Friday, January 25, 2013

Shroud Anti Chafe Cover End Caps

 In deciding to make my own shroud anti chafe covers, I came up with an idea for the end caps. These are usually split so they can be applied to the end caps of the tube and sit firmly against the wire rigging. The tube, (in my case I am using 32mm pressure PVC pipe), is slid over the shroud (the shroud has to be undone from the turnbuckle). Then, once the shroud is re-tensioned, the end caps are applied and secured in place with a small screw to each side.
I made mine from a hard wood called Rimu. The caps have a 10mm hole in the center to match my wire rigging.
 The problem with making end caps and then splitting them, is that if using a saw, the dimension for the end cap to fit in the pipe is changed by the thickness of the saw. Also it can be very difficult to get a straight cut down the center of a small round piece of "dowel".
Here's how I over came that problem. First I glued two pieces of wood together using a "light" type of PVA glue WITH a piece of paper between the two pieces of wood. This was set up over night with the two pieces under pressure in a press. You could try a heavy weight; I'm sure that would also work.
The ends of the wood were sawn square and on a drill press, the 10mm hole was drilled down the center.
A piece of dowel was tapered slightly and driven down into the 10mm hole at one end. This was cut and sanded square with the end surface, and a center bit was used to place a start "dimple" into the dowel.
Then the spindle that supports the wood was driven into the end, using the center of the dowel to help in the location.

This was then placed in the lathe and a running center applied to the outboard end. You can see in the picture to the right, how the two halves are glued together, with the paper between.

These were then turned down to the required size and shape. On mine, I placed 40mm of length, to go inside the pipe, and a mushroom type of head for the outside.
On the picture to the left, you can see in my left hand, a preformed gauge to give me the required dimension.

Finally, you can see the finished products to the right, in both a 32mm and a 50mm pipe, and one sitting outside the pipe, in it's two halves.
How did I get it into the two halves?
Once finished turning and finale sanding, take the  cap and place it on it's end. Then get a wide and sharp chisel. Place this at the interface of the two pieces of wood, right on the edge of the paper. Usually, supporting the wooden cap and chisel with one hand, and giving the chisel a knock with the other hand was enough to split the two halves along where the paper is glued. Some times I had to use a wooden mallet and give a little more of a knock.
Then when separated, sand the paper off on a belt sander.
These wooden end caps will have a couple of coats of epoxy "applied and dried" to them, before fitting. This will give the wood some protection from the elements and give a longer life. If you find one of your ends caps is a little smaller in the fit to the pipe than you would like, you could probably take up some of the extra slack with another coat of epoxy.
I'm using 32mm for the shroud anti chafe and the bigger 50mm for a back stay HF antenna stand off project still to be completed. The final of these two projects will be published in a later blog.

I would like to thank Paul Gooch for his expert knowledge and use of his equipment in the making of these wooden caps.

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.