HW35 Fettling

[TonyL]

Tone, the o ring won't "run in " as such , the lube however will take a while to move about and settle down, just make sure it isn't dieseling a little. If you can find a good spring , that would be better, but as long as you have more than 10 mm preload your spring is unlikely to hop off the guide .
Don't forget tinbums new springs are excellent, and available in three sizes .
I am about to build and set up a 24 mm 80. With a 31 coil one, will let you know how it goes

Hi Nick, thanks ever so much for the input.

Running very minimal lube now after the crazy power I saw following earlier build. I'll obviously degrease again and apply ever-so-sparingly again. I could detect a very feint aroma of combustion, but no visible evidence and consistency is amazing.

It is running one of Nick's springs.

Twice shortened already. I'll shorten more as the threaded portion of the end block is circa 19mm, so there's scope to shorten further whilst still retaining the 10mm preload as you point out.

Thank you.

[NickG]

That sounds good , looks like just a little off the spring, should sort it .

[Waddy]

My LGV pistoned 80 is now running a tbt spring, I got the full length one & had to chop a fair bit off, that still landed it slightly hot, so I took another half a coil & it's bang on.

I was going to take 1 coil off, but thought better of it seeing how much of the spring length a whole coil actually is.



.

[TonyL]

I'll hopefully get the time to strip it and play on Wednesday.

I've just had a quick look at the barrel vertical play....if I push the latch firmly towards the cylinder the play goes away. Like it did when I just tried the barrel, hinge bolt and cylinder. So it might just be the spring that's gone weaker? I've just ordered one from Chambers, so fingers crossed......

[TonyL]

So, I finally got some playtime yesterday afternoon........

Shortened the spring a little further, collapsed flat and ground flat again. Rebuilt with the same very sparing lube. The end of the guide now sits about 7 or 8mm below the end of the cylinder, so about 12mm preload.

Result, power still high. A nudge over and feeling to be a very quick cycle still. After a few shots my trigger finger was tingling a fair bit.

If there was scope to, the obvious thing would be to shorten the spring further. But as we're now at just 12mm of preload, no scope to do so, really.

So, Jon's suggestion all along of a softer spring is sounding to be the only way forward.

Guessing reducing this spring by more and making up the preload to an acceptable level by the use of washers, reducing the amount of "active spring" but keeping that preload will just result in too stiff a spring?

So, what we're working with is old-style piston with fixed-on steel 'O' ring head, made to the same dimensions as the synthetic head convertor. Older pistons being heavier than newer style ones, shorter stroke and then stroke reduced even more by the carrier. Plus a little heavier. TP in the 3 to 3.3 region, I seem to remember. Piston is a nice, sliding fit. A little bit of resistance. Prior to the 'O' ring head, a new HW parachute seal was a sloppy, loose fit.

Question is, this thing is seemingly so, so efficient, could I actually get away with that nice, weak TX spring? I'd be happy at 9.5 - 10ft.lbs and sweet, soft shooting. As I can't make guides and top hats, I'm guessing then that the TX rear guide would work fine with the flange being 30mm and guessing piston rod will work with the TX guide. If the flange is no thicker, rod should go through to the trigger okay, too?

Or a 77/97 spring?

Any suggestions, peeps?

[evert]

Are you sure the gun isn't dieseling?

[TonyL]

100%, evert.

VERY sparingly lubricated and velocities are very consistent.

[maximus]

I would try a 97 spring. My new 177 35 came with one with a massive amount of pre-load, so much so that I lost my bottle trying to get it back in! I think with the power numbers you're getting it would be ok and still retain a goodly amount of preload. Mine currently has a cut down titan no.1 in it that I had in my stash and shoots very nicely with FAP but not so nice with heavier pellets. I am happy with this though for the time being as it's accurate with the FAP.

[TonyL]

Are you sure the gun isn't dieseling?

100%, evert.

VERY sparingly lubricated and velocities are very consistent.

Sorry evert, I also meant to add to that previous post that there's also not even the feintist aroma of a hint of a diesel. When it was doing the silly powers previously there was, indeed, a slight whiff....

