4-40 Socket head cap screws

[Bootlegger]

  Guy's I am looking for some 4-40 x 1 1/2" -- 2 inch allen socket screws that are threaded all the way to the bolt head. I am using them for control horn set up's.

  Any help will be appreciated...

[Robert Zambelli]

McMaster-Carr

These guys are the best!

  https://www.mcmaster.com/#standard-socket-head-screws/=18o16pp

[Steve Helmick]

But McMaster-Carr doesn't have them fully threaded, per Gil's specification. I think the best you can do is "all-thread". Since the stuff from the LHS is made from cheese-whiz, you might search McMaster-Carr for something better, or up-size to 6-32. Alternately, look at Sullivan, DuBro, and Central Hobbies websites.

If you're doing what I think you're doing, watch out for control asymmetry.    Steve

[Bootlegger]

 Thanks Bob and Steve, Steve would you please elaborate on what you are talking about?  Thanks..

[11290]

The picture of the screws on this site are shown as fully threaded, not sure if they are or not but wouldn't hurt to check.

http://www.homedepot.com/s/%25234-40%2520x%25202%2520in.%2520Internal%2520Hex%2520Socket%2520Cap-Head%2520Cap%2520Screws?NCNI-5

[eric rule]

https://www.mutualscrew.com/socket-head-cap-screws-standard-/alloy-steel-fully-thread-socket-head-cap-screws-14630.html

Expensive but what you are looking for.
Eric

[Richard Imhoff]

Try https://www.albanycountyfasteners.com/default.asp  all they have is stainless and the prices are great.

[Brett Buck]

Thanks Bob and Steve, Steve would you please elaborate on what you are talking about?  Thanks..

   

   I think you will find the screws you want on this page, threaded all the way to the head:

https://www.mcmaster.com/#standard-socket-head-screws/=18o912s

  4-40 socket cap screws, fully threaded, 1/2 long - 100 for $8.47 Item number  91251A110   

    Brett

    Brett

[John Rist]

2" 4-40 fully threades   https://www.mcmaster.com/#standard-socket-head-screws/=18o9pfm

Then go-to 18-8 stainless steel.  Select 4-40.  select 2"

McMaster links always go to the top page and you have to drill down.

[Target]

If you're doing what I think you're doing, watch out for control asymmetry.    Steve

Boot-
I think that Mr H is saying that if you shove a bolt through a control surface, it will likely not be centered above the hinge line, and you will get unequal throws for equal control input.

R,
Chris

[Steve Helmick]

Boot-
I think that Mr H is saying that if you shove a bolt through a control surface, it will likely not be centered above the hinge line, and you will get unequal throws for equal control input.

R,
Chris

That would be correct, Chris. Also, I looked through a bunch of the links posted above, and most showed no full threaded 4-40 x 1.5"  or 2". One did show a 3", but the "units" was "one", and price was pretty rich for one...IIRC, $3. 

I gather that Gil doesn't know what "all-thread" or "redi-rod" is. Steel (or other) rod that's fully threaded, from one end to the other. McMaster-Carr probably has it in some decent high strength steel. Any Ace Hardware will have it in larger sizes, but not 4-40.

All the rest of my first post still applies. Sullivan, DuBro, Central Hobbies, etc., in that order. Lots of R/C bods use such stuff for horns. A lot of the CH stuff is Japanese and quite expensive to my view, but you'll see some good (and bad) ideas on all three sites.  Steve   

[Bootlegger]

  I have some 4-40 all thread, but thought that it would be too soft, as for symmetry the push rod is threaded also for adjustment.

  Thanks a lot for all the info guy's..

[Target]

  I have some 4-40 all thread, but thought that it would be too soft, as for symmetry the push rod is threaded also for adjustment.

  Thanks a lot for all the info guy's..

The pushrod being adjustable has nothing to do with the asymmetry of control throw, it is the non-perpendicular angle from the hinge line to the control attachment point that does it. You'll see when you put it together. The closer perpendicular to the hinge line you can be, the better.
You could angle the bolt forward, but then you would be at a one point of perfection setting, which is what it sounds like you want to avoid.
That is why a nylon hinge has the offset base with the 4 holes in a vertical line. That line is meant to be directly above the hinge line.

