Author Topic: PM Research Engine Number 1  (Read 6174 times)

Offline propforward

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PM Research Engine Number 1
« on: August 26, 2018, 06:53:54 PM »
A well known casting set - I have seen several excellent builds of this, all serving as really good background info to help me along.

This is the advertised finished model, from the PMR site. It didn't grab me straight away, but has grown on me somewhat.



I bought this kit back in 2015, got waylaid a bit, but am finally ready make a start.

I'm sure this will be a slow project, but I am keen to tackle the challenges posed by a set of castings, and today I actually took that tentative first step.

Here is the kit



And, since a journey of 1000 mile starts with a single step, I'll start with this.



Got the 'ol hacksaw out, and separated these parts. This one is getting some attention today.



All I've done so far is square the sides up, and clean up the sealing surface.



Annoyingly, the camera makes the machined surface look a lot rougher than it is. Can barely feel the machining marks. Even so, I'll give this a clean up and polish.

I had to take a little break, but I'm heading back down the shed shortly to spot and drill holes in it. I just wanted to shout about starting an engine. My work tramming the mill paid off, this part has the most square surfaces I have ever machined.

« Last Edit: October 10, 2018, 04:45:31 PM by propforward »
Stuart

Offline zeeprogrammer

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Re: PMR #1 - Props first casting project
« Reply #1 on: August 26, 2018, 07:23:36 PM »
Following along.  :popcorn:
I've always liked that engine.


My work tramming the mill paid off, this part has the most square surfaces I have ever machined.

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

Offline propforward

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Re: PMR #1 - Props first casting project
« Reply #2 on: August 26, 2018, 09:52:37 PM »
Now with added holes. I'll call it a success - machined a new material (cast iron), and got the holes in the right place. The casting is a bit rough. I fettled it a bit on the corners but a little more clean up work needed there. The bosses for the screws nearly disappeared entirely, and I'm tempted to machine the top surface around the whole perimeter to clean it up, but for now I'll leave it as it is.





Stuart

Offline b.lindsey

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Re: PMR #1 - Props first casting project
« Reply #3 on: August 26, 2018, 10:17:14 PM »
Nice start Stuart. This one never grabbed me either for a long time, the I kind of warmed up to it and now it's one of my best runners. It's a fun project in any case.

Bill

Offline Tennessee Whiskey

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Re: PMR #1 - Props first casting project
« Reply #4 on: August 27, 2018, 01:04:08 AM »
Looks like you are off and running Prop. Just take your sweet time and study each casting thoughorly. Marv ,very wisely,recommends, writing down the order of operations: and that really helps.

Eric

Offline propforward

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Re: PMR #1 - Props first casting project
« Reply #5 on: August 27, 2018, 02:33:01 PM »
That is solid advice, and it holds true on bar stock components too. I'm going to force myself to take that approach on this build.

That steam chest cover will benefit from some more attention yet. The rough corners are really bugging me, where there wasn't enough stock to clean up when machining the edges - plus the "recess" is just ugly. The casting used to have letters cast in it, which looked great, but the mould must have been changed or it's become beaten up over time. I had hoped to get nice clean boss surfaces on the top plate - but again not enough stock.

So, I may go back and clean the surface around the perimeter, and possibly even in the recess. But for now I want to concentrate on dimensional accuracy and fit. So I'll clean the rough casting corners by hand, get the backside polished on a surface plate and get everything deburred, and move on.
Stuart

Offline gary.a.ayres

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Re: PMR #1 - Props first casting project
« Reply #6 on: September 09, 2018, 08:47:46 PM »
a journey of 1000 mile starts with a single step,

So true! Love it...

Will be interested to see this develop.

gary

Offline b.lindsey

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Re: PMR #1 - Props first casting project
« Reply #7 on: September 09, 2018, 09:05:38 PM »
Any progress on the #1 Stuart? No rush and I know you have had other things to do also. I can relate to that as I haven't posting anything on the #5 or the Little Pearl in ages. Sometimes the diversions are good :)

Bill

Offline propforward

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Re: PMR #1 - Props first casting project
« Reply #8 on: September 09, 2018, 09:43:16 PM »
Thanks for checking in! No new parts yet - the last few weeks have focused on getting the lathe straight. Today I finished up mounting the new 4 jaw chuck, and sorted out my crappy old coolant dispenser with a new one, as well as miscellaneous other shop organization tasks.

