The Ambassador C14 and Alpha HW615 band saws come with two types of bearings: the 689RS bearing and the 608RS bearing.

The bearing information for the inner and outer diameters of the guide and thrust bearings are:

Lower Thrust Bearing 689RS: ID:9mm OD:17mm W:5mm 
Upper Thrust Bearing 608RS: ID:8mm OD: 22mm W:7mm

Guide Bearing 608RS: ID:8mm OD:22mm W:7mm

Note: 

Both the upper and lower thrust bearings are seated into a bracket with a circlip. If you have a groove wear into the thrust bearing bracket from the backside of the blade wearing in over time, this is normal to some extent, but if you would like to replace the thrust bearing bracket only or order the thrust bearings complete with the bracket and circlip installed, please submit a parts request here: Harvey Support - Submit a Parts Request

Changing the Blade Guide Bearings

To change the guide bearings on Harvey band saws, the guide bearings shafts must first be removed from the upper and lower guide brackets before separating the bearings from the bearing shafts. Please refer to the diagrams below for guidance on extracting the bearing shafts from the upper and lower guide brackets.

Tools Required: 

• Adjustable Wrench (or similar tool to grip the bearing shaft knurled knobs)
• Metric Hex Wrench Set (for Cap Screws 534 and set screws on the undersides of both the upper and lower guide brackets)
• Vise to hold the bearing shafts still while removing the knurled knobs.

Pictured above is one-half of the upper and lower bearing assemblies for a sizing reference. The longer one belongs to the upper guide, and the shorter one belongs to the lower guide. 

Put the bearing shaft assembly in your vise. Then with a pair of pliers, twist off the knurled knob. Once you have the cap loosened sufficiently, you can remove the knurled knob and take the bearings off of the shaft. 

Here is the bearing assembly fully disassembled. There are two bearings and two spacers/washers per assembly. If installing new bearings, place the new bearings on the bearing shafts in the same order as shown above and perform the disassembly in reverse to complete the bearing changeout.

If opting to clean and re-pack the bearings with fresh grease:

1. Remove the bearing side seals. 
2. Clean out the bearing raceways with Acetone, Odorless Mineral Spirits, or a similar metal-safe degreaser to remove the old grease and debris.
3. Pack general-purpose bearing grease i.e. Super Lube, Lucas Red & Tacky, or a similar product into the bearing raceways and check for smooth rotation of the bearings. If it spins smoothly, install the bearing side seals and clean off any excess grease before installing back onto the bearing shafts. 
4. If it does not spin smoothly after cleaning and applying grease, it may have reached the end of its useful life and should be changed out with a functional bearing.
5. Optional: After the bearing shafts are installed, apply a dry lubricant like Dynaglide Tool and Surface Conditioner or WD-40 Specialist Dry Lube to the outside of the bearings periodically to help the outsides of the bearings to repel dust and debris and promote smooth operation.