1. The Forum Rules have undergone some minor changes and updates.  Please take the time to read them; it will only take a couple of minutes of your time. By doing so, you lessen the chance of incurring the wrath of the moderation team or making yourself look foolish to other members.

    90% of users posting adverts in the Sales forums need to be reminded to read the rules as their posts are wrong.  This is unnecessarily time-consuming and will no longer happen - if your advert doesn't follow the Sales Rules it will be deleted and you'll have to start all over again.

    To close this box once you've read it (and the Rules), click on the X in the top right-hand corner.

    Thank you.

    AGF Staff



    Dismiss Notice
  2. A reminder of one of the Forum Rules:

    'Behaviour

    Do not make inappropriate or offensive posts - including threats, harassment, swearing, prejudice, defamation, deliberate insults or name-calling, other negative remarks about this forum, its moderators and administrators or your fellow members. Even if this is just your own personal opinion, RESPECT YOUR FELLOW MEMBERS.'

    There have been changes made to our censoring software in an attempt to help with this growing problem.

    Click the X in the top-right-hand corner to dismiss this notice.
    Dismiss Notice
  3. Dear members,

    Our membership (like our country) consists of people from all walks of life; different in far more ways than can be listed here and each with a different view based on their experience of life - regardless of their colour, religion or cultural heritage. Every single person in the UK has been born of mixed race – we are a multi-coloured and multi-cultural country.

    As many of you are aware there are a handful of individuals amongst this membership that persist in making provocative, inflammatory, racist and otherwise offensive comments. This has been happening across the forum to a certain degree but is most especially prevalent in the Adult section.

    The moderation team has tried to stay on top of this, however unfortunately because of the ‘offensive’ nature of much of its content we don’t monitor the Adult section quite as much as perhaps we should. As a result much of this behaviour has gone unnoticed unless it has been reported to us. While the team always intended to take a "light touch" approach to the Adult section it would seem that some people aren’t quite adult enough to be left unmonitored after all.

    This behaviour is, and always has been against Forum Rules as well as the specific stipulations of the Adults forum and it will no longer be tolerated. We feel it's time to draw a line in the sand and as such from this point onward offenders will receive an immediate and permanent ban from the forum.

    In order for us to achieve our goal of restoring the forum to the friendly and tolerant place it once was, we ask that ALL members be mindful of the content they post and help us to stop unacceptable behaviour by using the 'Report' tool at the bottom of any offending post - the results of which can be seen only by Admin/Moderators.

    You should all receive a copy of this message by PM. 

    To close this message box, click on the 'X' in the top-right-hand corner.

    Dismiss Notice
  4. Hotmail block emails from us entering your inbox. Unless you can setup a safe sender you will not get activation emails from the forum. Please use an alternative provider or complain to Hotmail.
    Hotmail addresses include.

    @Hotmail.co.uk @Hotmail.com @outlook.com @Live.com
    Dismiss Notice
  5. Postings on Politics, Religion & Controversial Off-Topic Material

    The majority of users do not want to read about these subjects and people have left the forum as a result of it – this is after all an 'Airgun' Forum. It’s all very well to say they don’t have to read it if they don't want to, but as most of us use the ‘New Posts’ button there is no easy way to avoid it.

    All AGF staff members are in favour of people being able to discuss what they want, but we have to draw the line somewhere if it is upsetting other users. We don’t want to read about these topics either.

    IMPORTANT- The discussion of politics and religion is no longer allowed anywhere on the forum (including the Adult section).  The only exception is if it's airgun related - they must be put in the Airgun Related Politics section..

    We will not tolerate bullying or personal attacks, racism or any other offensive 'isms'. we will remove these topics from the forum, we will not give you an area where you can abuse each other. We will not hesitate to ban offenders.

    To clear this text box, click on the 'X' in the top right-hand corner.

    Dismiss Notice

HW97 Stripdown and tune - UPDATED

Discussion in 'Stickies Only' started by Jackroadkill, Jan 26, 2014.

  1. Jackroadkill

    Jackroadkill Donator

    Messages:
    16,784
    Likes Received:
    114
    Location:
    Drenewydd, Powys, Cymru
    I bought a mk1 HW97, one of the last ones with a 25mm piston and was lucky to get it quite cheaply. The firing cycle was quite noisy, due in part to the square-section spring that they were fitted with, and also to the spring guide being too small. I am also of the opinion that the spring was too long (more of this later). I thought that a rifle such as this was being done a dis-service by being left in that state, so I thought I’d give it a full strip, de-burr, internal polish, fit a tuning kit, relube and re-assembly with the intention of letting the potential if what could be a great rifle be reached.


