Author Topic: Hammer springs????? (Read 1938 times))

scion19801 · « **on:** July 08, 2020, 02:41:37 PM »

ok so my jsar super tune kit hammer spring took a dump..
Anyone know where i can get gauntlet hammer spring assortment in different weights?
I put the stock spring back in as a temporary fix. .25 cal is very inefficient now running at 1400 psi on regulator to keep speed down. were talking 32 shots from 3000 psi to off regulator with a .380 cc bottle. i know its currently way over sprung.

RDB · « **Reply #1 on:** July 08, 2020, 03:10:28 PM »

See if you can match one up here.

https://www.mcmaster.com/springs/springs-and-shock-absorbers/compression-springs/mil-spec-compression-springs/

scion19801 · « **Reply #2 on:** July 08, 2020, 04:15:09 PM »

k gonna see what i can figure out. done testing or today. not happy with current setup. got it at 1600 psi reg set point. shooting 875 fps, 48 fpe with 28.4 grain noe 250-27-rf pellets. and major air hog. around 3 mags on a massive .380 cc bottle before it comes off setpoint.
guessing factory spring is massively over rated, especially with aftermarket poppet and .1875 through tp and barrel port. probably be way over 900 fps at 1900 psi factory setpoint. thinking i can make a spacer that is shorter behind the hammer and go back to 1900 psi and then shorten spacer to bring speed back down. I DON'T want to clip or shorten factory spring to get the efficiency back

scion19801 · « **Reply #3 on:** July 08, 2020, 04:50:02 PM »

McMaster Carr doesn't have the size i need.
Apparently i need a "qb series" hammer spring. Anyone know a source for the qb78 hammer springs.
my spring spec i need for replacement are:
id = .23"
od = .34"
wire dia. = .051
coils = 18 or so maybe even 20
length =2.3" or so may be max 2.5"

scion19801 · « **Reply #4 on:** July 08, 2020, 05:02:44 PM »

would this spring work?
https://www.centuryspring.com/catalog/compression-regular?page=product&cid=compression-regular&id=S-297CS

SpiralGroove · « **Reply #5 on:** July 08, 2020, 05:25:39 PM »

This may sound pretty basic, but my local "old fashioned" hardware stores sells a great selection of compression/expansion springs. I just find the ones that work and cut them to various lengths in combination with the hammer adjustment found built in on many airguns.

Together, you can adjust to whatever is needed.

scion19801 · « **Reply #6 on:** July 08, 2020, 07:23:41 PM »

hadn't thought of that. have to go check the local hardware store tomorrow. Pulled out my hammer spring spacer and put in 6 small washer equalling about .436" or so (stock spacer is .658") and set regulator to 1800ish psi. now got 25.4 grainers going 875 fps. if i put in another washer i get 910's or so. But cocking weight had dropped of and efficiency has picked back up and it's not as loud as it was so all headed in the right direction..

if i try for factory 1900 psi. my fps drops off. with the same spacer(washer) stack.
now once i get a usable spring replacement i'll be able to put my rear velocity adjuster back in.

KnifeMaker · « **Reply #7 on:** July 08, 2020, 09:12:30 PM »

Quote from: scion19801 on July 08, 2020, 05:02:44 PM

would this spring work?
https://www.centuryspring.com/catalog/compression-regular?page=product&cid=compression-regular&id=S-297CS

It probably will, however, Never/ever order stainless if possible. It is much weaker than music wire or spring steel, and they tend to break.
Stainless is NOT very dependable for long life and will get weaker and weaker. not go mention get metal fatigue fractures easily.

scion19801 · « **Reply #8 on:** July 09, 2020, 02:56:16 AM »

Ty for the tip on stainless knife. Hadn't thought of that. Will try to stay with music wire then. Found this that looks promising.
https://www.grainger.com/product/SPEC-Compression-Spring-54MU80
Seems that the spring I'm looking to replace from the jsar kit is a 20 lb spring. According to a spring calculator I tried. So these 18 lb ones should work. May have to add a small spacer to add a touch of preload. Kinda bummed that I got to get a 10 pack in order to get a spring, but it seems they aren't going to last very long so now have many needed extras. just hope the 2 lb difference won't be a big issue. Next time I pull the gun down I'll measure the factory spring to try to figure out its spring rate. I know I got a lot of free travel in stock spring currently to keep speed of pellets in optimum range and reg pressure down as well. At least now it is getting better efficiency and shot count it back up, but no current way to fine control velocity and the stock spring with the jsar rva is way too much spring and putting it in the 920-930 fps area with 25.4's. Too hot for good accuracy. Sure the 56 or 58 gram hammer doesn't help much either. Especially with the aftermarket peek poppet. Was almost going to try shortening the rva length to try and gain control over factory spring. But that didn't seem like a good idea.

