Question for all you mechs -
I want to change the seatpost and stem bolts on my bike. I bought some generic M5 stainless steel bolts in a bunch of sizes, which are the right length when compared to the original screws. However, the stem & seatpost original posts have a barrel-shape, whereas the bolts I have have a typical flat low-profile head.
I do have a torque wrench (god that thing is cool - just got it, don’t know how I managed without it!) so I doubt I’ll strip them.
Any problems with these non-bike specific bolt heads?
the concern is whether or not the new bolt head will fit into the area the old ones did. Some stems/seatposts have a recessed area for the head of the bolt to sit flush, if the head is drastically different it may not sit flush. Otherwise, bolt is a bolt.
You might find that with a button head cap screw your Allen wrench / bit doesn’t go in as far. Therefore there’s less contact area. And you’re more likely to round out the internal hex.
Having said that if your Allen wrenches are in good condition you should be fine. Plus most bike applications are minimal torque anyway. Just keep an eye on the heads when you service your bike.
Personally I prefer a standard or tapered heads as they provide maximum wrench depth but button heads are fine !
I regularly work on machinery where the heads are lockwired or use special washer arrangements to retain them so I’m probably overthinking it 
LG
You don’t need a torque wrench.
Any problems with these non-bike specific bolt heads?
Replacing with generic screws is OK, or Not OK, on a case-by-case basis.
I would be happy to offer you some specific guidance, but got any photos?