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Author Topic: PM Research Number 1 - Build Log  (Read 1693 times)

MasonvilleEngines

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Re: PM Research Number 1 - Build Log
« Reply #15 on: February 25, 2020, 05:39:24 am »
Nice setups! Keep us posted.

Len.



Hero

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Re: PM Research Number 1 - Build Log
« Reply #16 on: February 25, 2020, 07:55:48 am »
Excellent post. Provides all kinds of guidance for us lesser beings.

Thanks.
Bob

Nick

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Re: PM Research Number 1 - Build Log
« Reply #17 on: February 25, 2020, 09:12:57 am »
AWESOME build thread!!  8) 8)

Thank you for taking the time to take so many pictures along the way  :)
Nick

krypto31337

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Re: PM Research Number 1 - Build Log
« Reply #18 on: February 25, 2020, 11:52:11 am »
Great write-up!  I always find it interesting to look over someone else's shoulder and watch them make things.

One thing you might want to try for thin parts like the valve covers is to use CA (crazy glue) to temporary hold the parts to a scrap piece of round.  Some heat from a torch or acetone will release the part later.  Learned that trick from Clickspring on Youtube.

My Workshop Blog:  http://doug.sdf.org/

Swift Fox

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Re: PM Research Number 1 - Build Log
« Reply #19 on: February 25, 2020, 12:56:52 pm »
Fantastic build thread, look forward to reading more on your progress.

I do like these engines from PM (particularly the earlier all bronze model), i'd love them to do a machined kit version of this engine. ;D
Your nose is before your eyes, so trust it first!

propforward

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Re: PM Research Number 1 - Build Log
« Reply #20 on: February 25, 2020, 08:52:55 pm »
Thanks all - high praise indeed, and much appreciated. Make no mistake, I am very much a beginner in this hobby, learning a lot all the time, but things are going well.

Thanks for the tips - might well try out the CA adhesive trick for making the replacement bronze inner head spacer that got messed up.
Well everything seems to be in order then.

Steamandoil (Tim)

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Re: PM Research Number 1 - Build Log
« Reply #21 on: February 25, 2020, 11:32:18 pm »
Wow. A lot of time and effort in the posting alone! Thanks for a ton of high quality pictures and narrative. I'll never be a machinist but I love seeing what they do. Really an entertaining thread.
If you play with fire, you're gonna get burned.

propforward

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Re: PM Research Number 1 - Build Log
« Reply #22 on: February 26, 2020, 05:29:26 am »
Since I’ll be posting in real time now, progress will be somewhat slow, but I’m glad to post pics as they become available. I keep a cheapo digital camera in my pocket while in the shop, and the pictures are a handy reference for looking back on, plus it’s fun to share them.
Well everything seems to be in order then.

Belugawhaleman

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Re: PM Research Number 1 - Build Log
« Reply #23 on: February 27, 2020, 08:31:40 pm »
Enjoying this thread . I'm a big fan of PM Research products and service. I've had positive experiences with this company. I think your coverage of the steps needed to build this engine has been great so far and I'm looking
forward to following this thread to its completion. Nice job!😊
PAUL
Civilization is the limitless multiplication of unnecessary necessities.

txlabman

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Re: PM Research Number 1 - Build Log
« Reply #24 on: March 09, 2020, 10:40:46 am »
I am definitely looking forward to following this thread!

Mi Steam

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Re: PM Research Number 1 - Build Log
« Reply #25 on: March 10, 2020, 01:15:03 am »
Very enjoyable tread and keep posting. I am learning
a lot and have to go back to see what I missed.
Carl "There is a better way for everything. Find it."TAE


propforward

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Re: PM Research Number 1 - Build Log
« Reply #26 on: March 12, 2020, 07:31:46 pm »
Thanks all, I really appreciate your kind comments. Life being what it is I've not been in the shed as much the last couple of weeks, and have had to spend my time doing chores, which is a drag. Hoping to get back to the shed this weekend though, and make some more progress. Will post an update when that happens.

Stay well!
Well everything seems to be in order then.

propforward

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Re: PM Research Number 1 - Build Log
« Reply #27 on: January 22, 2022, 08:10:21 am »
I've decided that having the bearing caps ready when I do the next stage of machining on the base will be a good idea, so I made a start on those. Mostly just cleaning up and squaring up.