[TonyL]

I would try a 97 spring. My new 177 35 came with one with a massive amount of pre-load, so much so that I lost my bottle trying to get it back in! I think with the power numbers you're getting it would be ok and still retain a goodly amount of preload. Mine currently has a cut down titan no.1 in it that I had in my stash and shoots very nicely with FAP but not so nice with heavier pellets. I am happy with this though for the time being as it's accurate with the FAP.

Thank you for that, Max. The 77/97 spring was certainly among my list of possibles. It'd be nice if it fitted onto the TbT guides nicely. Or, I wonder if Nick might have some of his "old-type" more basic kits still knocking around?

I think Nick's 77/97 springs will be the same as the 35/80 ones, just different lengths?

I'll see who has genuine standard ones......

[Waddy]

Thank you for that, Max. The 77/97 spring was certainly among my list of possibles. It'd be nice if it fitted onto the TbT guides nicely. Or, I wonder if Nick might have some of his "old-type" more basic kits still knocking around?

I think Nick's 77/97 springs will be the same as the 35/80 ones, just different lengths?

I'll see who has genuine standard ones......

Nick is doing a heavier "Magnum" spring for the 35 (& 80) now. Must be better or he wouldn't be doing them ?

.

[TonyL]

Nick is doing a heavier "Magnum" spring for the 35 (& 80) now. Must be better or he wouldn't be doing them ?

.

They'll be for unrestricted power markets and FAC holders, Paul.

[NickG]

So, I finally got some playtime yesterday afternoon........

Shortened the spring a little further, collapsed flat and ground flat again. Rebuilt with the same very sparing lube. The end of the guide now sits about 7 or 8mm below the end of the cylinder, so about 12mm preload.

Result, power still high. A nudge over and feeling to be a very quick cycle still. After a few shots my trigger finger was tingling a fair bit.

If there was scope to, the obvious thing would be to shorten the spring further. But as we're now at just 12mm of preload, no scope to do so, really.

So, Jon's suggestion all along of a softer spring is sounding to be the only way forward.

Guessing reducing this spring by more and making up the preload to an acceptable level by the use of washers, reducing the amount of "active spring" but keeping that preload will just result in too stiff a spring?

So, what we're working with is old-style piston with fixed-on steel 'O' ring head, made to the same dimensions as the synthetic head convertor. Older pistons being heavier than newer style ones, shorter stroke and then stroke reduced even more by the carrier. Plus a little heavier. TP in the 3 to 3.3 region, I seem to remember. Piston is a nice, sliding fit. A little bit of resistance. Prior to the 'O' ring head, a new HW parachute seal was a sloppy, loose fit.

Question is, this thing is seemingly so, so efficient, could I actually get away with that nice, weak TX spring? I'd be happy at 9.5 - 10ft.lbs and sweet, soft shooting. As I can't make guides and top hats, I'm guessing then that the TX rear guide would work fine with the flange being 30mm and guessing piston rod will work with the TX guide. If the flange is no thicker, rod should go through to the trigger okay, too?

Or a 77/97 spring?

Any suggestions, peeps?

I would go for the tx spring , any thing else 77/ 97 will be stiffer than the tinners spring ( don't forget Jim Tyler uses one with 40 mm pre load to power the mk 2 stroke tx . )
If you need guides I will make you some , I have a mk 3 spring here , would need to know lengths.

[TonyL]

I would go for the tx spring , any thing else 77/ 97 will be stiffer than the tinners spring ( don't forget Jim Tyler uses one with 40 mm pre load to power the mk 2 stroke tx . )
If you need guides I will make you some , I have a mk 3 spring here , would need to know lengths.

Thank you, Nick. You're a star.

Will be in touch re those dimensions.

[maximus]

I would go for the tx spring , any thing else 77/ 97 will be stiffer than the tinners spring ( don't forget Jim Tyler uses one with 40 mm pre load to power the mk 2 stroke tx . )
If you need guides I will make you some , I have a mk 3 spring here , would need to know lengths.

Tinbums HW35 spring has 3.6mm wire and although a larger i.d. than the 97 spring, is stiffer in my experienc. Regards Max