As I said I'm using 4130 steel for my push rod because it is about 12" long which is over the 8" aluminum rod supplied with the servo...and I cleared this with Garmin. I know from previous experience that when tapping 4130 steel you must go really slow with the tap and I got one side done successfully, but...got 1/2" in on the other side and damn, it snapped. Went over to my Friend Al's hangar who has every tool imaginable. He had no tap extractor but another fellow popped in (Bob) and said I can do it. He got the welder and quickly welded a nut on top of the tap w/o welding it to the steel and we backed it out. WOW!!!. Then we finished tapping the hole on the lathe. I knew the tap I was using was not great quality but it was the only 10/32 tap I had. It pays to have hardened steel taps, like Greenlee or machine taps. I have oprdered some!