Model Engine Maker

Engines => From Kits/Castings => Topic started by: bwal on May 22, 2019, 11:27:02 AM

Title: PMR3A Mill Engine
Post by: bwal on May 22, 2019, 11:27:02 AM
Hi,

I decided to start on my PMR 3A Mill Engine.
I'll be following the steps of AOG for this build as much as I can. I've also watched the Texan guy on YouTube who made one a few years ago.

So I did what AOG did and straightened out the base (no photo's) and drilled the mounting holes (going to use M3).

I then found a piece of aluminum to use as a mounting plate/work holding fixture (great idea).  I drilled and tapped the holes tonight and bolted the base to the plate.  When I had a look at AOG build log I realized I need to move the base to the other side so the flywheel will have somewhere to sit.  Live and learn.

I'm hoping to do 30 minutes or so each night so it'll be a long build.

Ben.
Title: Re: PMR3A Mill Engine
Post by: b.lindsey on May 22, 2019, 12:53:13 PM
Happy you have decided to do a build log on it Ben. This is a popular engine and I feel sure many will be following along just as I will.

Bill
Title: Re: PMR3A Mill Engine
Post by: bwal on May 24, 2019, 12:25:03 PM
Hi,

I was able to do some work today. Firstly I moved the base over to the other side of the plate.

Then I machined the cross head bed flat. I'll need to do a check measure, as I was interrupted and wasn't able to finish off.

Ben.
Title: Re: PMR3A Mill Engine
Post by: b.lindsey on May 24, 2019, 03:01:11 PM
Ben, are you working with the aluminum castings or the cast iron ones?  Even a little progress is still progress :)

Bill
Title: Re: PMR3A Mill Engine
Post by: bwal on May 24, 2019, 10:18:46 PM
Hi Bill,

I have the aluminium casting set. I purchased them off ebay from the USA, it's an older kit. The flywheel has the four spokes instead of the current three. There may be other differences that I don't know about.
I forgot to mention, I did some "fiddling" - filing of the flash from the casting bed as well.

Ben
Title: Re: PMR3A Mill Engine
Post by: b.lindsey on May 25, 2019, 01:19:50 AM
I should have known that with the "A" suffix.  :facepalm2:

Bill
Title: Re: PMR3A Mill Engine
Post by: bwal on May 31, 2019, 10:19:12 AM
Hi,

Still plugging along. I made a few order of operations errors. For some reason I forgot to machine the face of the casting before drilling and reaming it. The centre hole is a bit off but it will be ok.

So I've machined it flat and driller the three holes hopefully in the right locations (I used the DRO for the holes).

Ben.
Title: Re: PMR3A Mill Engine
Post by: b.lindsey on May 31, 2019, 03:36:13 PM
Nice progress Ben!  If you are worried about the hole location of it is becomes an issue iti looks like there is enough meat there to bore it oversize at the right location  and put in an aluminum ring to bring the diameter back down to size. Hopefully it won't present a problem though.

Bill
Title: Re: PMR3A Mill Engine
Post by: Joe P. on June 03, 2019, 02:04:21 PM
Looking good, I will be following along.


Sent from my iPhone using Tapatalk
Title: Re: PMR3A Mill Engine
Post by: bwal on June 08, 2019, 10:06:20 PM
HI,

I started on the cylinder this week. I was following AOG buildlog.  I went to drill out the bore I didn't centre the cylinder enought. The first hole was about .7 mm out. I probably should of used a wooden dowel in the core to mark it out but as usual I was rushing and distracted by outside events and I made the bore even worse.

So off to the mill to fix the problem. I had to use the DRO to find centre of the bore and then drilled down with a endmill. I then milled the surface flat.  I want to drill the PCD on the face now but I can't remember what face is up, and if it's the 3 or 4 hole face or if it doesn't matter. That's tomorrow's problem.


Ben.


Title: Re: PMR3A Mill Engine
Post by: Jim on June 09, 2019, 01:07:29 AM
Enjoying this thread and thank you.
Title: Re: PMR3A Mill Engine
Post by: bwal on October 26, 2019, 09:02:40 PM
Hi,

I'm still at it. Made a few mistakes but plowing on. I'm trying to get back into it. See if you can spot the mistakes.

