My TX200 mkII experiment... Thrust Bearings.

[milegajo 595]

Cracked open my 16 year old TX to give her some luving the other day. I got curious...

Power is down to 10.6ft/lbs with JSB Exacts .177 and Davyt63 has kindly donated me some spacers/pre load washers to have a fiddle. Before his kind act of generousity however, i got swept up with the idea of thrust bearings and bought one. I blame Solware...

Now, I am aware of this argument about needle bearings failing, but this one is different! Its got balls!

 

Haven't received it yet but TX and I are very excited. The concern I have is that the existing spacers totalled 4mm/5mm and this bearing is 9mm on its own. It could boost the power by the 1 ft/lb required, or push it over in which case i suppose I'd have to snip the spring to keep it in which, in all honesty, I don't want to do.

 

Will keep you all posted!

[Daveo 61]

Where are you getting that bearing from?

It just so happens i have a MK1 tx in bits as we speak, im very interested to see how this works.

I often thought about the piston running on bearings instead of the synthetic bush, anythought?

[The Duncan 802]

I'm all a-quiver

[davyt63 1,840]

hi Mike

washers in the post tomorrow

have you a link to where you got this image.

 

9mm is a lot more than 4mm.the piston rod may not engage with the top sear?

you may have to get a smaller spring ? and this may lower the power even more?

 

regards

 

Davy

[Marksman 934]

Smaller spring doesn't necessarily mean less power, it's how it's wound that produces the power

 

Darryl

[shepp 2,285]

Are thrust bearings designed to be smashed into from side on, I would have concerns about one coming apart?

[milegajo 595]

hi Mike

washers in the post tomorrow

have you a link to where you got this image.

 

9mm is a lot more than 4mm.the piston rod may not engage with the top sear?

you may have to get a smaller spring ? and this may lower the power even more?

 

regards

 

Davy

 

Gunna be a real trial. I have a combro if it even engages the sear...

Had a ring around Stroud and found a small firm called G.E Engineering. That's a pic they emailed over for me. Charged me £4.50 inc p&p. Couldn't find em on eBay but that's not to say they aren't there. I got bored of scrolling on my phone if anyone else wants to try them pm your details and i'll get some more and send em out won't charge extra, postage shouldn't be that much, plus ppl like Davy and sweeney-todd have been very generous to me. I walk into town Friday's so let me know ASAP.

[milegajo 595]

Are thrust bearings designed to be smashed into from side on, I would have concerns about one coming apart?

 

Ask solware... i got the idea from their Genesis kit. Whilst i love my mk2, she's my best candidate for experimentation.

[milegajo 595]

Just found out they're £3.50 if I pick them up. Wish I'd known...

[milegajo 595]

So! After a day of tinkering, here's my conclusion.

 

Primary objective; Boost power from 10.6ft/lbs to 11.6ft/lbs.

 

Achieved. Combro says a consistent 791fps @ 11.67ft/lb. Happy with that.

 

Secondary Aim; Improve rifles performance or 'feel'.

 

Achieved. Cocking cycle is very smooth and very little 'twang' or internal noise.

 

The thrust bearing washers were a very snug fit. Too snug for my liking. However, when used (and pretty much jammed in) the rifle fired nice and crisply with little recoil. The fps and lbs varied however from 11.67ft/lbs - 9.6ft/lbs and 791fps - 783fps. I wasn't happy with that,am curious as to why, so I had another fiddle.

Much filing and grinding later, I put an original washer against the spring followed by ball bearing cage, thrust washer, then the other original. (The inside diameter of the thrust washer exceeded the width of the spring guide).

Now, I had a very smooth cocking cycle, a bit more recoil, but very consistent readings. nearly all 11.67ft/lbs 791 fps.

 

Would I bother again? hmmmm. Not with all the grinding... but I am very pleased with the rifle now, feels tuned and up to power.

 

Leasons learned;

 

1) Use calipers when measuring airgun components. Don't use a measuring tape, squint and wonder if you're supposed to include the silver bit, then order your part.

 

2) Thrust bearings are essentially two very well lubricated washers. I theorise that the same effects could be achieved by a generous amount of gun grease between two regular washers.

 

In so far as achieving the objectives, sure, the experiment succeeded. I will still test my theory with the pre load washers I've been gifted and may choose that for simplicity.

 

Watch this space...

[stoe 0]

well done

most interesting thank

you