Originally Posted by johnnygoose
These bolts are threaded the entire length, the bolts at the hardware store are not and it looked like the part that was not threaded was a larger diameter. Maybe that small difference won't matter. I would rather have the originals. I'll post a picture tonight and anyone that has three for sale that match can PM me.
Sounds like you have a compantion flange, not a yoke. Ergo, the strap screws aren't likely to work for you (for most light-duty automotive apps, the strap screws are 1/4"-28. Companion flange screws can be 5/16", 3/8", M8, or M10.)
As for the shoulder - standard practise (ISO or SAE) is to thread the screw for up to three times its nominal diameter - a 1/4" screw, 1" long, will be threaded for 3/4" of its length and the 1/4" directly under the head will be full nominal diameter with no threads (called "shoulder" or "grip.")
Most hardware stores and such will stick to this standard. You can get fully-threaded screws, but they generally have to be had from a fastener house - they can be had rather easily from Fastenal. Check their site (Home | Fastenal
) for a branch local to you - they're a handy source, and their only flaw is that they tend to keep banker's hours.
A CV-style pinion flange is probably late enough that it's an ISO screw, and light enough that it's probably an M8-1.25. Do you recall what wrench you used to remove it, and whether the head of the screw had hash marks (SAE) or a number (ISO?)