Shrink fit tool holders not unlike other tool holders will wear over time. Using a proper tool holder shrink machine with an electric induction heating coil will greatly increase tool holder life by heating the tool holder to the proper temperature and in an even fashion. Our shrink fit tool holders are made from a high quality H-13 tool steel that is made for cyclic heating and cooling cycles without loosing hardness. It is not unusual for a shrink fit tool holder to last several hundred or several thousand cycles if handled properly.
What is a shrink fit tool holder?
Shrink fit holders are very similar to end mill holders. The main difference is that shrink fit tool holders do not use any screws to hold on to the shank of the tool. Shrink fit tool holders have a bore that is actually too small for the shank to fit, but when the shrink fit tool holder is heated to several hundred degrees the bore expands and allows the cutting tool shank to fit in the bore. Once the cutting tool is inserted after a few seconds the cutting tool shank heats up and the tool holder cools around the shank and the 2 components virtually become one piece. No other clamping system can match the grip, concentricity, and performance of a shrink fit interface. Also because shrink fit tool holders do not need any collets, collet nuts, or set screws nose diameters can be very slim allowing you to machine hard to reach areas.
What is H-13 tool steel?
H13 Tool Steel is a chromium-molybdenum hot working steel that is widely used in hot work and cold work tooling applications. The hot hardness of H13 resists thermal fatigue cracking which may result from heating and cooling cycles. Because of its excellent combination of high toughness and resistance to thermal fatigue cracking H13 is used for more hot work tooling applications than any other tool steel.
What are the advantages of shrink fit tool holders?
Great concentricity, .0001" TIR or less
Maintains balance better than any other tool holder type
Thin nose profile for reaching around fixtures or hard to reach areas
Very strong 360 degree grip around the tool shank. Up to 10,000 lbs of force
Increased tool life and surface finish quality
What are the disadvantages of shrink fit tool holders?
Requires a heat shrink machine to properly heat the tool holder (torch not recommended)
Burn risk for inexperienced or careless people
Tool holder cannot be used until it cools which may take 30-40 minutes (much less if cooled with compressed air).
Tool holder can only clamp one size. Shank must be one size or .0003" maximum undersized. Sleaves or reducer bushings cannot be used.
Do your shrink tool holders have an internal stop?
Yes and no. We have created a new stop system that allows the flexibility of both thru hole and stopped tool holders. The shrink fit tool holder does not come with any internal stop and allows the shank to be inserted as deep as you wish (see cad files for max depth). With the optional stop system it is installed by screwing into the rear of the tool holder and the set screw allow precise depth adjustment. Thru the tool coolant is not hindered whether you use the optional stop system or not. We understand that preferences and opinions vary on this topic so we are proud that this feature allows both.
How hot do you need to heat up the tool holder?
Several hundred degrees, but less than 800 degrees.
How long does it take to heat up the tool holder?
Most electric shrink machines that use 200v power or higher can heat a tool holder in 15-20 seconds. Very fast.
Does is matter if the shank has a flat on it?
No it does not. As long as the shank is round and the flat is not excessively deep or wide. Flat must be at least 0.4 X diameter inside front of nose. Entire flat must be inside the tool holder.