These pretty much operate as advertised. The price is good for what they are. I used them on hard maple, which is not really a picnic, but it was my very first time. If you're a first timer, consider getting the magnifying eyewear w/ lights: then you will be sure to do it right and not mess up. Also, if you have tight corners, like the tips of the abalone stars StewMac sells, get the finest / skinniest sized bit! I botched the job my first time (on a strat headstock shown in photo), but fixed it after the fact by routing a more precise channel around the star inlays (w/ skinnier bit), then supergluing in glitter from my daughters art kit, then sanding! I know -- kind of a Bootsy meets glam rock final product. Anyway, the bits did fine in maple.
Am using these to route a dove into a cross. Use a Dremel tool (nonadjustable)to do the engraving. Have had problems with some woods, particularly hard maple. Am using donated wood so species are generally not by choice. After a couple of crosses the bits start to burn. This is ok in that it makes the dove stand out better. However it eventually takes its toll on the bits. Feed speed doesn't seem to matter. Still the best deal and bit I found so far. Have thought about trying a variable speed router????
Despite the low cost and other reviews stating these bits are fragile , I have had absolutely no problems routing out inlay channels other than the feathering on spruce which I expected as these bits aren't spiral downcut, but careful marking out with a sharp craft knife prior to routing quickly overcame this problem and lets you know when you are up to the line as the feathers fly off, all together great value for money and cheaper than buying equivalent bits here in England.
I saw the price was less than the carbide down cut bits I usually buy, thought I'd give them a try. The smallest one, for fine inlay cutting, worked well, didn't last as long as a carbide, but a good tool.
These are great for the detailed inlay work that is part and parcel of high-end guitar making. But expect to spend a good deal of time replacing bits, as these are by no means the most durable option on the market. And buy a few more than you think you need for the same reason. Low cost is good; short lifespan can be frustrating.
Good small size makes them very useful for inlays, but unlike the other reviewer I'm glad they come in a 6 pack, as they tend to break on me quite often.
These are extremely hard to break, stay sharp for a long period of time, and get the job done right. The 1/32" diameter made it really easy to rout a slot for a 5-way switch.