Elmer's #19 Standby - Arnold back to basics

[arnoldb]

I've been extremely busy of late and shop time was minimal.  While I'm making progress on the MEM Corliss, that is currently slow-going and mind-numbingly boring with making the fasteners needed to finish it.
With an itch to just get into some simple engine-making for a change, I decided to have a go at Elmer Verburg's #19 engine called "Standby".

Over the last 4 years or so, the contents of my shop have exploded.  I started with the well-kitted out Myford lathe and a drill press.  With lots of tools bought and many others home-made, building engines have gotten much easier.  So for this build I decided to go back in time a bit.  While I will use the milling machine, I will not use the DRO - it's back to layout on workpieces, milling to the line, and machining will happen from hand-wheel readings.  Got to keep the old hand in and remember things like backlash for a change.

Elmer's engines are all designed around imperial stock sizes.  In another thread it has been mentioned that it's becoming harder to get such stock, and in my part of the world it's all metric.  One option is to re-machine metric stock to imperial sizes - but this can be pretty wasteful and with the high cost of material does not sit well with me.  Another, and often much-easier, solution is to scale the plans using a different factor than 25.4.  A factor of 24 gives a slightly smaller model where for example 1/4" becomes 6mm.  A factor of 32 makes for a bigger model, where 1/4" becomes 8mm.

I use a slightly different method than pure factor-scaling.  I convert the dimensions to metric using the true 25.4 factor, then have a look at the result and use the most convenient metric size up or down stock I have.  This does require a bit of thought though; as one must first look at all the parts that will be affected and compensate on the different bits to make things match up.  For Elmer's simpler engines this works well and there have not been any major problems making any of the ten or so engines of his I've done to date.  The only "tricky" bits are figuring out which dimensions are crucial - these normally center around porting and timing, so it pays to first figure out exactly how the engine works before deciding on changes and sizes to use in those areas.  Another thing to look out for are fastener sizes - in general I use M2 for #2-56 and #3-48, and M3 for #5-40 in Elmer's builds.  These are normally not critical, and the only "gotcha" to look out for is that the fastener heads / nuts will fit.

Enough waffling...  If anybody have any questions or comments during the build, please feel free to interact 

I started of with some bits of 6mm aluminium plate for the column and base.  The base should be around 3mm from the plans, but it's thickness is not important at all:


To get rid of the worst surface crud on the plate that will be the column, I rubbed it over some 320 grit emery paper lying flat on the piece of glass that serves as my surface plate:


All edges on the workpiece was bandsawed and pretty rough, and the workpiece was still a lot over size, so off to the mill to tidy it up a bit before I could start lay-out.  I don't own parallels yet, so I use whatever is convenient to set things up in the vise - here a small square is used as a parallel:

I don't tamp down the parts if using something like the square - I just firmly press down on the workpiece while tightening the vise.

A light pass cleaned up the first edge.  I used an 8mm end mill - that's wide enough to clean up the 6mm stock in one go:


Then the workpiece was flipped around, and the other long side cleaned up as well.  I don't do endless feed and speed calculations; I just look at the size of the chips coming off and listen to the sounds of the machine to get an indication of whether things are about right.  This was a pretty rough pass as you can see from the surface finish, with fairly big chips coming off:


I follow the words of Philip Duclos quite strongly; he often mentions that one has to clean the vise thoroughly, as well as de-burring the workpiece each time before re-mounting.  A large paintbrush does the cleaning for me:


To square up one end of the workpiece, I clamped it up using an old business card against the movable jaw of the vise to take up any imperfections and provide extra grip:


Then milled the end square.  As you can see, the workpiece is bottomed out against two home-made "parallels":


All squared up and burrs removed from last milling operation.  Most of the time I use the fairly fine-cut flat file for de-burring:


Some "layout dye" spread on the workpiece - stuff like "Dykem" is unobtainable in my neck of the semi-desert, so I often use a permanent marker, or in this case just permanent marker ink from a re-fill bottle applied with a cotton bud (q-tip for those in the US  ):


Next I decided on reference edges to use for the lay-out.  In the following photos, the reference edges are the top and right-hand sides, so all calculations and measurements for laying out were done from those.