Now I have them set up and ready to receive the bolt holes:








I decided to add the stepped feature to the bearing caps. Not really necessary, and most builds I have read leave this out, but I figured why not give it a try?





Then I moved on to machining the bearing area on the base casting. I have been having trouble getting my head around how to locate the surface of the bearing area when at an angle. I couldn't figure out how to locate it relative to the center of the bore in the cylinder mounting. But then when I was at work I saw one of our machinists setting up an extremely complex item, and he was showing me how to use gauge blocks and pins to set up different features. Armed with this fresh insight, I was ready to have a crack at this base casting again.

I set up my angle block, getting it mostly square to the machine using a 2-4-6 block in my vise, which I had already trued up. I used the dial gauge to verify squareness of the angle block.



....and checked angle using this caliper. This was a gift from a small business I helped out with some design work. It's a handy tool, but not sure I'd splurge on it normally.



Before setting up the base casting, I used a pin gauge to verify the bore diameter in the end of the casting, and then used the pin gauge to measure height of the rail surfaces relative to the bore.



I didn't take a picture, but I did the same thing to establish the center of the bore relative to the guide rail edges.

Then I moved it to the mill and finished the set up - I clamped it to the angle plate and then clocked it to verify squareness again.



In this next picture, you can see a gauge block and a pin gauge in place against the machined surface where the guide gland goes. Using this, I was able to touch off against the top of the pin gauge, and establish a height to the top of the bearing surfaces. I could also calculate the position of the center of the crankshaft. Easy as it turns out - just some trigonometry. In the picture you can see a spot face and center mark I made some months ago, when I was trying to figure out how to do this. I made the center mark as a visual aid.



 Anyway - decided to have the courage of my convictions and went for it.





The bearing caps fit reasonably well.



One thing to notice is that because of an earlier error when machining the face where the cylinder mounts, the bearing caps are not perfectly located. I did not properly interpret the intent of the design and did not locate the mounting face of the cylinder correctly relative to the datum on the print. As a result I have had to machine more away from the bearings on the base casting than is ideal. I knew this was going to be the case, at this point I am continuing on, correcting things as I go, with a lesson learned. This should still work - it will always look a bit odd, but it's only my third engine, and 1st casting set. There are bound to be learning opportunities along the way. The next one will be better, for now forge ahead.

I'm pretty happy with how the bearing caps fit anyway.

I clamped the caps in place one at a time, and spot faced through the bolt holes, before drilling a tap hole for the screws, and tapping the threads.



Then screwed the caps in place.



After that, I cleaned up the outside and inside faces.



Normally the clean up would be done after bolting the part flat to the table - but I decided this was as valid a method as any, and looks a little "different". Odd? I don't know - put my own slant on it. Slant. Get it?

Anyway, I also dusted off the front edges of the caps to make them match up to the base casting a little better.





After that, I removed the part from the angle plate, and decided this was good a time as any to spot and drill the bearing caps for the oilers.



This is where it sits now. It is FAR from perfect. It can, at best, be described as adequate, but while that is true, there are a lot of successes on this part, in terms of setting up square and true, and learning how to indicate off available surfaces to establish geometries. I am actually very pleased. I was at least savvy enough to not just press ahead assuming everything was right, but measured the part to find out where I was at - as such I think I can recover it and make a working engine.



The two slide rails for example, are off center. But I now have the option to machine the wider one to match the narrow one, and get them both centered. Alternatively I'll machine the guide to suit. Once in place the difference in rails will not be obvious. So I need to give that some thought. Either approach means making mating parts fit what I have, and not achieving parts that are "made to print", which is a goal of mine - but I'm making progress, and enjoying myself. Therefore, I deem it a success, at least on some level.

Next - get the casting set up and drill and ream the bore for the crank shaft.




Well everything seems to be in order then.

propforward

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Re: PM Research Number 1 - Build Log
« Reply #28 on: January 22, 2022, 08:12:39 am »
 I went ahead and drilled and reamed the bore for the crankshaft.

It's close, but there's a mismatch somewhere. Need to evaluate my techniques more. But in the meantime I'll soldier on.



You can see how the nearside is mostly aligned, but the far side interior surface looks off - result of that error made much earlier on that I mentioned.



