Help stripping and sorting a HW35k

[u.k.neil]

Did you all notice that the spring that came out had been chopped at one end and then left "as is" with no flattening and grinding square?



Neil

[laverdabru]

Did you all notice that the spring that came out had been chopped at one end and then left "as is" with no flattening and grinding square?



Neil

I'm no expert, but the look of the spring 'leapt out' at me.

Fascinating thread, by the way. Great pics. I have a .22 35 of a similar age - with the opposite performance, v. easy to cock, & a very soft cycle - the opposite to my more modern one in .177.

ATB

Bru

[Mr.Fixit-Norm]

Maybe also worth changing the barrel latch spring?

I wonder if those horizontal markings in the "wear groove" from the barrel latch on the cylinder end occurred due to striction in the latch? Good idea to clean that latch recess and lube. Not sure if that wear groove can be tidied a little somehow? I've never had to do it. Guessing one of our engineers will have......

That transfer port sounds mahoosive and will need sleeving down to (circa) 3.2 to 3.4mm?

Spring and guide kits? Tinbum, Welsh Willy or a V-Mach one from Lyn Lewington if he has any remaining? And I'd be replacing the piston and breech seals (which you had already mentioned) and the barrel shims for good measure.

Hi Tony,
I’ve ordered up a tin bum maxi kit for it and I’ll change the breech seal as well I may need to cut down or compress the spring from the kit but that won’t be an issue.

It’s odd that the transfer port is so big, I measured it with callipers initially then found a 5mm drill and gently put the blunt end in, it goes in but not all the way through, does this mean the inside cylinder end is smaller

yup. I saw the huge TP marks on the end of the piston seal too - it's obviously slamming. Looks like 5mm - crazy.

It's long, so defo sleave it down to 3mm ish or it's always going to shoot horribly and with low power. Explains the recoil and harsh cycle too.

It’s certainly had recoil and needed a lot of effort to cock it, I did fire it when I picked it up and at about 10yrds into the side grain of a split piece of dried kindling log. The pellets were burying themselves right in so it certainly didn’t feel down on power !
I could’ve kicked myself for not running it over my combro now before I dismantled it

Looks like I’ve got a bit more work to do. It’s my first Weihrauch ( actually spelt it right there, you guys are obviously too polite to correct me ), and I was impressed with the build quality !

It’s my birthday today so fettling will cease until tomorrow as my sons coming over lunchtime and we’re round my daughters for a takeaway tonight

Thanks for all the help.

Norm

[Mr.Fixit-Norm]

Did you all notice that the spring that came out had been chopped at one end and then left "as is" with no flattening and grinding square?


Neil

Hi Neil, that was the first thing I noticed too, most odd. It’s looking more and more like someone in the past has cut down a longer Ox type spring, probably to up the power, without really knowing what they are doing

That spring will end up in my scrap metal bin, it’s certainly never going in any of my guns !

[Mr.Fixit-Norm]

I'm no expert, but the look of the spring 'leapt out' at me.

Fascinating thread, by the way. Great pics. I have a .22 35 of a similar age - with the opposite performance, v. easy to cock, & a very soft cycle - the opposite to my more modern one in .177.

ATB

Bru

That’s sort of what I’m aiming for, I want to get it shooting nice and smoothly with sufficient cocking effort to produce 10-10.5 ftlbs

[landymick]

It is an early 90’s stock with the cheek piece & wider finger groove . The second series Safari had the same style stock tinged green .

The 5mm T.P is way to big , 3mm will be much better .

[Mr.Fixit-Norm]

It is an early 90’s stock with the cheek piece & wider finger groove . The second series Safari had the same style stock tinged green .

The 5mm T.P is way to big , 3mm will be much better .

That would tie in with the date on the Weihrauch site which says it’s manufactured in 1991

Ive just re-checked the transfer port and a 4.5mm drill will go all the way through so going by the advice on here it’s still too big. I’ll get the rest of the fettling done and before I reassemble it I’ll see if I can make something up. Ive got a small model makers lathe which is ideal for this sort of thing

Norm

[T 20]

Hi Tony,
I’ve ordered up a tin bum maxi kit for it and I’ll change the breech seal as well I may need to cut down or compress the spring from the kit but that won’t be an issue.