You can do a mockup with two pieces of balsa taped together for a hinge, and a dowel representing your 4-40 bolt. Set it back a good distance from the hinge line, then start measuring your throw of your pushrod (shrink tube another separate dowel to the tip of the horn dowel to make a linkage) vs. the up and down throws you get. You will see that there is "differential" in the throws.

We USE differential in RC sailplanes to help combat unwanted adverse yaw, by having the up aileron throw further (typically 2:1 or sometimes more) than the down aileron. We do this by either offsetting the control horn (the oldschool way) or by having the servo arm tilted either towards or away from the linkage (depends on push or pull for up aileron) at neutral....

The closer you can get the 4-40 bolt to that hinge line, the less the effect will be, and in fact if it is very close, you might not really notice it, depending on the angle the pushrod is at from the flap horn and to the elevator horn.

I'm exhausted now from typing!

But, best of luck on your endeavor, and I mean not to dissuade you. Just don't want you to be disappointed or surprised.

V/r,
Chris

[Bootlegger]

  Chris, et al thanks for the heads up on this set up, I really do appreciate it..

[Matt Brown]

Our local Hobbytown has 12" long 4-40 stainless all thread. I have used it for exactly this purpose. I think it may be a Dubro offering.


Matt

[Bootlegger]

  Mr. Zambelli,
   I sent you a P/M...

[Randy Cuberly]

This link to McMaster-Carr shows 4-40, 18-8 stainless screws fully threaded in 1 1/2 and 2 "" lengths.  18-8 is plenty strong enough for what you're doing.

https://www.mcmaster.com/#socket-head-cap-screws/=18ook05

As stated above the screw must go through the elevator at the hinge line.  This can be accomplished by building a tab into the elevator that extends into the notched Stab and mount the screw into this tab.  It works I did it a long time ago.  Just make sure the tab material is strong enough to take the control loads.

Randy Cuberly

[Fred Cronenwett]

These are two sources that I have used

http://www.microfasteners.com/

https://www.boltdepot.com/

Fred

[Dan McEntee]

   The screw doesn't HAVE to be on the hinge line, but the fitting  that the pushrod attaches to should be on the hinge line. DuBro sells a fitting to do just that and uses the same fitting that aileron horns use. It has a large, triangular base plate on both sides of the control surface to spread outthe stresses.
   Type at you later,
   Dan McEntee

[Robert Zambelli]

  Mr. Zambelli,
   I sent you a P/M...

Got it and responded.
Hope the info helps.
Bob Z.

[Steve Helmick]

"The screw doesn't HAVE to be on the hinge line, but the fitting  that the pushrod attaches to should be on the hinge line. DuBro sells a fitting to do just that and uses the same fitting that aileron horns use. It has a large, triangular base plate on both sides of the control surface to spread outthe stresses.
   Type at you later,
   Dan McEntee"

Indeed. One idea to strengthen/stiffen the control horn would be to install it and build a "pylon" around it maybe 3/4" tall. Using hard balsa and cellulose glue, it would be easy enough to cut down a bit if needed.

I'll be up front and tell you that I haven't done this sort of elevator horn...when I flew combat, I always used the large Veco flap horns. They made a clean installation, had some adjustability, and spread the load over a fair amount of the stabilator's 3/16" or 1/4" balsa I used. But I'd likely be using the scheme Gil is looking at, if I was going to do combat again (ain't happening!). It would be a help towards get all my models to respond similarly. Seems like a big plus to me. Steve 

[Norm Faith Jr.]

  Guy's I am looking for some 4-40 x 1 1/2" -- 2 inch allen socket screws that are threaded all the way to the bolt head. I am using them for control horn set up's.

  Any help will be appreciated...

             


https://www.microfasteners.com/ast2468-2-56-4-40-6-32-8-32-socket-head-cap-screws.html

[Bill Mohrbacher]

  Guy's I am looking for some 4-40 x 1 1/2" -- 2 inch allen socket screws that are threaded all the way to the bolt head. I am using them for control horn set up's.

  Any help will be appreciated...

I just bought some 4x40 3 inches long, full length threaded from micro fasteners. 800-892-6917.  Part #SCA0448

I was surprised as shorter lengths were partially threaded.  Call and talk to them, they very nice people to deal with.