Professional Stop Collar Set - Drill Bit Depth Stop - 8 Piece Kit (1/2”, 7/16”, 3/8”, 5/16”, 1/4", 7/32”, 3/16”, 1/8”) Superior Aluminum Split Ring Design

Very high quality and easy to use. I like that the screw doesn't contact the drill bit. The collar is much more secure than a traditional set screw. One small quibble that I have is that the provided allen key is supposed to be 2.5MM. The one that came with mine is only 2.42MM so there is a lot of play and potential damage done to the screw head. Use a high quality 2.5MM allen screw instead. Much less play.

I had given this a bad review until I had a chance to try it on several drill bits. It is hard to tighten the screw down, but once you have it fastened, it's like a vise on the drill bit. Holds tight and secure without coming loose. I was too quick to judge. Glad I gave it another try. There is nothing wrong with the stops. They are just built solid, and a little hard to make snug around the bit until you get used to having to bear down on the screw a little. Glad I purchased these stops. Beats trying to use tape on the drill bit and trying not to go past the tape on multiple drillings.

I got this set because I wanted a stop collar that did not use a set screw which can damage the drill. They work well but require a lot of force to tighten, as the aluminum ring is very thick and stiff. I damaged the head of the tightening screw on one of them due to the amount of force required. You need to be sure that the hex key fits properly - too loose and you can strip the hex socket.

I like that this type of "collar clamp" drill stop has superior holding power compared to the "set screw" type drill stop I was using.

Fast shipping, good quality , holds position. Very happy for the price!

I liked the design of the collar gripping the drill bit all the way around instead of a set screw digging into the side of the drill bit. Plus I thought this collar design would stay square to the drill bit. I think they would have been great except that locking screw must be made of soft metal. The supplied Allen wrench stripped the socket in the screw head before the collar was even tight on the drill bit. Good design idea ruined by using junk screws. Product is unusable - returning.

This type of depth stop is very positive once it is set. I used for the same depth on several occasions. Then today, I had to change the depth on two different drill bits. In both cases, the head of the set screw stripped out. I took a screw from another stop and continued. The product is good the first time, but it is not very durable. I will have to find new screws for the ones that stripped. Maybe a steel screw will be more durable.

These stop collars work just fine for me. Other users have reported problems with the set screw heads stripping out. I found that the screws do take a bit of force for the collars to clamp securely, but I have no problem when I tighten carefully. I like that the design of these stop collars squeeze the bits rather than set screws pressing into them.

EXCELENTE PRESENTACION DEL PRODUCTO, BUEN MATERIAL PARA SU OBJETIVO .... PERO UN DEFICIENTE DISEÑO PARA FUNCIONAMIENTO.LAS BROCAS CON LAS MEDIDAS INDICADAS EN CADA ACCESORIO NO SE SUJETAN Y AL APRETAR EL TORNILLO DE SUJESION REALMENTE NO CIERRA LA CIRCUNFERENCIA.REALMENTE ESPERABA ALGO BUENO DE ESTE PRODUCTO.

Collars worked well on a project just completed. These collars are much improved over the old set-screw ones that insist on seating slanted to the drill bit - these firmly hug the bit at a level 90 degrees. A bonus that these are made of aluminum, so no more pitting on steel or titanium bit edges.Those, plus the vendor being very responsive made for a great buy.P.S. follow the suggestion to keep the side with the size marked on it up (toward the drill) - then you won't scrape off the size text and end up having to rewrite it in felt pen later ;-)

It does works but wobble alttle.

Es complicado la colocación de los discos. Además, las medidas no son las adecuadas

So far so good, no problems. Good design, compact height, pressure evenly distributed around the bit.It should come with a storage case. A plastic vial would be a nice addition. In the photo I'm using an empty super glue plastic vial, but it doesn't fit the largest collar, so I use a rubber band to secure it. Also, the Alan wrench should be the length of the all the collars stacked on top of each other, so that it would be easy to slide them all onto the Alan key, and then slide them back into the vial.Tips: #1. Avoid bending the drill bit by holding the collar using a pair of pliers. #2. Always put the sizes face up to avoid wearing them off.