Pretzel Yoke Disassembly

[6643]

NC76220 » Mon Mar 21, 2005 1:38 am

Tye:

I have looked around the office in China and do not have any yoke drawings, these must be at home in the USA.

I thought about using polished titanium tubes for the controls, but could never find the right tubes, but that would be nice as you could just leave them polished instead of having to plate them. I replated mine in nickel, as chrome can cause cracks - if you chrome them remind them to cook them afterwards to aviod hydrogen embrittlement.

The third leg of the control yoke was steel on mine, I made new ones from 6061 and slid the original rubber covers over them. The fasteners are long "j" hooks, these are heavy too. I replaced these with short ones.

Use 6061-T-6 for your machined parts. The covers are not structural in any way, the trick is to make them really thin, not so easy.

Erik Thomas
I want to be the last guy to fly across the USA with no radio

[6643]

Tye Hammerle » Mon Mar 21, 2005 2:41 pm

NC76220 wrote:
I thought about using polished titanium tubes for the controls, but could never find the right tubes, but that would be nice as you could just leave them polished instead of having to plate them. I replated mine in nickel, as chrome can cause cracks - if you chrome them remind them to cook them afterwards to aviod hydrogen embrittlement.

Hi Erik,

I'll have to go look again but I think i found a source for the right size titanium tube, I just got to wonder on how you'd drill it for the taper pin and didn't pursue it further.

The third leg of the control yoke was steel on mine, I made new ones from 6061 and slid the original rubber covers over them. The fasteners are long "j" hooks, these are heavy too. I replaced these with short ones.

The third leg of the yoke is steel on mine too. Titanium would be good for this piece, stronger than the steel and lighter.

Use 6061-T-6 for your machined parts. The covers are not structural in any way, the trick is to make them really thin, not so easy.

What about for the yoke hub itself, not the decorative cover but the hub the yoke tubes fit into? I was thinking maybe 2024 T-3 would be good since the hub is sort of a critical piece. I wouldn't want the yoke coming off in my hands!

Tye mbr#6449

N2180V-48-14409, N1887V-47-14067, N73096-46-10316, N72971-46-10172, N77045-46-11499, N2928N-46-13189, N58712-40 PT-17-[75-341]

[6643]

NC76220 » Wed Mar 23, 2005 12:09 am

6061 T-6 is fine for the hub parts, the originals are forged and machined.

The taper pins have a standard reamer that is used with them, this is available from McMasters or MCC supply as far as I know. You fit the parts together and then hand match/ream the pins to the hub. Then use a little red locktite on the joints and hammer the pins home. Make a special cradle to hold it, and use a concave punch to seat the taperd pins.

Drill the hole for the U joint last, squared to the hub assembly.

Erik
I want to be the last guy to fly across the USA with no radio

[6643]

Tye Hammerle » Thu Mar 31, 2005 11:49 pm

I ordered two pieces of 6061 T6511 from Metal Connections Inc. Square stock 2.75" x 23" long for $38 each. Comes with a copy of the material certification paperwork.

My brother has the CNC program for the hubs nearly done. The program he uses has a mode where it can show a simulation of making the part on the computer screen. Pretty cool.
Tye mbr#6449

N2180V-48-14409, N1887V-47-14067, N73096-46-10316, N72971-46-10172, N77045-46-11499, N2928N-46-13189, N58712-40 PT-17-[75-341]

[6643]

NC76220 » Fri Apr 01, 2005 1:56 am

Tye:

Titanium is not stronger than steel, though some types of it are similar in certain strengths.

Just as there are thousands of different types of steel which have been developed over the centuries, there are titaniums suitable for nuts and bolts, and that which can be firmed into tubes.

Titanium is prized for two reasons, light weight, ( about 5/8 of steel) with strength approaching that of steel and corrosion resistance.

Good luck with the new hubs, sounds like a fun project.

Erik
I want to be the last guy to fly across the USA with no radio