Advice re mounting a new pulley/block to my aluminum mast.  Since it will eventually hold the weight of my dink,  I am concerned about mounting security.  So mount the block using A) sheet metal type SS screws and under drill the hole size or B) drill and tap for SS type threaded bolts???  Also use Locktite or Tef-Gel around the screws for security vs corrosion of differing metas. Thanks Russ Be Holy or Die Trying"  St Stephen 33AD "Be joyful always; Pray constantly; Give thanks in all circumstances, for this is God’s will for you in Christ.....Test everything. Hold on to what is good. 1 Thessalonians 5:16 "Since you cannot do good to all, you are to pay special attention to those who, by the accidents of time, or place, or circumstances, are brought into closer connection with you." St Augustine

I have no experience with aluminum masts, but I would sure think about using through bolts with a backing plates rather than using screws of whatever variety for heavy lifting. David Sorenson Duluth, MN SNIP: Advice re mounting a new pulley/block to my aluminum mast. Since it will eventually hold the weight of my dink, I am concerned about mounting security. So mount the block using A) sheet metal type SS screws and under drill the hole size or B) drill and tap for SS type threaded bolts??? Also use Locktite or Tef-Gel around the screws for security vs corrosion of differing metas. Thanks Russ

> Advice re mounting a new pulley/block > to my aluminum mast.  Hi Russ, here's a few thoughts: I too, in addition to Dave, would go for thru-bolting, if at all possible. Using washers under the nuts goes without saying and Dave's idea of a backing plate can't do any harm and if cute-looking, that's even better. Another option would be to take a stroll thru a marina and see if you can identify an arrangement on another mast similar to what you want to do then use it as a basic idea. Always keep in mind that their setup might not be designed for the stresses that you'll be placing on yours and if in doubt, use thicker metal and more fasteners. Be sure to bed the fitting as you install it on the mast. As far as using an appropriate goop on the fasteners, reach over your shoulder and pat yourself on the back. When I saw that I knew that you were someone that I'd let work on my boat anytime, in fact, come on over now, I've got a few projects that need done! Go to the library and peruse a few books- Machinist Handbooks and others like it. If you can find the tensile strength of various fasteners in aluminum, that will help identify the number of fasteners needed and their size. Keep in mind that for the fastener to have its full strength, a minimum of 5 full threads need to be engaged. Also, fasteners in shear will be of less strength than those in tension; as much as 1/2. Better several large-ish bolts than many small ones. Nothing worse than to look up and notice that those small-ish bolts are breaking one at a time. If neither approach is satisfactory, and even if they are, also consider a fitting with wrap around legs, with the fasteners also placed along the legs. Get them to wrap all the way, or a least as far as the back radius of the mast and you'll have a fairly strong installation. Send us all a picture when you're done with the installation, with the dinghy hanging from your mast. If we can't see it, we can't critize your work, one of the more enjoyable aspects of belonging to the internet dock committee. Rudy Briney Bug, Panama City, Fl.