All,
Recently purchased a whole bunch of wheels an landing gears, etc. in a big grab bag box.

Some of the wheels are held on by 5/32" (?) collars and the set screw holding the collar is larger than the Allens I have for my wheel collars. Normally I use 3/32 and 1/8 inch collars from dumas, goldberg, etc.

These set screws are too large for the ones I have - i tried a no.2  allen and it is too large.

Is there a standard allen in between the number 2 and the small one I get with the wheel collars ? Can I purchase it somewhere?

       

Or, you could bypass the whole thing. Pat Johnston showed me the slickest way to make your own wheel collars.

I'll have to post a pic when I get home, but the process is really easy. Take some piano wire (maybe .021 to .027). You are basically making a spring. I used a wire post mayber .002 smaller than the size I needed for the collar. I drilled a hole that size in a chunk of steal and knocked in a the post. Then drilled a second hole for another post. The second post is a lot shorter. Clip the .021 (the size I used) around the shorter post and start wrapping it around the taller one untill you get maybe 5 or 6 winds. The clip off the excess wire. You can sort of screw the retainer onto the axel to retail the wheel. The little piece that you clipped to the shorter post can have a little loop spun in to give you a sort of handle to spin it on and off an axel. Pretty easy to put on and take off that way and it stays put once it's on there. This is a lot harder to describe that to do.

Randy, that is really a neat idea.  Do you put a washer between the wheel and the collar?  I've seen springs in various sizes in auto parts stores; maybe we could take the landing gear wire in and see if we could find the right size.  Then one spring, depending on length could be cut up to make quite a few collars.  Or, am I dreaming?  Glen

I'm assembling a Tower Hobbies "Kaos", right now, and they use little phillips head (probably JIS) set screws for their wheel collars.  They're a lot easier to use (and keep track of) than the little allen head jobbies.  Of course, these are for the larger (4mm) landing gear wire.  With a little thread locker, they seem to be pretty secure.  I still like the idea of the spring type.   Glen

Wheel collars typically use a 4/40 set screw.  I bought a quantity of 1/8" long 4/40 panhead screws and use them in place of the sockethead setscrews.  No worries about needing a special wrench, or stripping out the hex so you can't get them off.
Those who have bought my kits have seen them.

--Ray

The spring idea sounds good but I like the looks of the bullet style wheel collars from UHP. If you do use standard wheel collars, some are already 4-40, but if not; then you may want to drill and tap the holes for 4-40 x 1/4" allen bolts. I find the little tiny allens that come with the standard wheel collars a real PITA, and I throw them away. Ray's idea of using a common screw head has the benefit of not requiring a special tool (allen wrench) but I have always preferred the solid feel of a 4-40 allen. 

For this use, not all allen bolts are made alike. The ones with the concave shape on the end of the bolt are the best. They have a better bite on the LG rod. This, combined with a small amount of Blue Locktite, will insure a solid wheel attachment. I think Goldberg makes the concave allens?

But, hidden by wheel pants, the springs sure do sound cool, and KIS. 

Good tip, Bill, thanks, I hadn't heard that before.  Always learning something new here.

I find the cheap-o wrench itself rounds off rather than the screw socket.  I cut about 1/8" off the tip of the wrench and use it some more; discard it when finally too short. (I know, a "real" allen wrench won't do that.)

--Ray