What's the difference in a hinge mortise bit and a straight cut bit??

[Duane Bledsoe]

I got a set of Skil router bits and it comes with one that is a hinge mortising bit but it looks just like the straight cutting bits that you would use for rabbets and dados except for the center portion of it is hollowed out more but that's about it. Same blades on it and all otherwise. Is there any significant difference enough to worry about when mortising a hinge in a door slab?? I would think not but I'm new to this.

[Chip Lindley]

Duane, hinge mortise bits also cut a flat bottom without burning. Their blades have a cutting edge with more chip clearance on the end, where straight pattern bits usually do not.

[Duane Bledsoe]

As far as I can visually see, the edges of both bits are identical, even for cutting the bottom of the area as well as on the sides. The slot in the morising bit must be for chip clearing but that's the only difference I can see at all. Both bits have one but it's not at all large on the rabbet/dado bit. Looks like the larger chip clearing slot should be on the rabbeting bit since it is for making rabbets and dados that could be anywhere from 1/16 inch deep to even 1/2 or 3/4 versus the hinge mortising bit would only ever see 1/8 deep cuts at the most (strictly using it for hinge mortises only that is, no need to go deeper for setting hinges).

But like I said, I'm new to this and I have a lot to learn still. Was just asking since I noticed this and it didn't make sense. Thanks for the reply.