Author Topic: AOG's version of the PM -3A engine (Read 8691 times)

AOG · « **on:** December 05, 2016, 03:41:11 AM »

I've got that itch again so it's time to get started on another project. This will be my second engine from a casting kit so I wanted something that wouldn't be that hard. I decided on the PM Research 3A.

(Image from the PM models site)

Let's get started. First I leveled base casting in the vise using adjustable parallels. Then I milled the bottom flat.

With the bottom flat I flipped over the base casting and faced the mounting pads. Then I drilled the pads for 4-40 mounting hardware.

Next I squared up a piece of flat plate, transfer drilled and tapped the holes from the base. The casting shifted slightly so one of the holes is off. Three mounting screws is enough for what I need to do.

With the base casting mounted on the tooling plate I marked out the center height of the piston on the bearings and cross head. Then the part was placed in the vise to take advantage of its squareness and rigidity. Then I flattened the face where the cylinder will mate to the base casting.

Next I drilled and reamed the hole in the base that the piston rod passes through.

With the same setup I used the DRO to layout and drill the cylinder mounting holes. This particular operation almost got me. The three holes are no equidistant from each other. Two of the holes are only 90 degrees apart instead of 120 degrees apart. Thankfully I caught it before I drilled the holes.

Then I rotated the part and milled the lower cross head guide to dimension.

Next the part was rotated again and the rest of the cross head taken to dimension and the mounting holes drilled and tapped.

Following that the piece was rotated again and the holes for the crankshaft were drilled and reamed.

Then the tops of he bearing journals were spot faced, drilled and tapped for oil cups.

Here is the finished part with the oil cups installed.

Till next time

Tony

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b.lindsey · « **Reply #1 on:** December 05, 2016, 02:10:08 AM »

Very nice Tony, you have already got some of the hardest parts done!! Looking forward to the next installment.

Bill

Flyboy Jim · « **Reply #2 on:** December 05, 2016, 04:57:36 AM »

Looks like a good start Tony.

I'm guessing the #3A means it's the aluminum version. That looks like the only kit they have that has an aluminum version besides the #2.

I wish there were others.

Jim

Don1966 · « **Reply #3 on:** December 06, 2016, 05:59:56 PM »

Great start Tony and will be following you.....

Don

Tennessee Whiskey · « **Reply #4 on:** December 06, 2016, 08:12:22 PM »

I like the way you keep things rolling Tony

. I agree with Jim, after cleaning up behind C/I, ali would be nice.

Cletus

AOG · « **Reply #5 on:** December 07, 2016, 10:13:49 PM »

Time for round 2, making the cylinder. I started by facing one side flat.

That gave my a flat side to put against the chuck. Then I machined the other side. I left the part 10 thousands oversized to allow a facing cut with the boring bar to ensure that the face is parallel to the bore. Then the hole was drilled out to accept my boring bar.

The cylinder was then bored to size and the facing cut made.

Then the bore was lapped with some timesaver.

The part was flipped and the cylinder taken to final length.

The cylinder was taken to the mill and boss for drilling the valve ports was flattened and leveled. This will be one of my reference faces.

Since I was setup for it I drilled the straight ports. Drilling them first means that I don't have to worry about breaking into the valve hole and leaving burrs.

The cylinder was rotated to put the boss against the fixed jaw. The center of the bore was located and set as the zero reference. Then the valve hole was drilled and reamed.

Next I counterbored the port face at the cylinder.

The last thing on that side was to drill and tap the mounting holes for the cover.

The part was then reversed and the port face was counterbored and the mounting holes drilled and tapped.

The next operation was the one that always make me nervous. I drilled the angled port between the face and the vertical ports. I was quite relieved when it went well.

The last operation was to spot face, drill and tap the intake port.

I'll end this with the current family shot (such as it is).

Till next time.

Tony

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crueby · « **Reply #6 on:** December 07, 2016, 10:22:52 PM »

Lot of work in that sequence, very nicely done!

