Author Topic: PMR 7 Twin Cylinder Steam Engine  (Read 32074 times)

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #75 on: April 16, 2018, 09:16:44 PM »
I try not to think about it  :lolb:

Good luck with that. This forum never lets anything go. Sigh.  ;D

@Gas_mantle: That's the site I was referring to earlier. I should have posted a link. Thanks for that. Dean used to be a familiar member on the forum and, as I recall, provided excellent posts on spring making besides models. I get in touch with him once or twice a year.

I did the valve linkages which has added to my list of 'things I want...like right now':

a) A set of 5C collets to hold hex shaped bar.
b) A DRO for the tailstock of the lathe.
c) A carriage stop (which I should be able to make...I haven't looked but does anyone have plans?)

1st pic is after the lathe work where one end is drilled and tapped. Here I'm doing the hole for a holding pin.
I'd used a parallel to set the part.
I surprised myself to remember to put the other part at the other end of the vise to keep the pressure even.
I could have placed both for drilling (one on either end) but it was fiddly enough to get one true so I placed them one at a time.

Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline AOG

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PMR 7 Twin Cylinder Steam Engine
« Reply #76 on: April 16, 2018, 09:43:44 PM »
For a carriage stop, I just repurposed one of my vise stops. I clamp it to the back rail of my lathe which is square.



Tony


(updated to use a better picture)

Sent from my iPad using Tapatalk
« Last Edit: April 16, 2018, 09:48:01 PM by AOG »

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #77 on: April 16, 2018, 10:46:46 PM »
Thanks Tony. That reminds me I need to make a vise stop as well as some soft jaws for the vise.

 :help:

Dean did the flywheel by using Loctite 'blue stuff' to set a piece of drill rod in the flywheel. Then put a dimple in the end and, along with a live center, did the rim machining.

Can anyone clarify what 'blue stuff' he's talking about? Also, how the rod is released from the flywheel?

But I'm also wondering why I couldn't do the same with a bit of drill rod (no Loctite) and a lathe dog.
Now I don't have a lathe dog but it seems a simple matter to make one up that would 'bolt' onto the drill rod (in a flat) and then to the flywheel.

Thoughts?

Thanks.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline Gas_mantle

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #78 on: April 16, 2018, 10:51:07 PM »
Not sure what the blue stuff is but I often use Loctite 638 to turn wheels on a mandrel and it will be strong enough for what you need. It is easy to break the bond with a bit of heat.

Online crueby

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #79 on: April 17, 2018, 12:36:56 AM »
Well, Loctite Blue?



It holds pretty well, can still be broken loose with enough force. The Loctite Red is stronger, requires heat to break it loose. The Loctite Retaining Compound (green) is very handy too, made for round pins in holes rather than threads, acts like the Red does, can be removed with heat. They make dozens of versions, those three are the common ones, readily available online (all three) and home centers (red and blue).

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #80 on: April 17, 2018, 12:47:44 AM »
Thanks Gas_mantle. I've ordered some.

Chris...already ordered the 628 but I see you're showing 242 which I already have.

This stuff is very confusing. red, blue, green, numbers, etc.

You mention 3. Looks like 242 is blue. What are the other two?

Thanks.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Online crueby

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #81 on: April 17, 2018, 01:09:14 AM »
Red is 271, green retaining compound is the 603. The colors are printed on the containers, but the liquid itself is that color.
All of them cure in absence of air, so any left on surface wont dry, but easy to wipe off.

Offline Dave Otto

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #82 on: April 17, 2018, 01:22:33 AM »
Green is also 609 & 290; maybe the 603 is the old 609? 
The 290 is the wicking variety and can be handy at times.


Dave

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #83 on: April 17, 2018, 01:41:37 AM »
Green is also 609 & 290; maybe the 603 is the old 609? 
The 290 is the wicking variety and can be handy at times.
Red is 271, green retaining compound is the 603. The colors are printed on the containers, but the liquid itself is that color.
All of them cure in absence of air, so any left on surface wont dry, but easy to wipe off.

Yeeaagh. My head hurts.

I've got 242 and 271.

Some googling has led me to take some aspirin.

The best I can tell...most differences seem to be around curing time, temperature range, and disassembly requirements (heat and/or hand tools).

