Help I'm losing my....zincs !

[RG Miller]

Anyone else have this problem? I put new zincs ( two of them ) on my prop shaft and they keep coming loose. I bang them on with a hammer, tighten them, bang them again and again and in a couple of months they come loose again. This last time I tried some loctite on the screws. Maybe I should use epoxy but something must be wrong. Any ideas? My shaft doesn't seem to be bent...I don't feel any great amount of vibration. I notice it when I go in reverse. (Zinc slides up the shaft )Thanks, RG.

 

[Dave]

Loose Zincs

Just a suggestion but I have noticed the quality of zincs to vary greatly by manufacturer. In particular check the copper contact in the zinc. Make sure it protrudes a significant amount above the surface of the zinc. I have seen many where there was little to no contact as the copper was actually recessed. Pick through the bin until you find zincs that meet your quality criteria, this will help put more force on the contact.Secondly, I always do some work on my zincs before installation. Keep in mind these are not highly accurate dimensional products, they are basically as cast in a die casting machine so the tolerance is much greater than your shaft diameter tolerance.Take the zinc apart and clamp each half in a vice. Using a variable speed drill with a small grinding wheel carefully chamfer all edges around the flat face of the zinc, put generous chamfers to make sure no burrs are preventing the zincs from clamping tightly. Secondly just for added benefit use the grinding wheel on the flat face and grind away a little stock, A file may be used but the material is so soft it will clog the file quickly. Another alternative is use a belt sander on the face or a disc sander.This will effectively make sure the zincs are clampint tightly on your shaft and not coming in face to face contact preventing a tight clamp on the shaft. I'm positive this will solve your problem. A small amount of work to avoid a big problem forcing you to dive to fix it.Best regards and happy new year.Dave

 

[Harry A.]

Filing Zinc or other soft material

If you file your zinc's, before filing rub some chalk into the teeth of the file. This will stop the zinc, brass, or aluminum, etc. from clogging the teeth of the file. Also,whether strait filing or draw filing, always lift the file from the work on the back stroke, never drag the file back and forth on the work. Doing so shortens the life of the file and makes the work surface rough.

 

[Ken Sturgill]

I see Your in BC

I've bought zincs of Canadian make that are metric, and had to do what Dave has written. Most stores in Washington stock Canadian Zinc's, i.e...West Marine & Boaters World, they are metric. Your shaft is in inches, 1,1 1/4, 1 1/2.... Harbor Marine in Everett, Fisheries Supply and other smaller non-chain stores stock zincs in inches.

 

[Ralph M.Johnstone]

One Sure Fire Method ....................

..... that has always seemed to ensure the zincs stay tight is to snug them on first with an Allen wrench and then crush the bejabbers out of them with a 12" C clamp. Ensure that the force is applied WITH the alignment of the Allen screws. You should then get about one more turn on the screws.So far (touch zinc) I haven't lost one using this method.Regards,s/v Island Hunter