    While I was at it, I took lots of pictures with the intention of producing this guide. Although this guide is for a HW97 it will also be applicable to most HW’s with a rear block assembly (break barrels will not have the moveable cylinder, but you’ll get the idea if you don’t already know what I’m talking about).
    You will not need expensive tools or a fully-equipped workshop to service and tune your HW springer; I have used basic tools that most people will have around the home. The only real exception to this is the polishing kit that I used on the cylinder and piston, which was a ten pound special from my local hardware shop. It’s one of those ones that fits onto a drill – not posh, but effective.


    I have used a Welsh Willy tuning kit for this rifle. I use Will’s kits because I think they are good quality and have always produced the results I want.
    Finally, this is my own method; I will not be responsible for any damage caused to rifles whilst following this guide.

    The rifle as it came into my possession:

    HW97whenbought1_zps20c8662a.jpg


    Step 1
    Remove the stock screws and bolts. I put these in an old pellet tin to stop them getting lost, but an envelope will do just as well. Remove the action from the stock and store the stock carefully so that it doesn’t get damaged whilst away from the action. Also remove the plug that the large stock bolt screws into using a spanner.

    Storecomponentpartsinanoldpellettin_zpse45d8409.jpg


    Step 2
    Drift out the two pins that hold the trigger mechanism in place using a small punch. The trigger mechanism will then pull out. MAKE SURE YOU ALSO REMOVE THE SAFETY CATCH AND IT’S SPRING! Store the trigger mechanism carefully after wiping off any excess grease. If it’s caked in grease or soaking in oil, it could benefit from a clean. Use the punch to drift out the underlever retaining pin and remove the underlever and cocking link. You can also now remove the anti-bear trap gear (and, if you’re like me, throw it away).

    Refittriggerandsafety_zps57272773.jpg

    UsingapunchtoremoveULpin_zps62938206.jpg

    Removing the cocking arm and anti bear-trap:

    Removingcockingarm_zps1771a84c.jpg


    Step 4
    Unscrew the rear block from the main body (NB I am using the term “cylinder” for the compression cylinder, so I will not call the body the cylinder here to avoid confusion). This may be difficult due to thread locker being used, or just to tightness. You may need to heat the joint in order to free it, or use a bar to give more leverage. If you do need to use a bar, wrap masking tape around the end and apply it to the trigger slot in the block. Clamp the body to a wooden surface for extra leverage.
    BE VERY CAREFUL WHEN REMOVING THE REAR BLOCK – the spring may be under preload and this can cause the block to jump substantially when released.

    Screwrearblocktocylinder_zps0dcd1de9.jpg



    Step 5
    Withdraw the spring guide, spring, top hat, piston and cylinder from the body. Degrease the piston and cylinder using white spirit, meths etc. I use carb cleaner, which is very efficient and very nasty – don’t let it get in your eyes or up your nose. Also degrease the main body and the piston seal and the breech seal in this way. The spring in my rifle was totally dry and the piston was soaked in oil, for some unknown reason. The spring was also distorted and very badly cut at either end and the spring guide didn’t fit, so presumably didn’t do much guiding. At this point t’s also worth measuring the piston diameter if you have a HW77 or 97, as the diameter changed in the mid-Nineties from 25mm to 26mm. Mine was a 25mm. This will make a difference when you order your tuning kit as the top hat will need to be the correct size.


    Withdrawing piston from cylinder:

    Removingpistonfromcylinder_zpseaf8e8bb.jpg

    Piston and cylinder removed:

    Pistonandcylinderasremovedfromrifle_zps6cc51b49.jpg

    Piston covered in oil; this was removed:

    Pistoncoveredinoil_zps71e55cf3.jpg



    Piston measurement:

    Measuringpistonsize_zpsbce6bd0f.jpg


    Step 6
    Using a small file, de-burr the cocking slot on the main body, the cocking slot on the piston, and the cocking piece at the end of the cocking link. Make sure to keep all swarf and filings away from the rifle’s internals. When I do this I always wash the piston, cylinder and main tube in hot water and then put them to dry on a radiator to ensure that all the swarf and muck has been removed. If you do this, clean your barrel afterwards as light rust may form between the lands.

    De-burr the cocking slot - burrs can be seen here:

    [​IMG]



    Step 7
    Polish the piston (after masking the seal with tape, or if replacing the seal, chuck the old one away) with wet and dry (I use 120 grit, then 200, then finally 400) but do not remove any more material than you have to. Following this, polish the piston with a polishing kit or use Autosol polish and a cloth / buffer. Once the cylinder has been thoroughly polished wash it again and dry as before. If you are putting a new seal on, now is the time.

