5C Collet Block Set with Case

The plastic case is basically a throw away and was broken on arrival, but the blocks seem fine. I spent about an hour measuring them in different ways. Squareness, flatness, and consistency of the blocks is good. I think there was one pair of flats on the hex block that went a tad past the claimed 0.0005" tolerance, but everything was mostly under.Measuring the centricity and parallelism of the 5C taper is much more complicated, but it is reliably under a thou. I played around with a 5c to ER32 arbor, turning it and locking it in different orientations in the square block with the hopes of ruling out any runout from the arbor itself. Most measurements to the outside of the chuck/arbor were under five tenths. The hex block did have an 8 tenths runout across one pair of sides.The largest runout I got when mounting a 3/8 rod into the 5C>ER32 adapter was a couple thou (both with the square and hex blocks), but this includes all of the error in the ER32 collet and added distance from the block. In one test, rechucking the rod within the ER32 collet brought the runout from 2.3 down to 1 thou. This is why I did most of my testing on the outside body of the 5C tool.The quick lock dealy works fine, but it isn't a total time saver as I still had to tap the 5C tool out to release it from the taper.My only complaint is that I wish I could get these in a larger size. The blocks are barely bigger than the 5C taper, so if the thing you are mounting into it (such as the 5C>ER32 arbor I was using) is any bigger, you'll have to use a riser of some sort.Overall, I would buy these again.

Nice set, Looks good, but haven’t used it yet.

These Collet Blocks are Great! Extremely rugged and sturdy, they have performed flawlessly every time I have used them. 5C ER32? No Problem! 5C ER40? Got It! These have become a great asset to me and how I am able to get work done on my mill, and I didn't have to go broke in the process.

The set included both square and hex holders.

My set arrived properly packed and undamaged. All pieces were oiled and inside plastic bags. The very first thing I did was to verify the fit to my collets, it was OK. Next I checked the blocks for accuracy on a granite plate with a .0001" dial indicator. The flats were accurate to .0010" on the square block and to .0005" on the hex block. The faces of both blocks were significantly out of square, but I cannot provide any number.To check the centering of the collet socket I have used my very decent, new 1/2" 5C collet and the 1/2" gauge pin. I installed the collet and clamped the gauge pin in it. Next I checked the indicator reading on top of the pin near the collet and 1" away from it. The maximum variation between all flats was .0008" on the square block and .0014" on the hex block. The 90 and 120 degree angles between flats were generally OK on both blocks.These are very decent numbers for milling or drilling operation, but not for surface grinding. Well, if you have a surface grinder, you can fix these blocks and do a better job than Chinese did.

I received this collet holder set in excellent condition. I went right to work taking the oil off of all the surfaces. Than I used a stone to remove any burres off the edges. These collet holders are precision ground and finished. I used my indicater and surface gage to check the squareness and being parallel and for concentricity. They were with in .0005 per side. Than I installed a 1/2” C5 collet with a 1/2” gage pin and checked for total run out. It was .001 TIR. The set came in a nice plastic case. I am very happy with this purchase. I payed a little more for the set with a case, it was worth it. Thank you, Theodore Combs

The blocks are fine. Flat and square. Collet is on center. But no spanner wrench to actually tighten it and, you know, actually use it... I'm just gonna make my own, but kinda silly. But it is also $50.

Good value. My set was parallel within .0005" on all faces. No burrs. Collets fit fine