Steam Loco Spoked Wheel Making

[Cajonpassfan]

I still say etch the spokes 

...or cast them
    Otto K.

[peteski]

...or cast them
    Otto K.

 


We need one of those emoticons here on TRW!

[mmagliaro]

Peteski, what you say about cutting a groove or relief into the face of the rim may be a way to go, if I can figure out how to do it.
Notice how, even on the prototype photo you showed, the center insert with the spokes is indeed always set in a little lower than
the tire/rim.  So if I could machine a small lip down into the first, say, .005" of the inside of the rim, that would do the trick.
Once the spokes and that lip are painted black, and the rim is blackened metal, it would look just right.

Of course... machining that lip is no easy feat on those tires.  It would have been a trifle easier if I had thought of this
and done it before I parted them off the tube.

[peteski]

Peteski, what you say about cutting a groove or relief into the face of the rim may be a way to go, if I can figure out how to do it.
Notice how, even on the prototype photo you showed, the center insert with the spokes is indeed always set in a little lower than
the tire/rim.  So if I could machine a small lip down into the first, say, .005" of the inside of the rim, that would do the trick.
Once the spokes and that lip are painted black, and the rim is blackened metal, it would look just right.

Of course... machining that lip is no easy feat on those tires.  It would have been a trifle easier if I had thought of this
and done it before I parted them off the tube.

Sounds like a plan Max!  I agree that it would be much easier to do this before parting the rim from the stock tubing.

[Andrew Hutchinson]

Radgust wrote: "Assuming you can still put a hole in the center for an axle, and chuck it in that way to machine the outer surface to dimension... would the spoke wheel detail be good enough?   Strong enough?    I've never heard of ANYBODY attempting this or anything like it, but the alternative of a FUD-printed center, or individually-cut spokes seems rather daunting.  Home delrin-casting seems a bit farfetched.   Finish-maching a Shapeways printed metal wheel center for a tire?    I suppose you could even machine it and put in an insulating gap like Mantua used to do in HO.   Maybe.  Or not.....!"

I was given some practice prints of the Shapeways stuff. Pretty sure I posted them here a while back.  Their stainless/bronze material cuts a lot like Oilite bushings and other similar sintered materials. Use a super keen tool and don't rub. In the end I didn't tyre it as the owner/designer wasn't interested in that approach. It was interesting to do it but you get better results by just doing the work out of bar as with most work of this nature. The design in question was printed with a centre hole. I was able to sink the bore with a D-bit but can recall telling the designer to print a smaller centre bore to give me some more material to work with. The print was kind of like a casting in that it slumped a touch and even with a bit of work it was close getting the tyre, rim and bore to play along. If they were mine and I had to use such a material I would go with a free machining steel or stainless tyre.

Max: If you need to remount the tyres you usually turn a tapered mandrel that is a tight fit on the inside of the rim. The taper holds and drives the work piece. That's why you save all of your round bar ends. If it is turned in place truth should be good. On a lathe you can use tube trued up in the tailstock to lightly push the tyre on. If you try it on the mill you'll have to find another way. You can usually just snap them off the mandrel with your finger nails when you're done. It will be tricky getting the taper on the mill so that you have a mandrel that fits your tyres.  Through trial and error you can adjust the parting tool to where it acts as a form tool to cut the taper on the mandrel diameter (much as you did when cutting the wheels first time through). Go slow to avoid chatter. That's the best way I can think of getting the taper short of knocking the column over after which you'd have to re-tramm the mill.

 I'm a little leery of that drill chuck though. Some of the worst things that I've had happen at work and at home have been on drill presses. If your stock isn't too far undersize I'd try it in a milling collet if I had nothing else -less projection and designed for decent sideloads  of which there would be some if you are turning a mandrel from steel. I know the chuck you have has a draw-bar and you seem like somebody with an eye for safety... I'm just saying it so that it is said.

The reality is that you're well into territory where a lathe would be easier , handier and safer. Think about a second hand one, they're not that much.

Anyways, great to see the ingenuity you are bringing to the table.

Andrew Hutchinson

[Andrew Hutchinson]

Forgot that you can't tilt the head on the minimill the way I suggested. Machine I was just on can and did... easily confused at this hour. You'll have to use a form tool to make a mandrel - or just make more and count the others as practice.

Andrew Hutchinson

[mmagliaro]

Andrew, I thank you for that well-thought-out bit of advice.  I don't quite follow, however.  Are you suggesting that
I make a tapered mandrel so I can get my tires back on the mill, and turn them so I can cut that little recess around the inner
edge to simulate the inner spoke border?   I think that's what you are saying.

Yes, I supposed I could make a tapered mandrel where I could just press the tire onto it.  After all, I am just intending
to cut a little .005" or so recess aroung the inner front edge of the tire.  It won't even affect the roundness or
true of the tire unless I really mangle it.  This does give me some serious consideration of a way to do this.