AOG · « **Reply #7 on:** December 09, 2016, 04:14:55 PM »

I got some more shop time this week so here are the results. The next part made was the bottom cylinder cover. I used a bump center to center the part in the three jaw and cleaned up one face of the part.

Then I drilled and tapped the hole for the piston rod.

Then the part was flipped and put in a collet chuck. The outer edge was cleaned up and the center boss cut.

Then the collet was transferred to a collet block and the mounting holes were drilled.

Next up was the top cover

The three jaw was installed and the cover was bump centered to get it running true. Then the center boss was cut.

The part was flipped and installed in the collet chuck. The diameter was then taken to size.

Then over to the mill where the mounting holes were drilled.

With the covers done it was time to make the piston. The blank was turned to size and the ring grooves cut.

Then the center was drilled and counterbored.

The piston was parted off and the piston rod made by turning and threading both sides of the rod stock to the correct size.

Then I assembled everything for an alignment check.

That's it for now

Tony

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b.lindsey · « **Reply #8 on:** December 09, 2016, 10:25:13 PM »

You are making rapid progress Tony. The parts all look very nice so far. IN the last picture, what is that on the near side crankshaft bearing and down the side of the frame?

Bill

AOG · « **Reply #9 on:** December 09, 2016, 08:46:31 PM »

Bill, that's a piece of plastic that I was using to keep from dropping a screw into the cavity below the crosshead. It looks like I forgot remove it all the way before I took the picture.

Tony

b.lindsey · « **Reply #10 on:** December 09, 2016, 10:57:07 PM »

I figured something like that. The engine is looking great though.

Bill

AOG · « **Reply #11 on:** December 10, 2016, 02:04:21 AM »

Thanks Bill

Tony

Flyboy Jim · « **Reply #12 on:** December 10, 2016, 04:41:36 AM »

Looking good Tony.

Lots of similar parts to your and my PMR 2's.

Jim

AOG · « **Reply #13 on:** December 10, 2016, 03:35:13 AM »

I was thinking the same thing. Everything I learned doing the 2 has been directly applicable. The biggest changes are the base and piston valve. Drilling the valve ports is a very hairy operation.

Tony

Don1966 · « **Reply #14 on:** December 10, 2016, 06:42:55 AM »

Making good time Tony and she's looking good.....

Don

AOG · « **Reply #15 on:** December 13, 2016, 01:48:58 AM »

I got a lot done this weekend so let's get caught up. The next part to be made was the piston valve. I started by turning the blank to size.

Next I drilled out one end and parted off the valve.

Then the spools and valleys were cut.

The other end was drilled and tapped then the valve was placed in a collet block on the mill and the cross hole drilled.

Next up was the little fitting that pivots on the end of the piston valve
A piece of hex stock was turned to dimension.

Then the cross hole was drilled on the mill

Then it went back to the lathe where it was parted off, drilled and tapped.

Next up was the gland nut. A piece of hex stock was drilled and turned round.

Then the end was threaded and the piece parted off.

Next up was the crosshead guides. I started by leveling them and skimming the bottom surface to make them flat.

Then I spot faced the mounting pads and oiler pad.

Then the various holes were drilled, completing the parts.

Next I made the crosshead. After squaring up the blank I drilled the hole for the pivot pin.

Then I drilled and threaded the hole for the piston rod.

Next the center slot was milled.

Then the edges were milled out.

With the crosshead complete I made the four supports and some 5-40 nuts none of which I took pictures of. Here is a family shot.

I'm actually further ahead than this but that will have to wait until I recharge my camera.

Tony

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b.lindsey · « **Reply #16 on:** December 13, 2016, 01:58:30 AM »

Not too much left to do Tony. She's looking great. We should have a runner in no time at all!!

