Williams/Weaver Samhongsa gearbox drive train ratios (plus discussion about swapping gearboxes and motors for quiet running)

The ones which "should"  be slow like switchers came with 21:1 boxes. The ones which should be fast came with the 42:1 box.   Go Figure.   BTW, I always put the input number first.  Did you actually count the turns ?  Put a mark on the flywheel and actually count them.  Also can you make some pix of your gearbox.   I have owned dozens of Williams, Weaver, Samhongsa locos and yet to own the 44:1 version. All I have owned were 42:1 or 21:1.   I just wonder what a 44:1 box looks like. I don't doubt it's existence too many have counted to 44.  Some of Williams locos were made by Ajin and I wonder if that is who made the 44:1 box.    I have the Williams N&W  J and just to make sure have counted the turns dozens of times. Before you start counting get one drive rod full forward or full back then put a mark on the flywheel on the top centerline.   One thing which can be done is to swap the gear box from a PRR B6 switcher I have owned three of them and they were all 21:1.  The only difference between the 21:1 and the 42:1 box is the worm and the worm wheel. The 21:1 box has a twin helix worm and the 42:1 is a single helix worm also the skew on the worm wheel is different between the two, but not so much that they would not run if accidentally swapped The rest of the gear train is identical.  So I took the 21:1 boxes from my B6 switchers and swapped them with the 42:1 boxes in The N&W  J and my Weaver  PRR M1.  Now the slow locos are slow and the fast locos are fast. You will need a better motor to pull this taller gearing. The Mabuchi 550 so often used by Williams has really hot windings . Under 1 ohm static resistance and will pull a BUNCH of amps if you keep it.  One more issue with the early Williams and Weaver Samhongsa locos is often the flywheel is drilled off center. The ones I owned went in one side of the flywheel in the center and came out the other side off center.  That happens when a drill press is not dead on and is the reason your more likely to get a hole truly on center if you drill it in a lathe where the bit stays put and the flywheel turns.  I am away from home but when I return I will load some pix and a work around for an off center flywheel.                                  j

Thanks John - I was in error - the Williams/SAM. gearbox is 42:1 not 44:1 and have corrected the original post.

Your response was very timely as I purchased an up-detailed Williams B6sb at the April Strasburg show.  The B6sb was in my project queue for DCC and possibly re-motoring.  The PRR B6sb should make for a nice gearbox swap with the N&W J - improving the performance of both models.  Below is a shot of the J with NWSL couplings and an ESCAP coreless motor I installed last week.  It runs extremely smooth but far too slow with the J's 42:1 original gearing.  In the next day or so I'll press a 3mm NWSL female coupling on the 21:1 gearbox and mount it for layout testing.  If it is still too slow I'll try some higher RPM Pittman's I have.

Ahh.... more fun here. Good luck and thanks for sharing. I keep dabbling with mine and someday it may be perfect. Until then, it's much better with a cobbled together modified belt drive.

Joe I thought that belt drive you came up with was ingenious and potentially a cure for the  42/44:1 boxes. It could even be a slight (1:1.25 ~ 1:1.5) over-drive and take advantage of the torque a large Pittman can produce.              j

Ed I'm still not home. That is one nice motor. You should only need about 7000rpm with the 21:1 box to go more than fast enough. My RPM/ Speed charts for the J are at home.  Are you going to run your coreless motor with DCC or TMCC ?  I am not sure what the max RMS voltage the DCC boards can produce  (12v?) but most TMCC driver boards can reach about 15V  I have driven the Maxon coreless in one of my 42:1 B6's rated for 12v  to 15v on the bench with no problems so far.  I seldom, if ever, drive it that fast on the layout.  I put Mabuchi 545 motors in both my J and the Weaver M1. I have Pittmans to go in them If I decide to keep them.  However they run just fine with the 545's and eight passenger cars.  BTW; your going to need some lead in that B6 with a 42:1 gearbox.       j

As John suggested I swapped the gearboxes between a Williams N&W J and Williams PRR B6sb.  It was a drop in swap with the only fitting required being to fabricate a new drive shaft using NWSL's U joint shaft coupling sets.  The ESCAP motor driving a Samhongsa 21:1 gearbox ran beautifully but the top speed was only about 45 SMPH - a little too slow for passenger train service on my railroad.  Next I replaced the ESCAP motor with a Pittman GM8224 (Picked up on the bay for $20).  With minor effort I removed the gearhead and pressed on a NWSL coupling.  The new setup provides smoot/quiet running at modest passenger train speed.   The Pittman motored J with the 21:1 B6sb gearbox hauled 8 Golden Gate Depot aluminum passenger cars up a curving 2.2% grade.  All tests were run under DCC control using a Soundtraxx TSU4400 decoder.  I'd encourage anyone who has a Williams B6sb and a noisy Williams or Weaver mid- sized brass steam locomotive to consider a gearbox swap and re-motoring for improved performance.