But otherwise, this seems to be the kind of product that whatever you were introduced to by some mentor, teacher, or someone whose knowledge you respect, you just use the same thing they do.

So my next question is...of the 3 'popular?' ones , 271 (red), 242 (blue),  290 (green), why would you (I mean you guys specifically) choose one over another?

Also, there seems to be a series 2xx and 6xx. Not sure what that means. Industrial versus commercial? Military?

I'll keep digging once the aspirin takes effect.

Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline Gas_mantle

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #84 on: April 17, 2018, 01:55:19 AM »
I'm no expert but I've used both 603 and 638 many times, I think there are probably so many different flavours because a lot of Loctite products are used in industrial applications where a slight difference in properties could be vital. For the kind of uses most of us modellers need the difference is probably very subtle so some products are largely interchangeable.

In terms of 603 v 638 I'd say 638 is slightly stronger but cures very quickly with little 'manipulation' time where as 603 gives longer to adjust components.

I tend to use 638 for strength where a simple push fit is needed (like putting a flywheel on a mandrel) but use 603 if I need to locate components precisely and may need to adjust things.

Offline Johnmcc69

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #85 on: April 17, 2018, 02:06:55 AM »
So what was used in the days before Loctite?  :headscratch:

 John

Online crueby

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #86 on: April 17, 2018, 02:36:48 AM »
You asked why one over the other....


I am use medium strength blue for screws that I don't want to vibrate out but want to be able to remove without heating, like gunsight mount screws, cover bolts, etc. Red high strength for more permanent assembly parts, cranks, levers, parts to arbors, that can be heated to remove but need to withstand a lot of torque. Green for same use, its better with round rods and pins in holes.
Be careful of parts to be painted, clean off any squeeze out or paint may not cure. Most need time to cure to max strength, and bottles must be shaken before use.


Before loctite, um, chewing gum and goat spit.

Offline ShopShoe

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #87 on: April 17, 2018, 01:02:17 PM »
If you're a technical information junkie, this link may be useful:

http://www.supertechnical.com/CATALOGUE/Adhesives-and-Sealants/Loctite-Adhesives.pdf

My go-to loctite products I keep in stock are:

Blue - If I want to take it apart with hand tools.

Red - If I don't want to take it apart, but I can with the help of a torch.

Green - If I want to secure something after assembly or want the wicking.

Other types I occasionally acquire for situations like bearing retention.

ShopShoe

Offline Tennessee Whiskey

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #88 on: April 17, 2018, 08:04:50 PM »
Late to the party, but, I did bring wine  :lolb:. Zee, I’m liking how you are jumping right back in here with us and showing us the good, bad, and ugly (ain’t seen that one) and doing a splendid job. Don’t worry about the con rods. PM does a great job on casting, but, sometimes the bosses don’t line up. I center the one that is most likely to be seen and let the other end fall where the prints say they should (which is usually a little off center). One of my employees with the most seniority, may have come up with a plan on the getting zapped thing; I’ll send you a PM :mischief:. Remember your safety glasses and always look for pinch points  :old:

Cletus

Offline zeeprogrammer

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Re: PMR 7 Twin Cylinder Steam Engine
« Reply #89 on: April 17, 2018, 09:09:59 PM »
Thanks all.


Nuts. Brass ones at that.
Yet another area where I need much improvement. But they'll do.
I tested some on the rods I had threaded. Too tight.
I'll need to re-thread some parts.

About here is when Marv et.al. would step in and mention the very good idea of matching taps to dies.
Okay...so I forgot...  :facepalm2:

Update on the flywheel...I tried blue Loctite. It didn't take at all. I realized I hadn't shaken the bottle and I've got another go at it drying.
But I suspect it won't work. The rod I'm using, I believe, is a close fit so fluid may not have gotten in there. I may luck out though because there was a good size dimple on the rod where I put the flywheel. Still, I have deep doubts. For one thing, the blue stuff says the parts can be realized with hand tools (no heat). Makes me think that as soon as I start cutting, the flywheel will let go.

Other things I could try...1) score up the rod so the fluid has a place to go, 2) try the red, or 3) figure out a lathe dog.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

 

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