Bill

AOG · « **Reply #17 on:** December 13, 2016, 04:51:59 AM »

If all goes well I'll have it running tomorrow

Tony

crueby · « **Reply #18 on:** December 13, 2016, 03:00:11 AM »

Great progress! Looking forward to seeing it go.

b.lindsey · « **Reply #19 on:** December 13, 2016, 05:02:09 AM »

Yes, looking forward to the maiden run already Tony!!

Bill

Flyboy Jim · « **Reply #20 on:** December 13, 2016, 05:07:17 AM »

Won't be long now Tony. When you have this engine finished, I'll be interested to get a comparison of how this build went, compared to your PMR #2.

Are those ER32 collet blocks you have there?

Jim

AOG · « **Reply #21 on:** December 13, 2016, 05:28:43 AM »

They are indeed ER32 blocks. I have a square and a hex block both of which are in one of the pics. I picked them up on a trip to the U.K. A couple of years ago.

Tony

Flyboy Jim · « **Reply #22 on:** December 13, 2016, 05:39:14 AM »

Quote from: AOG on December 13, 2016, 05:28:43 AM

They are indeed ER32 blocks. I have a square and a hex block both of which are in one of the pics. I picked them up on a trip to the U.K. A couple of years ago.

Tony

And in Post #15, 4th picture: They're not only collet blocks........they're a "machinist jack" as well!

I have a set of ER16 collets. Maybe someday I can figure out how to make a pair of collet blocks that use that size for my Sherlines.

Jim

Don1966 · « **Reply #23 on:** December 13, 2016, 04:05:56 AM »

Nice work Tony and also waiting to see it running.

Don

Kim · « **Reply #24 on:** December 13, 2016, 08:03:11 AM »

Looking great Tony! Can't wait to see it go!

Quote from: Flyboy Jim on December 13, 2016, 05:39:14 AM

I have a set of ER16 collets. Maybe someday I can figure out how to make a pair of collet blocks that use that size for my Sherlines.

Jim, that little Taig ER-16 adapter you have for your lathe actually makes a great hex collet block. And you can use it for a square block if you use the flats against the sides of the vice, then use the same sides against the base (clamping on the pointy edges). Not quite as secure as a true square block, but I've used it, and its serviceable. The sides on the Sherline vice are tall enough to make it work. Give it a try!
Kim

AOG · « **Reply #25 on:** December 14, 2016, 12:39:05 AM »

Ok let's finish this build out. Time to build the crank. I started by milling one side flat.

Then it was flipped around and placed against my chuck stop and the other face cleaned up.

Then it was flipped again and and held by the boss. The face was trued up and the center drilled and reamed.

Next up was some mill work. The spindle was centered on the boss and the hole for the crank pin was drilled and tapped.

The part was finished by drilling and tapping a hole for the set screw.

Next up is the flywheel. I mounted it in the three jaw and cleaned up one face.

Then I flipped it and cleaned up the other side. I also drilled and reamed the center hole.

Next I did an initial cleanup on the outer rim.

Over to the mill while I drilled and tapped the set screw hole.

Then I mounted the flywheel onto the shaft and did a final true up.

Next up is the connecting rod. I spot faced both sides of the bosses.

Then the required holes were drilled.

The eccentric sheath was next. It was placed in the collet chuck and bored out.

Then the mounting hole was spot faced, drilled and tapped.

Now for the last part, the eccentric it self. I setup the four jaw and turned the offset.

Then the center was drilled and reamed.

The four jaw was recentered and the groove was cut.

Then the eccentric was parted off and the set screw hole drilled and tapped.

That completes the machining on the the engine (or so I thought). I tried to assemble it and I couldn't get the crosshead in. It turns out that I had misread the plans and hadn't widened out the crosshead area enough on the base casting. I took care of that it want together ok. After getting everything adjusted I applied the air and it took right off. It was running on 15 psi with no gaskets or rings. Here is a picture after the first run.

Now I have to tear it down and paint it. The next posting will be in the showcase.

