Rogerborg
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- Aug 22, 2017
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where would i find that part? i didnt see anything like that in the hop unit when i took it out, so im not sure where id find it
Here's an SHS hop unit for illustration purposes only, the Specna is similar.
View attachment 89689
It's under the hop arm. The arm presses down on the nub, which pressed on the bucking.
You'll generally want to remove the hop arm, and the nub, before putting the barrel and bucking in or out, then replace the nub, and then the hop arm on top of it.
If you've pulled the barrel and bucking out without realising that the nub was sitting on top of it, it might still be in there, or it might have dropped out and vanished into hyperspace. If it's all back together now, I'd get the hop arm out and see if the nub is still in there. There's a pin running side-to-side that the arm rotates on, you just push it out then the arm will lift up and out.
A typical nub is just a little cylinder of rubber, it might be solid, or more often hollow. If you have lost the nub, then the traditional bodge is to cut a piece of biro tube, or a section of insulated wire (18g or 16g), or just the insulation from the wire. Essentially anything round that will fit inside the C section on the end of the hop arm, with a little give in it.
However, I mention the "flat hop" style nub because your Specna may have a flat-hop bucking with no internal mound. If so, then a regular cylindrical nub won't put enough pressure on it to hop anything.
None of this is a concern if you're replacing the bucking with a Maple Leaf: they're great buckings and pretty tolerant of nubs. You can throw just about any nub in there and it'll work, whether it's a standard round, Maple Leaf Omega, H-nub or just about anything else you fancy.
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