylon (Nylatron) but I've found that Delrin is easier to machine since the nylon is incredibly tough.........
Uploaded at Snapagogo.com

When are you going to put all these things together and write a book?
LOL.....I HARDLY consider myself to be more than a tinker who enjoys simply playing with new (to me) ideas and giving them a try. A couple decades ago I had an issue with point of impact changes  at a field target match when I zero'd my gun during snow flurries, however the temp rose to the mid 50s before the match ended. I had a "theory" that this change had a lot to do with a factory parachute seal and "velocity tar" that I was gooped on my spring. After the match the R9 spring was stripped of the "goopy stuff" and only molly paste was used for all internal lube. This helped a lot but I still had some "poi shifting issues" so the thought was that the combination of lube changing viscosity and factory piston seal changing durometer were contributing to the "temperature induced poi shifts".  It was at that time when I THOUGHT I had the novel idea of lathe cutting an aluminum piston cap with an oring that replaced the piston seal. The scheme worked great so in my excitement I posted my "wonderful new findings to the world". LOL  It was then that a reply to my post was greeted with "you're only reinventin' the wheel since BSA used orings decades ago".  The "two piece guide" is simply an effort at taming "spring squirm" and only time will tell if the benefits outweigh the disadvantages (if there are any).

Anywhoo.......I really "ain't all that" so I simply post my ramblings for others to try so THEY can write a book if they desire! 

[ptpalpha]

Thanks, Ed...that all makes sense.
You're too modest, however...a man who turns an 8mm bolt down to 7mm with a .75 pitch to replace an HW axis-pivot bolt, then fashions a socket-head "nut" for the other side; who makes his own barrel vice to do chokes, turns his own necked screw cups...this is a guy I can (and do) learn from!
Just keep doing what you're doing. Please.

[VillageSniper]

   Looks like a cool design.  I suppose that where the spring broke, in the pic, is where it typically bends the most when cocked, and is inside the piston?  I don't have any tuning experience, outside of one old, broke down HW75 pistol.  Does a spring usually contact the inside of the piston when cocked and fired (vibrations).  If so, it would be interesting to see a liner made of delrin or some sound deadening material to further eliminate any possible metal to metal contact once fired. I understand the guide helps keep the spring centered, but does it flex or shift at the free end?

How much room is between the guides when cocked and how do you know the distance?
Vs

[nced]

   Looks like a cool design.  I suppose that where the spring broke, in the pic, is where it typically bends the most when cocked, and is inside the piston?  I don't have any tuning experience, outside of one old, broke down HW75 pistol.  Does a spring usually contact the inside of the piston when cocked and fired (vibrations).  If so, it would be interesting to see a liner made of delrin or some sound deadening material to further eliminate any possible metal to metal contact once fired. I understand the guide helps keep the spring centered, but does it flex or shift at the free end?

How much room is between the guides when cocked and how do you know the distance?
Vs

"I suppose that where the spring broke, in the pic, is where it typically bends the most when cocked, and is inside the piston?   Does a spring usually contact the inside of the piston when cocked and fired (vibrations). "
Here is close-up pic of the break.........

As you can see, the outside of the coils in this area were "polished" by rubbing the inside if the R9 piston liner (R9 pistons no longer come with liners). Since my fitted guides don't allow spring twang (even my normal one piece guides) the ONLY purpose "spring tar" served me was breaking the metal to metal contact with a film of molly.

If so, it would be interesting to see a liner made of delrin or some sound deadening material to further eliminate any possible metal to metal contact once fired.
This is the Vortek approach where the guide is made with and inner and outer guide. Personally, I prefer not to have an "outer spring guide tube" because this forces the use of a spring wound for a rather small OD so it will fit in the tube which in turn needs to fit in the piston. With two springs identical in coil count and wire size......the one with the smaller ID will be the stiffest and it will be more highly stressed.  Personally (again) I prefer the lower stressed spring with the larger OD

I understand the guide helps keep the spring centered, but does it flex or shift at the free end?
"flex and shift at the "free end"?? The R9 spring has a base flange that can center the "rear half" of the guide until the piston latch rod enters the reamed hole in the guide. At the other end the piston latch rod centers the guide in the piston, and since the whole assembly is under some preload there really isn't a "free end" unless you're speaking of the end in the moving piston. As mentioned, the spring in the piston s centered by the top hat with the long "stem" that forms the "other half" of the guide.

"How much room is between the guides when cocked and how do you know the distance?"
Werry Werry technical....LOL, I really DON'T know. I simply made sure that when both halves of the spring guide are in the piston, the base flange JUST sits on the rear of the piston skirt. This way I know that whatever spring I use, if the gun fails to "latch up" when cocking there is too much spacing in the top hat or spring seat and the spring gets "coil bound" before the seal latches and the length of the guided is too long. After making up my "two piece guide spring kit" I installed it in the R9 and the gun cocked. Looking at the compressed spring through the cocking shoe slot (new R9s don't have piston liners) I could see a bit of spacing between each coil so I'm pretty sure that I could even add a bit more preload with another washer. The gun is CURRENTLY working well with a rather nice shot cycle so it will stay where it is. If the spring kit didn't allow the R9 to cock then I would either have to lessen the thickness for the "top hat flange" or reduce the stack-up by another method like perhaps removing the front thrust washer, or whatever.

[VillageSniper]

Thanks for the additional info.  Sounds like a good shooter.

Vs

[IRONWORKER]

Beautiful work sir

[TyRyanosaurus]

hey Ed,
I agree you are a wealth of info, I have learned a lot from your posts.

I am not sure that all new R9's do not have a sleeve. Mine I got last Aug. and it had the new style cocking shoe, the new style piston seal, and a sleeve. In typical HW fashion I think there is some variation. I dunno, just some info. I was emailing with Steve Pope (V-mach) and he said they went to no sleeve and then back again because people got too much grunge up in the piston. I always thought the sleeve was to keep the cocking shoe from rubbing the spring. I do have to admit that sometimes I do not understand what he is saying though so I could have misunderstood.

-Another R9 lover-
Ryan

[nced]

hey Ed,
I agree you are a wealth of info, I have learned a lot from your posts.

I am not sure that all new R9's do not have a sleeve. Mine I got last Aug. and it had the new style cocking shoe, the new style piston seal, and a sleeve. In typical HW fashion I think there is some variation. I dunno, just some info. I was emailing with Steve Pope (V-mach) and he said they went to no sleeve and then back again because people got too much grunge up in the piston. I always thought the sleeve was to keep the cocking shoe from rubbing the spring. I do have to admit that sometimes I do not understand what he is saying though so I could have misunderstood.

-Another R9 lover-
Ryan

The new style cocking shoe looks like this..........


Here is a poor pic showing the new style shoe installed on my R9..........
Uploaded at Snapagogo.com

[TyRyanosaurus]

Yep, looks just like mine.