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P/W Link Repair

Discussion in 'Shooting Related Threads' started by skeeljc, Jun 26, 2012.

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  1. skeeljc

    skeeljc Supporting Vendor Supporting Vendor

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    My Upper/Lower Link assembly was beginning to show signs of wear which created play between the links and the hex shaft. The play was causing the screws that hold the links on to come loose. If the wear becomes excessive the powder and shot drops can be affected.

    Here is how I repaired it.

    I drilled a 3/32" hole centered on the link/shaft interface and installed a 3/32" split pin. The single upper link takes a 1/4" long pin and the double lower link takes a 1/2" long pin.

    Jim Skeel<BR>
    P/W Dealer/Distributor

    [​IMG]

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  2. deadnout

    deadnout Member

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    good thinking jim. thats called field engineering.
     
  3. riflegunbuilder

    riflegunbuilder Member

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    How many shells does one have to load for this link to wear?
     
  4. Unknown1

    Unknown1 Well-Known Member

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    How long is a piece of string?

    A number of factors contribute to this wear, but I have never bought a 900 that did NOT need new arms and a hex shaft and a couple were relatively new.

    The best repair I've seen on here was one where the guy drilled and tapped the arms for a small hex set screw that went in from the edge of the arm and locked against the hex shaft. I built a wood jig to position arms for drilling and have done that to all my 900s.

    Keller
     
  5. himark

    himark Well-Known Member

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    Good post!

    I loaded 18000 on a counter not to mention several more thousand prior to adding a counter before I noticed considerable wear. I might add I was still getting consistant powder drops even with excessive wear IMO as you can see in video.

    <embed width="600" height="361" type="application/x-shockwave-flash" allowFullscreen="true" allowNetworking="all" wmode="transparent" src="http://static.photobucket.com/player.swf" flashvars="file=http%3A%2F%2Fvid147.photobucket.com%2Falbums%2Fr320%2Fhimark900%2Fphotobucket-5187-1329865020438.mp4">
     
  6. skeeljc

    skeeljc Supporting Vendor Supporting Vendor

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    Keller,

    I thought about the set screw idea but the links are very narrow (3/16" for the lower links I believe).

    What size set screw did you use?

    My split pin repair will be easier to disassemble. I thought about using two pins per link but decided to see how just one works.

    It is easier to drill the 3/32" hole if you use a three flute split point carbide drill.

    Jim Skeel<BR>
    P/W Dealer/Distributor
     
  7. Dave S

    Dave S Active Member

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    For those of us lacking the tools and skills to drill the holes. Would it help to glue the arms to the shaft hexs and locktite the screws that hold the arms to the shaft if there is no play at this time?
     
  8. whiz white

    whiz white Strong Supporter of Trapshooting Banned

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    Jim: Why not simply replace the hex shaft? They are cheap.

    You still have signs of wear on the edges of the hex.

    One thing I like to do is to shorten a new hex shaft about 0.010", and then install larger fender style washers, star lock washers, new Allen head screws, and blue loctite.

    Whiz
     
  9. skeeljc

    skeeljc Supporting Vendor Supporting Vendor

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    Dave S, I have thought about a bonding agent. My choice would be LocTite 638 which is for cylindrical fitting parts with a slip fit. 638 works with gaps up to .010". I am not sure if 638 will hold up to the tension/compression forces due to the play in the hex joint. My guess is 638's strength is its ability to resist shear, not tension/compression.

    A new hex shaft will fix the problem temporarily. Neither the hex shaft or the links are hardened. The initial clearance required for assembly allows the two parts to move which causes wear which causes the looseness. My split pin fix should eliminate any movement which will prevent any wear. Two pins per joint would probably be better.

