Author Topic: PMR 7 Twin Cylinder Steam Engine  (Read 3743 times)

Offline crueby

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #60 on: April 14, 2018, 11:03:35 PM »
Is that Frog tape? 


Nice progress!


 :popcorn:

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #61 on: April 14, 2018, 11:53:49 PM »
Is that Frog tape? 

No. Tamiya Masking Tape. Generally used to mask off plastic models for painting.
I had gotten it so I could paint a balsa kit of an Me109 and a Stuka 87. Both rubber band powered.
Haven't finished the Stuka. The Me109 looks like crap and will be used to let the grand-daughter have some fun destroying flying it.

P.S. That tape was probably not a good idea for the balsa model. When I took it off, a nice square of rice paper came off too.  :cussing:
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline crueby

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #62 on: April 14, 2018, 11:58:36 PM »
Is that Frog tape? 

No. Tamiya Masking Tape. Generally used to mask off plastic models for painting.
I had gotten it so I could paint a balsa kit of an Me109 and a Stuka 87. Both rubber band powered.
Haven't finished the Stuka. The Me109 looks like crap and will be used to let the grand-daughter have some fun destroying flying it.

P.S. That tape was probably not a good idea for the balsa model. When I took it off, a nice square of rice paper came off too.  :cussing:
I've used the 'delicate surface' version of Frog Tape, comes off of airbrush painted surfaces very well, but holds just enough to mask for the next coat.

The rice paper mention reminds me - it can be used to make the equivalent of a decal by taping it to a sheet of paper and printing on it in your inkjet printer (make sure you have pigmented ink or it will run in the next step). Cut around the image, and epoxy coat it onto a surface - it goes transparent like fiberglass cloth does. I used it to put eagle and wolf heads on some kayak paddle blades once.

Anyway, back to the engine model!

 :popcorn:

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #63 on: April 15, 2018, 08:09:28 PM »
Found some time to work on the connecting rods.
Had to finish T's trellises and install a phone jack.
Geesh, the days are flying by!

Not a good job on the rods. Holes appear pretty off center but so long as the distance between holes is correct, the rods should work.
The 1st pic shows me using a 1/8" end mill. I took that hint from Dean's website.
Otherwise the dimple would force the center drill and/or drill off.

You may recall I'd 3D printed a spindle stop for the mill. Very handy as otherwise I would need a 3rd hand.
One to twist the draw bar, one to hold a wrench on the spindle, and one to hold the tool so it doesn't drop out.
The spindle stop takes the place of the wrench on the spindle.

Unfortunately, too often I would turn on the mill forgetting the stop was in place.
This resulted in two types of noises and the stop sometimes getting flung off.
One noise was the rattling of the draw bar in the stop.
The other noise was me.  :cussing:

So I made a little reminder and we'll see how that goes.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline crueby

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #64 on: April 15, 2018, 08:23:39 PM »
Good progress on the conrods. I like the idiot proofing too.


We used to joke about making our software foolproof. But they kept coming out with even better fools!!   :Jester:

Offline Admiral_dk

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #65 on: April 15, 2018, 09:01:51 PM »
Quote
I like the idiot proofing too.

I really wished I used that one too last year - though it should probably have read - "Remember to fill up with oil before pressing Start, or you are an idiot" ....  :facepalm: ....  :cussing:

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #66 on: April 15, 2018, 09:30:08 PM »
Oil? That reminds me...

I've noticed quite a bit of oil loss below the carriage on the lathe.
I can oil everything and then 3-5 days later I see a lot of oil in the pan.
Always under the carriage.

Not sure this is normal. Anyone have thoughts?

I haven't been able to see where it's coming from.
I'll place some paper underneath and watch for a drip.
Hopefully I won't be watching paint dry.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Stuart

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #67 on: April 16, 2018, 09:24:18 AM »
Zee
Most lathe carriages are incontinant.

At least it has clean oil

Stuart
My aim is for a accurate part with a good finish

Offline Flyboy Jim

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #68 on: April 16, 2018, 03:00:14 PM »
Looking good Zee.  :ThumbsUp:

Your little sign reminds me of a computer joke where a computer repair tech tells a customer that their computer is suffering from an "ID ten T" error. AKA an "ID 10 T" error  ........... AKA an "ID10T" error ........AKA "Idiot" error!  :lolb:

Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #69 on: April 16, 2018, 06:26:30 PM »
Thanks Stuart.

Jim...I will use that. I still get questions about the project I was on at work. Once in a while I get a question where that would be appropriate.

Did a couple more parts. I'm waiting on a tap and pushing off parts that need the 4-jaw.

1st pic shows the crankshaft. It required two flats 90 degrees apart. This is what I came up with to ensure the 90 degrees.
I worried a little in that I could only hold onto a little over an 1/8" on both ends.
But seemed to do the job.

2nd pic includes the two crank bearings with one placed in the connecting rod.
Rather than measure the part that goes into the connecting rod...I turned the bearing until the connecting rod slipped on.

Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Online b.lindsey

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #70 on: April 16, 2018, 07:33:08 PM »
Zee, what are the flats for? I looked at my single cylinder version and the con rods don't have that, but it was built a lot of years ago too.

Bill

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #71 on: April 16, 2018, 08:08:52 PM »
Zee, what are the flats for? I looked at my single cylinder version and the con rods don't have that, but it was built a lot of years ago too.

For the cranks. It may be that a flat is not needed for single cylinder. In this case, the two cranks have to be 90 degrees out of phase with each other and the flats help achieve that.
(I can only guess. I am no expert.)

46!  :Lol: Going slow ain't it?
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Online b.lindsey

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #72 on: April 16, 2018, 08:11:34 PM »
I try not to think about it  :lolb:

Bill

Offline Gas_mantle

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #73 on: April 16, 2018, 08:28:30 PM »
Carl, while looking to see what the flats are for I came across this site which may be of interest to you  :)

http://www.deansphotographica.com/machining/jobs/pmr7/pmr7.html

Online b.lindsey

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #74 on: April 16, 2018, 08:38:48 PM »
Zee, I misread the post and was thinking connecting rid rather than crankshaft. The out of phase makes perfect sense for the crankshaft. Sorry for the confusion on my part.


Bill