It’s odd that the transfer port is so big, I measured it with callipers initially then found a 5mm drill and gently put the blunt end in, it goes in but not all the way through, does this mean the inside cylinder end is smaller



It’s certainly had recoil and needed a lot of effort to cock it, I did fire it when I picked it up and at about 10yrds into the side grain of a split piece of dried kindling log. The pellets were burying themselves right in so it certainly didn’t feel down on power !
I could’ve kicked myself for not running it over my combro now before I dismantled it

Looks like I’ve got a bit more work to do. It’s my first Weihrauch ( actually spelt it right there, you guys are obviously too polite to correct me ), and I was impressed with the build quality !

It’s my birthday today so fettling will cease until tomorrow as my sons coming over lunchtime and we’re round my daughters for a takeaway tonight

Thanks for all the help.

Norm

Happy Birthday Norm.

The first thing I'd do is stick it back together and run a chrono string.
Then I'd sleeve the transfer port down to 3mm and run a second chrono string, then I'd be looking at fitting a tuning kit.

The cut down OX Spring is not to everyone's taste but whoever tried to tune it was heading in the right direction by cutting it down.
I have a HW35 that I was given in 1986 and even though I've changed almost every other part of the gun it still has the same OX Spring in it that it came with.
The only preload on this OX Spring is created by screwing the trigger block into the cylinder.





All the best Mick

[Shed tuner]

That would tie in with the date on the Weihrauch site which says it’s manufactured in 1991

Ive just re-checked the transfer port and a 4.5mm drill will go all the way through so going by the advice on here it’s still too big. I’ll get the rest of the fettling done and before I reassemble it I’ll see if I can make something up. Ive got a small model makers lathe which is ideal for this sort of thing

Norm

easier to clean the port out to 5mm all the way through, then turn up a brass sleave, centre drilled to 3mm. if you leave it a fraction tappered, all the better. And make is 2-3mm over length. Drive it in with some tough (green) locktite from the cylinder end (after a trial fit obviously) and leave to set overnight. I have a length of rod with a small 3.0mm spigot / nipple on the end. This locates into the bore of the TP sleave, and makes it easy to locate, and then drive in effectively using it as a punch.

I tend to do it such that the TP sleeve remains about 1-2mm proud in the cylinder. Then when driving in with the loctite in place, it'll either end up flush or just slightly proud (max 1mm, normally around 0.5). Then using a countersink bit on the end of a length of rod to get down into the cylinder (see why the sleeve is made of brass), take it down till it's flush with the end of the cylinder, and you get a small taper too. Whatever is slightly proud at the breech face end is easily removed with a dremel, and then squared off with a file, finally a countersink just tidies the edge and takes off the sharp lip.

You may find 3.2mm a fraction higher output, but if it's .22 and shoots nice with 3.0m leave it as is. And bin that spring

HTH - JB

[Mr.Fixit-Norm]

Happy Birthday Norm.

The first thing I'd do is stick it back together and run a chrono string.
Then I'd sleeve the transfer port down to 3mm and run a second chrono string, then I'd be looking at fitting a tuning kit.

The cut down OX Spring is not to everyone's taste but whoever tried to tune it was heading in the right direction by cutting it down.
I have a HW35 that I was given in 1986 and even though I've changed almost every other part of the gun it still has the same OX Spring in it that it came with.
The only preload on this OX Spring is created by screwing the trigger block into the cylinder.





All the best Mick

Thanks Mick, I’ve got time to put it all back together tomorrow so it might be an idea. I’m curious now to see what power it was putting out. It might be a job getting the trigger block back in as even though that preload doesn’t look like much that spring is really hard to compress, it’ll be blocks of wood and a sash clamp I reckon

Or, I could cut the end off the spring and grind and polish it flat which would make reassembly easier…..

