How to make a rod end greasing adapter


First, get some aluminum bar stock about 1 inch by 1 inch in cross section. Steel will work as well, but will be a lot harder to drill and tap.

Cut the aluminum bar to a length of about 1.25 to 1.5 inches. I used 2 inch lengths for the first few I made but you will find that shorter lengths will be easier to use. The idea was to make the length enough to allow the adapter to easily be clamped in vise, but the shorter lengths should work for that as well and are easier for the machining.

Drill a 3/16 inch diameter hole about 1 inch lengthwise into the bar. Then use a 21/64 drill bit and enlarge that hole; do not go deeper than 1 inch.

Then take a 13/64 drill bit and drill through the bottom of the 21/64 hole out the other end of the aluminum rod. If you wish you can use the 13/64 drill bit instead of the 3/16 one for drilling the initial hole. You will find it much easier to drill the 21/64 hole if a smaller pilot hole such as 3/16 or 13/64 has been drilled first. You will find it much easier to drill the 13/64 hole out through the other end of the rod by completing the hole by starting at the bottom of the 21/64 hole; it gives the aluminum chips produced by the 13/64 drill bit somewhere to accumulate, a problem when drilling such a deep hole.

Take a 3/8-24 bottoming tap and tap the 21/64 hole. A 1 inch depth of tap should be more than adequate.

Take a -28 tapered tap and tap the other end of the hole, the one made by the 13/64 drill bit. Insert a suitable grease fitting in the hole.

Note: grease fitting come with different threads. I chose -28. However, they can also be purchased with pipe thread fitting threads. Choose what you wish and select the appropriate tap accordingly.

Now when you go to use the adapter, here is some advice:

1. Run some grease through it to clean it out.

2. I would screw the rod end in with the jamnut on it and tighten the jamnut against the adapter. There is no need to tighten the rod end into the adapter all the way; the threads are aluminum and you might damage them if you do that.

3. Adding an O-ring at the base of the jamnut where it goes against the adapter will help prevent grease coming out there, although there probably won't be enough to worry about anyway if you use the jamnut.

Wayne (Robert Eleazer)



Page last modified on May 16, 2013, at 11:46 PM