SteelexM1089 R-8 End Mill Holder Set, 5-Piece

worked well

Have used these for 4 months on a new to me 30 year old import 8 x30 knee mill. I never checked the run out with an indicator, but then again, I never did that in 25 years as a professional tool & die maker either. These are no worse for run out than any well used American made holders you would find in any tool & die shop.When I received these they didn't fit up inside the opening in my machine. Searched the web for the R-8 dimensions and tolerances, and my machine was about .001-.0015 too small. I took a wood dowel, cut a slot thru one end, and wrapped sandpaper around it. chucked the other end in an electric hand drill. Stuffed it up there and was able to open up the hole till these fit OK, and the other collets I bought fit OK. After that, these holders have worked well.I did not have any trouble with the key slots - they just fit perfect. Only thing that I have a slight annoyance with is 2 of them had the drawbar go in slightly tight. I ran a tap in them and no more issues.Good set for the money.

These are hardened and ground and as such must be properly tapped to accept a drawbar (7/16-20) to accept the drawbar before they are heat treated. Two of these were not tapped properly preventing the drawbar from threading completely in. It was very difficult to tap the two defective ones and although I was able to do it, I ruined my tap doing it. Not a quality product.

Pretty nice set for the price, I didn’t check runout but i used a fly cutter in the 3/4” and it worked great! Hope this helps :)

Getting setup for a home machine can be a major expense. However these holders are friendly to your budget but still perform adequately.

The tool holder are accurately made have minimal runout and allow a much easier setup. Easy to change tooling and return to zero, makes the job easier working with precision. They work as close as you.

I am not a pro machinist and I have not used all sizes, but the 1/2 I got has .8 thousandth run out, indicated from inside bore. My spindle has less then .1 of a thousandth. The set screw on the 1/2 holder can not be tightened with standard hex wrench. It falls between #5 and #6 hex. The head of the setscrew has terrible finish. You have to grind down a #6 hex wrench to tighten the set screw. For my home shop it works.

great quality