Help stripping and sorting a HW35k

[Shed tuner]

as tinners said... also check the piston seal is in good order/not been sliced/cut on sharp edges during assembly...
and once done, if the cocking effort is still a bit high, just cut the spring down. it doesn't need to run at 11 to hit stuff !

[Mr.Fixit-Norm]

The guides and new spring work together, that twang should go when we get the right parts in

Haha, how did I know you were going to say that Nick

I was wondering if the Ox spring would always twang anyway as the flat section has far more contact with the inside of the piston, which is where I’m assuming the twang originates ??

I am definitely putting the new spring in as I’m not happy with the cocking effort which I think is down to it’s really stiff compression characteristic.
By the way I was guessing it was down to the spring rather than your very nice guides

Based on what I’m getting so far Nick, would you have any suggestions as to what length I cut that spring down too ?

It would be nice to keep the power level around 10.5 with much less cocking effort but maybe I’m asking too much.

Cheers,

Norm

[coburn]

I bought a .22 35K off here some years ago. It was down in power, about 9ftlbs from memory. I sized the piston seal and fitted a new HW mainspring. I made 12.7ftlbs before I turned it down a bit.

You should easily achieve the same, at around 11ftlbs they make a lovely shooting rifle.

Makes you wonder why people buy those snappy HW95's, when the newer synthetic sealed 35's run smooth at 10.5 to 11.

[Mr.Fixit-Norm]

Norm, DO NOT be dis-heartened, my good chap......There's a good chance that, once the supplied spring has been suitably sized, cocking effort will be reduced as the coils will be less beefy. And a new, more supple piston seal will help as long as it's not silly tight. Those other pellets should give higher energy readings, too. Please also double check that the cocking lever isn't bent and, therefore, dragging on the cylinder or spring. The twang will be gone once those guides are fitted to the correct spring as Nick will have made them to suit that spring. Keep at it; you're getting there.

Thanks Tony, yes I’m sure Nick’s set up will do the job, I’m very suspicious that that nasty Ox spring is a major part of the problem !

It’s certainly been a weird evenings tweaking. The bit I couldn’t understand was the reduction in power when I first put it back together with nothing more done than the attempted ‘porous’ cylinder seal ?

At least I ended the evenings work with a win ( we’ll sort of ), it shows the gun is capable of hitting 11ftlbs, and hopefully with less cocking effort.
I’ve a completely free day tomorrow ( apart from some dog walking ) so should be able to improve on the current situation. You’d all be laughing if you’d seen me cocking it at the end, with the combro attached, the amount of barrel left as leverage is very small, it was ‘bend forward slightly, rest butt at top of right thigh and use both hands to cock it ‘ ( we definitely need a crying with laughter emoji ! )

I should also like to say a big thank you to everyone who’s contributed so far with ideas and suggestions, it’s very much appreciated and I will get there !!!

Norm

[Mr.Fixit-Norm]

I bought a .22 35K off here some years ago. It was down in power, about 9ftlbs from memory. I sized the piston seal and fitted a new HW mainspring. I made 12.7ftlbs before I turned it down a bit.

You should easily achieve the same, at around 11ftlbs they make a lovely shooting rifle.

Makes you wonder why people buy those snappy HW95's, when the newer synthetic sealed 35's run smooth at 10.5 to 11.

That sounds encouraging, can you remember what the cocking effort was like ?

[tinbum]

Haha, how did I know you were going to say that Nick

I was wondering if the Ox spring would always twang anyway as the flat section has far more contact with the inside of the piston, which is where I’m assuming the twang originates ??

I am definitely putting the new spring in as I’m not happy with the cocking effort which I think is down to it’s really stiff compression characteristic.
By the way I was guessing it was down to the spring rather than your very nice guides

Based on what I’m getting so far Nick, would you have any suggestions as to what length I cut that spring down too ?

It would be nice to keep the power level around 10.5 with much less cocking effort but maybe I’m asking too much.

Cheers,

Norm

My 35 arrives tomorrow and I will cover this in the video, but....

The 35 has had different piston lengths over the century or so it has been made. Because of this you need to put the slip washer and top hat in the piston and measure from where the spring sits to the piston skirt in mm. This is the spring room.
Divide this number by 3.6 (the wire gauge) and it will tell you how many complete coils will fit before it gets coil bound.

Once that's done test power and report back

[T 20]

I think Mick also draws up some of the thread sealant via vacuum having firstly forced it down.

When Gerald Cardew wrote in Airgunworld about filling the void in a 35 cylinder he mentioned using a vacuum chamber, Tone.
The reason for using a vacuum is that the Loctite may bridge the gap between the cylinder and breech plug and not drop down far enough into the void to fill it.
As the Loctite drops down the cylinder wall towards the void the air pressure in the void will increase slightly and hold the Loctite from fully flooding the void.
By putting the Loctite in the bottom of the cylinder and then applying a vacuum the air is drawn out of the void so when the vacuum is released the Loctite is sucked into the void to fill the gap where the air was.