KnifeMaker · « **Reply #9 on:** July 09, 2020, 11:02:38 AM »

Seems the slightly light spring may very well help in this case.

Knife

scion19801 · « **Reply #10 on:** July 09, 2020, 02:14:00 PM »

https://www.grainger.com/product/SPEC-Compression-Spring-54MN28
heard from hajimoto. was told the jsar tune kit spring was 22 pound for the .25 cal. so i went with the above spring. so now patiently waiting for it to arrive by the end of the month.
I hope this will allow other who have bought the kit to find a replacement spring easier.

Sbak · « **Reply #11 on:** July 09, 2020, 09:47:10 PM »

They sell them on Amazon, search for music wire spring in small parts

scion19801 · « **Reply #12 on:** July 10, 2020, 02:24:31 PM »

ty sbak. i checked it out but the majority of their springs are stainless steel. not a good choice according to what knifemaker said. i ended up going with the ones in my last post. waiting for them to arrive. i'll update this as to how well they work as a replacement for the jsar tune kit spring once i get them tested out.

KnifeMaker · « **Reply #13 on:** July 10, 2020, 05:25:40 PM »

When I was still actively in business, I did a lot of business with Granger. Back in the day it took forever. No idea how it is now.I do know that McMastercarr is annually two days. I'll bet
Granger is faster now days as well, as dealing with businesses, time if paramount for jobs.

FWITW, I have broken many a ss spring. Not one music wire! Well, not in an airgun at least.

Knife

sb327 · « **Reply #14 on:** July 10, 2020, 05:57:17 PM »

.051 music wire is quite common. Making springs is quite an easy task, just have to cook them in the oven at 450 for about 30 minutes when done. I keep several sizes of music wire on hand just for this type of situation.

Hope you get it going like you want.

Dave

scion19801 · « **Reply #15 on:** July 10, 2020, 07:07:39 PM »

Quote from: sb327 on July 10, 2020, 05:57:17 PM

.051 music wire is quite common. Making springs is quite an easy task, just have to cook them in the oven at 450 for about 30 minutes when done. I keep several sizes of music wire on hand just for this type of situation.

Hope you get it going like you want.

Dave

Now that would be worth investigating how to do. i tried to find info on making springs but it seems people were just coiling wire around and arbor and that was that. I know there must be more to that just that. one would really be able to do some trick spring work making your own and probably be cheaper and easier as well. definitely easy to get repeatable results.

sb327 · « **Reply #16 on:** July 10, 2020, 08:48:16 PM »

That’s really about all there is to it.

The hardest part is finding an arbor that is the correct size smaller than desired final id.

And there is not an easy formula. But a little trial and error gets you there.

Then draw out some marks to guide you to get the correct pitch. And wind it....WHILE WEARING SAFETY GLASSES. Music wire needs it’s respect.

After shaping, it will have some work hardened areas that create stresses. You need to relieve those stresses by cooking at 450 for half an hour.

If you have access to a lathe, it’s even easier if the lathe has threading capabilities.

Dave

scion19801 · « **Reply #17 on:** July 11, 2020, 01:32:10 AM »

Interesting.... Wish I had a lathe. Oh the fun that could be had with one.

scion19801 · « **Reply #18 on:** July 12, 2020, 06:47:28 PM »

just did a quick shot count test....
with current 1700 psi reg set point. 43 FPE with .25 cal. factory valve measurements. Custom tp .194" valve side - .1875" receiver side, and .1875" through to barrel port. 1000 psi used from full fill 3000 psi shot down to 2000 psi = 48 shots. Factory hammer spring, with no spring preload or tension on spring. Average FPS 882.
Did find that gun has a leak...Pretty sure it is my foster fill fitting on my JSAR Flex reg. gonna see if i can use the fill fitting off my ninja reg till i can find a replacement or a new o'ring for it possibly if it is replaceable.
edit>>>
this is not the factory bottle. I have a .38l or 380CC. the factory is 13 cu in which is 213 cc.. not quite double the tank size, but twice or better than the factory bottle. Gun is heavier due to it as well.

scion19801 · « **Reply #19 on:** July 13, 2020, 10:32:25 AM »

leak found and fixed. it wasn't the foster fitting after all. Did a water dunk test and it was the replacement gauge i had put on the flex regulator. Blow dried the water off and out out it after testing with air compressor. Then tested settings and it looks that my current shot count above wasn't at 1700 psi afterall, it was 1650 psi. regulator now set to 1700 psi. my replacement gauge is apparently 100 psi off to the high side. reading more than what its at. Good info to know when further adjustments are made in the future.

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Hammer springs?????

Author Topic: Hammer springs????? (Read 1938 times))