Wheel flange turning that you (yes YOU) can do at home

[mmagliaro]

Once again, I was revisited in my sleep by an idea for turning down locomotive wheels.   
I have done this a myriad of different ways over the years:

- flipping the engine on its back and using files
(works on some engines, makes a mess of others, spins drivers on their axles requiring requartering)

- a 00-90 screw through the wheel hole chucked in a drill, and holding a file on the flange (if the wheel bore matches a 00-90 or other handy screw, which it often does not

- and most recently, a scheme made of some bearings and a pointy tool in a drill press or milling machine,
which was greatly enhanced and improved by our friend, John LeMerise with his custom-made spring-loaded
center holder.

But what if you don't have a mill or a drill press?  What if you want something you could just make
with simple hand tools and use at your bench?  What if you just wanted something that would let you do
a wheel flange in 10 minutes without setting up any complicated jig?

What if  all you have is:

- a 1-72 screw
- a Dremel
- some files
- an old flywheel with a recess in it lying around from some engine or other (like the ones in lots of Kato
and Atlas engines)
- a 1-72 tap you can get from Walthers or Micro-Mark for a few dollars?

What if... indeed.


What you see in these photos took me less than 1/2 hour to construct, including the time to actually
turn down a test flange to prove the idea.  The wheel took under 10 minutes to do once I made the tool.

All this is, is a "wheel holder", but good luck finding or buying such a thing to suit our N Scale wheel sizes.
As the saying goes, "Why didn't I think of this before???"

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[chicken45]

Hmm... Lemosteam and I were just talking about wheel grinding yesterday...

[u18b]

I love it!

This solves another problem I have had.

When trying to re-shape a flywheel, the problem is the metal gets, hot, expands, and then is not tight on the shaft anymore.

Your method does not rely on the shaft to hold the item you are cutting.

THANKS!

[mmagliaro]

Thanks, Ron, although I don't think I quite follow you.
The wheel has to slip over that shaft with a snug fit so it will be centered, or this will never work.
But yes, I suppose it's really the pressure of the threaded flywheel pressing on the driver that really keeps
it in place.

So, you are trying to reshape a flywheel?  I suppose this would work for that.  The threaded rod would have
to be a little longer, but I suppose you could sandwich a flywheel in there where I have the driver, and then
cut on that with files.

[u18b]

Forget your flywheel for a moment.

My old way.  Imagine a flywheel on a worm shaft.
Chuck it in the drill.
Spin it.
And try to shape it (I don't haver a lathe).

It gets hot and slips on the worm shaft.  Usually ruined.

Your way.
Press worm off the flywheel I want to shape.
Insert your smooth screw shaft.
Now tighten you new threaded flywheel.
The new flywheel hold the one I want to cut/shape (assuming I have enough room to work).

[Lemosteam]

Max that's just sweet.  I only caution that the threaded shaft will only work with a smooth bore wheel.  The minitrix b6 wheels are pressed onto a knurled and if you push them off they are screwed up for good.  Remember my L1s axles from a minitrix decapod were this way and I had to file the shaft down to remove the knurls.  The original wheel was essentially shot.

Also it stands to reason that drivers with different bore diameters will need different shaft diameters made.

What was the ID of the flywheel?

A cupped flywheel makes sense in that it will likely clear the crank pin boss.

Excellent idea Max!

[mmagliaro]

Got it, Ron. 

John,
The flywheel OD is 0.392" (9.95mm, so it's a 10mm flywheel).   
The inside machined-out clearance in the recess is 0.255" (6.47, so nominally 6.5mm)

And yes, as I noted, you need to make a different shaft for every different bore diameter you need.
But that just means chucking another 1-72 screw into your Dremel, cutting off the head, and then running
it against a file until you get the bore you need, like the one I showed being made.
It's really a 5-10 minute job to make one, and after you build up a set of a few of them, you are set for
almost any wheel that comes along.

And yes, the recessed flywheel clears the crank boss. 

Another important note:  You can do small wheels with this.  Just flip the flywheel around, slip 3 or so  1-72 washers
on the shaft first to give you some clearance, and then screw the flywheel on.

EDIT:
Like so:





I did 20, yes, 20, wheels this way.  It really works!

