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manuel
Joined: 08 Oct 2007 Posts: 1158
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Posted: Sun Dec 17, 2017 2:24 pm Post subject: Mast Base Regular Maintenance |
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I have been using an old Streamlined mast base for years. It has been great. I regularly replaced the tendon. I used to replace the tendon often until I realized that I needed to add a washer inside to make a tight tendon fit.
At the time of tendon inspection I often tighten to the top nut. At first, the nut used to loosen fast so I wrapped a small piece of plastic from a heavy plastic bag around the thread. This worked wonderfully.
However, after years of use (maybe over a decade!) I was worried about aluminum wear and plastic cup wear as well. So I purchased a new one.
Now on the new one, the top cup is already loose (a couple of months), I tried tightening but it won't budge. The cup has up-and-down play.
The bolt inside needs an Allen wrench so I can't apply much torque. Also, unlike the old design, the nut seems to be stuck to the aluminum top piece. Before putting unnecessary stress to the base, I wanted to ask, how do you all maintain your mast base? Can this nut be adjusted by holding the top aluminum piece instead? _________________ *NEW* - Manu's Windsurfing Blog, The STORE! |
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isobars
Joined: 12 Dec 1999 Posts: 20946
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Posted: Sun Dec 17, 2017 7:40 pm Post subject: |
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I bend my hourglasses 90 degrees and inspect them closely every time I rig. When I see any hairline cracks, I grab a new one. Last joint failure I had was way last century on a brand new hourglass's first day. |
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manuel
Joined: 08 Oct 2007 Posts: 1158
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Posted: Sun Dec 17, 2017 8:25 pm Post subject: |
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I have seen at least two hour glass bases fail including one I owned. The lower part oxidizes and the rubber separates... This was after rinsing religiously after each session. Naturally, I tried something else !
How do you deal with the increasing looseness? _________________ *NEW* - Manu's Windsurfing Blog, The STORE! |
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swchandler
Joined: 08 Nov 1993 Posts: 10588
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Posted: Sun Dec 17, 2017 10:05 pm Post subject: |
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I hate to say it, but sometimes the best strategy is buying a new universal. That's what I did for years, especially when I was using the US two-pin cup design. The wear on the plastic cup was a bit much, and it would get so wobbly that I thought that things could be dicey using it.
I guess the decision line falls on whether you want to screw around with and replace the components. Not a bad path, but you have to have the tools and the workplace. Then, there's the time to do it. Admittedly, I have many old wobbly universals in my van.
There's nothing better than using a fresh new product, and it's arguably one of the cheapest components in windsurfing. |
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manuel
Joined: 08 Oct 2007 Posts: 1158
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Posted: Sun Dec 17, 2017 11:43 pm Post subject: |
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I got carried away with describing my problem. The problem is on the new one, the old one is nice and tight, just old... The new one is already too loose to my liking! _________________ *NEW* - Manu's Windsurfing Blog, The STORE! |
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GURGLETROUSERS
Joined: 30 Dec 2009 Posts: 2643
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Posted: Mon Dec 18, 2017 5:33 am Post subject: |
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It seems inevitable Manuel that all types of UJ assemblies will develop slackness in either the base plastic fitting, or the top pin fitting into the plastic mast feet. It is possible to fit shims to the top pin fitting to eliminate up and down excess play ( I used to Araldite a shim to the top of the UJ) but it is essential to leave a little play to keep a secure fit. But, as stated, it seems best to keep replacing the UJ when subject to heavy shock loadings in surf.
I'm currently using the newer North two piece tendon assembly, and it is now well into the second year of use, albeit with some slack in the lower assembly (wear) but with absolutely solid and tight fitting tendon fastenings at top and bottom. The saving, for me, is that the tendon has a hole through its middle with a rope threaded through and firmly looped over the tendon securing bars, top and bottom. Should the tendon split, the rope is designed to hold the joint together. (Proven to work for me, when the original developed a fault and a sub standard tendon did break without me realising while in use.)
The reason I switched solely to tendon use was because it is impossible to check for wear or impending breakage of the hidden inside GLUED TOGETHER sections of the hour glass type UJ's. Bending them to check can only reveal cracks in the outer sheath, not the hidden inner sections. Too many of them failed under surf shock loadings.
I think Manuel, that for use in surf you cannot accept excess up and down play (shock loadings) for peace of mind. When buying new it makes sense to reject those which feel to have too much slackness built in. That was my reasoning in changing to the North tendon UJ's. |
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GURGLETROUSERS
Joined: 30 Dec 2009 Posts: 2643
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Posted: Mon Dec 18, 2017 8:27 am Post subject: |
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In addition, to second your point about hidden salt water corrosion within the unexaminable moulded in metal plates at top and bottom of bobbin UJ's, they can fail without any obvious evidence which can be checked.
Unless, that is, you can sometimes spot some hint of green (corrosion) seeping out around the pin fittings. But that is a seperate issue to the possible failure of the hidden glue interior pieces.
It is conventional wisdom to relace those bobbin UJ's every nine months or so,if used in sea water. |
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bred2shred
Joined: 02 May 2000 Posts: 989 Location: Jersey Shore
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Posted: Mon Dec 18, 2017 12:23 pm Post subject: |
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The way the US Cup system works, there is typically a "bush-washer" (large plastic bushing + washer) that sits between the top of the joint (hour glass, tendon, mechanical, etc.) and the bottom of the cup. Then a 5/16" bolt with washer threads down through the cup, through the bush washer, and into female threads in the joint.
The bush-washer acts as a wear point for the bottom of the cup and also acts as a pivot point for the cup so the bolt doesn't wear into the cup and the cup is less likely to cause the bolt to unscrew.
If the cup is sloppy, it means that the boss section (raised section) of the bush-washer could be a little too long. Or the bolt itself could be a little too long and is bottoming out in the joint. Either condition would leave you with a gap between the bottom of the bolt head/washer and the inside of the cup which would make the cup fit sloppy.
If you can't eliminate the slop by simply tightening the bolt, then I would remove the bolt and see what is causing the gap (again, most likely either to boss on the bush-washer is too tall or the bolt itself is too long). The fix is probably as easy as simply filing a couple thousandths off of one of those components to snug things up.
As always, be sure to re-assemble the bolt with a healthy dose of RED Loctite to prevent accidental loosening.
sm |
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PeconicPuffin
Joined: 07 Jun 2004 Posts: 1830
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Posted: Tue Dec 19, 2017 4:01 pm Post subject: |
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What SWChandler said. The cost/benefit/safety factor makes it an easy decision for sailing in places/conditions where a breakdown could be trouble.
I buy a new uni every two years...the new one becomes my uni for waves, sailing far from shore, and other conditions where breakdown would be major trouble. My "old" (two year old) uni gets demoted to shallow flatwater service, nonplaning freestyle etc. _________________ Michael
http://www.peconicpuffin.com |
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manuel
Joined: 08 Oct 2007 Posts: 1158
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Posted: Thu Dec 21, 2017 2:04 pm Post subject: |
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It surprised me that the play got so important so quickly. I understand that parts need to break in... and would like to be able to tighten the nut. Maybe the red loctite is the problem. Maybe I can find a vise to hold the base. I doubt the hex bolt can handle high torque.
I'd hate to have to change a base without changing the tendon even once! I must have replaced the tendon 5-6 times on my old one maybe more. _________________ *NEW* - Manu's Windsurfing Blog, The STORE! |
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