Tony

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Tennessee Whiskey · « **Reply #26 on:** December 14, 2016, 01:23:45 AM »

Tony, I joke and tell one of my managers she's so slow that it takes her an hour and a half to watch 60 Minutes

You on the other hand can get it done in 45

Nice job.

Cletus

b.lindsey · « **Reply #27 on:** December 14, 2016, 02:14:36 AM »

No video yet Tony?? I'm crushed. It looks great though and will take your word that it's a runner

Bill

AOG · « **Reply #28 on:** December 14, 2016, 02:29:22 AM »

I thought about doing a video but decided against it. If I took a video i knew that I would have put it on the shelf and never looked at it again. Since there is no video the project isn't over so I can try to stay motivated for the part that I hate (painting).

Tony

b.lindsey · « **Reply #29 on:** December 14, 2016, 02:32:35 AM »

Works for me then Tony. I will stay tuned till the very end!!

Bill

Flyboy Jim · « **Reply #30 on:** December 14, 2016, 05:04:27 AM »

Quote from: AOG on December 14, 2016, 02:29:22 AM

I thought about doing a video but decided against it. If I took a video i knew that I would have put it on the shelf and never looked at it again. Since there is no video the project isn't over so I can try to stay motivated for the part that I hate (painting).

Tony

I "resemble" that remark Tony!

My PMR #2 is running, video'd, and sitting on the shelf. I'll get around to painting it soon............. maybe!

Glad to hear you got a runner. You made quick work of it.

What's next? Well other than painting this one.

Jim

AOG · « **Reply #31 on:** December 14, 2016, 09:20:48 PM »

I got it torn down, prepped, degreased and in primer. I will sand it and put on the first coat in the morning. My next project will be an Elmer's engine. Specifically I will be making his number 50 "the educational model". I'll probably get started on it while I'm waiting for the paint to dry.

Tony

AOG · « **Reply #32 on:** December 20, 2016, 06:51:03 PM »

I completed the painting and mounted the engine on a wooden plaque I got from Michaels (a chain of arts and crafts stores). Unfortunately I just don't like the way it runs. The thing leaks air badly. It won't run on less than 30 lbs of air. I'm going to remake the piston valve and see if that helps.

Tony

AOG · « **Reply #33 on:** December 20, 2016, 09:44:47 PM »

That did the trick. I measured the original valve and I was within a thousand of the print value. Then I measured the hole and it was almost 6 thousandths oversized. I think I need to go have look at that reamer. I made a new valve to the correct dimensions and it sealed much better. It's a piston valve so it's going to leak some but I can live with the current state of affairs. Final pics and a video are in the showcase.

http://www.modelenginemaker.com/index.php/topic,6730.msg137710/topicseen.html#new

Now I can go concentrate on my Elmer's engine.

Tony

bwal · « **Reply #34 on:** May 18, 2019, 08:30:19 AM »

Hi,

Is there anyway I can "save" this thread for ease of finding it in the future? I'm about to start on a new project and going off my last project it'll probably take me two years! And I'd like to use this thread as a reference.

If not, at least by re-opening the thread I can find it quicker than using the search function.

Ben.

crueby · « **Reply #35 on:** May 18, 2019, 11:55:54 AM »

Quote from: bwal on May 18, 2019, 08:30:19 AM

Hi,

Is there anyway I can "save" this thread for ease of finding it in the future? I'm about to start on a new project and going off my last project it'll probably take me two years! And I'd like to use this thread as a reference.

If not, at least by re-opening the thread I can find it quicker than using the search function.

Ben.

Ben, what I have done in these cases is open the thread, and make a bookmark in my browser, takes it back directly without searching again.

bwal · « **Reply #36 on:** May 19, 2019, 12:43:47 AM »

Thanks Crueby. I didn't think of that.

Ben.

b.lindsey · « **Reply #37 on:** May 19, 2019, 12:54:15 AM »

Ben, hope you will do a build log as well on yours. It's a nice little engine.

Bill

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Author Topic: AOG's version of the PM -3A engine (Read 8691 times)