Model Engineer Beam Engine - Reeves Kit

[propforward]

Anyone want to see a build log? Well, I guess I might as well post it here. I have it going on two other forums and there will be a *GASP* youtube series that you can also avoid.

The ME Beam is a very pretty engine when finished, with quite a lot going on. As a basis I am using the Reeves offering of castings, which I purchased about 2 years ago I think. My initial look over the castings says they are OK - not warped or twisted or anything so I'm looking forward to an enjoyable, completely trouble free and relaxing experience. 😞

Don't worry, I can usually steer myself down paths that bring their own trouble and woes.

So all I've done so far is spend some time with the base plate. As seems normal on casting kits, the way the parts are dimensioned is largely inappropriate, and if not interpreted correctly could steer the unwary quite wrong I think.

For now all I've done is best condition the casting and skim the underside flat. Hey - it's a start. this done in such a way as to maintain enough machining stock on the top side features to get everything where it needs to be.

Best conditioning is the term we used at my last job to essentially balance the set up of a weldment or casting for the best combination of maximum machining stock on all features that get machined, while at the same time not distorting the part with clamping, and then also maintaining visual appeal as needed. What it means in this case is that I measured the casting all over as well as probing it with a height gauge on my surface plate to figure out how twisted / distorted it was. In reality actually pretty decent - about 25 thou variation across the main surface that is to be unfinished, same on the underside, with about 1/16" of stock on most surfaces, so pretty easy to level up and get going on.

The numbers on the casting represent height differences in thousandths of an inch from one corner.



Then up on the mill and skimmed the underside a few thou at a time until it cleaned up. I'd established that the center square feature where the column goes is actually the least out of flat, and indeed that resulted in only skimming about .020" off the highest point to get full clean up. I supported the part on a couple of machinist jacks as well to stop it flexing during cutting. It was a bit of a lightly clamped set up so I just took it really easy. After checking the finished cut on the surface plate there is no rock, so now I can get it clamped really well, best condition it on the table and start on real features.




Not much of a start - on the other hand quite the setting of the foundation.

I see I need to get back into the swing of taking pictures as I go. Blasted YouTube channel has me focusing more on that than still pics. In due course there will be video offerings as well but man they take some work editing.


Stumbling forward at a breakneck pace, I actually clamped the base to the mill table tonight. It is clamped on top of a sacrificial aluminium plate which has been skimmed flat on both sides.




In order to get it lined up and ready I indicated the 4 red surfaces (edges) of the raised square, and the two long sides (blue).




I didn't drag the indicator - just went in and touched at several points along these edges, checking the DRO for offset. The part is basically within .005 along each of these 4 edges. They are surprisingly straight, which is why I used them. This is about as evenly set up as I can get it.

With it aligned, I will establish the center of the raised square in both the X and Y directions, and that will be the datum for drilling all the holes. Seems to me that basically everything on the engine is relative to the center of the beam column (and therefore beam pivot).

The heights of the various steps on the base will all be machined relative to the machined top of the square also. In this way, all these machined surfaces will be parallel to each other, so that everything is as square and true as it can be when assembled. What I am going for here, is an engine that runs without having to do much "bedding in".

So I started re-dimensioning the drawing to better show that and make for an easier reference. I did it long hand, by just doing the basic maths and writing it out on a copy of the drawing, but it started getting far too messy and I couldn't read my own writing.



It was more legible to make a basic model and show all the features using ordinates - and I can plot this out nice and big.





Also - I am using UNC and UNF threads instead of BA threads, just because of tap and fastener availability. I did a comparison of BA thread OD's and TPI numbers against the UNC and UNF series and found threads that are close enough. Not equivalent - they won't play together - they are just physically very similar in size. Should work out OK.

Then my evening of shed time ran out. So maybe tomorrow I can actually get some machining done. It's all in the prep anyway - do that right and the machining goes much more smoothly.
 

[propforward]

Of course, I put this in the wrong effing spot.     

[4GSR]

I moved your thread over to the correct topic category.

[34_40]

Of course, I put this in the wrong effing spot.     

