Press and freeze fitting Vesconite
Vesconite can be fitted in a number of ways. Different methods are used depending on the size of the bearing as well as the equipment that is available.

Bearings with a diameter < 200 mm (8") – Small bearings
Press fitting
Freeze fitting

Bearings with a diameter > 200 mm (8") – Large XL bearings
Press fitting
Freeze fitting with dry ice
Freeze fitting with liquid nitrogen

Bearings with a diameter < 200 mm (8")

Press fitting small to medium bearings
A Vesconite bearing can be easily pressed into a housing with a hydraulic or mechanical press. Take care to make sure that the bearing is well supported. The forces to fit a Vesconite bearing can be rather high especially where large bearings with big interference fits need to be pressed into place. Take much care when fitting long bearings (L:D > 1) due to the possibility of buckling. Press fit together with freeze fitting especially with larger diameter bearings. Ensure that there is a sufficient lead in chamfer on the bearing and on the housing.

The force required to fit a Vesconite bearing into a standard housing can be approximated by the equation :

Metric calculation - all measurements are in millimeters.

Imperial calculation - all measurements are in inches.

Use a press that can give double the required force to ensure that the bearing does not jam mid way through the installation.

Freeze fitting small to medium bearings
Freeze fitting is an easy way to install Vesconite bearings. Dry ice is ideal, but liquid nitrogen can be used if dry ice is not available. Extreme care needs to be taken when cooling Vesconite with liquid nitrogen.
If a Vesconite bearing is sufficiently cooled with dry ice or liquid nitrogen, the outside diameter will decrease to below the housing diameter and therefore the bearing can be easily slid into place.Vesconite has a thermal expansion coefficient of 6 x 10 ^-5 mm/mm/°C (3.3 x 10^-5in/in/°F).

Dry ice (CO2)
Place the bearing into a container and surround the bearing with dry ice. Within a few minutes (depending on the wall thickness) the outside diameter of the bearing will decrease and allow the bearing to be slid into place.

Liquid nitrogen
Place the bearing into a insulated container and pour the liquid nitrogen into the container.  It is important that the liquid nitrogen does not come into contact with the Vesconite bearing as this could cause the bearing to crack.   Within a few minutes (depending on the wall thickness) the outside diameter of the bearing will decrease and allow the bearing to be slid into place.

Bearings with a diameter > 200 mm (8") – Large XL bearings
With large bearings especially when there are large interference fits and the bearing is long, extra care needs to be taken when fitting. It is often useful to use a combination of press and freeze fitting to make it easier.

Press fitting large bearings
A Vesconite bearing can be pressed into a housing with a hydraulic or mechanical press. Take care to make sure that the bearing is well supported. The forces to fit a Vesconite bearing can be rather high especially where large bearings with big interference fits need to be pressed into place. Take much care when fitting long bearings (L:D > 1) due to the possibility of buckling. Press fit together with freeze fitting especially with large diameter bearings.

The force required to fit a Vesconite bearing into a standard housing can be approximated by the equation :

Metric calculation - all measurements are in millimeters.

Imperial calculation - all measurements are in inches.

Use a press that can give double the required force to ensure that the bearing does not jam mid way through the installation.

Freeze fitting large bearings
Freeze fitting is an easy way to install Vesconite bearings especially when bearings are large with big interference fits. Dry ice is ideal, but liquid nitrogen can be used if dry ice is not available. Extreme care needs to be taken when cooling Vesconite with liquid nitrogen.
If a Vesconite bearing is sufficiently cooled with dry ice or liquid nitrogen, the outside diameter will decrease to below the housing diameter and therefore the bearing can be easily slid into place.Vesconite has a thermal expansion coefficient of 6 x 10 ^-5 mm/mm/°C (3.3 x 10^-5in/in/°F).

Cooling with dry ice (CO2)
Cooling in dry ice for three to four hours reduces Bearing temperatures by 30 to 40°C (50 to 70 °F).
Pack the dry ice on the inside and the outside of the bearing. Use a container slightly larger than the outside diameter of the Bearing and a sleeve slightly smaller than the inside diameter of the bearing to contain the dry ice.

Good ventilation must be used in confined spaces to avoid possible lack of air and appropriate personal safety equipment is to be used.

Cooling with liquid nitrogen Use a container or metal drum insulated by layers of bubble wrap or cardboard as indicated in the sketch. Place the bearing on wooden blocks or bricks to raise it 150 mm (6") above the bottom of the container. Do not place the bearing directly onto the floor of the container. Place a loose fitting lid on top of the container. Slowly pour liquid nitrogen into the bottom of the container about 50 mm (2") deep.

  It is important that the liquid nitrogen does not come into contact with the Vesconite bearing as this could cause the bearing to crack.
Allow the bearing to cool for approximately 1 to 1½ hours which should be enough to shrink it sufficiently for a sliding fit. Measure the top outside diameter with a vernier to ensure that sufficient shrinkage has occurred before removing the bearing from the container.

Use nitrogen only in well ventilated areas. Take care in handling and adhere to the general safety rules for liquid nitrogen. Ensure that all personal safety equipment is used.

Updated Jan 25 2002