And sure enough, once the bearing cap is removed, the hole is way off center relative to the locating steps, and indeed a little off height wise, but not by much.



I think it will run. I did not seem to get any "wandering drill" when I drilled all the way through the second side - I drilled the hole out in steps, leaving some stock to clean out with the reamer. So I am confident that the bore is centered height wise to the rails. I will measure that and check.

However, going to call this "acceptable (just)" and keep going. Not sure what to do next - maybe a few of the simpler components, like upper slide rails and spacers.

I checked the crankshaft bores with a gauge pin today. It's .002 oversize, which surprises me a bit given that the hole was reamed, and in a single set up without ever moving the table. Still, that's OK, I will make the crankshaft to suit.



The bore may not be as far off center as I had thought. Looking at it here with the gauge pin in place, the center of the pin seems to fall pretty close to the split line at the bottom of the bearing cap locating slot. I didn't need to chamfer the edges or anything to get the pin in - it popped right in  from the top, so I think I'm not as far off as I thought. The only mystery is the difference in width of the locating slots. Maybe I'll just pretend that's an orientation feature.



This went very well, and now the rails are even about center of the bore in the end of the casting - they are also matched in width.



This means that the mating part will have to be adjusted, but I'm OK with that.

Speaking of the mating part............



I set measured up the casting and discovered it had a good amount of stock all round, and would accommodate the changes in dimension to match my rails (I did that before adjusting the rails), so set about getting some datums.

I set up as level as possible for a first cut - I got a run iut of very roughly 0.005 along the length of the part.



And took off the minimal amount of material possible.



Then on to parallels to clean the opposite side.



The two faces measured parallel as best as I can figure it, so I then used those surfaces to set up and register to clean the back side.





Then it was time to get on to the nitty gritty. I machined the width of the guides and the thickness in two set ups. I set up like this so that I could mill all around the guide tab on one side.



The result...........



This gave me a solid set of perpendicular surfaces to clamp the part square, and get registration to match the features on the opposite side. Notice how the 1-2-3 blocks are staggered - so that later on I can register off the 1-2-3 block face, and match the upper tab to the lower one.



As I machined around and got close to final thickness, I actually mounted a DTI to the quill, and measured the position of the tab face relative to the 1-2-3 block - and hence the lower tab face, so I was able to keep the tabs co planar within about 0.002" as near as I can measure.

I measured the part after machining - pretty much within 0.001 to 0.002 on all dimensions. So I had to do a quick fit check.........



It's perfect!



After so many bungled attempts on previous parts, I was thrilled and overjoyed at how this part has progressed. Everything is square, parallel and true, and it fits into the base casting just so well - it's a real boost. No wiggle or play, and it slides between the rails really well.

So back to the mill, and set up for the tapped hole.



After drilling and tapping that, I popped it back on the bast, along with my temporary aluminum packing, with a drill bit inserted into the tapped hole just to get a feel for alignment with the bore.



I'm very happy with this part - everything went according to plan, no drama, just enjoyable machining. I think this will clean up a treat and look very nice on the finished engine.

Couple of ops left on it - first I need to drill and ream the cross hole, then mill the slot for the connecting rod. But I don't have a 1/4" reamer on hand, so I'm going to wait a bit before finishing this. Should have one this week some time.



Continuing on - I realized last night that on my cross slide I probably hadn't assessed the center of the rounded boss properly with respect to the other final features on the casting - and sure enough when I did a measurement this morning, when I put the cross hole in at the correct dimension relative to the rear of the casting, it will appear off center relative to the cast feature. Haven't decided how to address it yet - I can actually shorten the casting and skim a little off the rear end, or attempt to re round the casting. Or leave it. It will be functionally fine. Probably I'll skim the rear of the casting.

Based on these experiences, and some excellent set up info on you tube, I have resolved to ask myself a new set of questions when writing out a plan for machining castings, to try and force myself to understand the casting before cutting anything.

Anyway, today I worked on the rail and spacers. I saw a technique using gauge pins to visually center the mill to casting bosses, as part of achieving a pleasing overall look as well as dimensional accuracy, so I tried that. The first rail didn't work out so well, and I altered the technique a bit for the second rail. Which frankly didn't help in the end, so I need to revisit this approach. Before machining, the underside of the rails were cleaned up on my little belt sander. That worked well at least.

