A. Gear Mesh

40:1 Gear Ratio, 48 pitch - adjustable motor mount. Slow movement; i.e., freight train

The mesh of the stainless steel worm and the nylon worm gear is extremely critical. First, there cannot be any side play in the driven axle carrying the worm gear. The worm gear profile is slightly concave to follow the contour of the worm. Any side play would cause the worm to chew up the worm gear.

Mesh has been determined by first engaging the gears as tightly as possible, then backing the mesh off ever so slightly until any bind and the generation of heat is gone. The heat is determined during a short duration run, a minute or so, if the stainless steel worm becomes hot to the touch.

30:1 Gear Ratio, 32 pitch - fixed motor mount

The mesh is determined dimensionally and fine adjusted by the insertion of spacers (thin washers), when necessary, under the motor mount bracket and the bottom of the frame.

B. Logos

Two dry transfer logos are included for your use, one white and one gold, if you choose to use them. I identify my demo locos by affixing the logo to the rear of the tender.

C. Spares and Replacement Parts

Currently, the unit is warranted to some, as yet undetermined limited capacity. The only situation which I feel we should not cover is one which may involve inappropriate abuse.

The wear items on the unit are the pickup plungers and perhaps, the springs. The nylon worm gear has an unpredictable wear factor. The nylon gear will fail if the mesh is incorrect or there is sideplay on the driven axle. Until we are more familiar, we will be covering these gears as a warranty item.

A list of items which may be necessary for an owner to order will be created; i.e., like the plungers and springs.

At some point we may offer raw components, such as the frame's custom extrusion, for scratch builders. This will become part of the spares list. As more models are created there will be more items made available.
PILOT MODIFICATION APPENDIX G

FIRST:
Set the screw aside from the top of the post for use later. Put the large spring and the washers into your parts bin ("you never know").

From the drawing, notice the cut line on the pilot post. Set the lead wires out of the way, measure up 1/4" on the post and make a cut through the post.

The inside of the post may be too large to take the screw you just removed. Insert a tight-fitting piece of tube or scrap plastic. Cement it in place. Drill a 3/32" hole for the screw. When everything is dry trial fit the screw. Remove the screw.

Thread the lead wires through the long section of shrink tube provided. This is to reduce abrasive damage to the wires. Route the wires up through the crescent slot in the pilot section of the bottom plate. Then through a hole (sometimes present) in front of the screw boss in the chassis enlarged to 3/16". This hole can be replicated in the front portion of the bottom plate, in order to route the wires, rather than through the crescent opening. Then use the enclosed 1/8" wiretie wrapped around the tongue about 1" back from the post hole with the wires running under the wire tie on top of the tongue. Then route the wires up through the holes.

SECOND:
Most all of the pilots from Bachmann sit very tightly in the rails. This has a tendency, not in all cases, to cause derailments. It has been more succesful to narrow the track of the pilot wheels: pull the wheels from the black center insulator, trim the insulator just under 1/16" with a razor saw. Reinsert into the pilot, press the wheels together. Repeat for the second set of pilot wheels.

Follow the instructions in the electrical section for hookup.

LOCOMOTIVE WEIGHT APPENDIX H

The BBT DRIVE 460 requires the addition of a weight of about two to three pounds to provide adequate traction for the new power. I had intended to provide these weights as an extra- cost item, but the availability and price of lead and the cost of shipping have ruled this out. Therefore, please consider the following drawings to cast your own weights. The mold is made up of 1 x 2 boards on a plywood or particle board base. The actual dimensions of a 1 x 2 are 5/8" thick by 1 5/8" wide. Filled with lead this size will yield a weight of two to two and a quarter pounds (1 kilo). If you need to produce more than one weight from this mold the boards should be tapered slightly, wider at the opening. If just a one off, screw the boards down and un-screw them when the lead has cooled, pound out the 3/8" dowels for the posts. In multiple casts, use new posts for each application (although I have been able to reuse these post for a few weights). The wood should be fairly dry, and there will be a bit of smoke, but the end product is just fine (keep some water handy, sprinkle it on if a flame develops).