When calculating and converting fractional inch dimensions to metric, I normally just jot down things and convert to the common denominator.  I also combine the measurements to calculate each from the reference edge; this minimizes accumulative errors:


Then I use the digital caliper to lightly mark things out - heavy scratches in the workpiece are difficult to clean up later:


If the caliper is off by 0.01mm or so, it's not a biggie.  That's less than half a thou and with manual positioning nearly impossible to hit on ordinary hobby equipment like mine.

Just in case the ink gets rubbed off during handling, I use the point of a scriber to press a dimple at the intersection markings...


Then lightly punch each intersection.  The tip of the punch easily locates in the dimple made by the scriber earlier:

Of course, punching does not happen on top of that glass plate.

Next it's time for some machining, so the post will be continued later.

Kind regards, Arnold

[Jo]

that is currently slow-going and mind-numbingly boring with making the fasteners needed to finish it.

You should have tried doing all of them for my DTC 

Then I use the digital caliper to lightly mark things out -

Naughty boy.. I do that as well 

I am with you Arnold this idea of needing a basic engine build running alongside a more complex one. The S&P seems to have been running forever but fiddling around with the little Tangye has been a breath of fresh air.

Looking forward to seeing this come together

Jo

[sshire]

Good one, Arnold. Elmer's designs are forgiving enough (for the most part) that this should be no problem for you.
My first engine (2.5 yrs ago) was Stan Bray's Slim Sam. I had no lathe, no DRO. The turned bits were chucked in the mill spindle with the cutting tools clamped in the vise. I think we should all make one engine every so often without benefit of all of our neat tools. (My Starrett electronic micrometer displays to 6 decimal places. I wish my mill and lathe were that accurate).
I recently watched one of the WW2 South Bend instructional movies. All dials, 6" scales and chalk for marking.

[wagnmkr]

This will be an interesting thread ... basics are good ... especially for a newby like me.

Cheers,

Tom

[steamer]

Awesome thread Arnold!   

I'm watching!

Dave

[tvoght]

Good to see you in the shop Arnold.

This promises to be a thread that beginners (and those in need of rehabilitation) can be referred to.

Thanks for detailing your methods and the reasoning behind them.

Takes a special kind of person to have a working DRO and to switch it off!

--Tim

[arnoldb]

Thanks All 

Jo, I could have used jenny calipers (odd-leg calipers) and a rule instead of the digital calipers - especially if all measurements fell nicely on whole or half mm sections.  In fact, I did use the jenny's to mark out the width-wise locations of the screw holes and bearing hole, as they ended up at nice 2, 6 and 8mm sections.  I took a photo of setting the jenny to scribe the 6mm width; will post that below. 

Stan, yes, it's nice to have super-accurate tools.  But then, once one goes past a certain level of accuracy things become very temperature dependent.  For example, the air spindle on my (yet to be commissioned) tool and cutter grinder has a warning label on it not to operate it below 21^oC...  I've noticed the temperature effect on some of my tighter-built engines as well - some tend to run better when it's cool in winter, and others when it's warm in summer.  So for us hobbyists, maybe it's a good thing not to chase "ultimate" accuracy - it might just bite back . I agree with you on Elmer's plans  - most of them are very forgiving.  So far from the ones I've done, the only one that was a major challenge was the Kimble...

Thanks Tom  - if you have any specific questions or want more detail on some of the processes those are very welcome - please don't be bashful about asking.  I'm not much more than a newbie myself so may not necessarily show the best or only way of doing things, so anybody with ideas on doing things in simple ways with the minimum of tools are welcome to add suggestions.

Tim, switching off the DRO was easy...  I thought KEEPING it switched off would be really hard to do, but so far it's actually been a lot of fun.  More activity for the brain cell, and in general a much more intimate interactive machining experience; something I'd nearly forgotten existed on the mill.  The DRO is really nice to have and use, but it actually takes some of the challenge out of machining  .  I didn't do a whole lot of machining on the mill before fitting the DRO, so never got truly hands-on with it.  Maybe that's why I love working on my "Old Girl" (the Myford) more than any other tool in the shop - nothing fancy there and she has a couple of quirks (besides being a Myford, that is  )


I mentioned the jenny/odd-leg caliper above.  I didn't take any photos of it in use; just the one below to show setting it to 6mm width against a rule.  IMHO, they can be useful, as long as one can set it against marking lines on a rule with the needed markings - for this build I'd need a rule with 1/32" divisions in addition to my metric rule shown, as I'm mixing up imperial and metric measurements in the build.  Using the rule shown, I could set it to approximately 0.5mm accuracy if I use the top scale on the rule:

The thing is, it's much easier to be a "naughty boy"  and use "cheap and cheerful Asian made" calipers for scribing as well - it gives the same result, if not better.  I have actually honed the outside edges on the digital caliper shown in many of my photos to sharpen them up a bit.  Would I do that to a, for example, Mutitoyo brand caliper if I had one - definitely not.

