View Full Version : MACHINING DRIVERS
02-23-2005, 12:49 PM
Dear Fellow Machinists,
I'm working on my first 1.5" loco project, an Allen Ten-Wheeler. My frame is complete and I am ready to move onto putting some wheels under this baby. I'd like to know if anyone knows of good, internet-based resources where I can read about the "how-to's," "do's," and "don'ts" of machining wheels?
02-23-2005, 01:04 PM
Welcome aboard! I use this link (Village Press, I believe):
Not online, but Village Press has several books on building live steam locomotives. In particular, look for anything by Kozo Hiroka (I may have spelled that wrong). His writing is exceptionally clear and complete.
[This message has been edited by SGW (edited 02-23-2005).]
02-23-2005, 02:24 PM
The method I use for machining drivers is as follows:
Step 1. Mount the 4 jaw chuck on your spindle. Set the jaws so you can hold the wheel on the OD of the flange.
Step 2. Mount the wheel casting in the chuck. Hold the casting about 1/8" deep in the jaws. Don't worry, it wont come out of the chuck. Use a scale to get the "back" side of the casting to run within about 1/32" by eye. I like to use a sharp pointed toolbit in the toolpost to get the ID of the "tire" running true. Watch out for the counterweight. Get the wheel running true by eye using the toolbit just clear of the casting. You want the ID of the tire running true so the casting doesn't look like it's running eccentric. Double check the back of the wheel and the face of the chuck with the scale. Adjust as necessary.
Step 3. Face about 1/2 of the metal off the machining allowance that's on the casting on the tire only. Face your counterweight/crank hub to dimension. Take a couple of cuts if you need to. Rough turn the tire diameter. You may have material enough to rough the flange in this case. If you do; turn the flange diameter down to about 1/64" oversize. Rough turn the tread the same amount oversize. Some people like to drill and bore their wheels at this point. You can certainly do this if you want. I just drill undersize at this point. Remove the wheel and repeat these operations until all 6 are done.
Step 4. If you have a good repeatable 3 jaw; mount it at this time. I personally use a 3 jaw chuck with soft jaws and bore them to fit the drivers. Or you can use your 4 jaw. Turn the wheels around and make sure everything is running true. Face the hub (if one is shown on your print). Then face the wheel to thickness. Make sure your wheel is parallel. Adjust as necessary. Within .002" is close enough. I will then bore the wheel using a good quality gauge pin for sizing and sneak up on the bore diameter. Bore until the pin just goes in the hole. Or you can ream after boring. Repeat until all 6 are done. You should have 6 drivers all within about .003" of each other. Take your time.
Step 5. I have a fixture that I made for finishing wheels. It's simply a piece of 6" diameter steel bar that's about 1 1/2" thick. It's been turned and faced so its faces are parallel and the diameter is square with the faces. It has a 5/8"-11 thread in the center with a register diameter bored about 1/8" deep in it to locate the stub that I mount the wheel on. The stub is turned on the fixture to make sure it's true. There's a thread on the outboard end.
I slide the wheel on the stub and put a thick washer on the thread and tighten a nut down on it. Finish turn the flange. I like to finish all the wheels with a form tool for the fillet and get the od close. Then, I'll set the compound over to about 3 degrees and turn the tapered tire with a pointed tool. I don't change the setting when finishing so all the wheels will be the same. I then use a concave radius tool to cut the outside edge of the tire. 1/16"- 1/8" radius is fine here. You may need to pull the chuck over by hand to get a good finish.
You can either file the flange radius or use a dedicated flanging tool to cut it. Rogers Cooke sells a flanging tool, but it's got no side relief so it will chatter. Turning the flange so it's tapered will alleviate the chatter.
Step 6. You can use your turning fixture to do your crankpin holes on the mill. Drill and counterbore a couple holes to bolt it directly to the mill table. Indicate the stub and eyeball the center of the cranks and clamp the casting down using the washer/nut combination. Drill and ream after setting half your stroke. Be sure to countersink the crankpin hole about 1/32" deep.
If you have any questions, yell...
02-24-2005, 12:20 PM
Wow! Thanks for taking the time to write such a detailed response. I printed it off and put it with my blueprints.
02-25-2005, 07:15 PM
Damphmann, I assume your in Germany? Building
an american style engine, and here I am, an American who would like to build a BR64 loco. Hehe.
02-25-2005, 10:37 PM
Andy, Have you poseted any pics of your work?
02-28-2005, 02:40 PM
I don't have access to a digital camera, and I haven't figured out how to work the scanner. Look on www.discoverlivesteam.com (http://www.discoverlivesteam.com) under their E-magazine. Scroll down until you see an article titled "Steam in the Juniata Valley". The top pic on the article is of me and Wayne Godshall doubleheading our model steam switchers at Railfest 2003. There's another pic of me in their (general) bulletin board in the Pennsy Power3 posting.
Scroll down and you'll find a pic of me feeding my locomotive while firing up...
Thanks for the interest.