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All Springer/NP/PCP Air Gun Discussion General => European/Asian Air Gun Gates => German AirGun Gate => Topic started by: YEMX on October 12, 2017, 03:26:49 PM
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I have a HW30- Does anyone torque down the stock and pivot point (breech block screws) to a specific spec? If so, what is the spec?
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Not a weird question at all in my opinion, and I have been wondering the same for the Diana 34. With the recoil/vibration from springers, I'm not sure the torque values would make a whole lot of difference with accuracy, but I'm curious. One of these weekends I'll play around with it and see if I can ascertain any differences.
Thanks,
Joe
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G'day YEMX,
I find that the tension of the pivot bolt at the breech is absolutely critical with my .177 HW 80. I re-tension it frequently and the tension must be such that the rifle barrel [after cocking] will remain where-ever I position it against gravity prior to closing the breech after loading. If the barrel slowly droops down, I tighten the barrel pivot bolt on this rifle.
Jim
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I believe I read on this forum that the front stock screws are torqued to fifteen inch pounds. Be aware that when you tighten a screw against wood the wood will compress over time and the screw may no longer be tight. I've not had front stock screws loosen on me but the rear screw has been a different story.
As far as the pivot screw there are two schools of thought. One is stated above by NTSOG. I don't personally like that method. I tighten the pivot until the barrel doesn't quite stay in place. That holds my barrel stable and lessens wear on the bearing surfaces.
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Not a weird question at all!
As to the exact torque numbers, I don't really know. My pivot bolts have never loosened even though I check them every so often. When the gun has been cocked, and the barrel lifted up a bit, it will not pivot down by its own weight. That is tight enough in my book.
The stock screws and front trigger guard screw are reasonably tight. At first they loosened every 50 shots, now only a little every 250 or so. (I use a little less muscle on the rear trigger guard screw).
There is some belief, and I am in that camp, that one of the reasons the stock screws loosen more on new guns is that it is actually the wood that is taking a set. The beech wood used on Beeman/HW rifle stocks is rather soft. I once drilled a small hole in the but section of my R1 for a sling swivel stud and was surprised at how soft the wood was. We're not talking walnut here.
That being said... If you decide to Blue Locktite your stock screws in on a new rifle, THEY WILL STAY TIGHT, HOWEVER... the reciever/stock interface may give you the results usually found with a stock with loose screws, but you will never know.
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With barrel pivot bolts on break barrels I Think the important point is that when the barrel is closed there should be no lateral play at the pivot.
That calls for different bolt tension on different rifles.
I have a Hatsan that has a barrel latch and when closed there is no play at the pivot, open the latch and the barrel falls away. Other rifles , Diana, Webley need a bit more tension to keep the barrel in place. Stock screws should be tight but not too tight. It is possible to damage a stock, wood or plastic, by over tightening. I have never found any need to use loctite but I do use small neoprene washers. The stock screws just don't come loose.
15 inch pounds sounds like screw driver tight to me.
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Roadworthy wrote: "I tighten the pivot until the barrel doesn't quite stay in place. That holds my barrel stable and lessens wear on the bearing surfaces."
I believe/accept that is generally desirable and correct, but on my old HW 80 it did not work, hence my tightening that extra little bit. I suspect the age and wear over many years is a factor with this HW 80 of mine. I do not have the same issue with any other HW rifles I have.
Jim
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YEMEX-
Hector has written a fair bit about "tuning" the front stock screw and trigger screw. Look it up, it is very informative.
-Y