Ben.
Title: Re: PMR3A Mill Engine
Post by: b.lindsey on October 26, 2019, 10:53:30 PM
Looks like you recovered from them nicely.  The 3A is a great little project and a nice runner.

Bill
Title: Re: PMR3A Mill Engine
Post by: Flyboy Jim on October 27, 2019, 12:14:25 AM
It's good to see you working on this Ben.

I started on a PMR #5 last week and I think we may use some of the same parts.

Jim
Title: Re: PMR3A Mill Engine
Post by: rick41 on October 27, 2019, 11:54:44 PM
Hi Bill,

I have the aluminium casting set. I purchased them off ebay from the USA, it's an older kit. The flywheel has the four spokes instead of the current three. There may be other differences that I don't know about.
I forgot to mention, I did some "fiddling" - filing of the flash from the casting bed as well.

Ben
I believe the word is "fettling", not "fiddling"
Rick
Title: Re: PMR3A Mill Engine
Post by: Flyboy Jim on October 28, 2019, 01:32:18 AM
Hi Bill,

I have the aluminium casting set. I purchased them off ebay from the USA, it's an older kit. The flywheel has the four spokes instead of the current three. There may be other differences that I don't know about.
I forgot to mention, I did some "fiddling" - filing of the flash from the casting bed as well.

Ben
I believe the word is "fettling", not "fiddling"
Rick

I know that for myself I spend a lot of time 'fiddling' with 'fettling'.  ;D  In fact I did a bunch of that today.

Jim
Title: Re: PMR3A Mill Engine
Post by: bwal on December 05, 2019, 05:15:08 AM
Well things have progressed slightly. Unfortunately i fractured my scapula (shoulder blade - I think) in two places, so I'm out of action for a month or two. I had just started on the flywheel and was going to finish it up on Sunday after the kids went back to their mother's house. Machining the flywheel is my favorite part of the model.
Regards Ben.
Title: Re: PMR3A Mill Engine
Post by: Admiral_dk on December 05, 2019, 11:30:27 AM
Quote
Unfortunately i fractured my scapula (shoulder blade - I think) in two places, so I'm out of action for a month or two.

Ouch - I haven't tried this, but I would expect quite an amount of pain - both when moving around and when trying to sleep .... I really hope you mend soon and well Ben.

Nice parts so far - the family shot looks great  :ThumbsUp:
Title: Re: PMR3A Mill Engine
Post by: Flyboy Jim on December 05, 2019, 04:41:05 PM
Your project is coming along nicely Ben.  :ThumbsUp:

Sorry to hear about your shoulder. That sounds pretty debilitating for sure. When the time comes, be sure and take advantage of any Physical Therapy offered..............it makes a huge difference in a persons recovery time.

Jim
Title: Re: PMR3A Mill Engine
Post by: gary.a.ayres on December 05, 2019, 10:49:48 PM
A fractured scapula sounds like no fun.

Commiserations.

The build is looking good, though.

gary
Title: Re: PMR3A Mill Engine
Post by: Joe P. on December 05, 2019, 11:03:09 PM
I made the same engine in cast iron and bronze a while back. I followed mostly Tinker John from Texas who did a fantastic job, but I felt he left some gaps in the setups and operations. (Not knocking him because I know first hand videoing and machining at the same time is very time consuming and distracting) So I did a video series of how I went about making the engine. I am just a hobbyist and this was my first engine, but if you can pick anything up from it then itís well worth the time.

https://www.youtube.com/playlist?list=PL3EdvTvwbAmR7Pe-suLnDOCGaVUdVwy0g


Sent from my iPhone using Tapatalk
Title: Re: PMR3A Mill Engine
Post by: bent on December 06, 2019, 06:09:46 PM
I too have built the iron/bronze version, it was my 1st engine.  Learned a lot building it.  I had trouble getting the packing nut thread centered relative to the piston rod bore, and ended up over-boring the hole to keep it from rubbing on the piston rod.  The engine runs ok on air without packing.   :popcorn:
Title: Re: PMR3A Mill Engine
Post by: b.lindsey on December 06, 2019, 06:24:52 PM
Sorry to hear about the injury Ben. Hope it heals soon and we'll so you can get back in the shop.

Bill