You may be trying to fill the top groove or both grooves --- who knows ? :-


image.jpg



I've tried solder without success, mainly due to not being able to clean the void well enough coupled with the fact that there's a lot of metal breech end of the cylinder to warm up without damaging the bluing --- Loctite is by far the easiest way of filling the void.




All the best Mick

[coburn]

That sounds encouraging, can you remember what the cocking effort was like ?

About average for a 35, although the shorter barrel tends to make the effort feel greater than an Export with the 22 inch barrel.

[Mr.Fixit-Norm]

About average for a 35, although the shorter barrel tends to make the effort feel greater than an Export with the 22 inch barrel.

Yes I guess it would. I may add a moderator or even maybe a muzzle break, either would lengthen it a bit and make the cocking easier

[Mr.Fixit-Norm]

When Gerald Cardew wrote in Airgunworld about filling the void in a 35 cylinder he mentioned using a vacuum chamber, Tone.
The reason for using a vacuum is that the Loctite may bridge the gap between the cylinder and breech plug and not drop down far enough into the void to fill it.
As the Loctite drops down the cylinder wall towards the void the air pressure in the void will increase slightly and hold the Loctite from fully flooding the void.
By putting the Loctite in the bottom of the cylinder and then applying a vacuum the air is drawn out of the void so when the vacuum is released the Loctite is sucked into the void to fill the gap where the air was.

You may be trying to fill the top groove or both grooves --- who knows ? :-


image.jpg



I've tried solder without success, mainly due to not being able to clean the void well enough coupled with the fact that there's a lot of metal breech end of the cylinder to warm up without damaging the bluing --- Loctite is by far the easiest way of filling the void.




All the best Mick

Hi Mick, before I tweak Nicks kit spring and fit the new piston seal I may have another go at sealing it. I was thinking if I put some Loctite round the bottom inside edge of the cylinder plug, leave the port unblocked and slowly push the piston in but not quite to the bottom so I don’t drag any Loctite up the side walls of the cylinder. Then block the outside of the port and keeping the cylinder upright I’ll pull the piston up as far as I can to create a vacuum in the voids and allow the Loctite to seep in.

Then release the port block which should allow air in possibly pushing the Loctite further in, then block the port again and push the piston down to force the Loctite further in ( are you still with me )

I think the sequence sounds right in my head, perhaps you could confirm or correct this

Incidentally, the Loctite 270 I got should ‘cure’ in 24hrs according to the spec sheet, the drip I had left in a bottle lid is still wet tonight so I don’t know if I need something that sets more quickly ?

Cheers,

Norm

[T 20]

Yes that's about how I do it, Norm, but I machine up a piston head using an O ring as a seal to draw a vacuum --- imagine a syringe.
Saying that you should be able to draw a vacuum as you describe using a well fitting piston seal, if you superglue a button in the middle of the seal it will prevent you pushing it down to far into the superglue.



All the best Mick

[Mr.Fixit-Norm]

Yes that's about how I do it, Norm, but I machine up a piston head using an O ring as a seal to draw a vacuum --- imagine a syringe.
Saying that you should be able to draw a vacuum as you describe using a well fitting piston seal, if you superglue a button in the middle of the seal it will prevent you pushing it down to far into the superglue.



All the best Mick

Cheers Mick, nice tip !

I was perusing the net and came across a product called Permabond F201 which is designed to fill the voids in porous metal to prevent leaks ! It comes in three viscosities, F200 the lowest, F201 - medium and F202 - highest.

They suggest warming the metal with a hot air stripper or even a hairdryer and using a fine artist paintbrush to apply a small amount of the sealer, which is drawn in as the metal cools.

I guess this would work if you can get the end of the cylinder warm enough without damaging the blueing !

[Mr.Fixit-Norm]

Yes I guess it would. I may add a moderator or even maybe a muzzle break, either would lengthen it a bit and make the cocking easier

Hmmm looks like silencer adapters don’t work with Weihrauch barrels that have front sight grooves - like mine so machining up a 4” alloy muzzle break may be the way to go, might even make a hardwood sleeve to go over it with stippling as a grip, that might even be unique

[uiooloa]

Who can tell me if I can buy some piston here if I am from Canada, see here. Is that possible at all? I think I will have to go to the US? But will I than be able to go through the border? It looks like I will be able to get such goods only at home. If you know more in this respect, please inform me. I will try to look for more information on the internet.

[CapitalBee]

I've tried solder without success, mainly due to not being able to clean the void well enough coupled with the fact that there's a lot of metal breech end of the cylinder to warm up without damaging the bluing --- Loctite is by far the easiest way of filling the void.

All the best Mick

I'd agree with that. I tried solder and with the mass of the breech block, it was just too much mass for my measly gas torch to get up to temperature, so I reverted to Loctite.