Important things I may not have made obvious:

1. Use a STEEL  1-72 screw.  Stainless if you can (hardware stores stock these if you look)
Anything like brass will not hold up and you will bend it while turning a wheel.

2. Don't go all gung ho with the files when grinding the flange.  That just makes for bounce and
bad out-of-round flanges.  A light touch and about 10 minutes, followed by running some 400 grit
sandpaper on the flange makes for a nice smooth job.

As for the knurled shaft problem, yes I can see that might cause difficulty.  But I'm not completely sure.
You should be able to carefully press it out, and make a 1-72 smooth shaft that fits snugly in there
without ruining the little knurl indentations in the inside of the bore hole.  As long as it's centered,
it should work when you tighten the flywheel down against it.

[glakedylan]

I think this is a wonderfully thought out and processed means of accomplishing exactly what it is designed to do

wow! kudos Max on a terrific solution for this need

I must ask, however, what about re-quartering? I know that the drivers themselves need not be a perfect 90 degree offset
but that all drivers have to be the same in degree of offset (as the drivers are being driven by motor and gears and not the
pistons of the 1:1 prototype)

I keep trying to come up with a tool that will allow one to quarter drivers all the same and as close to 90 degree offset as
possible

and I have come to the conclusion that the tool will need to be made of metal to be within acceptable specs and strong
enough to accomplish its work (which means it is a real challenge to me without tools for milling)

when will someone produce an N Scale quartering jig like they have for HO Scale and larger?

I know I would be standing in line to purchase!

thanks again for this information and your always creative solutions!

kindest regards,
Gary

[mmagliaro]

I think this is a wonderfully thought out and processed means of accomplishing exactly what it is designed to do

wow! kudos Max on a terrific solution for this need

I must ask, however, what about re-quartering?

....

That has not been lost on me.  Believe me, an N Scale quartering jig that could work with any set of drivers
is still an elusive "Holy Grail".    For now, the Mark I Eyeball is still the only way I do it.
 

[mmagliaro]

... and by the way, if you are turning 20 wheels to do a steam loco, even if you have a tool like this that can get the time down to 10-15 minutes per wheel and produce accurate results, you still have to press the wheels all off, grind them, press them back on, requarter the drivers, remount the rods and valve gear, etc.
In other words, it's still a lot of work. 

[Lemosteam]

As for the knurled shaft problem, yes I can see that might cause difficulty.  But I'm not completely sure.
You should be able to carefully press it out, and make a 1-72 smooth shaft that fits snugly in there
without ruining the little knurl indentations in the inside of the bore hole.  As long as it's centered,
it should work when you tighten the flywheel down against it.

About the knurled bit; it wasn't really about being able to grind them down, what was not obvious in my post is the fact that its nearly impossible to get them back on the original axle.  I think those are modled in place somehow, so the plastic flows arouns a quartered and centered driver and axle.

[mmagliaro]

John,
Now you've really got me going.  I have a B6 with turned-down flanges.  But to be honest, I cannot remember how I did them.  It was years ago.  Maybe I just did them with a file with the engine flipped on its back (which would have avoided the knurl problem because I wouldn't have had to press them off and then back on).

I suppose they could have molded the plastic centers around the axle.  But also, if the wheel, plastic center and all, were held firmly in a jig, and the axle would be pressed into it with a tool to keep everything aligned (like a machined recess in a steel block that holds the wheel dead-still, with a hole bored through tghe block through which the axle is pressed), then the plastic would be molded smooth, and the initial press of the axle would create the knurls in the plastic the first time.  That would have the added advantage of being pressed on there very tight and straight the first time.

I need to go try this.  Why can't the axle be pressed out and then pushed back in?  You would think the ridges would just line up and let the axle back in.

[Chris333]

Everybody is missing the most important thing here...  What are you building with those drivers? 

[mmagliaro]

Everybody is missing the most important thing here...  What are you building with those drivers? 

LOL!  Nothing exciting.   This is just a repair job for a customer.  It's an old Trix "Flying Scotsman" (a Trix K4 with
a British body shell and tender design).  He needs it to run on code 55 track, and the pilot, trailing
and tender wheels are very specialized on this model - not like a US K4, so everything needs to be turned down.

[eric220]

That explains the green drivers.