I decided to try this one out as it is mid priced and has a reasonable TIR spec. The claim is 0.0001" at the collet face. I figured if I wasn't happy I would send it back and spring for a Bison or similar.
Prior to installing, I thoroughly cleaned the taper in the Bridgeport and tested it with the same setup. 0.0004" TIR. Not perfect, but I'll take it.
I tested a known good ground rod in an R8 collet. The collet came with the machine and any markings have worn off, so I can't be sure what it is. About 1" from the collet face I measure 0.0007".
The first test with the Shars chuck was terrible. I have to assume user error with some dirt or something getting in there. After cleaning everything again and reinstalling I measured the ER40 taper. This was surprising at 0.0004". With the same bar in a Techniks collet I have tested on my lathe, 0.0005" 1 inch from the collet.
I repeated the tests and got the same results a second time. Tests were done with a Compac 1 tenths DTI in a Noga arm.
After the tests I looked up inside the taper and I think there is a little cleaning still possible in there.
The chuck has a nice heavy feel and the machined areas are very smooth. Like the lathe ER40 chuck I got from them, the threads have some small chips in them. Nothing that doesn't clean up easily with compressed air. No burs or other signs typical of junk tooling. At this price point, I'd rather they cheap out on cleaning than machining, so I'm fine with it.
Prior to installing, I thoroughly cleaned the taper in the Bridgeport and tested it with the same setup. 0.0004" TIR. Not perfect, but I'll take it.
I tested a known good ground rod in an R8 collet. The collet came with the machine and any markings have worn off, so I can't be sure what it is. About 1" from the collet face I measure 0.0007".
The first test with the Shars chuck was terrible. I have to assume user error with some dirt or something getting in there. After cleaning everything again and reinstalling I measured the ER40 taper. This was surprising at 0.0004". With the same bar in a Techniks collet I have tested on my lathe, 0.0005" 1 inch from the collet.
I repeated the tests and got the same results a second time. Tests were done with a Compac 1 tenths DTI in a Noga arm.
After the tests I looked up inside the taper and I think there is a little cleaning still possible in there.
The chuck has a nice heavy feel and the machined areas are very smooth. Like the lathe ER40 chuck I got from them, the threads have some small chips in them. Nothing that doesn't clean up easily with compressed air. No burs or other signs typical of junk tooling. At this price point, I'd rather they cheap out on cleaning than machining, so I'm fine with it.