How I lap an Outer Probe to a Barrel

[Ca_Varminter]

Hello Fellow Rabid Rapid Owners.
This post is to show you how I fit the Bolt Outer Probe to the Breech of your barrel.
This is needed of you are fitting a new Barrel, Outer Probe, or both!

Actually it pretty simple if you have the right tools.....
I made a probe lapping rod fixture out Delrin.
It is turned to the same diameter as the bolt body.
Then I bored a hole in one end to the same(-.001 to be tight) diameter as outer probe.
here are a few photos..




Now to start the Actual Lapping of the Outer Probe to Barrel..
First the barrel is install normally with the barrel Pinch clamp tight.
Next I insert a small wad of paper towel down the breech of the barrel to keep any debris from going down the barrel.
Remove the bolt body from your Rapid and separate the outer probe.
Insert the outer probe into the lapping rod fixture.
Next apply a small amount of Valve lapping compound around the tapered mating surface of the outer probe.
Slide the fixture down the Bolt channel until it against the breech of the barrel.
Use moderate pressure pressing the probe against the breech, now spin the lapping tool by hand.
Check your progress frequently.
Once you have a nice even polished ring on Outer Probe and Barrel's Breech, you are finished!!




I hope this helps...
Good Luck,

Stuart

[Brooksy]

Nice one Stuart.
Can I just reiterate your final comment? Don't use course paste and don't go too hard, the probe is softer than you think and will very quickly develop a ridge.

[The Robin]

Superb and very handy to know. Thanks for sharing 

[Ca_Varminter]

Nice one Stuart.
Can I just reiterate your final comment? Don't use course paste and don't go too hard, the probe is softer than you think and will very quickly develop a ridge.

Yes ...Very true...
That is why I use Valve Lapping Compound....Very Fine Grit....
Also use Moderate pressure and done by hand...
Some has ask if the can use Power tools!!!     No!!!

Thanks for the input!
Stuart

[KCE]

What a cracking post Stuart.
Im always learning new things about rapids on here.
Thank you for the upload and the pics.
Regards kev.

[Daztilley]

Great info on how to get a perfect probe to barrel seal 👌