Ball Bearing installation on Bachmann J&S trucks

[veetwelve]

This treatise pertains to installing ball bearings on the wheel trucks of the Bachmann Jackson & Sharpe passenger cars, but the methodology probably spills over into other applications.

Thanks to a tip from Old John, I was able to track down a cheap source of 1/4 inch OD stainless steel ball bearings that were only 1/8 inch thick, and they had the requisite 1/8 inch ID to fit the Bachmann axle shafts.  That contact is Bill Butler at HPD Inc. out of Florida, phone 386-719-7113.

The first step is to remove the side plates from the trucks, and this can be done without removing the trucks from the car.  Each side plate is held onto the truck with a single self-tapping screw, plainly visible once the car is turned over.  I used a foam cradle to hold the cars upside down, being careful not to damage the stovepipe located at one end of the roof.  Once each screw is removed, that side plate can be slid sideways and the wheel sets will just fall free.  Now is a great time to roll each wheel set on a flat counter-top, replacing any that show signs of wobble.

The next step is to build up a jig to hold the side plates firmly on a drill press table.  I started with a small piece of 5/8 inch plywood, just because I happened to have that lying around the shop.  I next cut small blocks from a strip of basswood, arranging them on the plywood so that they cradled the side plates firmly with no lateral motion.  Once the placement of the blocks was determined, they were glued down with Elmer's wood glue and left to dry overnight.

At this point it is wise to place each of the side plates in the jig to determine that they are all in fact identical.  Since I have cars from several sets, plus some purchased separately, I was skeptical that they were all identical, and sure enough, one of the cars had side plates that were just a hair larger on one dimension.  I saved these parts for last, so I could shave my jig just a bit to make them fit.

To align the jig in the drill press, chuck a 1/8 inch drill bit (or one of your axle sets) into the drill chuck and slide it down into one of the axle bearing journals.  With the drill press chuck locked down in this position, use parallel clamps (or "C" clamps) to secure the jig to the drill press table.  Now unlock the drill press chuck and make sure that the drill bit (or axle) slides smoothly up and down in the side plate's bearing journal.  If the shaft binds, then the placement of the jig needs to be adjusted slightly until the centerline of the chuck is perfectly aligned with the bearing journal.  The jig, in this position, will be used to machine one-half of the bearing journals (either "left" or "right" on the side plates) before it will have to be re-aligned to machine the other half of the bearing journals.

The next step is to enlarge the existing bearing journals, at least to the depth that they are currently.  Why?  Because the ball bearings are only 1/8 inch thick, and any part of the axle that protrudes through the ball bearing will continue to ride on the old bearing surface, negating the low-friction advantage of the ball bearing.  I used a 3/16 inch drill bit, with the point ground almost flat so as to leave a flat-bottomed hole.  For this step, it is critical to accurately adjust the depth stop on the drill press, lest you go all the way through the bearing journal and leave a gaping hole visible on the outside of the side plate.

Now it's time to counter-bore the side plates to accept the ball bearings.  I used a Dremel #654 router bit because it's 1/4 inch in diameter, leaves a flat-bottom hole, readily available at home improvement stores, and relatively inexpensive.  You could use a 1/4 inch drill bit, but be sure to grind the point flat first because the ball bearings will not seat well against a tapered hole.  The depth stop on the drill press should be adjusted so that the router bit cuts to a depth of slightly over 1/8 inch.  This allows the ball bearing to be fully recessed in the side plate, and maximizes the peripheral contact area; this is important because friction is the only thing that should be required to hold the ball bearing in place.

Once the first side plate is counter-bored, test-fit a ball bearing to ensure a proper fit and make adjustments to the drill press as necessary.  An axle set should spin freely in the bearing.  I used a 1/4 inch wooden dowel rod to seat the ball bearings in the side plates, and was delighted to find out that a friction fit was all that was necessary to hold the bearings in place.

Once all of the side plates have been machined on the "left" or "right" side, it's time to re-position the jig on the drill press table and repeat the process for the other bearing journal on each of the side plates.  If you are blessed with a multi-head CNC milling machine, you can just perform all of these steps on each side plate without ever removing it from the machine table, but few of us are so fortunate.

Once all of the side plates have had their ball bearings installed, reassembly is just the opposite of disassembly.  When I reinstalled my side plates, I used Kadee #209 gray fiber washers to take up some of the lateral slack between the wheel hubs and the side plates.  An added bonus is that the cars run a bit quieter on curves with the washers installed.

The reduction in friction with the addition of ball bearings was truly remarkable!  I was still using my "Christmas tree oval" as a test track, and I had so many Jackson & Sharpe passenger cars behind my Big Hauler that the pilot of the locomotive was just inches behind the last car in the consist... never could have done that with the stock bearings!

Happy rolling,
Jay

[Joe Zullo]

...and here are the pictures to go with the above...

[Loco Bill Canelos]

Jay and Joe,

Thanks for a great post!!!!

[petertoot]

 :Dthat is a great article ,looks like a job for the cold days in Melbourne,aus,thanks,will get to work,!!!,while I'm here are there any tips for the k27plugs so that they are not hard to pull apart,thanks,Peter..