I believe I could part off a piece of tubing, place it in the chuck as a ram, then put the mandrel flat on the milling table
with the tire on its top edge, and bring the milling head with the tubing down to press the tire onto the mandrel.
Then chuck the mandrel, clamp a little tooling cutter into the clamp on the table, and cut.    It is worth a try.

And like you say, if it fails, I suppose I can cut a whole new set where I can cut this recess before parting the tires off.
After all, I've got 2 feet of tubing stock, and I made 8 tires from only about 2"

I hear you on the chuck vs collet.  That's why I tested and measured them.  But the runout gauge doesn't lie.
The collet has about 10x the runout of the chuck, and the chuck seems darn good at .0002".  Frankly, I'm surprised that
anything on a mini mill is that good.

[peteski]

I hear you on the chuck vs collet.  That's why I tested and measured them.  But the runout gauge doesn't lie.
The collet has about 10x the runout of the chuck, and the chuck seems darn good at .0002".  Frankly, I'm surprised that
anything on a mini mill is that good.

I don't think that Andrew is worried about the runout. Drill chucks are designed for drilling vertically, not for lateral forces (which are in play during milling or turning).  I'm not a machinist but I have heard that warning many times.  He is worried that the chuck jaws will loosen up and the part being machined will fly out and injure you.

But personally I'm guilty of doing what you are doing.  I sometimes use a small drill chuck in ma lathe's head stock to hold small diameter parts being turned.  But for anything larger than 1/8" aluminum or brass stock I use a lathe chuck specifically designed for the task.

[Chris333]

I find it odd that the chuck has less play than a collet. On my mill the chuck and collets are both tapered and pull up into the head from the top. Guess it doesn't matter if it works though.

[Chris333]

Guess I'll post this since it sorta looks like a spoked wheel 

I got a lathe before a mill and I bought a milling attachment for my lathe. For my first big project I wanted to build a very small steam engine (not a train) like this:
http://www.sherline.com/images/05NAMES15.jpg
http://www.sherline.com/images/03Katona1.jpg

I found the plans and started. The flywheel is about the size of a quarter, but a little thicker. In the link above they just drilled 5 holes for spokes (like the plans showed). Well I stopped working on it like everything else I do. But one day I was searching for other small steam engines and saw I guy on Youtube making the same one, but with a spoked wheel. Here is the video of it being made:

/>
And after a few e-mails he sent me one:


I doubt in a million years I could make this myself by turning little dials and counting 

[randgust]

Hmmmmm.....

I don't consider myself as God's Gift to either 3D design or RP, but my one little project in Shapeways did convince me of one thing, the ability to draw and print precisely in complex geometry is WAY better than my ability to hand-construct it from stock.    The only downside I've seen so far is the surface finish and/or structural integrity.

So, if you can deal with those issues... I guess I'm at a loss why you wouldn't do it this way other than a personal challenge, which I can also appreciate.  I've been known to do stuff like that myself.

I guess if I was doing this, I'd get something already designed there (some kind of similar wheel) and print it in the test material and see if you could actually machine it and see how strong it is.  I wouldn't draw anything new, but I sure would want to test it as a concept.   If you CAN actually print it in metal, and machine it down to tolerance to fit the centers and your tires... wow.   That's a lightbulb moment for all of us here.    I wouldn't design anything new until you'd see if you could work the material.   I've never seen anything but FUD.

I do think you could etch overlays but you'd have to start from a solid wheel, and my impression here was 'see-thru spokes or bust', right?

Your frame design sounds excellent, but you're going to have to do some manner of a split-axle, right?   

I'm trying to figure out how to modify (backdate) the spokes on an FVM Hiawatha and it's all handwork.... so yeah, I'm really interested in this one.

[Sokramiketes]

Great idea, but unfortunately, no.  That page, if you click for specs, shows that the maximum temp for those phenolic materials to
be around 275 - 288 F.   It will never stand up to soldering heat.

Well, the RC car guys like it for holding battery connectors.  And it should be machinable.

http://www.hobbyking.com/hobbyking/store/__50486__Phenolic_Soldering_Jig_for_Bullet_Connectors.html

[bbussey]

I still say etch the spokes 

Why not etch them?  A spokes/hub/wheel assembly consisting of laminated etched pieces would be stronger than plastic or resin and serve the purpose I would think.  And that would solve the wheel/tire seam issue.

[Andrew Hutchinson]

Max wrote: "Andrew, I thank you for that well-thought-out bit of advice.  I don't quite follow, however.  Are you suggesting that
I make a tapered mandrel so I can get my tires back on the mill, and turn them so I can cut that little recess around the inner
edge to simulate the inner spoke border?   I think that's what you are saying."

Yes, that is what I'm saying.

My warning, if you can call it that, is purely with regard to safety. If your drill chuck spins true at that opening you are very lucky indeed. I wouldn't try it with a bigger piece though.

Cheers,

Andrew Hutchinson

[sizemore]

Throwing my vote in for etched centers. A lot of the European steam scratchbuilders go the etched route and get much finer detail and relief.

The S.