I have non shar tool holders as well, the blue fit is the same.
Setco is working with me on this, thanks for the comments.
@Zahnard Kopf I think you misunderstand. I used sandpaper to spot sand the burrs inside the taper. I don't understand where the burrs came from exactly, unless a piece of aluminum can really do that kind of damage.
As far as shars go, its not real easy when you are starting out to know where you are going. There is very little concrete proof of the difference between toolholders, mostly just comments like "they are junk". Finally, I decided to try them. Sometimes you have to buy cheap to learn the difference.
If it turns out that they really are a cause of problem, I'll replace them with maritool or something. However, some people say Maritool cat40 holders aren't any good either. Show me some blue proof, I say, or something.
I understand completely the issues of starting out and being on a budget. I am not that far away from there myself.
However...
Having been there, and traveled the very same path, I can tell you without hesitation that these things do make a difference. There is absolutely nothing wrong with questioning. And there is nothing wrong with being economical. Both are values that serve well the man or woman in your position.
There is however, a difference between inexpensive and cheap.
Some times cheap chinese goods are all one can afford as they wind the road toward growth and eventual success. ( however that is determined ) More often than not however, those cheap chinese goods cost one more than they think both monetarily and in other core values like time and effort. ( not to mention aggravation and stress )
I have used MariTool tool holders in the past, and continue to use them. And I do so because they are very well made and well priced to boot. I have bought them as an employee for a large, global company and now I buy them as an individual shop owner as well. I can tell you without hesitation that they have always been of good quality.
In fact, I am getting ready to pull the trigger on what is for me, a fairly large amount of money's worth of tooling from them. As the sole person responsible for how this business spends its money and how that relates to its success or failure, I would not do so with frivolity or chance.
I do so because they are worth it.
Want numbers? Go scan YouTube or Instagram for any number of videos showing their tool holders throwing .0001" or less movement on a millionths clock.
Can a Shars tool holder do that? Maybe. Maybe one gets lucky with one. But can they do that repeatedly and reliably? Not that I have ever seen. And I have looked... I know I can count on my MariTool holders. I don't have to question it. One of the reasons is because Frank and Tom care. Bluntly, they give a shit. You cannot say that about Shars.
But my point about this is not about how a business spends its money. It is about trusting one's spindle taper
( inarguably one of the most important things on a machining center ) and subsequent modifications to a cheap, $30 item. My original equivalency regarding it, stands.
Just my two pfennig.