Large Scale Central

REGEARING THE K-27

General Discussion
#1

I have not been around for awhile cause I had a lot of stuff I needed to get done and I’m starting to build some live steam shays. I’m tiring to get the gears made and I will proceed with that when I figure out how to make bevel gears. As some of you know this has been a project that I have worked on for sometime. After a lot of failures, I have a prototype done and installed that works, BUT is is a little noisy. With the sound on I can just barely hear the gear noise and for me is OK. My original idea was to put a gearbox between the motor and the stock B-man gearbox. When I first tried this, the gears I was using were of 32 pitch and I couldn’t get the gearbox small enough. The next smaller pitch gear that was commercially available that I could find that was affordable was 48 pitch. The 48 pitch I felt would not have enough teeth contact being as narrow as I needed. So the search went on till I was at a buddy’s house and he had a set of 40 pitch gear cutters. I never even thought about cutting my own gears. First thing you need for gears is a blank that is the OD of the gear that you are going be cutting. The blank goes into the chuck on a indexing head or rotary table with indexing plates (I didn’t have the plates for my table so I used the degree index). The pictures I took while I was cutting got deleted so I staged some for you to see how spur gears are made

When I get the gears cut on the blanks they look like this.

Then it to the lathe to cut to length

To get the correct length I have a DRO (Digital Read Out) on the saddle of my lathe.

My gears are cut to .190 wide plus the thickness of the cutoff tool This is what I have after I get all of them cut off.

I have another fixture to drill and ream the hole in the center

So now I have the gears done the gearbox was made (didn’t take any pictures of that) I made 18 and 24 teeth gears. A 18 tooth gear gets pressed on to the motor after I take press off the worm. I make a compound gear shaft with a 18 and 24 teeth gears and then press a 24 tooth gear on the output shaft.

Press the worm onto the output shaft and it is ready to install on the stock gearbox. This is the first K-27 I bought and you can see that I added about 5 lbs of lead to it. I have a lot of running time on this engine and the extra weight has not hurt it that I can see. It pulled 20 stock (no axle bearing) Accucraft cars up my 4% grade before I added this gearbox, so I know it will only get better with it.

The compound and output shafts are running in ball bearings. The gear noise is because I used brass for the gears. I have a few sticks of Derlin that I will remake the 24 tooth gears again. With the Derlin there should not be any gear noise at all. The final ratio is about 26 to 1 When I get the Derlin gears done I will give a update on how the noise is. Then I will make about 25 gearboxes and will sell some. Rodney

#2

Rodney,

What is the final drive ratio when your reduction is added to the Bachmann 14.5:1? Barry of Barry’s Big Trains currently has one in beta testing with TOC at I believe 29:1. I have been watching that thread with great interest, as I will now watch yours to see how each turns out.

Bob C.

#3

Bob
The final ratio is about 26 to 1. The motor has a 18 tooth gear that drives a 24 tooth on the compound
with another 18 tooth that drives a 24 tooth on the output shaft. I get lost doing ratio’s on compound gearing.
The gearbox is just under 2 to 1.
Rodney

#4

Rodney,
Excellent news!! I know we talked about this at Marty’s but seeing your progress is really getting me pumped!! Let me know when you have one of the delrin versions ready for sale as I definitely want one!

#5

Rodney,
You are a very skilled craftsman and quite ingenious. Well don!

#6

What gem. Well done.
I too will take at least one when when they are ready.

#7

I have the Derlin gear blanks done and if thing goes well I will
have the gears cut tomorrow. The boxes themselves will start
when I get 2 taps and 2 reamers that I will need for production.

Jerry
Thank you for your kind words.
It really just having the equipment and knowing how to use it.
I do have a lot of ideas in my head and I try different thing to see
if they will work.

Tony
Thanks and you will get one also.
Rodney

#8
Steve Stockham said:
Rodney, Excellent news!! I know we talked about this at Marty's but seeing your progress is really getting me pumped!! Let me know when you have one of the delrin versions ready for sale as I definitely want one!
Rodney, Put me on the list for one, too..............;)
#9

Nice! Add me to the list.

#10

Rodney,

Great news.

I would love to try one of your gear sets on one of my K27s. Please add me to the list.

Stan

#11

Rodney,

I to would be interested, did you replace the stock motor? I was hoping Barry would get his to market sooner that the connie drive, which is excelent, but the delay is painfull. i want to run my k27 down a 4% grade at a walk and not warp speed.

#12

Nice work Rodney. Glad to see you’re back!

#13

Rodney,

Proud to know someone with that talent. Pretty cool stuff.

#14

Ken and Bob
1 for each of you.

Stan
Sending you a e-mail.

Al
This is only a gearbox that goes between the stock motor and the
stock B-man gearbox.
I know what you mean about going down a 4% grade with 20 + cars in tow
as well as pulling up the same grade. You are working the throttle all the time.

I have spent a few hours on the phone with Barry with different ideas and he
has also given me his ideas on how to go about solving the regearing issues.
Barry will get 1 also.

Rodney

#15

So does this mean Barry will be your customer for the gears for his conversion?
I’m still holding faith in Barry.

#16

I mentioned it on MLS, but since there’s a tab going here, consider me interested as well.

Later,

K

#17

Dear Rodney,

Here’s my guess on your gear ratios:

14.5 (to start) X 24/18 X 24/18 = 25.778

You claimed “The final ratio is about 26 to 1.”

Lost? You’re about as lost as a military grade GPS.

It’s nifty to see the gear cutting process…

Thanks.

Sincerely,

Joe Satnik

Edit: spelling

#18

Rodney, how hard is it to disassemble the K to the point where I could put the gearbox in? Bear in mind that I’m not afraid of a Bachmann 4-6-0, but the K seems a tad complex.

#19

You could add me to the list as well.

#20

Rodney,

Like Robbie, I am a bit intimidated by the K. Do you plan on any form of installation instructions? Even if they are just a series of photos it would help a lot. My budget is a bit tight, so I would like to see what the budgetary cost will be before I commit. However, I am interested.

John,

If I under stand the last posts from Barry on his rework, his will be a complete replacement of the Bachmann unit. That being said, Rodney’s sounds like a simpler solution, and 26: vs 29:1, I don’t think it will make enough difference to matter.

Bob C.