3782 posts
How much play or end float in a universal male extension before it requires replacing?
I have both types but just been replacing them but its getting expencive.
Can these units be serviced?
(this is directly related to your down-haul rope size??????????????????????????)ready to emergency wrap down haul in extension base
Just need to know what wears in that universal and if that "wear"will create failure?
Has anyone got a diagram?
VIC
819 posts
You might consider the following:
For Boge joints, the rubber usually fails at its minimum diameter. If you connect the UJ to the board, fit the extension, then bend the extension parallel to the board, any cracking in the Boge will show up and it should be replaced.
Excess vertical movement of the Boge from the star base may indicate that the nyloc nuts are loosening, so the joint needs to be serviced. During bolt/nut replacement, the Boge should be free to rotate but should not have more than say, 1/4mm (0.010") vertical movement.
The bolts and nuts that connect the Boge to the assembly should be replaced during the Boge replacement. Loctite the bolts/nuts and then wait 24 hours for the Loctite to set.
Tendon joints are a little trickier, because the most common failure I've seen is where the small bolts pass through the tendon and unfortunately this area is hidden from view. It is necessary to remove the small bolts and nuts to inspect the tendon for cracking/stress in this area and if you do that, you might as well replace the tendon. Also replace the bolts and nuts and Loctite them into place. Allow 24 hours for the Loctite to harden.
I replace my tendon joints on a 12-month cycle.
Nyloc nuts (both types of UJ's) SHOULD NOT be reused! The nylon is an interference fit on the thread of the bolt and, once used, will not give the correct clamp load onto the thread of the bolt thereafter.
Loctited nuts and bolts require a good set of tools to get them undone. As a suggestion, if you do not have the tools, your local windsurf shop may be able to service the UJ for you, but remember that Loctite takes time to set correctly. Best way out of this, is to have a spare UJ so that you can keep on sailing.
Hope this helps.
NSW
510 posts
the onlt part on my uni join that has failed was the rubber cylinder that suports all the flex .. i always carry a spare now in the car..
3782 posts
Sweet thanks windman your a knowledgeable man!! thanks for your time and explanation.
Ill take them to work and service the lot seeing as there is no wind for a few days!
WA
6277 posts
Hey Buster, I think I see the problem...
A kiter's shorts are caught in the mechanism. Might be an idea to take them out before they cause more damage.
116 posts
Rubber U.J.'s seem to come in a variety of types.We use mainly Boges over here.
The last one I had fail (one and a half years ago) failed on its second outing. The top part pulled clean off.
On examination it consisted of three seperate pieces which were GLUED together.The central bobbin, the top rubber section which was moulded around the disc into which the pin screwed, and the bottom part ditto. The three pieces were sheathed in a thin continuous rubber skin on the outside to give the appearance of being all one solid piece.
Mine was part of a faulty batch (change of factory) which hadn't been properly glued together. Unfortunately there is no way of inspecting or testing the glued joints as they are hidden inside the outer casing.
Experience seems to show that if they don't pull apart on the early outings, they will be O.K. But it's still a worry. The only answer seems to be to renew them regularly, especially if used in surf.
116 posts
Should have added: the Boges which are attatched to the base plate seemingly can't be dismantled.
I sawed and chiselled the plastic parts off the base of an old one to see how they were made. (It had developed too much play in the swivel part, and I'd thought it was about to fail. Most unlikely after what I found.)
The part which screwed into the moulded in base in the bobbin was a one piece steel ring (swivel bearing) with a 1/2 inch diameter central boss which stood out another 1/2 inch and had a deep vertical sided groove machined all the way around it. A large steel hexagon shaped block with a matching hole for the boss to fit into, is embedded in the plastic base, and when the two are fitted together a round steel pin is slotted in through a hole in both the plastic base and steel block to lock into the groove. The hole is then sealed with plastic. Clearly, we're not supposed to dismantle it.
The reason for the play was a flat worn on the steel pin from the swivelling. I doubt it would have broken. The pin was too substantial for that.
116 posts
Tendon U.J.'s don't stretch much, just bend, so why don't the manufacturers fit a thin strong steel wire (bike brake cable sort of thing) through the middle with firmly attached loops at each end for the bolts to slot through? It wouldn't feel much different but it would be a damned sight safer and stronger!
I'd make one myself but the tendons are already joined and there's no way to thread a wire with pre-attached loops each end, down the middle.
I'm looking at a new Bic tendon now and it has a seam down the middle so it's clearly two halves joined together. If I split it, hollow out a small groove, and fit the wire with loops at each end, does anybody know how the two halves should be rejoined? Are they glued, welded, or fused together somehow during manufacture?
WA
708 posts
That line would be where the two halves of the die meet, that the rubber is injected into.
116 posts
Ah. I'd hoped that wouldn't be the case. If one was split down the middle (to insert wire) would it be possible to bond the two halves back together? Are there any glues or solvents or whatever for rejoining tendon material?
VIC
819 posts
Hi, Mrgob,
No way to successfully join them.
During manufacture they are joined under heat and pressure, neither of which is available to you.
If you need a safety device in a tendon joint, suggest you consider going onto the Chinook or Neil Pryde sites to inspect their offerings, both of which have a safety rope as part of the assembly.
Hope this helps.
116 posts
Thanks WindmanV. Chinnok products do seem to be reliable. I use their tendon U.J. on the long board - the one with the single piece top and pin, and tendon with metal inserts in the stud holes - and have never had one fail.
Like most others, Boges are used on the wave board which is where failures usually occur. To be fair though, something has to give in a heavy enough rinsing. I once made a mechanical Battleship proportioned U.J. with ball bearings, but the bloody thing was so heavy that it almost sunk the board, and would have ripped the mast track clean out at the sight of a wave!!!
Oh well. Most bright ideas come to nought.
VIC
819 posts
Mr G,
For windsurfing, 2 rules apply:
1. Keep it simple
2. Don't re-invent the wheel.
Your battleship-proportioned UJ reminds me of my dear-departed friend, Dieter, who turned up at our beach one day with his home-made, stainless steel boom clamp. After coming in contact with his 6.5 kg slalom board a couple of times, the board eventually weighed 13 kg.
