I remember seeing a add a while back (years?) where someone was marketing 3-56/2/56 dies for making one's own 2-56 push rods or threading others. Also it seems like he had 5-40 /4-40 for doing 4-40 size. Anybody out there have a recollection on this??
I have been using 2mm bicycle spokes to make 2-56 rods. While they are somewhat hard cutting the diameter works and the wire is much stiffer than standard rolled thread pre made rods. Multiple passes with a split die work best.
I use a 2-56 die from K&S. Works OK, but is a carbon steel die, not high speed. Since it's a split die, I put it in a Vise-Grip with the split facing out. Chuck the rod (A piece of welding rod) in a variable speed drill, lube it up (I use Rapid Tap) and make a pass. Then tighten the Vise-Grip to squeeze the die and make deeper cuts. When it spins into a Sullivan 2-56 clevis, it's done. What you end up with is a rod that is bigger diameter than a standard 2-56 with tight threads. Later Bill
Another method is to clamp the edge of the die in vise, chuck the rod in a large (slower rpm) drill, and "feed" the rod into the die while lubing as needed.
I take strong issue with that. In fact you have to close down the die in order to avoid making it too tight. Refer to this picture
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The upper thread, cut from a spoke, is .085" in majour diameter which is at the upper range of a class 2A fit while the thread on the Sullivan eye bolt has a majour diameter of .081" which is at the minimum end of the same class. AFAIK the Sullivan product doesn't have a history of failure. I certainly haven't had any with the spokes used over a number of years of use.
Since 2mm = ~ .079" I assume the metal is worked up in cutting multiple passes.
I don't know what you may have seen but I have every confidence in what I have suggested. Perhaps you are referring to flimsy ARF hardware.
Then take issue with "Machinery's Handbook", The Industrial Press, by Erik Oberg and F. D. Jones.
In numerous places and charts in this 2000 page manual, they state that the major diameter for a standard 2mm threaded bolt, stud, or screw is .0786". They also state the major diameter for a standard 2-56 bolt, stud, or screw is .086". It's only a difference of .0074, but in this size, with nylon clevises, it makes a difference.
I was. However, if it's manufactured to industry specs, a 2mm thread will be smaller than a 2-56 thread. If a 2mm clevis is replaced with a 2-56 clevis, there will be a chance it will pull out.
And I have none. I'll stick to like threading systems and not risk my plane, property, or safety.
The diameter of the rod the threads are cut or rolled on is also specified. Of course, if someone is shade-tree engineering thread systems and cutting, anything goes. Dr.1 Driver "There's a Hun in the sun!"
Hmmm, who is talking about 2mm threads and mixing sizes? The ones I cut are 2-56 with a majour diameter of .085" are superior in fit to any of the pre made 2-56 hobby hardware I have examined.
Only if the information is accurate. You are the one who mentioned using 2mm bicycle spokes to cut 2-56, or did I misread something? Dr.1 Driver "There's a Hun in the sun!"
Be careful. The pushrods you buy are 'rolled' threads which are Larger than regular 2-56. The metal Dubro clevises, etc., will be a loose and sloppy fit on threaded rods.
2-56 thread is a 2-56 thread, whether rolled or cut. The problem comes when people try to cut a 2-56 thread on the same stock that had the rolled tread. This material is a smaller diameter than required to get a full cut thread.
I've been using cut threads with Dubro clevises ever since I got my Rod Chuck system. I just uses the proper diameter wire. NOT wire that had rolled threads originally.
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