EDIT: The following pics don't show every step. I cleaned the undersides of the rails first and got them flat. Then squared the side of the rail to my vise using a machinists square. I was playing with the gauge pin approach in the pictures, but then secured the part with the various clamps before finishing all the locating. Obviously I didn't attempt to drill with just the middle clamp, the parts would have ended up spinning across the shop, probably.







As you can see, I ended up off center one end.



I still ended up off center even after drilling assessing both bosses, and then splitting differences in X and Y location.



I tried a similar approach for the center hole. The first one didn't work out, but the second was a little closer.




Anyway, after all was said and done, and having made some simple spacers, the cross slide does go together and the slider slides without rattling, it actually fits quite well.



So, a few steps forward, a few back, but on average more steps forward than back. It can be frustrating at times, but I think I'll win out in the end.
Well everything seems to be in order then.

propforward

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Re: PM Research Number 1 - Build Log
« Reply #29 on: January 22, 2022, 08:14:24 am »
I started the crank shaft quite some time ago. This is as far as I got it.



I decided at the time that I would be better off making the base first, so that the crankshaft could be turned to fit the bearing journals, and that was a good decision.

I swapped over to my collet chuck to proceed. It bums me out that I have to true up my collet chuck every time I refit it - but I suppose expecting to rely on the large threads on the lathe to accurately locate a chuck in terms of concentricity was naive at best. It actually only takes me about 10 mins to align it now in any case. The collet chuck has a set of 4 adjustment screws for fine tuning.





I can get it set up and running true enough that I can't detect run out on this DTI, and the ER collets are a lot better to work with than the 3 jaw on diameters 1" and down.

So - bit of clean up on the face:



Drill center hole:



And clean the diameter.





Then I cleaned up the outer faces of the cranks a bit:



It is necessary now to turn the larger diameters next to the crank to an exact length, to locate the crank shaft centrally in the base casting. It was at this point I decided that it would really nice to have a fine adjustment carriage stop - or any carriage stop come to that. So I have paused work on the crankshaft to make one.

The plan is to get the larger diameters turned to length using the collet chuck to hold each side, then I will turn the 3/8" diameter shafts to size between centers to get best concentricity.

My 1/4" reamer arrived, so I decided to finish up the cross slide. Got it all set up, found the edges and positioned the center of the pin. Did a quick visual with a drill blank to make sure it looked centered in the casting boss.





Then spot and drill. I drilled to about .015" undersize, but drilled out half way to that first.





Then reamed to 1/4"



Checked with a pin gauge - got it spot on this time!



Then set up and milled the slot.



Finding hole center by using pin gauge and a feeler gauge.



I plunged the slot to get most of the material out.



Then cleaned up the sides and bottom of the slot. The end mill was just long enough. Worked well though.



Finished!



And it even fits and slides easily up and down the rails. Will wonders never cease?





Decided to finish off the valve. I had faced and pocketed this some time ago, but was not happy with the amount of error I was getting milling depths. I now have that resolved, and so......





I tickled out the slot until the material to be used for the nut just fit in.



And then the same for the other slot. Again - plunged most material out, leaving 0.01" on depth, then cleaned up.



Finished part - still needs some deburring.





Then I started thinking about some other components. I was enjoying milling so I moved on to making a collet to hold square bar stock, which will be used to make linkage components for the valve drive rod.



The overhang of this aluminum rod did cause some chattering at the end, but by making a finish pass it cleaned up fine.



After taking the shaft about 0.01" past centerline, I rotated the part 45°, positioned the cutter and milled a slot.





Chopped into two pieces, and being used to hold the sqaure stock in the lathe.



That's as far as I got today. Next stage is either the linkage components or go back to the crankshaft.

OK - I made a new holder. Same idea as before, but turned the body down to 3/8", leaving a stock 1/2" lip to stop the adapter disappearing inside the collet, per Marv's recommendation. This has indeed turned out to be a good move.

New holder:



And using it to start making the linkage.



The little holder is not perfect - it is not quite centered. Off by about 0.002 I think, which is really not acceptable - I could center much better than that in a 4 jaw, but my 4 jaw is a bit big for this job. I may attempt another holder. It's actually quite a good exercise for tuning in my milling techniques.
Well everything seems to be in order then.