Canadian Airgun Forum

The #1 Community for Airguns in Canada!
It is currently Fri Nov 22, 2019 5:29 pm

All times are UTC - 5 hours


The Canadian Airgun Forums are a place for people to discuss and learn about airguns and the airgunning sport in Canada. There are lots of discussions about airguns, airgun accessories, reviews, modification and repair information, airgun events, field target and free classifieds!

 

You need to register before you can post: click the register link to proceed. Before you register, please read the forum rules. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload your own pictures, and access many other special features. Registration is fast, simple, and absolutely free! To start viewing messages, select the forum that you want to visit from the selection below.








Post new topic Reply to topic  [ 7 posts ] 
Author Message
 Post subject: AT 44 Valve Stem?
PostPosted: Sat Oct 29, 2016 12:42 pm 
Offline
User avatar

Joined: Wed Apr 11, 2012 7:30 am
Posts: 81
Location: Northwestern Ontario
Looking for a full power valve stem for the Hatsan AT 44 22? Sniper does not have any. Any suggestions? Anybody making them? Thanks Bob

_________________
Hammerli Pneuma Elite 10 .22


Top
 Profile  
 
 Post subject: Re: AT 44 Valve Stem?
PostPosted: Sat Oct 29, 2016 3:03 pm 
Offline

Joined: Wed Jan 05, 2011 12:35 pm
Posts: 6019
Location: P.G. B.C.
Although not identical to the AT44 stems and being BT65 stems, the 'work' is similar. Start with a sub 500fps stem, and turn off just a tich of diameter. A lathe is prefered, however a 3/8" electric drill held in a bench vise and a fine mill bastard file will do the same work.

Image

Left is a stock, 500fps stem. Middle is a 20fpe stem with VERY slight reduction of the stem's "shank" diameter. A very little metal removed allows a LOT more air due to the pressure of a PCP.

The third is a full power stem, ie: 1,300fps or more. Note from it's shape, it is a waste of air. Something between the middle shank and third from the left, is the desired stem shape. I would think even a straight shank would waste air and perhaps deliver higher speed than useful. Try for about 900fps to 950fps.

Note the middle stem and now only a slight amount of material was removed. THUS, one removes only a tiny amount, then tests using a chronograph. The angle (shoulder) of the sealing shank must be maintained.

_________________
Best Wishes
Daryl


Top
 Profile  
 
 Post subject: Re: AT 44 Valve Stem?
PostPosted: Sat Oct 29, 2016 3:42 pm 
Offline
User avatar

Joined: Wed Apr 11, 2012 7:30 am
Posts: 81
Location: Northwestern Ontario
OK, Thanks daryl. Thanks for the detailed info. Have a friend who is a machinist, so will give it a try. Bob

_________________
Hammerli Pneuma Elite 10 .22


Top
 Profile  
 
 Post subject: Re: AT 44 Valve Stem?
PostPosted: Sat Oct 29, 2016 5:24 pm 
Offline
User avatar

Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8979
Location: Coalmont BC
IIRC, I made my stem straight, and then set the velocity using the hammer spring preload.... That was in .25 cal....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


Top
 Profile  
 
 Post subject: Re: AT 44 Valve Stem?
PostPosted: Sun Oct 30, 2016 7:53 am 
Offline
User avatar

Joined: Wed Apr 11, 2012 7:30 am
Posts: 81
Location: Northwestern Ontario
Bob. Thanks for the info. I think I will try modifying the valve as I may use the cylinder on more than one rifle. Keep them in the 10 ring! Bob

_________________
Hammerli Pneuma Elite 10 .22


Top
 Profile  
 
 Post subject: Re: AT 44 Valve Stem?
PostPosted: Mon Oct 31, 2016 6:35 pm 
Offline

Joined: Wed Jan 05, 2011 12:35 pm
Posts: 6019
Location: P.G. B.C.
Beautiful standard Atlantic Salmon fly, btw - too bad the picture wasn't a tich longer, to show the gut eye.

_________________
Best Wishes
Daryl


Top
 Profile  
 
 Post subject: Re: AT 44 Valve Stem?
PostPosted: Sat Dec 24, 2016 2:39 pm 
Offline

Joined: Wed Jan 05, 2011 12:35 pm
Posts: 6019
Location: P.G. B.C.
You could actually start here and go from there to possible links by rsterne - he is, afterall the magician with AT44's.
this was a simple search for AT44 power mods

search.php?keywords=AT44+Power&terms=all&author=rsterne&fid%5B%5D=14&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

Each one of those has it's own thread, btw - like this one:

topic48843.html?hilit=AT44%20Mods

_________________
Best Wishes
Daryl


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
News News Site map Site map SitemapIndex SitemapIndex RSS Feed RSS Feed Channel list Channel list

Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group

phpBB SEO