@Keystoned Ed posted:

As John suggested I swapped the gearboxes between a Williams N&W J and Williams PRR B6sb.  It was a drop in swap with the only fitting required being to fabricate a new drive shaft using NWSL's U joint shaft coupling sets.  The ESCAP motor driving a Samhongsa 21:1 gearbox ran beautifully but the top speed was only about 45 SMPH - a little too slow for passenger train service on my railroad.  Next I replaced the ESCAP motor with a Pittman GM8224 (Picked up on the bay for $20).  With minor effort I removed the gearhead and pressed on a NWSL coupling.  The new setup provides smoot/quiet running at modest passenger train speed.   The Pittman motored J with the 21:1 B6sb gearbox hauled 8 Golden Gate Depot aluminum passenger cars up a curving 2.2% grade.  All tests were run under DCC control using a Soundtraxx TSU4400 decoder.  I'd encourage anyone who has a Williams B6sb and a noisy Williams or Weaver mid- sized brass steam locomotive to consider a gearbox swap and re-motoring for improved performance.

Nice job with the gear box swap. Do you have a large Pittman ( 9000 series ) to try?…..the Williams brass large steam have cavernous shells, and the larger motors fit just fine…..the larger motors will provide substantially more torque than the smaller 8000’s …..now that you’re 20 odd something to 1, any of the 12-15V large 9000’s that top out in the 6K rpm range should have no problem getting to 70 or even 80 SMPH…….it’s nice to see another enthusiast interested in speed, …my good buddy Lou & I routinely discuss high speed service, …I do believe Lou still has me covered, as he’s broke the century mark with his highly modified ATSF speed demons, and my personal best with a modified Hudson was 94 SMPH with 9 heavies in tow,…..I’m still working on reaching that 100 mph mark…..

Pat

Hi Pat - you're right, there is plenty of room in firebox for a larger motor.    I have a Pittman 9233 lying around so I'll give it a trial run.  Mounting it will be a piece of cake as the hole spacing matches that of the Mabuchi.  The 9233 has far more torque than the 8000 series gearhead motor so slow speed starting under load should be smoother.  It will be interesting to see what top end speed I'll get with the 9233 driving the 21:1 box.   With 70" drivers I would like something in the 70s smph neighborhood.  I can live with less as during operating sessions we generally run through freights around 35-40 smph and passengers around 50-55 smph.   What I couldn't accept with the original Williams/Mabuchi/41:1 setup was the drive train noise drowning out the DCC sound.

@Keystoned Ed posted:

Hi Pat - you're right, there is plenty of room in firebox for a larger motor.    I have a Pittman 9233 lying around so I'll give it a trial run.  Mounting it will be a piece of cake as the hole spacing matches that of the Mabuchi.  The 9233 has far more torque than the 8000 series gearhead motor so slow speed starting under load should be smoother.  It will be interesting to see what top end speed I'll get with the 9233 driving the 21:1 box.   With 70" drivers I would like something in the 70s smph neighborhood.  I can live with less as during operating sessions we generally run through freights around 35-40 smph and passengers around 50-55 smph.   What I couldn't accept with the original Williams/Mabuchi/41:1 setup was the drive train noise drowning out the DCC sound.

At 21:1 Ed, you might be winding her up, but you should see 70 mph,…..did you do a final gear ratio based on driver diameter?…if you get down around 19-20:1 final, she should scream well above 70, ….you’re gonna get close to the top of the motor range, but should have some rpm to spare,…..a ball bearing motor might give you the edge you’re looking for …..large ball bearing inserts on Pittmans make for a quieter motor in the higher rpm’s …

Pat

Hi Ed, Pat and John,

Congratulations on your skill at swapping gearboxes.  Unfortunately, some of us, me in particular, have no clue as how to do it.

Please post pictures showing the steps in a gearbox swap.

Thanks,

Ed

Best.  
Motor.
Conversation.  
Ever.

thanks!

- Mario

Ps- videos please.

@Ed Kelly posted:

Hi Ed, Pat and John,

Congratulations on your skill at swapping gearboxes.  Unfortunately, some of us, me in particular, have no clue as how to do it.

Please post pictures showing the steps in a gearbox swap.

