We grind our end mill holders tighter than most manufacturers do. During final grinding we use a certified gage pin that is exactly on size to 40 millionths undersized. This method ensures that our end mill holders are a nice tight fit to your cutting tool shank for low runout and great dampening ability. Unfortunately, some cutting tools that are double ended and coated may be a tight fit or not fit at all. For example if a 1/2" double ended end mill is TiAlN coated the shank is .4999 and the coating is 2 microns per side, the shank will end up being .50015. More than likely the tool will not fit in our end mill holders. But if the shank is .4998 before coating the tool will fit. Compromising our end mill holders by making them larger for double ended coated end mills is not a good solution since this represents less than 10% of applications in our experience. Please make a note of this when selecting tool holders and cutting tools. If you are using double ended end mills that are coated you may want to look into our precision ER or SK collet chucks.
Do coated end mills fit in your end mill holders?
Yes they will fit without any problems. Single ended end mills that are coated will not have any coating on the shank so size of the shank is not increased. Double ended end mills are different. Please review the previous question on that topic.
Do end mill holders have more grip than collet chucks?
Yes. If you are concerned about an end mill slipping due to heavy roughing it is always advised to use an end mill holder. Once the set screw is locked on to the flat of the cutting tool shank there is no chance of the tool slipping or pulling out.
What are the disadvantages of using an end mill holder over a collet chuck?
End mill holders need a flat on the shank to properly hold the tool. End mill holders don't allow the tool to be held at any length unless you grind multiple flats on the shank. During a tool crash or breakage the cutting tool may "kick back" and damage the end mill holder and may be difficult or impossible to repair. If the same breakage happened in a collet chuck only the collet would need to be replaced not the entire tool holder.
What are the torque specs for the side set screws?