No matter where it landed... it's going to be great! I really like your "foundation" approach, it all starts there as everything rises above it.  You know I'll be watching 

[propforward]

Thanks for moving it - and thanks for looking in. I did get a bit of time at last to actually cut the casting.

Simple enough really - touch off on the highest feature (having first measured heights of all the features to know what was to come off), fix the quill, touch off by raising the knee, establish the highest plane and raise the knee accordingly to clean off the other surfaces.

One feature had to be centered and machined on the width also to accept a bearing block later on.

This just shows my scratch where I recorded data about stock and heights etc.



Then the machined article. Ran out of time now so can't get the various holes in at the moment, but it's all set up well for that.





Hoping to be able to knock out a video on it in some down time later.

[propforward]

Aaaaaaaaaaaaaaaaaaaaand here's the video, which explains better than the post what I am trying to do. Need to up my game on making detailed posts as well as improving my machining.

[TerryWerm]

Thanks for posting, Stewart!   

Crap! I cannot remember is it Stewart or Stuart??        
I would prefer to get it right! If memory serves me correctly it is the former.

Anyway, I am looking forward to following along on this thread. I have long been a fan of that engine as well as some others in the Reeves line. Bravo!

[propforward]

Thanks for posting, Stewart!   

Crap! I cannot remember is it Stewart or Stuart??       
I would prefer to get it right! If memory serves me correctly it is the former.

Anyway, I am looking forward to following along on this thread. I have long been a fan of that engine as well as some others in the Reeves line. Bravo!

The latter (Stuart) is correct - but I've been called a LOT worse than the former so I'll gladly take it. 

Glad to have you following along - I'm looking forward to a very enjoyable build. It does make for a very pleasing engine - lots of motion, and there are plenty of new machining challenges for me along the way.

[propforward]

I got time to drill holes. If you want you can watch the process here. It's just drilling holes. I've been kept from machining somewhat by freelance engineering so this is all I got to do for the last month.



Bonus! Shedland Christmas light show spectacular!



Not much to it really. I did a minimum clean up of the main bearing mounting surface and also the pump mounting surface. the plans don't call for that but I want those surfaces parallel to the other machined surfaces, so that all the final engine components play nicely together.







With that done I mounted a drill chuck - a cheap (it wasn't that cheap) and nasty import chuck which had loads of run out in it - fixed by clamping the jaws of the chuck to a nice piece of drill rod in the lathe and then turning the shank lightly - and installed a center drill and went around my ordinate dimensions and pecked every drill location. That was simply to look at the pattern and see if it was centered well enough on the casting.

I didn't take a pic of the pattern.  :facepalm:

I was happy enough with it - it looks well located overall. The patterns on the round boss are shifted relative to the boss center by about .015 in the X and .020 in the Y, which is easy to see by eye. I think this boss will be completely covered in assembly and not noticeable. If it is noticeable I may put the casting on my rotary table and lightly skim the diameter just to true it up.

Then, happy with that, I went around and drilled and tapped.



Followed up by dusting off the outside edges of the base to make them straight and clean. I also cleaned the flash out of the openings in the base. Did all that by eye and by feel just to get the ugly off, as Joe Pie says.





And that's that for the time being.



I have a little hand fettling to do yet. I chose not to do the base mounting holes quite yet as I have not decided on the final presentation - although really what else am I going to do other than bolt it down through those bosses? Need to hand fettle them round first where I had to cut into them. Or maybe mill them off altogether all the way round - hence not worrying about drilling them quite yet.

Video!

[propforward]

I made a thing.

I had some communications with a writer at Model Engineer, and was discussing the shortcomings of the base casting on this model. In the end, rather than wait until later, I went ahead and completely removed the circular boss and the two rails next to it. Those features are way off center and will look horrible if left in place.

As a result, I needed to either make the boss as a new disc on its own - or do as I ended up doing and incorporate the disc into the outboard head.

The head is a circular wedge shaped item - you can see it here in cross section, at the bottom of the cylinder.



I made mine like this, to replace the boss at the same time.



Before I go any further, I want to make it clear that the approach I have taken is one of achieving best accuracy I can, because I felt like it. The wedge feature can be achieved by simple marking out perfectly well - in fact I'm sure the engine would run fine if the head was just made with a flat, non angled face. I just decided to go this route because I find it satisfying.

