Theoben Rapid Forum

Everything Technical About Rapid => Technical => Topic started by: Chips on September 05, 2023, 11:51:56 AM

Title: MK2 Double Hammer Spring Assembly
Post by: Chips on September 05, 2023, 11:51:56 AM
Hoping to clear up a mystery - discovered x2 springs ( one fitted inside another ) in my mk2 hammer spring assembly.

1. wtf ?
2. best way to set this up in future ?

FAC Rapid Mk2 currently running at 30.5 Ft/Lbs with 18.13gr JSB Jumbo Heavy - would love power to stay around 32/33 ft/lb with this pellet. Consistency / accuracy paramount.

Thanks in advance,

Charlie.

IMG_4657 02.jpg

IMG_4662 02.jpg
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Accurate1 on September 05, 2023, 12:29:23 PM
I think it was a phase Theoben went through on FAC rifles , totally unnecessary and will run more consistently with a good single spring . Always singles in any of my fac rapids

A1
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Ca_Varminter on September 05, 2023, 03:11:43 PM
(https://photos.imageevent.com/scl_electronics/gun/ultimaterapid/websize/20201012_134920.jpg)
That is what is used in the export/FAC version of the Rapids...
Also they used them in .177 12fpe Rapids..
I used this setup in my Titanium Rapid1!!
I have polished the springs, makes for a smooth cocking cycle..
But I know KevG doesn't care for them... a good single spring should good for up to 40 fpe...
Just depends on the setup...

Good Luck
Stuart
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Blitzking on September 05, 2023, 04:04:03 PM
That's the same set up as mine. It's running at around 32ft/lb with 18.13gr JSB Jumbo Heavy
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Chips on September 05, 2023, 04:19:02 PM
Interersting, thanks. Will replace with a single spring and keep it simple.
Am sure everyone has their preferences and specific requirements but any tips to ensure smooth and efficient firing cycle would be appreciated.
In the process of stripping and cleaning ( rifle acquired a year ago in ok condition but clean needed ).
Am open to upgrading selected parts if necessary.
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Dr Fox on September 05, 2023, 06:24:27 PM
Dr Fox.
Mine came with the same set up, but with one difference. The inner spring was allowed to ride down onto the inertia weight the buffer spacer was omitted. It was not to my mind the best way to go, so I found Kev G who did the single spring method. Much cleaner fit, easier tune, with just one spring to cut and tailor! While I was about this I got Kev G to send me all his innards, now tuned with 21.5 grain pellets at 40 ft lbs.
(I know you inherited this set up.)The main spring you show, should have been finished into the flat coil shape shown on the other 3 ends. That pointed spring end, besides scoring components, is not a bearing surface for compression.
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Chips on September 05, 2023, 07:33:06 PM
The pointed spring end had me baffled for that very reason.
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Ca_Varminter on September 06, 2023, 01:11:25 AM
Quote from: Chips on September 05, 2023, 07:33:06 PMThe pointed spring end had me baffled for that very reason.
(https://photos.imageevent.com/scl_electronics/gun/air/websize/conical-spring.jpg)
This is an Anti-Rattle spring!!
I use a Conical Spring for the Inertia weight/DoubleTap setups..
If you have a short protrusion of the Pip in the Hammer.
The spring tends to pounds itself into DUST!!
The Conical spring will collapse upon itself... with the risk of crushing..
Just an added safeguard to my HP Rapids..

Stuart
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Chips on September 06, 2023, 08:39:38 AM
Quote from: Ca_Varminter on September 06, 2023, 01:11:25 AM
Quote from: Chips on September 05, 2023, 07:33:06 PMThe pointed spring end had me baffled for that very reason.
(https://photos.imageevent.com/scl_electronics/gun/air/websize/conical-spring.jpg)
This is an Anti-Rattle spring!!
I use a Conical Spring for the Inertia weight/DoubleTap setups..
If you have a short protrusion of the Pip in the Hammer.
The spring tends to pounds itself into DUST!!
The Conical spring will collapse upon itself... with the risk of crushing..
Just an added safeguard to my HP Rapids..

Stuart

Good to know - my hammer pip is indeed the short variety. Am thinking this spring has less friction against inside of hammer ? Can you point me in the direction of a conical inertia spring ?
Charlie.
Title: Re: MK2 Double Hammer Spring Assembly
Post by: KevG on September 07, 2023, 08:47:07 AM
stuart mean the pip protrusion inside the hammer,it would not be the pip its self at fault some hammers were not bored out deep enough,easy fix is to have a pip made to give you more thread length,standard thread length is 14mm.
kevG
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Chips on September 07, 2023, 01:21:26 PM
Ok understood - my hammer has very little pip protrusion inside - about 3mm - no thread so poss a different design altogether ?
Have no reason to change this hammer - unless there's worthwhile room for improvement by doing so. Am going for the simplest route here !
Any thoughts ?
Title: Re: MK2 Double Hammer Spring Assembly
Post by: KevG on September 07, 2023, 01:58:56 PM
no that will be threaded if you heated the pip up it would screw out,if its extended around 3mm into hammer chamber that's fine
kevG
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Chips on September 07, 2023, 07:11:15 PM
Quote from: KevG on September 07, 2023, 01:58:56 PMno that will be threaded if you heated the pip up it would screw out,if its extended around 3mm into hammer chamber that's fine
kevG

Ok interesting - thanks Kev. So would you recommend I use a conical spring as Stuart suggests ? or just replace the old one - am suddenly in a world of springs here - lots of options !
Cheers,
C.
Title: Re: MK2 Double Hammer Spring Assembly
Post by: KevG on September 07, 2023, 07:34:20 PM
I've never had a problem with the standard springs and it's not very often I've seen smashed one only those with the dodgy hammers I mentioned.though having said that the springs Stuart is using look a great Idea
kevG
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Ca_Varminter on September 08, 2023, 05:48:04 PM
The source for all my spring needs is Century springs....
The don't sell direct anymore...
So I go through MWCompnents..
here is a link to the Conical spring page
https://www.mwcomponents.com/century-spring/shop/tapered-springs
But I am sure you must be able to source them on your side of the Pond!!!

Stuart
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Squinty on September 09, 2023, 06:53:48 AM
Quote from: Ca_Varminter on September 08, 2023, 05:48:04 PMThe source for all my spring needs is Century springs....
The don't sell direct anymore...
So I go through MWCompnents..
here is a link to the Conical spring page
https://www.mwcomponents.com/century-spring/shop/tapered-springs
But I am sure you must be able to source them on your side of the Pond!!!

Stuart

I looked for conical springs a while back after seeing one of your pictures, one of the UK online suppliers keeps stock items.
However even adding 10 to a larger order (hammer/valve/probe) the cost is pennies under  £4 each... for a trial.
Title: Re: MK2 Double Hammer Spring Assembly
Post by: Chips on September 12, 2023, 08:32:26 AM
Quote from: Ca_Varminter on September 08, 2023, 05:48:04 PMThe source for all my spring needs is Century springs....
The don't sell direct anymore...
So I go through MWCompnents..
here is a link to the Conical spring page
https://www.mwcomponents.com/century-spring/shop/tapered-springs
But I am sure you must be able to source them on your side of the Pond!!!

Stuart

Thanks Stuart -