Bandsaw wheel bearings

The Timken AP class is very similar to their TDO industrial design. The magnitude of the interference fit(s) is one (1) thing, but the life of tapered roller bearings is moreso determined by the amount of proper preload or sometimes endplay-whichever is approprate for the application.

Tapered roller bearings normally have a very long useful life when they are appropriately sized, fitted, and lubricated. The interference fit between the journal and the inner races is critical, as about 75% of the size difference is transferred to the pitch line of the rollers, effectively reducing the running clearance in the bearing assembly.

In other words, let's say the application calls for an end play of 0.003" to 0.005". Without knowing the interference amounts of the shaft and bore, you can set this end play distance and verify it at the "bench" if you have the proper equipment and training. But, if you set a bearing assembly in this manner and fit it to a shaft that has a 0.004" interference, the pitch line of the rollers will swell as much as 0.003"-effectively reducing and possibly eliminating your preset clearance. Now, add any interference from the fit of the outer race to the bore, and you have compounded the problem.

Timken does offer a tremendous amount of online services concerning the application of their bearings, as well as formulae to assist with bench setting the end play (or lack of if when a preload is desired) when the diameters of the shaft and the bore are known. And you can usually have an answer in a couple of days. You do need to give them certain information, such as the MEASURED shaft size and the MEASURED bore size, application, etc.. From that information they can determine the thickness of the spacer ring that is placed between the inner races to achieve the proper end play (or preload-probably end play in your application) when the unit is assembled and secured.

Check it out at http://www.Timken.com There you can find contact e-mail addressed and telephone numbers to assist you.

Best Regards,

Ing. Robert Forbus

Without knowing the particulars of your application the interferance fit you request can only be offered as a general guide and this can be found on page 27 of the Timken AP Bearing Catalog available from via the following link

http://www.timken.com/en-us/products/Pages/Catalogs.aspx

When you arrive at the link, the third item in the left column is All-Purpose (AP™) Bearing Catalog click on Downloadable (EXE) and follow the simple instructions to place this catalog on your hard drive.

Before replacing your bearing with a new one, you should really look to understand what is causing the mode of failure you're starting to see. Otherwise you may just find yourself in this same position in another 2 years time. Try using the following link to help diagnose the root cause.

http://www.timken.com/en-us/products/maintdiag/Documents/6347.pdf

Where to buy a new bearing??

New Zealand - try one of the following;

Saeco Bearings & Transmissions Ph: 9 634 7540

Precision Bearings Ph: 9 634 5333

Farrell Bearings Ph: 7 850 4123

Wilson Brothers Ph: 3 338 8533

Any of the above companies will be able to help you out with your Class E bearing requirement. Let me know if you need help to identify the correct part number.

You could try this contact from SKF they might be able to help you.

john.p.baker@skf.com