600 EW Headstock Bearings
by Doug Kephart
On the 600cc EW Douglas and its descendents, with the double taper roller bearing headstock, direct bearing replacements may prove impossible to obtain. Unless you are fortunate to find some old stock on a shelf, these bearings are long out of production. Time came to replace those on my F-28 model Douglas and I had to find an alternative.
What I used was a Timkin #44649 (cone) and #L44610 (cup) taper roller bearing. These had the proper inner diameter but were a lighter duty bearing with a smaller outer diameter and not quite as high. Since they have quite a few more rollers packed in than the original bearings, the roller contact area equaled or exceeded the originals. So the load capacity was equivalent to the original, and would hold up well.
Adapters to the dimensions above are required to increase the outer diameter and the height. The original upper and lower headstock bearing cones races were different, though the cup races were the same. Resulting in different ASSEMBLED heights. As the same new bearing is used top and bottom, the difference is allowed for in the adapters.
© 2002 D. Kephart