NOTE: Some owners are running weights up to FIVE pounds. No known complaints, yet. I have several units running with 3.25 and 3.75 pounds quite successfully.

BILL OF MATERIALS - BBT DRIVE 460 APPENDIX J

QTY DESCRIPTION

1 BASE CUSTOM ALUMINUM EXTRUSION - BLACK ANODIZED
2 ALUMINUM END PLATES - BLACK PAINTED
2 4-40 X 1/4" Stainless Panhead
2 4-40 X 5/16" Stainless Flathead

1 MOTOR MOUNT ASSY 48P
1 1" X 2.5" Channel
1 `L' Tab
1 6-32 X 1/4" Stainless Flathead
1 4-40 X 1/4" Stainless Panhead
1 4-40 X 3/4" Stainless Allenhead Set Screw
1 4-40 X 1/2" Stainless flathead
1 STAINLESS STEEL WORM 48P - SINGLE THREAD (40:1)
1 ACETAL & BRASS WORM GEAR 48P - 40 TOOTH
OR
1 MOTOR MOUNT BRACKET 32P
1 STAINLESS STEEL WORM 32P - SINGLE THREAD (30:1)
1 ACETAL & BRASS WORM GEAR 32P - 30 TOOTH

4 NMB BALL BEARINGS, SHIELDED, STAINLESS 5/16" x 3/16"

2 BRONZE BUSHINGS 1/4" x 3/16", FLANGED (40:1)
OR
2 BRONZE BUSHINGS 5/16" X 3/16", FLANGED (30:1)

2 CONTACT SETS
2 3/16" X 1" Plastic Tube
4 3/16" X 1/2" Teflon tube bushings
4 Springs
4 Plungers
4 Brass Tubes
20" 26 Ga. Wire White
20" 26 Ga. Wire Black
3 CENTERLESS GROUND STAINLESS STEEL AXLES - MACHINED
6 1/16 STAINLESS STEEL ROLL PINS X 3/8
6 4MM STAINLESS WASHERS
6 3MM STAINLESS WASHERS
6 4-40 X 1/4 STAINLESS HEX HEAD BOLT
4 4-40 X 3/8 STAINLESS HEX HEAD BOLT
2 4-40 X 5/8 STAINLESS HEX HEAD BOLT
2 4-40 X 3/8 STAINLESS PANHEAD SCREW
6 NYLON WHEEL BUSHING ADAPTERS
2 AMP CONNECTORS
1 PLASTIC LUBE HOLE PLUG
1 STAINLESS STEEL TONGUE 4" X 1/2"
1 BRASS TUBE SPACER 3/32" x 5/32" DIA.

BATTERY-POWERED BIG HAULER ADDENDUM

There are some variations necessary in the installation of the BBT Drive into a battery-powered Big Hauler.

1) The chassis sides are a bit thicker on the battery Big Hauler, so some of the insides of the chassis sides must be removed for a proper fit of the drive unit. The test of this is to observe if the outsides of the chassis touch the drive wheels after the drive is fitted into the chassis - the wheels must not touch. This extra material is removed with a large coarse file or the rotary file in a Dremel tool. The material to remove is in the area where the motor fits into the chassis.

2) Routing the wires back from the pilot truck to be joined with the other pickup wires can be aided if a 3/16" hole is drilled in the front of the battery box.

3) Create a platform for the weight you may have cast from the previous plan (Appendix H). I have found that two nails placed through holes in the battery box walls just above the sills will prevent the weight from resting on the motor. These nails/holes should be near the holes described in the weight. Trim the length of the nails so they do not interfer with the installation of the boiler/cab, but not so short that the nails will fall out of the holes if they are moved from side to side. A long wire tie or length of heavy copper ground wire (14 or 16 gauge) under the nails and up through the holes in the weight will hold the weight securely (after the wire is twisted together or the wire tie is pulled tightly and the tail trimmed).

Always, if you run into a problem, please write or call.