Thanks,

Ed

Ed, the Williams are funny creatures, ….some of the engines use the same axle gear, so doing a gear box swap is fairly easy to do…..the gear box is divorced from the chassis. Remove the 4 base pan screws, and sometimes a mounting bracket, and the whole gear box will come out,…the ratio aspect is changed in the tower, not on the axle gear,…..but you need to know what’s what and what’s the same as…

Pat

Ed not sure if the diameter of your two rail drive wheels is exactly the same as on my three rail version 1.525" (73.2") but the rpm constant at 1mph is 96.4308 rpm with the 21:1 gear box.  Just multiply by the top speed your after and you will get the motor rpm needed to get you there.  Even if your scale drivers are a bit smaller, like 70 scale inches, it will still be very close.   Something I find very helpful, I bought an IR digital tach pistol on ebay. Their under $20. Mount a small  cardboard disk painted black with a quarter or so in white .  If the motor is mounted in a frame it's easy to add a piece of white tape on the drive shaft or flywheel.        j

Keystoned,  to differentiate from Ed Kelly.  You may want to think about a flywheel on that big Pittman, where coreless motors with no iron in the armature freewheel quite well the Pittman will screech to a stop if you loose power suddenly as going through a switch or whatever the cause and a long train may pile up behind the loco.  Another point, that ESCAP motor is available with a winding which will give 9000rpm at 12v that will provide plenty of top end for your J.  Around 90smph.  That'll almost keep up with the real J.  They have a 36mm version, same diameter as a Mabuchi 500 series and the Pittman 9000 series,  which also has the 9K winding that would make your J a beast.          j

This morning I installed a Pittman 9233 motor in the Williams N&W J chassis with the swapped Williams PRR B6sb 21:1 gearbox.  It ran quiet at all speed ranges and gave me a top end speed suitable for passenger service (faster than the slower 8000 series Pittman I tested last week.  I found the Pittman 9233's 6730 RPM and 31.6 oz/in starting torque to be a nice pairing with the 21:1 gearbox.  I need to complete the DCC installation by mounting a speaker in the boiler, syncing the chuff, and configuring the sounds (whistle, bell, pumps, ...).  I'll do a similar drive train mod in the Williams B6sb which now has a slower 41:1 gearbox for working the yard.

JohnActon - I haven't found the need to install flywheels when repowering my 2 rail steam locomotives.  Some of the factory drives do have flywheels but the ones I've repowered run just a smoothly (better in most cases as I generally use better motors than the importers).  Over many years of running the railroad I've never had cars derail due to a locomotive losing power.  Body mounted couplers, broader curves, and properly weighted cars make a difference.

Ed Kelly:  The Williams gearbox swap requires removing 6 screws.  4 on the gearbox cover, 2 on the torque arm just above the frame. Lift the J gearbox off and screw the B6 gearbox on.   The Mabuchi -Pittman motor swap was also easy as the screw locations match.  The metric screws were replaced with 2 English 6:32 screws.  The bracket's motor screw holes were enlarged for the slightly larger screws. The only real work in the conversion was connecting the gearbox to the motor.  I used a Northwest Short Line 495-6 coupling set to mate the gearbox's 3mm shaft to the Pittman's 5/32" shaft.  The coupling set's horned balls were pressed on a piece of 1/8" shafting (NWSL #2125-4) cut to fit between the gearbox and motor shaft sockets.  The NWSL catalog has a table showing which of their coupling sets to use when pairing various shaft sizes.  Very brief instructions are on the card that comes with the coupling set (see picture below). The coupling costs $5.95 plus $5.95 for 1/8" shafting. The only skill required to do the installation is knowing how to pull off the existing couplings and press on the new ones without doing damage to the gearbox and motor.  There are quite a few different ways to do the pulling and pressing depending on the tools you have on hand.  I used a gear puller and a drill press.

Below is a picture of the final chassis setup with the Pittman 9233 and the NWSL.

Put all the leftovers in the B6, ….voila!….problems solved,….😁…I’m curious if you calculated the final drive ratio after the swap into the J??…..I wonder if it got to 18-19 to 1 …..if that’s the case, you shouldn’t have any problems making 80 mph,…which is hauling two s’s with an a,….Nice work BTW, …looks like clean work!..

Pat

... a very tidy workbench, too!  😁

Mark in Oregon

Ed,

Thank you for the very clear instructions!  I might do this for my Williams SP GS-4.

Rob

@swrr posted:

Ed,

Thank you for the very clear instructions!  I might do this for my Williams SP GS-4.

Rob

Sounds like a job for the CPR motor Rob!…I’m still waiting to see your reaction when you spin those motors…..😁

Pat

Ed,

Thanks for explaining the process.  I do appreciate it.

Ed Kelly

With the model's 70" drivers, a 6730 RPM (12v no load) motor, and confirmed 21:1 gearbox I calculate a projected top speed of 66.6 scale MPH.  My NCE DCC boosters are putting 15.7 v AC on the rails.  I ran the chassis on blocks at max speed (DCC speed step 128) and measured the decoder's output to the motor at 14.5 DC.  Theoretically the model's top speed would be 80.5 smph.  In reality it would be a little less as the motor is under load.  IMO the gearing/motor match couldn't be better for the way I like to run the railroad. 

Thanks for the comment on the shop Mark.  Along with no steps walk out access and a rest room, one of the top priorities in designing my retirement house basement was space for the workshop.