On to some machining.
On my mill, positive in-feed as read from the dial on the X axis is with the table moving from right to left.  Positive Y infeed on the dial is with the table moving toward the back of the mill.  So, in order to get easy-to-use positive incremental readings on the dials, it's easiest to zero the dials on a reference point on the workpiece on the left, back part of the workpiece.  To make it easier to compensate for backlash in the lead nuts, I prefer to take backlash up in the positive direction as well - so that If I locate the reference point, any positive feed on the handwheel will result in immediate movement of the table.  I hope that's not confusing  - maybe the following will share light on it if so.

The next photo was taken along the x-axis of the mill, from the right hand side.  A sharp pin would have been better to use than the drill bit shown, but I couldn't find a suitable sharp pin, so I went with the 1.6mm drill.  I'm using it to set the zero reference point on the Y axis.  I turned the mill spindle so that the point of the drill bit showed it's V shape in profile, and that the tip is just a very short distance away from the surface of the workpiece (in fact, it could have been even closer...).  I moved the X axis away from the spotted hole position on purpose - it's easier to set things independently for one axis at a time rather than right above the hole position.  Then, looking at things from the same point of view as the photo was taken, I turned the Y handwheel in the positive direction to feed the workpiece in so that the tip of the drill bit's V was centered on the line.  Then I turned the mill spindle by hand through 180^o and checked the alignment again.  This rotation serves a dual purpose.  If the next visual indication is far off-center, the drill bit might be bent, so one can detect that.  The other is to find the center slightly more accurately.  I've noticed that even my best quality center drills doesn't indicate true on the line using this method if only using one side to check - even though they do drill fine center holes.  So what I do if there is a difference between the two orientations of the drill, is to "split the difference" so that there is an equal amount of deviation from the tip of the drill's V point to the center line - always making sure to make up the feed for the last adjustment in the positive direction to compensate for initial backlash direction from the reference point:


After locating the Y reference point above, I set the adjustable collar on the Y handwheel to zero:

(Difficult-to-get photo; the DRO X scale is in the way at the top)

The X reference point was set the same way and the X handwheel zeroed.  The next photo is taken from the front of the mill along the Y axis, and even though it looks like the drill bit is directly above the marked hole position, it is actually about 2mm more toward the back of the mill and directly above the line:


Obviously I'd moved away from the Y zero point set in the previous photo to set the X zero point, but it was simply a matter of feeding the table slightly past where the reference point was toward the front of the mill, and then feeding back in to read 0 on the dial.

Now for some turn-counting and handwheel reading.  My mill has 3mm pitch leadscrews on both X and Y axis.  One can be brave and mentally try to keep track of all the feeds needed.  I'm a wimp though, so prefer to work things out and jot it down first.  Going back to the calculations I'd done earlier on the piece of paper, I calculated the amount of turns and scale reading to go to for each hole.  Then I jotted that down in a short-hand notation I use ( a turns b.bb mm).  For example, 3t1.0 means three full handwheel turns from 0 to 0 on the scale, then an additional 1.0mm - this would give 3x3mm+1mm = 10mm of feed.  On the bottom part of the page, I jotted down the coordinates for each hole in a reference pattern, as well as two arrows showing direction of feed - just in case I got interrupted and forgot...:

If you're sharp-eyed, you might notice a "problem" with one of the coordinates.

