[skyking902001]

Trying to adjust the rod end bearings on the elevators prior to drilling the horns thru the center bearing hole. How does one measure 13/16" from spar to center of the rod end bearing? I can eyeball what looks like the center and get close, but due to the swivel in the rod end, how can I be certain that I am measuring to the center of the bearing. Advice appreciated.

Skyking902001
RV8-emp almost done
Wings & fuse on order

 

[cfiidon]

Try this

If I recall correctly, I stuck a bolt through the rod end. You can pretty much see that it is orthogonal to the shaft. You can then use a ruler or caliper to measure to the center, or perhaps to the inside and outside of the bolt shaft, add or subtract half the diameter, etc. I think you'll find that to be accurate enough.

Don

 

[Lockard]

If I recall correctly, I stuck a bolt through the rod end. You can pretty much see that it is orthogonal to the shaft.

Do you mean hexagonal or perpendicular?

If you were to scribe 2 lines on the top of the bolt head that go from peak to peak on the hexagon, they would indicate the center. You may be able to get a satisfactory amount of precision from that. Inserting a bolt is a great idea, though.

Maybe I'm over thinking this.

 

[rzbill]

Bolt and scale

Like Don said, use a bolt as a visual aid.

Also, if you have a 6" scale (Starrett for example) that has marks on both edges, you can use that feature to help get the measuring bolt parallel to the Elev spar by reading the same measurement on both edges of the scale.

 

[Dan Langhout]

I used a piece of 3/16" steel rod . . . . .

. . . . . through both rod ends. This pretty much takes care of ensuring that the bearing bore is parallel to the spar (once the two measurements get close). Measure to the center of the rod or to the edge with a 3/32" offset.

 

[Bullseye]

I just tried to center the bearing and eyeball it.

If I remember correctly, it was clear when it was correct, as another half a turn was definitely too much, and a half a turn less wasn't enough.

http://n999za.files.wordpress.com/2010/07/20100731-012-large.jpg

 

[skyking902001]

Thanks!

Thanks for the responses. I probably way over thought the issue--just didn't want to mess up. I ended up drawing some parallel lines on a ruler. I inserted an Averey alignment pin thru the rod end bearing, using the ruler behind the bearing to assure the pin was parallel with the spar. Although the alignment pin does not come to a sharp point, using another starrett rule, I was able to measure from the spar to the tapered end of the pin. Seemed to work out ok. Thanks again for the help!

Skyking902001

 

[Experimental Chaos]

Over thinking?

You think you?re over thinking it? Not even close. I made a fixture by cutting two pieces of ? by 1 inch aluminum bar stock, drilled a 3/16 hole in each, and cut one end (of each) to the required dimension, as measured with a digital calipers. Actually, cut long and then sanded to the precise length. The two pieces eliminate the possibility of having the bearing cocked, by having one on each side. Simply slip a bolt though, with 2 washers on each side of the bearing, and the 2 fixture pieces outboard of that. The problem comes from the fact that you have to make adjustments a whole haft turn at a time?Don?t talk to me about over thinking things?.

 

[bret]

You will never get it perfect because you can only make 1/2 turn adjustments, your only concern will be to get it close to the specs, and then look at where you will drill the horns at the center bearing (bolt interfering with weld) and counter weight swing clearance at the HS.