Needle Bearings On The End of the Spring?

[Hsing-ee]

Is this still a thing? I'm sure I have a packet of them in the parts boxes somewhere...

[TonyL]

Not sure if anyone still goes down this route, Al. It is something I always fancied trying but never got round to. Many would say that using the polished steel washers that we tend to use anyway (or a combination of these and synthetic ones), to give a plain bearing work just as well and will prove more durable / reliable?

[pellet sniper]

yeah i wondered a bout these some time ago
spose it depends if the springs turn as a norm ?
ive also wondered if you have a load of washers
at the guide end to get a plastic bush turned
instead it would certainly look better

[u.k.neil]

Always a chance this happening with bearings under load.


Brinelling /ˈbrɪnəlɪŋ/ is the permanent indentation of a hard surface. It is named after the Brinell scale of hardness, in which a small ball is pushed against a hard surface at a preset level of force, and the depth and diameter of the mark indicates the Brinell hardness of the surface. Brinelling is permanent plastic deformation of a surface, and usually occurs while two surfaces in contact are stationary (such as rolling elements and the raceway of a bearings) and the material yield strength has been exceeded.
Brinelling is undesirable, as the parts often mate with other parts in very close proximity. The very small indentations can quickly lead to improper operation, such as chattering or excess vibration, which in turn can accelerate other forms of wear, such as spalling and ultimately, failure of the bearing.


Neil

[Neil54]

I have some thrust bearings both ball and roller, I have often considered trying this in a top hat.

One thought I had if the spring becomes slack under recoil, the bits may fall out of the bearing.

[Shed tuner]

I did try it, and it does "work", but I couldn't detect any advantage over just a couple of hard steel slip washers and a dab of moly... on the downside however, their physical constraint mean they are tricky to fit to many smaller clylinder bore guns, plus there are the concerns about long term reliability.

[NickG]

And spring room .

[Rikard]

Airmasters were fitting these in the 1980’s, I have a few of their tuned HW77’s rifles with them fitted

[Dornfelderliebe]

How would a ptfe washer sandwiched between two steel washers fare?

[gtfreight]

I've just bought a txsr with one of these bearings fitted between the rear guide and the trigger block. It does shoot very well. Would it be advisable to remove it?

[Born Again]

How would a ptfe washer sandwiched between two steel washers fare?

You'd be better with two PTFE washers between two steel washers. The coefficient of friction of PTFE on PTFE is similar to ice on ice.

[Dornfelderliebe]

You'd be better with two PTFE washers between two steel washers. The coefficient of friction of PTFE on PTFE is similar to ice on ice.

Thanks. I shall now try to find some on my favourite auction site. I'm sure that the ptfe will be protected by the steel.

[NickG]

PTFE deforms and migrated , so you will probably see velocity varying , delrin is probably better.
Your piston rotates in the tx anyhow, just make sure your piston weight/ top hat isn't stuck and grease it .

[Dornfelderliebe]

I have noticed, admittedly in my budget guns that the rotation has been pushed back (layman's terms) to the rear of the spring guide vs the end block.
I saw this most visibly in my Paratrooper even though it's spring guide allows rotation there is a shiney circle worn into the rear block corresponding to a similar circle of the rear of the spring guide.

It just goes to show how important a good spring bearing set up is.

[Shed tuner]

And spring room .

true....