Then it was back to the mill, and at location (0,0), I spotted the first hole (even though there was a punch mark for it):

By the way, that's not a true spotting drill...  Its a broken 1mm center drill that at some point I ran in reverse against a grinding stone to "true up" the broken point a bit.  It functions surprisingly well as a spotting drill though 

The hole was drilled next - easy-peasy with no wandering at all:


On to the next hole - same reading on the X axis so that was left alone, and two full turns and 2mm dialed in on the Y axis to get the needed 8mm Y offset:


Rather than adjust both X and Y for the next hole, I left Y as-is, and dialled in the 6 turns and 1mm on the X axis for the next hole:


On location and ready to drill:


That hole was drilled, and the last one as well - simply by over-feeding the Y axis again to make sure backlash could be taken up on the way to (y=0) for that one.

The bearing hole was left to do - and that's where I picked up the problem made in my notes earlier...  The 5t1.7 offset I jotted down was incremental and based on a starting reading of "0" on the X handwheel, but it's last position was on a reading of "1".  As this was the last hole, I didn't bother too much, and fed in 5 turns and to a reading of 2.7mm on the handwheel to get the correct location.  The Y readings weren't affected, and as the last Y reading was at "0", I just dialed in the 1 turn 1mm offset needed.  Then I drilled the bearing mounting hole:


Some more lay-out followed:


Time for a bit of a break in the thread again 

Kind regards, Arnold

[b.lindsey]

Nice start on this on Arnold and a good one for newer hobbyists to make as well as a step up from an oscillator. The detailed pictures will be a great help too!

Bill

[EmanMyford]

Hi Arnold, Thanks for taking the time to post this. This is great info for beginners like me.

Kind Regards.
Ewald

[smfr]

I quite often use the "skinny drill" technique to locate a punch mark too. Something I do that you didn't mention is to actually lower the quill so that the drill touches the work; with a thin drill, you can see it deviate to one side if you're not centered. As you say, rotate the spindle 180deg between tries though, to account for any runout in the chuck or a bent drill bit.

Simon

[Alan Haisley]

Lacking DRO's myself it's great to see a dial twiddling build and the methods for keeping track of the dials.

Alan

[arnoldb]

Bill, Ewald, Simon & Alan, thanks for checking in Gents

I like the "skinny drill" name Simon gives for the centering technique.
It's a variation on what I described - and a way I've found especially useful on the drill press in the past when drilling pre-punched hole locations.  Centering the thin drill in the punch mark rather than picking up readings along the X and Y lines like I described works just dandy for one-off holes in the mill, or when one's not going to use the handwheel readings to count turns and measure distances.  I've found setting to the lines rather than the hole for pattern-drilling slightly more accurate, but if the first hole for a pattern is spotted in an accurately punched center hole, it will work just as well - Thanks Simon!

Time for a wee bit of an update again...

In the last photo I posted I'd laid out the outline of the column on the workpiece.  The horrible-looking punch mark was for a hole to leave rounded corner later on.  It's not dimensioned on the plans, but is shown as a rounded corner.  I have a hunch Mr. Verburg intentionally left little details like this out of the plans, as it's not a critical dimension and open to individual interpretation.  I guesstimated that a 6mm hole would be about right so after marking out the basic frame layout, I added 3mm to the height thickness and width of the column base measurements to mark the spot.  That was located and drilled using the "skinny drill" method, this time centering on the hole just like Simon described:


Next it was off to the bandsaw to saw away the excess from the workpiece to shape the column.  A hacksaw would have done just as well, but I'm a lazy rotter and it was hot here, so I didn't particularly fancy the manual exercise.  A simple job, but there's a "gotcha" I can add here.  When sawing into a hole like the one drilled above that will form part of the looks of a workpiece, the last bit of sawing takes a bit of additional concentration.  Once the cut breaks through into the hole, it's all too easy for the blade to slip through and cut into the nicely rounded corner one wants to preserve... :

Sawing on the "off-cut" side of the line helps a lot as well.  Closer to the line means less clean-up work, but also makes it easier to make a stuff-up in the process...

That was then taken to the mill, and milled to the lines with a 6mm end mill:




After de-burring with a file and another rub over 320 emery things started to look up.  The "steam" passage is specified at 1/16" - which pretty much translates to 1.6mm.  The 1.6mm drill bits I have are a bit on the "short" side, and I don't have any longer length ones, neither are those available here in Windhoek:


I needed to check the drill length - the bit of the tip left protruding into the bearing mounting hole must be there, as once the bearing is fitted in the mounting hole, the hole must be extended into that as well.  That leaves very little left on the drill bit to chuck up when going full length into the hole - and I don't particularly like chucking up that little...
My 2mm drill bit is a bit longer, and after checking over the plans, that will also work for the port hole - and might actually add a bit of performance to the engine in the process:


Port hole location laid out, but this time, intentionally not punched:


Mounted in the mill vise and set vertical with a small square:

I love this little square with the "foot" on it.