So first off a piece of 2" steel rod went into the lathe. 2" is the largest diameter I can fit through the chuck and spindle, but that's pretty good - saved me having to saw off a lump and make more scrap. That was turned to a top hat shape at final OD of the part that fits in the cylinder - at .0005" under the nominal diameter of the mating bore (when I get to that).



Incidentally - and this is a bit extravagant but REALLY nice - the domestic authority desired a new TV in the house so I repurposed the "old" one as a monitor. It is in full view of lathe and mill. I didn't really think it would work out so well but it is unbelievably nice to have drawings magnified right there in view.



So then that was parted off, turned around and the dowel hole put in the back side.

And there is the top hat - all very simple. A fun bit of turning.



So, the fun bit is getting the angled face on it at the right height and clocked correctly to the bolt pattern. Not all that hard - and as mentioned, if one were to eyeball it and mark the height front and back, paint some blue on, scribe a line etc it would all work out.

But I decided to make a holding fixture out of a piece of scraptonium, including a mating dowel pin hole at the center, the bolt pattern in the head / ring and another dowel pin for a tooling ball. The tooling ball acts as an easy to establish reference, the holding fixture is then angled making use of a sine bar.

I'm changing all the BA threads over to UNC or UNF threads which are easier to deal with stateside. There are close enough sizes. Not equivalent – they won't play together – just similar physical sizes. I tabulated the whole arrangement. I was surprised I couldn't find anything already done, figured that must surely have been done and shared before.

Anyway – the fixture block was all squared up and the center hole drilled and reamed, and bolt pattern added. Here it is tapped with my home-made small tap holder.



The idea of using a tooling ball to establish location actually came to me after making the fixture to that point. My original plan had been to use a dowel pin, but it would have been difficult to keep perpendicular to the vise jaws. The tooling ball is easy – here is a reamed hole being added. I'm using a kool mist mainly to blow chips away so nothing gets jammed in the reamer to make the hole go oversize.



Tooling ball fitted – a nice close, slip fit.



So, this drawing helps to explain the point of the ball.



The drawing has the dimension from the top of the ball to the finished wedge surface – so now you can see that it is possible to set up the fixture in a vise on a sine plate, touch off an end mill on top of the ball (by way of a feeler gauge so as to not damage either end mill or ball), and then bring the tool down (actually the mill knee up) until dimension from top of the ball to finished surface is reached. Now the wedge is very accurately created.

Although I have CAD and it's easy to measure the dimension needed, I like to do the trigonometry. I'll show the triangles here and how that works for the fun of it. I feel like making the effort to do the maths increases overall understanding of geometry – and it's just a bit of trigonometry. I drew this up to show the relevant calculations and geometry.



Hopefully that's self-explanatory. For anyone interested in the details I will go through the calcs on the video I am putting together for this, but basically the numerical dimensions are the known values – dimensions desired on the final part etc, and the dimensions in letters are what have to be calculated to get the vertical dimension that references from the top of the tooling ball to the finished angled face, when the part is set up in the milling machine.
So OK – with that known here is the set up – using a sine bar to get the angle as accurate as possible. Yes – more trigonometry! I expect you all know this. The center distance of the pins on the sine bar are 5" apart, so to set the angle calculate the height of a stack of gauge blocks to put under the rear pin. Sin (5.572) X 5.0" is the calculation.
Enough waffle – pitchers here.





So then after touching the face of the end mill off on the top of the tooling ball (using a feeler gauge) it's just a matter of raising the knee gradually and carving away the material.







Simple enough and quite satisfying.

2 parts down, lots more to go.

[TerryWerm]

FISHTURE?   Stuart, I believe you have something else on your mind, but opening day isn't for another 19 days.  


Or, are you just trying to see who reads your post? 

Either way, I enjoyed the read and the pics. Keep 'em coming!

[propforward]

I'm not much of a fisherman honestly. Tried it - enjoyed it - never catch anything. I just started calling it a fishture one day and well, now it stuck. 

[propforward]

Video for the angled head here: