Please comment on this steam valve - proportions and looks?

[mmagliaro]

Yep, I knew about the Grandt Line parts, but I'm sure they would be huge for N

[mmagliaro]

Okay, so Precision Scale does make a brass valve handle for HO that is .040" in diameter, round handle, 4-spoke.

I found a pack on eBay and bought them.  Although .040" is oversized, (that's about a 6.5" handle), it's still a lot smaller than the original one I tried.  I'll have to judge whether the spoke detail is worth the added size.  The one I have on there now is 0.70mm = .027"  = 4.5" in N Scale, so it is still oversized. 

I know, we're really splitting hairs here on one detail part, but after all, three years, so umm... may as well try.  I'm willing to
forgo actually making the handle myself if I can get a nice spoked handle on there.

 

[up1950s]

I ordered some Precision Scale 4840 cored to .012 Globe Valves .

https://www.precisionscaleco.com/wp-content/uploads/2017/03/HO-Steam-WOP.pdf

[metalworkertom]

Okay, so I tried the idea of scoring lines along a .020" rod.  I'm afraid it's not really feasible.
Making them with a saw blade or file, no matter how thin, either distorts the outer rim of the "wheel" so much that it doesn't even look like a round thing with nubs anymore, or (trying it with an Xacto blade to make the scoring very very thin) it's so small that you may as well not bother.

What kind of watch gears are there that are only .025" or so in diameter?  Is there really a watch gear that small?

So, I went back to the washer idea.  I ended up remaking the whole pipe/elbow/valve body again because with the tiny handle, everything else has to be much neater and to scale.  A piece of .012" wire (a 2" pipe) is the elbow, with a bit of insulation slid onto it to form the valve "body", then a .008" stem for the valve handle, and the washer all on that.
All of delicately held together with some 2-part epoxy so it has a chance of holding up and has some flexibility (ACC would just snap off the next time I breathe on it).

Photos later...

I have some of the smallest gears I could find on E-bay. The smallest tooth gear in my selection is .047" everything with hubs was much larger. The hub itself was much larger.

[up1950s]

I would think that some HO group / forum would have figured this out at some point . The manufacturers sometimes give pipe size , sometimes unidentified numbers , sometimes a mix within the same manufacturer . Very often the valve knob " man machine interface device " is at 90 degrees and therefor faceless . Maybe somebody here knows somebody somewhere else and is willing to get the straight dope and share it with us little folks ?

[mmagliaro]

Precision Scale parts are often frustrating, because it's hard to know what the real size of the parts will be until you hold them in your hand.  Even the N Scale parts have this problem.  They make an N Scale cross compound compressor, which is very nicely done, but it is just too darn big.  The ones I can get from other sources, even scarfed off old Kato Mikado shells, are so much smaller and more delicate that I won't use the PSC ones.

[narrowminded]

OK, Max.  This has now become a challenge.   I think I'm going to make something and even if only for my own education and future use.  Of course, you'd be welcome to what you need if it works.

How about an epoxy resin part?  I think that would have the best chance of making something with the detail needed in something this small.  The mold would be a permanent mold with the features machined in.  I'm thinking about ordering a .005" tapered ball end mill which would be used for the pocketing.  I think it could be done and at the dimensions you want plus the mold would be reusable.  Also, instead of painting and losing the detail the resin could be colored.  I currently have black but red is available.  Maybe mauve, too!   I will very likely run into the same need so this wouldn't be dependent on your project.

What dimensions would you envision being best and then maybe a range that considers the size/ strength.  Maybe .006"/ .008" thick?  And the stem diameter?  Could it be .008"/ .010"?  For strength without being too large?

[mmagliaro]

Well, okay, narrow... if you are really game for this.

A .005"  endmill???  Holy Cow.  You can cut with something that small?

I had considered cutting a mold in a piece of aluminum and then filling it with 2-part epoxy to get this effect, but realized that the milling dimensions required are way out of my league.

I like the ball end mill.  That will give the bottom of the mold grooves a rounded shape so the handle will come out with gently curved faces, which is correct!

I'd say the diameter of the whole wheel should be .01875" (3" in N Scale) if you're really going to do this.  Thickness should probably be .010".  Even though that's way oversized, I don't think the part will have enough realistic strength if you push it to, say, .005".  Given that a handle like this is probably no more than 3/8" thick, that would be .002", which is ridiculous.

Stem diameter: .008" would be good.  But I think the wheel should just have a tiny hole in it so that you can put a .008" phosphor bronze wire in as the stem.  I think anything else like that will be too prone to breaking off --- unless you can pour a resin that is as rubbery and resilient as Delrin.

And I'd go for 4 spokes.  5 would be way cool, but let's not get greedy.

[Chris333]

Machinable wax.

[narrowminded]

Well, okay, narrow... if you are really game for this.

I'd say the diameter of the whole wheel should be .01875" (3" in N Scale) if you're really going to do this.  Thickness should probably be .010".  Even though that's way oversized, I don't think the part will have enough realistic strength if you push it to, say, .005".  Given that a handle like this is probably no more than 3/8" thick, that would be .002", which is ridiculous.

Stem diameter: .008" would be good.

And I'd go for 4 spokes.  5 would be way cool, but let's not get greedy.

Well, at those dimensions .005" is too big.   Leaves no real hole.  OD .019" means ID .009".  Stem at .008" and spokes at .005" leaves almost no hole.  Let me try something tonight with stuff I have.  I'll let you know.

[mmagliaro]

Well, at those dimensions .005" is too big.   Leaves no real hole.  OD .019" means ID .009".  Stem at .008" and spokes at .005" leaves almost no hole.  Let me try something tonight with stuff I have.  I'll let you know.

Well, the one I have on there as a plain disk is 4.5", or .028", and I think the size looks good, even though technically it is oversized.  So if that helps, sure, go to .028" diameter.

[up1950s]

I like the size of some of these Max . I am glad you brought this up , now I have some to use .

[narrowminded]

Sorry to not be back sooner but was quite busy with some life stuff the last couple of days.

I tried something the other night with a fine engraving cutter I have and it seems to have some promise BUT the rotary table I have that fits this machine isn't tight enough to do the whole thing.  I kinda' knew that but had had never tried it for something this fine.  It's just not tight enough. The one I have that has a reasonable chance won't fit this machine for lack of throat.  A riser block (which I want to do anyway) would fix the height problem but I don't have a suitable piece of material on hand to make one and will take some other mods to complete the installation when I do. 

What probably would work with existing stuff would be the spokes extended out like nubs on the handwheel and the center disc just solid.  That could also have a chance at the smaller requested size.  I may do some more with it this weekend if time allows and again, if only for my own use one day.  The one thing that would work is the machining center at my customer's shop but that's near impossible to get time on.  It performs amazingly well on this kind of tiny detail. 

I'll post again in a few days with anything new to report.  I have another idea that has struck me for this piece.  Not holding out great hope but it's worth a try and uses existing tools.  Wish I had better to report.

[mmagliaro]

Not to worry, narrowminded...  I am grateful that you are delving into this.

Richie, can you put a caliper on those various Grandt Line wheels and report what the diameters are?

Some of the smaller ones look like they might work for N.

[narrowminded]

OK, Max.  I would like to send you one of my nickel silver pieces that wasn't totally successful due in large part to not having the proper cutters and it may not be doable as planned in the machines I have due to collet and spindle runout/ play.  (It's not bad but when drilling a .004" hole a half thousands runout is like drilling a 1" hole but over 1/8" off center.)   

The reason to send it would be to have a general size reference to tell if the general dimensions look OK or not.  Just holding it up to a steamer in my fleet it looks pretty good but I'll leave that up to your good eye.  What I would send has a wheel diameter around .028" x .012" thick and a stem diameter of about .012" with sufficient stem length (approx. 1/16") to glue into your valve.  Excess length could be trimmed with your flush cutters if needed.  The wheel thickness could and probably should be a little thinner and the diameter of the wheel could be reduced dependent largely on the ability to machine the features in the face small enough.  The stem could probably be reduced to .010" and an effort could be made to go for .008" but I'm not sure that would survive the cutting load.  I could shoot for it but it might decide to part ways before that's reached and it would then be whatever it is.   Being largely hidden behind the hand wheel I'm not sure it would hurt even at .012" but...

Doing the features is where I need the proper cutters.  I tried to get a spotting drill to work but it's a little dull (for this work) and the angle and diameter was way too big to hold true while only drilling .004" deep.  There are ways to try this but would want new cutters to give it the best chance of success with these hobby machines.    One attempt could be to cut the pockets deeper to let the drill find center and then face the excess back off leaving the dimension and shallow pattern at a hopefully acceptable visible tolerance.  With these small dimensions and in proximity to a .002"/ .003" wall, a half thousandths will be visible to the eye (when under magnification).
 
I would like to get some feedback before to order any cutters and go at this again.  I think the features in the face don't necessarily have to be through holes because at this small diameter I'm not sure that they would be visible anyway and would likely be hard to color without just filling the holes.  A patterned texture would be useful..  And through holes would be tried but not as important as getting some feature in it.  (Maybe some duralube would work to finish.)   What does seem to be useful is the difference in texture on the face and in some pattern and that idea is at least represented in this sample, albeit poorly.  It's TINY! Challenges are fun!  ... to a point.   This is still being fun.

Send a PM with address and I'll get it off to you.