With all that done, I picked up the plans and castings, intent on making a part - but realized that I have not yet made any work plans for any parts. I really want to take a disciplined approach to planning how I make each part this time, so the drawings will go to work with me so that I can make some run cards at lunchtimes. That probably means two weeks before I can cut more metal, since next weekend I have other plans, but it means I'll hit the ground running come the next shop session.
Stuart

Offline gary.a.ayres

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Re: PMR #1 - Props first casting project
« Reply #9 on: September 10, 2018, 07:25:13 AM »
Your patient, methodical approach will bear fruit in due course - you can be sure of it.

gary

Offline propforward

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Re: PMR #1 - Props first casting project
« Reply #10 on: September 22, 2018, 02:42:52 PM »
This isn't a very exciting post, but I've been trying to decide which parts to get started on, now that my lathe and mill are adjusted. I've been going over the plans in detail, and reading Bills excellent log on this engine. Thought I'd share with you an example of my planning notes - this one for the very simple oil cup:



I like using spreadsheets for this - easy to change. Plus I have a pooter in the shop, and I keep these files on a cloud based server, so I can access them from work during lunch. I'd really like to scan the drawings and have each part drawing on each run card too. Might do that.

The idea is to try and figure out the "gotchas" before I get there. I do so hate painting myself into a corner.

The oil cups might be a nice starting point, but really it looks like this engine actually needs some of the complex parts made fairly early on - especially the cylinder, since so much depends on that.

I will likely be spending some time doing dry runs on scrap stock with my rotary table for bolt hole patterns, since I've never done that before. A big advantage of a little pre planning is that it does highlight risk areas.

Well, hopefully I'll have some tangible making to report on later on.
« Last Edit: September 22, 2018, 02:52:20 PM by propforward »
Stuart

Offline b.lindsey

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Re: PMR #1 - Props first casting project
« Reply #11 on: September 22, 2018, 04:27:46 PM »
Looks like a plan Stuart. One thing you might consider is using grub screws instead of threading the small end. You can get full threads the whole way then, and drill your #60 hole through the grub screw. They aren't that hard. Just a thought.

Bill

Offline propforward

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Re: PMR #1 - Props first casting project
« Reply #12 on: September 22, 2018, 11:15:00 PM »
Do you mean use a grub screw instead of the hex brass stock Bill? Interesting idea. I haven't started the oil cups yet.

Instead, I made a start on the outboard cylinder cover. A tricky item, being a somewhat thin casting. I turned the OD in 2 stages - from one end, then flipped around. I couldn't think of another way of doing it.

Since the part has to be machined down to a step, that more or less got rid of the line on the OD from the two stage turning, and the OD is close enough that when I clean and polish parts that mark will go away.

 



Mostly finished part. I actually need to skim the face and shave 3 thou of the small diameter. I didn't plan to do it this way, I had intended these turnings to be finished. However, since I am only a few thou oversize, I'll wait until the cylinder is done before dressing this up.



So I turned my attention to said cylinder. I have been scheming about this part for a while, so I decided to proceed.

Started by dressing some of the uglier bits of flash on the belt sander.



Then used a dead center to get the casting mostly straight in the chuck. There is plenty of material to get a clean bore, so this seems to be as precise as needed to start making datum faces.



I basically just did a minimum clean on each end, leaving plenty of material, to get parallel faces for holding in the mill. My plan is to get each end to length once the steam chest is made, and reference everything off that.



So I set the cylinder up in the mill. I used a height gauge to get each side of the steam chest area level before starting to clean up, then took the top close to the valve gland boss.



Then I started cleaning up the inside of the steam chest.



Now that I have straight edges, I can locate those accurately, and mill the sides and bottom of the chest to depth. Then I'll move on to the port slots.

Fairly happy with how things are going at this point.
Stuart

Offline propforward

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Re: PMR #1 - Props first casting project
« Reply #13 on: September 22, 2018, 11:17:47 PM »
It does seem to take me a long time to get stuff done though. But on the other hand, the day flies by, so I must be enjoying it. I wonder if I'm going about things the most efficient way, but I'm basically approaching the project to minimise set ups. That's a form of efficiency, though my driver is one of not losing datums.
Stuart

Offline crueby

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Re: PMR #1 - Props first casting project
« Reply #14 on: September 22, 2018, 11:47:13 PM »
What are those narrow pieces between the chuck jaws when turning the cylinder cap? Do they attach to the chuck somehow?