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TX latch rods

Posted: Mon Dec 04, 2017 6:13 pm
by cooper_dan
Anyone know who can do longer latch rods for the TX?
Planning on getting mk2 spring and guides from Julian on here, and a longer latch rod to convert mk3 to mk2

I've tried short stroking with piston extensions but they didn't feel anywhere near as good to me. I think its because of the shorter stiffer spring
Shaun a ISP might be able to do one, but might be out of the steel he needs and not sure where else to turn...

Re: TX latch rods

Posted: Tue Dec 05, 2017 11:51 pm
by sherlock1963
You could try Tony Leach on the 'Lost Volume' FB group for a new latch rod. Removing the old one will require a fair amount of heat to melt the loctite and you will have to perfectly centre the new one. The Lost Volume group is a wealth of info about tuning TXs.

T R Robb has TX latch rods listed on his website. There are mixed reviews/opinions on his stuff. I bought a set-back Rekord trigger which was fine.

Knibbs are selling MK1/2 pistons again (about £50) They must have a new consignment in recently.

I'm not sure what difference a longer latch rod would make compared to a piston nose. The added weight is about the same but you could use a more efficient seal (Walther or Weihrauch) on the extension. Both options require more spring or extra pre-load to counteract the loss of swept volume.

Good luck

Re: TX latch rods

Posted: Wed Dec 06, 2017 7:58 am
by cooper_dan
Applying heat and getting the nose centred aren't a problem

J Knibbs have been listing these for years but Air Arms don't make them anymore. They never have them in stock
Piston nose extension means you lose spring room. i.e 13mm nose extension means the spring has 13mm less space to fit into. That's why the short stroke kits use the stiffer titan kits. Longer latch rod just needs an Air Arms spring (which are very good springs)
I've compared both and the short stroke nose doesn't feel as good to me as a mk1/2 piston

I'll try Tony or TR Rob. Thanks

Re: TX latch rods

Posted: Wed Dec 06, 2017 1:21 pm
by sherlock1963
Ahh. I see what you mean about the spring.

I'm pretty sure that Knibbs got some in recently as there is a thread about this on Airgunforum.

A latch rod will be a lot cheaper anyway. :)

Re: TX latch rods

Posted: Wed Dec 06, 2017 1:29 pm
by TenMetrePeter
sherlock1963 wrote: I'm pretty sure that Knibbs got some in recently as there is a thread about this on Airgunforum.

Can we use the K word in this forum?

Re: TX latch rods

Posted: Wed Dec 06, 2017 6:43 pm
by cooper_dan
sherlock1963 wrote:Ahh. I see what you mean about the spring.

I'm pretty sure that Knibbs got some in recently as there is a thread about this on Airgunforum.

A latch rod will be a lot cheaper anyway. :)


I don't know where they would get them from. Air Arms don't make them for anybody and haven't done for a while
Either way it looks like Tony Leach is helping me out. £27.50 posted. It comes very long, and you have to cut it down to required length. Again not a problem, I've got enough tools for this kind of thing. I'm going to set it to 80mm stroke and see how it is in my mk1 (no anti beartrap). I only want 10 ft-lb so should be a good compromise.

When it turns up I'll do a blog post about it

Re: TX latch rods

Posted: Wed Dec 06, 2017 9:32 pm
by Blackbaronfish
Could you put a photo of the latch rod on here when you get it please.

BBF

Re: TX latch rods

Posted: Thu Dec 07, 2017 2:15 am
by FPoole
Make sure you have some way to center the rod while the Loctite cures.

Re: TX latch rods

Posted: Thu Dec 07, 2017 8:58 am
by cooper_dan
FPoole wrote:Make sure you have some way to center the rod while the Loctite cures.


This is probably the most important thing to get right (apart from cutting it the right length)
I'm planning to use my pillar drill. Latch rod will go into the chuck and tighten. Then the piston will be screwed up onto the latch rod. The outside taper of the chuck will centre the piston to the rod.
It will take a bit of trial and error to set how far into the chuck the rod has to go. But it should work nicely. Would be easier on a lathe but I don't have one :cry:

Re: TX latch rods

Posted: Fri Dec 08, 2017 12:42 am
by FPoole
After I posted this, I saw that Tony offers some sort of aid for this. Something out of plastic with a slight taper to fit the inside of the piston, but not all the way inside it, and a hole in the center that's a push on fit to the rod would work. Sort of like a cork with a 10 mm hole in the center. Not sure what the part Tony uses looks like.