Combines rasp bars drive can not believe it

What you see is what it is supposed to be. If the spider closest to the drive end was clamped to the drive shaft, it would twist the shaft much easier. Same load is distributed over a much longer shaft. Torsional load would break shaft.

deere uses a good grade of shafting, it is undersized as w_ the keys for the horsepower that is driven to the cylinder. you won't have problems until you try slow speeds and high torque, i.e. dry edible beans.

You have just discovered a real money making bonanza for the JD parts and service dept. I have taken cylinder bars out of many JD combines, and cracked spiders are very common.