The hole was located using the "skinny drill"  method on the lines and spot drilled - after first checking that I'd be able to remove the spotting drill and mount the 2mm drill bit without having to move the mill tables at all:


Why all the fuss about not punching this hole, and then not moving the mill table between spot drilling and then drilling the hole?  I tried to minimize any possible drill bit deflection as much as possible at the start of the hole.  When starting to drill a deep hole, a tiny amount of deflection at the start can translate to a lot of deflection once the hole is to depth...  A punch mark can still deflect the spotting drill slightly, and the thin drill to follow will then start off slightly deflected as well.  This does not guarantee 100% success on the drill not deflecting in the deep hole, but at least helps a bit.

On to some drilling.  Another thing that can very quickly make the hole wander is too much feeding pressure.  I literally use a single finger on the quill feed for small drills to feel how much pressure I'm applying - it only takes a small amount.  And I look at the chips coming out of the hole - a steady stream of fine spirals is good in aluminium.  There's different opinions about how deep one can drill before starting peck-drilling; I generally immediately stop once the chip spirals stop feeding themselves out of the hole - that indicates that the drill tip is getting clogged up.  This photo was taken when I reached this point:


That was about 15mm down the hole - and time to start peck-drilling and the addition of a bit of lubricant as well.  My personal preference for lubrication for aluminium is methylated spirits - I keep a vinegar squeeze bottle with a tiny hole in the spout filled with meths and about 20% water added around for this.  The water dilutes the alcohol a bit and makes it less smelly; with the shop fan running across things, I don't get any fumes at all:


On to the peck drilling; I've found I can go about 5mm at a time and with the meths added, the chips will nicely fall off the drill bit after every removal.  more than that at a time, and the chips will stick to the drill bit's tip, but will come off easily by running the cleaning brush against the drill while it is disengaged from the hole.  I just always make sure to add a couple of drops of meths in the hole and that the drill bit is completely clean of swarf between each "peck".  I'd started with the drill bit chucked up fairly deeply in the chuck, and at about 75% of the hole depth, I had to stop and extend the drill bit further out of the chuck to be able to reach full depth.  Here the hole's done:


Even with all the precautions, the hole did wander slightly - but that's not a disaster; this engine will run with it like this:


More layout for the mounting holes - this time just with a permanent marker:


Back to the mill, and I drilled and tapped the mounting holes.  The plans calls for #2-58 which is closer to M2, but for mounting this, M3 is a more convenient size for me, so that's what I used.  Meths used for "tapping fluid" as well:


To start to tidy things up a bit, I spent some quality time rubbing the workpiece over the 320 emery sheet.  Here you can see how the machining marks are starting to disappear:


I'd forgotten to take the corner off - so I just scribed it up at 45 degrees:


And visually positioned it in the vise.  This is purely cosmetic, and not at all critical:


The corner milled off - just approximately to the line:


After a final bout of clean-up, the column was pretty much done.  I like the "brushed" finish the 320 grit paper gives on aluminium, and that's how it will stay:


If you're sharp-eyed and know this engine, you might have noticed that the column's not quite done yet 

On to the foot - first the mark-out:


Off to the mill, and an action shot of just milling to the line:


The holes followed - with generous counter-sinks to make sure an M3 countersink screw will sit just below the bottom plane:


The (to me) obligatory rub followed - making sure I kept the "grain" direction on the foot the same as that on the column.  It's just a small detail, but should make a difference in looks later on:


Well, what do you know...  It fits together  :



Time for a break again...

Kind regards, Arnold

[b.lindsey]

More nice progress Arnold ! This should be a good primer for making a first or second engine.

Bill

[smfr]

Nice work Arnold, and I like your surface finishes. 

Simon

[Don1966]

Great surface finish Arnold and nice work. I do like your lubricant and need to try it out.


Don