Norm

[Mr.Fixit-Norm]

easier to clean the port out to 5mm all the way through, then turn up a brass sleave, centre drilled to 3mm. if you leave it a fraction tappered, all the better. And make is 2-3mm over length. Drive it in with some tough (green) locktite from the cylinder end (after a trial fit obviously) and leave to set overnight. I have a length of rod with a small 3.0mm spigot / nipple on the end. This locates into the bore of the TP sleave, and makes it easy to locate, and then drive in effectively using it as a punch.

I tend to do it such that the TP sleeve remains about 1-2mm proud in the cylinder. Then when driving in with the loctite in place, it'll either end up flush or just slightly proud (max 1mm, normally around 0.5). Then using a countersink bit on the end of a length of rod to get down into the cylinder (see why the sleeve is made of brass), take it down till it's flush with the end of the cylinder, and you get a small taper too. Whatever is slightly proud at the breech face end is easily removed with a dremel, and then squared off with a file, finally a countersink just tidies the edge and takes off the sharp lip.

You may find 3.2mm a fraction higher output, but if it's .22 and shoots nice with 3.0m leave it as is. And bin that spring

HTH - JB

Thanks for the info JB, I’ll remember that when I sleeve it down. I’ve got some bits of brass rod I should be able to use

[T 20]

easier to clean the port out to 5mm all the way through, then turn up a brass sleave, centre drilled to 3mm. if you leave it a fraction tappered, all the better. And make is 2-3mm over length. Drive it in with some tough (green) locktite from the cylinder end (after a trial fit obviously) and leave to set overnight. I have a length of rod with a small 3.0mm spigot / nipple on the end. This locates into the bore of the TP sleave, and makes it easy to locate, and then drive in effectively using it as a punch.

I tend to do it such that the TP sleeve remains about 1-2mm proud in the cylinder. Then when driving in with the loctite in place, it'll either end up flush or just slightly proud (max 1mm, normally around 0.5). Then using a countersink bit on the end of a length of rod to get down into the cylinder (see why the sleeve is made of brass), take it down till it's flush with the end of the cylinder, and you get a small taper too. Whatever is slightly proud at the breech face end is easily removed with a dremel, and then squared off with a file, finally a countersink just tidies the edge and takes off the sharp lip.

You may find 3.2mm a fraction higher output, but if it's .22 and shoots nice with 3.0m leave it as is. And bin that spring

HTH - JB

Ah --- I knock sleeves in from the breech side on break barrels, Jon.

I also make the reduced port from brass with a slight taper but I finish the cylinder end into a Venturi before smearing with Loctite and knocking it in from the front.
When the sleeve is in place I finish off the breech face with a small jeweller's file --- job done.

One reason I do it this way is that on some break barrels with sloping transfer ports you can't knock the sleeve in from the cylinder side --- HW50s, b2s and most Dianas, etc.

The other reason I do it this way round is the small amount of force acting on the sleeve when you fire a springer --- most folks seem to quote a cylinder pressure of between 1000 to 1200psi.

On Norm's gun he has the following :- 0.5mm/0.2" existing port needing to be sleeved down to 0.3mm/0.12".

The cross sectional area of a 0.2" circle equals 0.0314 square inches.

The cross sectional area of a 0.12" circle equals 0.0113 square inches.

So the cross sectional area of the sleeve equals 0.314 - 0.0113 = 0.0201 square inches.

From the above the force acting on the sleeve when firing at 1000psi is 0.02 X 1000 = 20 Lbs.


Obviously at 1500psi there'd be a force of 30 Lbs trying to push the transfer port out on firing, so as long as the force needed to knock the transfer port into the cylinder exceeds this it should never move --- mine haven't so far.




All the best Mick

[TonyL]

Did you all notice that the spring that came out had been chopped at one end and then left "as is" with no flattening and grinding square?

Neil

Indeed!

Hope you're keeping well, sir.

[TonyL]

Happy Birthday Norm.

[TonyL]

Swiftly developing into a most excellent thread with all the expert engineer input. Rated accordingly.