You didn't say what type of spot weld drill you have in mind or what price range you are looking for but don't waste your money on these from Northern tool, Tractor Supply and several other discount tool suppliers.
These are total junk and although they may look like the higher quality cutters you will be lucky to get 3 or 4 holes drilled before the teeth dull and/or break off. These are are almost certainly the exact tool you have from HF so you already know what I am talking about. The same type of tool from Snap-On and other major pro suppliers works quite well however but are more expensive.
Northern does also carry the H&S Industries Cobalt spot weld cutter and these work quite good, at about $30 for each bit they are not cheap but they last a long time and do a really good job.