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Technical Terms confusing? A simple English guide
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Bearing retention Keeping your Vesconite bearing in place.
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Bearing groove design Appropriate groove design suggestions
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Production sizes Vesconite and Vesconite Hilube stock range
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Press and freeze fitting Vesconite bearings
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Machining guidelines How to machine Vesconite quickly and correctly
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Materials, tolerances and surface finishes for housings and shafts
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Material safety data sheets(MSDS) for Vesconite and Vesconite Hilube
| Coefficient of Friction | Resistance between two surfaces to the force that causes sliding |
| Coefficient
of Linear Thermal Expansion |
Amount a material expands or contracts as a result of a change in temperature |
| Compressive Strength | Maximum compressive load on a material before material change |
| Creep | Amount that a material squeezes thinner as a result of being under a load for a long period of time |
| Deflection Temperature | Temperature at which material bends a given amount when under a specified load |
| Dielectric Strength | Number of volts per millimetre thickness of material required to cause some electricity to flow through the material |
| Dielectric Constant | Ability of material to store an electrical charge |
| Dimensional Stability | Change of height, length and shape in a material due to changes in temperature, water absorption and pressure |
| Dynamic
Mechanical Analysis (DMA) |
Mechanical properties of a material as a function of temperature |
| Elongation | Amount of stretch before material damage |
| Fatigue Strength | Resistance to a cyclical load |
| Flexural Strength | Maximum strength of a material when bent |
| Hardness | Ability of a material to resist indentation. Usually measured with a small standard size point or ball |
| Heat Conductivity | Ability of a material to transmit heat |
| Infrared Spectroscopy | Unique "fingerprint" of a chemical |
| Izod Impact | Resistance of a material to being broken by a swinging pendulum. Usually a notch is machined into the sample so that a clean break can take place at the notch |
| Melt Point | Temperature at which crystalline phase melts from solid to liquid |
| Modulus of Elasticity | Ratio of the force applied to the deformation that results |
| Shear Strength | Strength of a material when punched or cut (See Compressive Strength) |
| Specific Gravity | The ratio of the mass of a volume of the material to the same volume of water |
| Surface Resistivity | Ability of material to prevent the flow of electricity across its surface |
| Tensile Strength | Maximum pulling force (tensile force) on a material when pulled apart. It is a ratio of the pulling force divided by the cross section of the material |
| Tensile Impact | Energy required to break a material by pulling it apart in a quick stretch |
| Tg | The glass transition point is the temperature at which a material changes from solid to rubbery/viscous |
Drilling of Vesconite and Vesconite Hilube solid rod
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Drill a pilot hole of ±15mm (0.6") initially
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Cooling is very important. Use cutting fluid or water. This is one of the biggest reasons for failures.
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It is very important to remove the shavings when drilling. It is best to regularly withdraw the drill and remove shavings, and then only continue with drilling.
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Once the 15mm (0.6") hole is achieved, machine to the required inside diameter using a boring bar on a lathe. Do NOT use a larger drill, this could lead to cracking.
Example: A 50mm (2") diameter hole is required · Drill a 15mm (0.6") pilot hole.
· Now use a boring bar on a lathe to reach the required size.
Low Temperatures: Guidelines for sizing Vesconite bushes
The following guidelines are incorporated in the Design-a-Bearing online calculator for industrial bearings.
- Preferably use bushes with a wall thickness of
about 10% of shaft diameter.
- Use the following equations in determining the press fit:
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Metric |
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|
Minimum temperature |
Press fit mm |
| + 5 oC | 0,05 + 0,002 x (housing diameter) mm |
| - 20 oC | 0,05 + 0,0035 x (housing diameter) mm |
| - 40 oC | 0,05 + 0,0045 x (housing diameter) mm |
| - 60 oC | 0,05 + 0,0055 x (housing diameter) mm |
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Imperial / USA units |
|
|
Minimum temperature |
Press fit inches |
| +41 oF | 0.002" + 0.002 x(housing diameter)" |
| -4 oF | 0.002" + 0.0035 x(housing diameter)" |
| -40 oF | 0.002" + 0.0045 x(housing diameter)" |
| -76 oF | 0.002" + 0.0055 x(housing diameter)" |
- Provide a 30o lead-in chamfer
on bush outside diameter to facilitate fitting.
- The leading edge of the housing should be
chamfered so as to avoid shaving bush during press fitting.
- Use a press to fit bushes.
- Note that there will be a slight increase in the running clearance when operating at lower temperatures.
For a nominal size bush of OD 120 x ID 100 mm (OD 4.7" x ID 3.9"), the running clearance will increase as follows:
Metric Temperature Increase in clearance due to shrinkage on a nominal 120 x 100 mm bush -20 oC 0,11 mm -40 oC 0,16 mm -60 oC 0,21 mm
| Imperial / USA units | |
| Temperature | Increase in clearance due to shrinkage on a nominal 4.7" x 3.9" bush |
| -4 oF | 0.004" |
| -40 oF | 0.006" |
| -76 oF | 0.008" |
Impact Strength at Sub
Zero Temperatures
Data on impact strength show that impact strength declines slightly between 20oC
(68 oF) and 0oC
(32 oF),
but thereafter is unaffected up to -60oC (-76
oF).
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Vesconite Impact Strength (J/m) at |
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|
20oC (68 oF) |
0oC (32 oF) |
-10oC (14 oF) |
-20oC (-4 oF) |
-30oC (-22 oF) |
|
35 |
29 |
30 |
29 |
30 |
Our direct experience of sub-zero conditions is limited. While we do not expect difficulties in standard applications, in making the above recommendations we suggest that they be incorporated in applications on a trial basis so that experience is gained before continuing on a larger scale.
Feedback on successes and problems in cold conditions would be greatly appreciated. e-mail us at vesconite@vesconite.com
Vesconite Static and Dynamic Friction
A characteristic of Vesconite is its low friction, both static and dynamic. Here is data for Vesconite against steel, lubricated and unlubricated.
Test conditions
1. Vesconite against steel surface.
2. Loading: 8 MPa
3. Surface velocity: 1 metre/minute.
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Lubrication condition |
Static friction |
Dynamic friction |
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Unlubricated |
0,17 |
0,15 |
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Greased |
0,07 |
0,06 |
Updated Nov 05 2003
