Milescraft 5342 6-Piece Drill Stop Collar Set - 3/16", 1/4", 5/16", 3/8", 7/16", 1/2" Inch Sizes for Precise Drilling Depth Control - Perfect for Woodworking, Metalworking & DIY Projects

These work good on wood bits but will not work with a hammer drill and masonry bits.I used this to assemble a multi section Toyota transfer case per Marlin Crawlers recommendation. This stuff worked really great, and I'm not sure how I've survived so long without it. It held the paper gaskets perfectly in place during assembly so I didn't misalign a single bolt hole. Especially useful for the rear transmission seal since I didn't drop the transmission to do the job. This is so cheap compared to the whole job, it is just a must have for any gasket work.I wish I had this when I did the water pump, but I will use it next time! So far my Transfer case has no leaks. I was concerned about excess build up inside the case that could clog oil orifices, but I think this stuff will either stick where it's put or disperse harmlessly in the oil. Really excellent product.A little off-sized - for example, the 3/16 stop doesn't fit onto a 3/16 drill bit - so you'll have to use the next larger size stop and really tighten, but you have to really tighten the drill stops anyway or they're a real work hazard. Also, no storage case so when you first open the original package, make certain have a zip-loc bag handy to store both the stop collars and the original package with the info on sizes. Aside from those minor probs, the drill stops will do fine for my limited use.These are handy, but I find you have to tighten them very tight if you want to avoid slipping.As you've noticed, these stop collars are a few bucks more than some of the other options, but after using them, I can see why. The collars fit precisely and lock up tightly, but the best part is the collars are beefier and taller than others so they are truer to the spinning drill bit and stay locked in place. Great product!!I have used the drill stops on smaller diameter drills and liked they worked as advertized.Nice set of drill stops. I can see they are definitely made a lot better then the really cheap sets.However I can also see where the set screws are the weak link.I haven't had a problem yet but I know they will be a problem in the future.But for the price, come on! You can always buy better set screws or a couple sets of drill stops.First off, over reliance in general of all products to use set screws as more than an anti slip mechanism is getting really old. Set screws are only to be used for situations where you are expecting little to no force pushing against the screw laterally.Obviously this is not the case for a drill bit stop. If you are pressing forcefully to get the drill into the material then substantial force is going to be pressed against the set screw.In short, do not rely on this stop to be reliable. It will move.Furthermore, the stop can not be tightened perfectly perpendicular to the bit. Because you need to tighten the set screw as much as possible against the outermost body of the drill bit, you torque the entire stop while tightening and it is impossible to keep it level.Stop using set screws to hold pieces based on friction when lots of force will be acting against the piece to be held.I wish these had been supplied with the Milescraft dowelling jig. However, since they did not, I had to get these. They are quite essential. They work well. I did notice that the set-screw is larger than one I had been loaned by a friend of mine, which was most likely from a knock-off brand, as it seems cheaply made (I cannot verify this tho). These collars do slide on the appropriate drill bits with little to no play in them, and once the set-screw is tightened, it doesn't move at all. I am pleased with this purchase, with one exception. It is a very minor detail, but it would have been even better, had each collar been stamped with the size it goes with. That way, when I'm looking for a specific collar size, it's not all guess-work and I could save myself some time. I might find a way to engrave some kind of marker myself... we'll see.I gave this a 3 star only because I'm not keen on how it secures to the drill bit. Do they work? Yes, however if you tighten down on the set screw, you could inadvertently break or damage a flute. If you don't get it tight enough, the stop will "walk" up the drill and your hole will be too deep. This happened to me a couple of times. They were delivered on time and look exactly as shown in the picture. It doesn't beat out the adjustable stop on a drill press, but where you can't use a drill press and need to use with a portable drill, they do the job, just beware of tightening them down appropriately.This works as expected and I've use them on many projects. Be warned though that it can slip on a drill bit if the set screw is resting in the bit's channel rather than on it's outermost surface. So when tightening these you have to rotate it to the proper place on the drill bit otherwise it can slip up and down (following the spiral of the bit's thread as it goes).Es un poco complicado fijarlos perfecto y paralelo a la superficie pues es común que queden inclinados debido a los bordes de las brocas. Solo los uso cuando de verdad son varios orificios que deba a hacer. Probablemente me haga falta más práctica para poder mejorar esto