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

With all the negative reviews, I hesitated a bit to purchase this set. However, what I received was essentially perfect in every detail. All the collars fit the corresponding drill bits closely, the hex wrench fit the screw heads, and the collars tightened up easily. The size markings are a handy feature. These things were basically a pleasure to use. I compared this set to a high quality (Taiwan) steel set that I also purchased. That set was not marked but otherwise worked well. But while doing the comparison, I found an advantage that aluminum has over steel in this application. With the steel collars, the torque needed to tighten the collar was greater than with the aluminum collars. This matters with the smaller drill bits because when you crank the screw down while holding the bit, the drill bit tends to bend. I did not have any trouble with the aluminum marking wood because I always used these while drilling through a jig of some sort.

They’re anodized aluminum. I thought maybe they might be plated steel. Aluminum invariably leaves behind marks that must be sanded off. A professional carpenter would NEVER use aluminum, but as I am no such thing, I do not care. I am extremely pleased with price, quality, and performance. Also, they’re conveniently marked with sizes in large, easy to read laser script.

I've always had a certain dislike for the standard set-screw stop collars. More than half the time they sit crooked after tightening. These stop collars are much easier to set and sit true on the drill bits. A definite welcome improvement. They do have some room for improvement though: 1. The size markings are on the flat surface and if you install that side down (which you eventually do at some point) the markings will be scratched off. I had to write the sizes on the side with a Sharpie. 2. The provided 2.5mm Allen wrench is too flimsy and flex too much when trying to tighten the screws. I use a 2.5mm from my set of Eklind Allen wrenches. 3. The screws are a bit too tight when tightening on the drill bit and difficult to hold in place. This might be because the collars are made of aluminum, but something I can live with.

good durability

These stop collars are accurately sized, I checked all 8 sizes with a digital caliper. In the un-tensioned state (fully open) they are 2-3 thousandths bigger than nominal--eg, 1/2" measures 0.503" and so on. I don't know what was going on with customers who thought that the size was off. Tightening is straightforward, 1 to 1.5 turns of the screw is enough to secure the collar on the drill. Only the 1/8" collar requires more force, due to the shorter lever arm of the collar--the distance from the screw to the hinge at the opposite side of the collar is shorter. The included hex wrench is mediocre, nominal 2.5mm measures 2.45mm which gives a lot of play in the socket head cap screw for tightening. To make it worse, the hex is rounded at the end, likely caused by the shearing tool used to cut off the hex stock. Reocmmend to buy a quality set of hex wrenches like Bondhus, which are true size. The screw head socket is poorly machined which contributes to the poor wrench fit. For regular use it is best to replace the supplied stainless screws with Grade 8 capscrews. These are metric, 3mmx1 thread. This design is what is needed to keep the collars square to drill bit axis, other collars with setscrews that push on the drill helix are unstable and always tilt. Satisfied with the purchase.

Collets showed promise, but the set screw is made of low quality metal and strips easily.

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've had to replace a bit because the collar is stuck to it and won't unscrew. When I bought this, the title said it was the Powertech brand. Now it is a no-name brand in the title. Calling these professionals would require higher-quality materials. 1. These arrived loose in a bag. 2. The screw head, where the hex key goes, stripped before it was even tight on the drill bit.

It does works but wobble alttle.

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.

I hope he's go on sale, I want to buy another couple of sets for myself and for other people I know. They really hold on to the drill incredibly well compared to the old style of drill stop. I need some more of these so I can throw out my old ones now.

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.

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