    Lightly polished piston and cylinder. You can go further than this if you wish:

    Cylinderandpistonafteralightpolish_zps45367728.jpg
     
  2. Jackroadkill

    Jackroadkill Donator

    Messages:
    16,784
    Likes Received:
    114
    Location:
    Drenewydd, Powys, Cymru
    Step 8
    Fit the new spring kit as per manufacturer’s instructions. I used a single top hat washer and the two thickest power bands on my WW kit. I used dry slide to lubricate all the Delrin parts and a small amount of molybdenum disulphide (moly) grease on the spring. Use a very small amount of moly grease on the sides of the piston seal – too much grease or grease getting in front of the seal will cause dieseling, which could damage your seal and potentially ruin accuracy as well as sending your rifle over the 12fpe power limit. Also lubricate the piston with a small amount of dry slide. A few drops are plenty – rub it over the piston with a finger. You can also do this to the outside of the compression cylinder – only a small amount is needed.

    WW kit:

    WWHW97kit_zpsc2d5e809.jpg

    Dry slide-lubricated Delrin washer being placed onto the cocking rod:

    Washergoingintopiston_zps49a3921a.jpg

    Two power bands placed onto the lubricated spring guide:

    Powerbandsfittedtotophat_zps646c5807.jpg



    This spring guide fits! It should be tight-ish but not so tight that it has to be forced into the spring coils:

    Tophatasnugfitinspring_zps42598990.jpg

    Moly grease on the spring:

    Molygreaseonspring1_zps29a9d86b.jpg

    Molygreaseonspring2_zps9f3e34e1.jpg


    A SMALL amount of moly on the sides of the piston seal:

    Molygreaseonpistonseal1_zps97e2b0bc.jpg

    Molygreaseonpistonseal2_zps351de4af.jpg



    Step 9
    Have a brew.

    This is most important....:

    Haveabrew_zpsdbf76031.jpg


    Step 10
    Begin re-fitting the components; it’s basically the reverse of removing them. Be careful to align the cocking slots and make sure that you don’t snag the piston seal as you replace it in the compression cylinder. Make sure that you refit the safety catch BEFORE you fit the trigger mechanism. The trigger will need to be cocked before you refit it. Once again, be careful when refitting the rear block to the main body – the spring could well be under some preload. Some tuners use a spring compressor for this job.

    Aligning cocking slots:

    Aligncockingslot_zpsc43c20ff.jpg

    Aligncockingslots_zps90342499.jpg

    Lubricate the back of the spring guide using dry slide before fitting the rear block:

    Drislideontophat1_zps96d8846b.jpg

    Drislideontophat2_zps4aad7237.jpg

    You can use a punch to keep the alignment whilst tightening the rear block; if the alignment is not right the cocking link will not fit and the cocking rod will not latch to the rigger sear:

    Useapunchtoaligncockingslots_zps040ab41a.jpg

    Alternatively you can refit the cocking arm at this point to help. Drifting the pin back in:

    Refitunderlever_zpsd7db56c5.jpg

    Tightening the rear block:

    Screwrearblocktocylinder_zps0dcd1de9.jpg

    Refitting the trigger:

    Refittrigger_zps30170d93.jpg

    Action now back together; can anyone guess what's next for this rifle?!

    Whocanguesswhatsnext_zps00416eaf.jpg

    Step 11


    Chrono and adjust as necessary - this is most important; it is the responsibilty of the shooter to ensure that the rifle is legal at all times.


    Parts removed:

    Removedcomponents_zpsc13c8e68.jpg

    A - anti bear-trap mechanism
    B - trigger mechanism
    C - Rear block
    D - stock bolt block
    E - trigger locating pins
    F - spring (which is bent)
    G - spring guide
    H - underlever and cocking link
    I - trigger guard and bolts
    J - safety catch and spring
    K - stock forend screws
    L - underlever retaining pin
     
    Ntcash, Wheezey, Susube91 and 3 others like this.
  3. Andy_J

    Andy_J Replica Airgun Enthusiast

    Messages:
    17,071
    Likes Received:
    25,917
    Location:
    Lincoln County
    Excellent thread. Many thanks. This will come in useful for me.

    Cheers

    Andy
     
  4. martin22

    martin22 Donator

    Messages:
    1,172
    Likes Received:
    0
    Location:
    chesterfield
    great write up owen i bet it shoots lovely :cool:,the internalls on your 97 are practically the same as my 77,the 77 is the first rifle ive stripped/tuned but ive found it very satisfying so far,it was a beat up old thing when i got it and allready its starting to come together to make a nice rifle,i cant wait to get it out in the field as its got to be a lot more rewarding knowing youve tuned it yourself instead of just dropping it off somewhere and picking it up done :up:
     
  5. Jackroadkill

    Jackroadkill Donator

    Messages:
    16,784
    Likes Received:
    114
    Location:
    Drenewydd, Powys, Cymru
    Self tuning is the way forward - quite easy to do and very rewarding.
     