    Jim Skeel<BR>
    P/W Dealer/Distributor
     
  10. wivanr

    wivanr Member

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    They are some items that should not be tempered with on these loaders. The upper and lower actuating arms along with the hex shaft are three of those items. They are made of soft material for a reason, to break under alot of pressure. They are a cheap fix. If they were made of a harder material something else would have to give, and that would be an expensive repair bill. The links are made of a powdered material called sentering they were designed that way for a reason. They are soft and by drilling holes in them you'll only make them weaker.
     
  11. likes-to-shoot

    likes-to-shoot Well-Known Member

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    Whiz just described my fix to the situation.
     
  12. Unknown1

    Unknown1 Well-Known Member

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    <blockquote><I>Keller,
    I thought about the set screw idea but the links are very narrow (3/16" for the lower links I believe).

    What size set screw did you use?</I></blockquote>Jim, I have less trouble with the lower links than I do with the top link. I have replacement hex shafts turned so they're about .008" short. I tighten the cap screw on the upper shaft end of the hex first which leaves the shaft on the lower links end slightly recessed. A soft washer under that cap screw locks the outer lower link really tight and that helps keep the inner from moving as well.

    I use the set screw only in the upper link through either of the hex flats at the end of the arm. I have used both a 6-32 x 3/8" and 3mm x 0.5mm x 10mm set screws. The metric screw is about .008" smaller in diameter and leaves just that little extra material on either side of the hole.

    <blockquote><I>"The links are made of a powdered material called sentering they were designed that way for a reason. They are soft and by drilling holes in them you'll only make them weaker."</I></blockquote>Obviously there was some thought behind the design of this part of the press but I can't see that the slop that develops in the linkage because of the component material does anything at all to contribute to the protection the linkage provides to the rest of the press. I only reduces the service life of the components.

    I also can't see that finding a way to delay or eliminate this slop does anything at all to defeat the protection provided by the design. If the slop isn't useful, necessary or contributing to the intent of the design, why put up with it?

    I like Jim's solution; even if the introduction of that little 3/32" roll pin was to slightly weaken the components it's installed in (which I seriously doubt), the very slight decrease in strength would do nothing to reduce the protection of the design; if anything, it would enhance it.

    Good idea, Jim!

    Keller
     
  13. skeeljc

    skeeljc Supporting Vendor Supporting Vendor

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    Wayne,

    The sintered powder metal link is probably harder than the hex shaft. It would not hurt anything if you added a heat treatment to the ends of the hex shaft. The link would still be the "weak link" in the mechanism.

    Jim Skeel<BR>
    P/W Dealer/Distributor
     
  14. whiz white

    whiz white Strong Supporter of Trapshooting Banned

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    Himark: The Rack Gear, as stated in the manual, can be pulled out about ½" and this is to gain access to the shot and powder bushings for their removal. The extra movement is standard and not a bad thing.

    However, you should NOT operate the Rack Gear with the reservoir top off the machine. The Rack Gear has a tendency to rise up and out of its channel. I have had machines here in the shop with the right-rear of the channel broken off because the owner operated the reloader without the reservoir top.

    If you must, at least hold the Rack Gear in place with something, a finger (ouch!) or small piece of cardboard, etc.

    The hex shafts are of 12L14, if I remember correctly; they are SOFT, and therefore wear.

    I have a PDF white paper on my website discussing reasons for breaking Upper Actuating Arms.

    WW
     
  15. grunt

    grunt TS Supporters TS Supporters

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  16. Unknown1

    Unknown1 Well-Known Member

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    Since 12L14 isn't heat hardenable because of its low carbon content, it should be easy to create stronger hex shafts using 1144 steel in stead. It has a carbon content of .44%, can be hardened and is a "free-machining" alloy like 12L14. It should eliminate at least the hex shaft wear issue without compromising the protection of the design/materials of the link arms themselves.

    In fact, I will contact the machine shop this week about doing just that!

    Keller
     
  17. whiz white

    whiz white Strong Supporter of Trapshooting Banned

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    Keller: You're dead on!

    Thanks.

    Whiz
     
  18. TjayE

    TjayE Member

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