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Vehicles & Models / Re: Chris's Marion 91 Steam Shovel
« Last post by ddmckee54 on Today at 08:31:04 PM »

I'd get bored watching it work

Now you wouldn't, but even if you did you'd be in good company because the rest of us would be watching too.

It's like the man said," I like work: it fascinates me.  I could sit and look at it for hours."  I always thought it was W.C. Fields that said that because it sounds like a line he'd use.  Turns out it was Jerome K. Jerome.

Don
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From Plans / Re: Muncaster Grasshopper - Work in Progress
« Last post by kvom on Today at 08:17:08 PM »
The new longer boring bar arrived by post today, so I was able to bore both the main bearing and eccentric to fit the 5/8" crankshaft.

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Chatterbox / Re: Phone problums
« Last post by b.lindsey on Today at 08:08:16 PM »
Just went through this recently with my 4 year old Motorola Droid Maxx. It wasn't doing the reboot thing but the battery was getting eaten alive by something called Google Play Services which is a core part of the operating system and controls most everything else so you can't disable it. It got to the point also where I had to turn data off unless I was either at home or work where there was Wifi, else my data usage went through the roof as well along with battery life. The story I got was that the 4+ year old processor in the phone couldn't keep up any longer with all the additions made over the years to the Android operating system. This may be a crock of manure, but the truth is they pretty well have us over a barrel....planned obsolescence...like with so many things these days. Save yourself some heartache and just find the best deal on a new phone of your choice. They are still willing to deal somewhat, especially if you have been with one carrier a long time.


Bill
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Vehicles & Models / Re: Chris's Marion 91 Steam Shovel
« Last post by crueby on Today at 07:25:12 PM »
Get a CNC mill.  You won't be so "cranky".   :Doh:


 :Lol:


I'd get bored watching it work, leave it to the elves, they would make steel elf hats or something... Not worth the risk!


 :Lol:
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Although this thread is aimed at beginners it's difficult to know how much detail to show and when to be brief, I guess most beginners can turn a piston but I did take a few photo along the way.

I think detail and discussion is good regardless whether it's aimed at a beginner or not.
Beginners read a lot.

And I learned a few things from this post.  :ThumbsUp:
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Vehicles & Models / Re: Chris's Marion 91 Steam Shovel
« Last post by kvom on Today at 06:42:38 PM »
Get a CNC mill.  You won't be so "cranky".   :Doh:
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Although the no4 bearing blocks still need a bit more cosmetic work I decided to tackle the bottom cylinder cover and piston next. I did take a few photos of machining the cover but somehow seem to have deleted them before uploading to Flickr. Anyway it was a simple turning job from a casting I bought followed by cutting a M12 fine thread to accept the gland nut.

The 2 taps and the die I bought for the job were only cheap ones (I think I paid about 11) but I was quite impressed by look and feel of them and they did the job :-)



Although this thread is aimed at beginners it's difficult to know how much detail to show and when to be brief, I guess most beginners can turn a piston but I did take a few photo along the way. My initial intention was to make the piston from cast iron but after a bit of advice and  a bit of thought I settled on aluminium. I've never used aluminium pistons before so we'll see how this performs on the hot stuff later but the lightness may be useful in high speed running ?

I like to turn the piston on the rod it will be coupled to, it is 7mm rod threaded at 2ba with a centre for stability.



Creeping up on the final diameter it's a nice close fit  :)



I think it may have been in Brians Oscillator build thread that the subject of graphite yarn piston rings briefly came up so for the benefit of those who have never tried it this is how I do it. The yarn for this piston is 1/8" sq so with a parting tool I just gradually cut a piston groove until the yarn will just fit width ways but to a depth that it sits wider than the diameter very slightly.

Here I am getting close to the size of groove I want



A bit deeper then cut to length and this looks about right



Soaking the yarn in oil and packing it down it's possible to get a good seal around the piston, the ring is in place here and a couple of loose strands / graphite can be seen. It is a good seal though and slides smoothly in the bore  :)



I'm now at this stage





With the covers in place I'm happy with the suction effect so hopefully the finished engine will have a bit of oomph  :pinkelephant:





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Chatterbox / Re: Phone problums
« Last post by gldavison on Today at 06:14:48 PM »
Replacing battery was the first thing i did.
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From Kits/Castings / Re: PMR #5 - as a fill in project
« Last post by b.lindsey on Today at 06:03:21 PM »
A little more progress on the cylinder. Got the three port holes milled in the steam chest (photo1), then the holes from each end of the cylinder to intersect the ports (photo 2), and photo 3 shows that they do in fact intersect. More later today.

Bill
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Vehicles & Models / Re: Chris's Marion 91 Steam Shovel
« Last post by crueby on Today at 05:45:38 PM »
Continuing on with the rear track plates, laid out the first set of recesses in the sides, being sure to have two right side and two left side arrangements. Then double checked. Again....

With the first plate clamped back on the rotary table, using the outline traced there when milling the outside profile as a guide to placement, milled out the first set of openings.In this position, the arc around the end is centered on the table, so milling the rim shape was easy. I left the material around the axle boss large, that will be done in next step with the hole centered on the table.


After milling all four plates to the same stage, the axle hole was centered on the plate and held with a bolt in a bushing sized to the hole plus the hold down clamps. Then milled around the hole to form the boss.

After all four were done, put in a larger bushing to center the main axle hole on the rotary table, and went around the larger boss there.

And took out the rest of the opening, again leaving the lower axle boss roughed in, it will be taken to shape next.

So far so good, lots more cranking to go....
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