  6. martin22

    martin22 Donator

    Messages:
    1,172
    Likes Received:
    0
    Location:
    chesterfield
    it is that and a lot cheaper :up:
     
  7. couzensmark

    couzensmark Busy Member

    Messages:
    535
    Likes Received:
    0
    Location:
    Boston uk
    Self tuning is the way forward. I have done my hw97k stl .177 . It's took me ages to get to a stage I'm happy with. I have a friend with a sfs stage 2 97 and you can't pick between them. It has a average spread of 5 fps and it hardly kicks at all. I bought a tuning kit from konceptus in Poland. It's been great fun. The only problem is I'm desperate to do something else. I'm thinking I might buy a hatsan striker and see if I can tame it.
    Anyway nice job mate ;)
     
  8. andy draper

    andy draper Posting Addict

    Messages:
    1,137
    Likes Received:
    0
    Location:
    Ribchester
    Nice one jack,cant wait for the trigger block strip and sear polishing,will you be fitting the rowan trigger? Only joking mate,anything that contains small springs is a definate no no.the rowan trigger looks easy enough though,a bit expensive but great quality.
    andy.
     
  9. Jackroadkill

    Jackroadkill Donator

    Messages:
    16,784
    Likes Received:
    114
    Location:
    Drenewydd, Powys, Cymru
    Haven't tried doing anything to the trigger, Andy. It came pretty well set up, so I'm going to leave this one as it is. However, my 80's trigger isn't as nice, so maybe that'll get a trigger tune soon. If I do it I'll post a thread about it.
     
  10. couzensmark

    couzensmark Busy Member

    Messages:
    535
    Likes Received:
    0
    Location:
    Boston uk
    Jack my trigger was really sticky when it came but it was caked in grey gloop. I washed it through with brake cleaner and just oiled it with Parker hale gun oil and it totally transformed it.

    Mark
     
  11. scoie

    scoie Busy Member

    Messages:
    914
    Likes Received:
    658
    Location:
    Newent , Gloucestershire
    What a great post ,many thanks for the detail and time spent , ordered my WW kit beginning of Jan so any day now and these piccies help no end
    rgds
    craig
     
  12. UrbanFox

    UrbanFox Well-Known Member

    Messages:
    66
    Likes Received:
    0
    Location:
    Nr Wigan
    Don't have a HW97 YET, but a nice concise, informative post which I will bookmark.

    atb
    Bri
     
  13. JD

    JD Donator

    Messages:
    7,308
    Likes Received:
    1,033
    Location:
    Dorset
    Good write up jack, will you be doing a up date on the chrono test ?
     
  14. Jackroadkill

    Jackroadkill Donator

    Messages:
    16,784
    Likes Received:
    114
    Location:
    Drenewydd, Powys, Cymru
    Yes, will do. Am sorting the stock next so it might be a few days yet before I get a chance to get the chrono out, assuming the fantastic Welsh weather holds out for me.
     
  15. JD

    JD Donator

    Messages:
    7,308
    Likes Received:
    1,033
    Location:
    Dorset
    If your relying on the Welsh weather, lets book a update for mid June shall we. lol

    Time for a brew, where would a tuning write up be without a cuppa. ; )

    Forgot to ask, is the end of the mod removable, as I've seen on a German web site, where one was on a Hw97 Mk1, but this could just have been converted to a threaded end.?

    In the future I can see there being some confusion regarding the mk1 Hw97 rifle, as Hw are selling the same model in Germany with the lastest stock design. theres also sfs now selling the cheiftan, which is their tuned version, looks just like a mk1 97 to me.
     
  16. SteveO

    SteveO Top Poster

    Messages:
    11,080
    Likes Received:
    10,170
    Location:
    Kek
    Great thread Owen! :up:

    Just illustrates how easy there HW's are to work on, I think everyone should know how their gun works inside (if possible)... I think it helps you feel more in tune with it!
     
  17. 177

    177 Donator

    Messages:
    7,704
    Likes Received:
    576
    Location:
    Berwick upon Tweed
    Nice write up :)

    If you can be bothered, next time you tear the rifle down mirror polish the compression tube.

    If you lube with something like Ultimox 226 it will cock like it's on oiled glass :D
     
  18. lone wolf

    lone wolf Pro Poster

    Messages:
    7,614
    Likes Received:
    3,019
    Location:
    Bishop Auckland
    Great write up jr and really nice to see the pics along the way.

    Im going to strip and have a play with newly aquired superstar and after reading this its given me a much better understanding of things as its a new venture for me this tuning malrky.

    Looking forward to seeing the stock refurb!

    Gaz
     
  19. Egg

    Egg Major Poster

    Messages:
    8,460
    Likes Received:
    13
    Location:
    Dunfermline
    Nicely done O..... and stop biting your nails, it's a filthy habit!
     
  20. lone wolf

    lone wolf Pro Poster

    Messages:
    7,614
    Likes Received:
    3,019
    Location:
    Bishop Auckland
    Only one brew as well?:)
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice