Author Topic: Textile Mill Diorama  (Read 27871 times)

Online zeeprogrammer

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Re: Textile Mill Diorama
« Reply #330 on: June 12, 2018, 10:53:09 PM »
@ John: I remember you talking about the paper models before.
I don't remember if you created/printed them or if you got them as kits.
Seems I remember you providing a link to kits. Would you mind posting again or sending me a PM?
I wonder if there's one for Lichtenstein. I can't tell if you had one. I recall it being on a cliff.
Thanks.

Beautiful work. Your threads always remind me of the things I wanted to do as a kid.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline J.L.

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Re: Textile Mill Diorama
« Reply #331 on: June 13, 2018, 01:27:20 AM »
Hi Carl,

Thanks for the interest. I sent you a PM with details of the model and the flyover.

Here are the photos.
« Last Edit: June 13, 2018, 01:31:22 AM by J.L. »

Offline J.L.

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The Partition
« Reply #332 on: June 13, 2018, 02:39:13 PM »
The east wall of the boiler room is complete. It will now allow  beams to sit on it later, thus becoming a load bearing partition.

The third picture puts us back on track with the engine.

When I was given the 3/16" x 1 1/2" o-ring, the lad slipped a second one in my hand. I think I can cut that second one with one slit to open it. It will then become a template for the width and depth of the groove in the piston head leaving the other one unmarked by trying to dig it out after each trial.

Offline J.L.

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The Piston
« Reply #333 on: June 14, 2018, 03:34:27 PM »
The piston rod was threaded using the smooth walled collet chuck and a tailstock die holder.

The chucks were changed and the piston material (cast iron) was chucked and turned. The extra o-ring I mentioned earlier was cut open and used for testing the width and depth of the groove.

About half way through the job...  :)

 

Offline J.L.

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Opinion
« Reply #334 on: June 14, 2018, 09:12:45 PM »
Gentlemen,

I would like to have your opinion on the suitability of the 0-ring I hae been using to test the width and depth of the groove as the permanent 0-ring.

It closes to an invisible gap as it stands now. The pencil is pointing to the joint.

When the cylinder is slid onto this piston, there is a pleasing tension. I wonder if this slit 0-ring might be a good thing to create allowances. It may very well be, at this point,  allowing for some compression in size.

The understanding is that this is an air pressure situation, not steam.

Your thoughts?

John

Offline J.L.

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Re: Textile Mill Diorama
« Reply #335 on: June 15, 2018, 11:01:09 PM »
Okay... moving on.

Ernest Winter suggested in his 1992 construction notes that the piston rod be threaded only 9/32" unlike the full witdth of the piston  - 9/16".

I am holding the previously cut rod.

His suggestion was to drill the entire 9/16" all the way through with a 7/32" drill, but back off and ream the first 9/32" to the piston rod diameter which is 1/4". Then thread the remaining 9/32".

In effect, he is creating a rod that passes into the piston shouldering itself and then threading itself on to the full 9/16".

The photos show the setup to wind in the pistorn rod with a chuck in the headstock and a chuck in the tailstock.

It will be interesting to see the result. Note that the piston is still attached to its chucking mass in the headstock.

Offline b.lindsey

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Re: Textile Mill Diorama
« Reply #336 on: June 15, 2018, 11:44:23 PM »
John, as for the split o-ring, if you are pleased with how it feels and with the understanding that it will be running on air only, I would sure be tempted to give it a try. Does it feel a lot different if you use the non-split o-ring? I think most would say a full o-ring would be best, but a little more tedious to get to fit just right. Worst case...if the split one doesn't work or wears prematurely, you can always go back to the full o-ring as plan "B".

Bill

Offline J.L.

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Re: Textile Mill Diorama
« Reply #337 on: June 16, 2018, 02:02:55 PM »
I agree Bill. That second 0-ring, if not used will be hanging on a hook in the engine room.  ;)

Photo 1:  Success

Photo 2 & 3: The piston was manually cut off the lathe with a hacksaw, turned around and mounted for facing.

Photo 4:  Oops. The groove was not deep enough for the 0-ring to slide in the cylinder's bore. On Stuart's Victoria, I remember cutting the groove too deep and having to fill the bottom of the groove with narrow brass shims. So I guess I was a bit gun shy when turning this one. So the pistorn was remounted in the collet chuck by its piston rod and is set for a deeper grooving cut with the parting tool.

Offline b.lindsey

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Re: Textile Mill Diorama
« Reply #338 on: June 16, 2018, 02:47:41 PM »
Far better to sneak up on the diameter you need than to have to shim it John. Takes a bit or trial and error but definitely the way to go.

Bill

Offline J.L.

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Re: Textile Mill Diorama
« Reply #339 on: June 16, 2018, 02:54:41 PM »
Right you are Bill.

I think I have it! The proof of the pudding will be to see if the piston and its rod are concentric with the gland in the end cover and will operate nicely.

If I am correct, there is a natural amount of resistance to operating the piston rod by hand. I guess that's where a heavy flywheel and air pressure come into play.

So, I guess resistance to expected easy sliding motion can be misleading to a novices like me.

John

Offline Jasonb

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Re: Textile Mill Diorama
« Reply #340 on: June 16, 2018, 06:41:19 PM »
Bit late to this John but there are published groove sizes for O rings both for commercial applications as well as model ones, the model sizes do not compress the ring any where near as much so you still get a seal but far less friction.

A nominal 3/16" section ring is actually 0.210" and the groove for that should be cut  0.186" deep and 0.281" wide this allows the ring to expand sideways like a football when it is compressed into the cylinder.

Offline J.L.

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Re: Textile Mill Diorama
« Reply #341 on: June 16, 2018, 06:56:54 PM »
Thank you Jason.

That was the information I was looking for. I have a run of the mill 0-ring given to me free gratis from a hydrauic shop.

I like your compression comparison of the sideways expansion to a that of a squished football.

I've learned something today. If the piston does not behave, I have a plan of action.

Thanks,
John

Offline J.L.

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The Steam Ports
« Reply #342 on: June 16, 2018, 09:10:46 PM »
Now we get serious.

The pencil lines are drawn over the scribed line just to show up in the photo. The exhaust port in the middle is 1/4" x 5/8". The two side ports are 1/8" x 5/8" with a 1/8" web between each one.

The construction notes suggest starting by using a sharp 3/16" end mill and locate it in the centre of the middle port face using the marked out lines for reference and plunging it in to a depth of 5/8".

Now I've never done this plunging type of cut with an end mill. Any problems to anticipate here?  :shrug:

John

Offline crueby

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Re: Textile Mill Diorama
« Reply #343 on: June 16, 2018, 09:36:59 PM »
As long as you have a center-cut style end mill, that should work - you can tell if there is no gap in the ends of the flutes at the end. Or make a test in some scrap.
Sometimes you will still get a little chatter on the plunge cut - you could always drill a hole with a regular drill bit just a little smaller than the mill diameter. A lot depends on how rigid your mill is, if it will chatter and give a rough hole on a plunge cut. If your end mill is not the center-cut style, definitely need to drill the pilot hole first.

Offline J.L.

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Re: Textile Mill Diorama
« Reply #344 on: June 16, 2018, 10:22:09 PM »
Thank you Chris. I understand.

I think if you use a twist drill first, you have to back off early and not let the drill go to its depth - it has an angle on the end that deepens the hole. The whole point of using a milling cutter is to get a flat bottomed hole to an exact depth - if the flutes of the cutter wlll let you go down that far.

Also, there is a suggestion that the side ports (1/8") be chain drilled before using a milling slot cutter.  I guess getting rid of some of that metal makes the milling cutter's work easier. It's very small (3/32"). I've had some break.

It is not advised to use a 1/4" or a 1/8" drill to make these holes. A smaller hole is suggested so that you can snuggle up to the scribed lines with more precision with milling cutters.

Intereting stuff. Thanks for the advice guys. Keep it coming.

John