How do I fit additional cleats to aluminium mast

[Jcorstorphine]

Years ago, I built two masts from kits supplied by “Bowman Boats” for a ketch I was building. In the kit were 6 mm and 8 mm threaded Aluminum inserts which expanded when the machine screws were driven into them. The were a bit like metallic Rawlplugs.

Does anyone know where I can buy these fixtures as I want to fit some additional cleats to my mast.

Thanks

 

[KenMcCulloch]

Years ago, I built two masts from kits supplied by “Bowman Boats” for a ketch I was building. In the kit were 6 mm and 8 mm threaded Aluminum inserts which expanded when the machine screws were driven into them. The were a bit like metallic Rawlplugs.

Does anyone know where I can buy these fixtures as I want to fit some additional cleats to my mast.

Thanks

They are called rivet nuts or rivnuts, google these words. If you use S/S ones you should also use some duralac or equivalent to prolong the corrosion-free life of the joint.

 

[Jcorstorphine]

Aluminium fixtures.

They are called rivet nuts or rivnuts, google these words. If you use S/S ones you should also use some duralac or equivalent to prolong the corrosion-free life of the joint.

Belated thanks, forgot my manners!

The fixtures I was supplied with 35 years ago were more like split collets which widened when the machine screw was driven in and I was never very happy with them. The Rivnuts you suggested look much more robust.

Regards

jc

 

[vyv_cox]

Rivnuts are excellent but you need to experiment a little with the setting in the thickness of metal in which they are being inserted. It is all to easy to set the shank into the gun too far so that massive force is exerted to get the thing to close, or alternatively to set it too loose so that it turns when the bolt is screwed in.

 

[William_H]

Cleats ona a mast

It seems to me that plastic cleats attached by metal thread screws into a hole tapped into the aluminium mast is very adequate. Just use Duralac as said. A metal thread tap is fairly cheap and very useful.
good luck olewill

 

[Scotty_Tradewind]

that's intersting William, although if done well into a good thickness the thread would hold, but wouldn't the Duralac be removed from most of the thread when screwed up and so the barrier it provides between the two dissimilar metals is more likely to be lost?

If using s/s cleats on an alloy mast its also a good idea to put a barrier between the two. I tape mine with gaffer then usually monel rivet them if the gun can be got into position. With a sharp blade the extra gaffer can then be peeled away.

 

[rogerthebodger]

It seems to me that plastic cleats attached by metal thread screws into a hole tapped into the aluminium mast is very adequate. Just use Duralac as said. A metal thread tap is fairly cheap and very useful.
good luck olewill

That's how I did mine. I also fitted pad eyes for my reefing blocks that way.

IMHO Duralac is only needed if you wish to remove the cleats at a later date.

 

[William_H]

Duralac

Yes it is needed on all SS screws or rivets into Ali and no I don't think the duralac is lost when you screw the screw in. Rivets are OK for cleats if you can find them long enough. olewill

 

[john_morris_uk]

Another solution is to rivet the cleats to the mast - at least that is how my mast was built. I had to replace a (missing) cleat a few years ago, and the rigger sold me the correct length monel rivets etc to put the new cleat on. Admittedly its only used for the lazy jacks, but its remarkably strong for what it is.