Chris's Holly Pumping Engine Build

[crueby]

Been doing some stock prep for the engine frames 'kit'. Bunch of rails cut from 1/2" square bar and the blanks for the pad feet at the bottom cut down from some thicker stock.

And before anyone chokes on the amount of brass I go through, this stock was only about $50, for six engine frames.
Milling and drilling for the frame jig starts this afternoon....

[cnr6400]

After brief self-resuscitation,  I can only say 

When I see Chris with those piles of cut solid gold stock, I know there are great parts to be made, coming soon! 

[Kim]

Looks so pretty just sitting there!   

Kim

[crueby]

To go along with the pile of 'gold', here is some 'silver'   
These are the aluminum and steel blocks for the engine frame jig, cut to rough size, ready for cutting in the steps and drilling lots of holes...

[cnr6400]

Aluminum, silver, it's just 6061 or half a dozen of the other! 

[crueby]

Aluminum, silver, it's just 6061 or half a dozen of the other! 

 


I got the jig support blocks milled to shape, that went easy. Drilling the holes through them is going slower, having to clear chips and add oil halfway through each hole. Also glued the pattern for the holes to the main plate. Not using it for lining up holes, that will be handwheel measured, but it will let me keep track of which holes are drilled and which is next. Pictures of that tomorrow.

[crueby]

This morning got going on the frame fixture parts. Started with the supports that go on top and hold the frame pieces. Six of them are U-shaped to cradle both sides and bottom of the frame rail, six are L-shaped to support bottom and one side. They were milled from some 3/8" aluminum bar. Holes were also drilled/tapped in the supports for 8-32 screws.


Checking the fit, want it to be a snug fit so no movement.

Then made up the main plate from some 5" wide x 3/8" thick aluminum. I used some glue-stick on the paper pattern, printed at full size, to glue it to the plate. Now, I am just using this as an easy way to see the X/Y coordinates for each hole and keep track of which one I'm going to next - I know from past experience on R&D team for printer development that you cannot trust the layout printed on paper - the printers have paper feed errors (distance and direction) plus the paper changes with humidity quite a bit. I zeroed the handwheels on the mill table at the back left corner of the plate, and worked my way across it drilling the holes for the screws, keeping careful track of where I was and how many cranks till the next hole.

After lots of careful drilling, and then counter drilling the holes with an end mill (which was not critical for placement, just needed to be close to center of each hole so the screw heads would go in past flush) the supports were screwed on and some of the rail pieces pushed in to check the fit. Worked out perfect, big relief there!


I still need to drill the holes in the steel bars (left side of picture) that will be used as clamps on the rails, using hex nuts to squeeze them down. The supports were tapped for the screws, so they will stay tight to the plate whether the nuts are tight or not. Also need to make a bar that bolts to the back, using the unused holes in the plate, to make alignment to the mill table easy  at an angle matching the opposite rail piece. This bar will be drilled for t-nuts/screws to bolt it to the mill table. More on that later...
Here is a picture of the back of the plate, showing how the screws are countersunk in.

So far so good, may be able to start shaping frame rails tomorrow.

[ddmckee54]

Chris:

You've probably already said, but how are the frames parts going to be held together, bolts, solder, elf spit, bubble gum, baling wire?

Don

[crueby]

Chris:

You've probably already said, but how are the frames parts going to be held together, bolts, solder, elf spit, bubble gum, baling wire?

Don

All of the above....      Wait, I thought Loctite was just purified elf spit?! 


The way I did the lower pump frames was with mortise/tenon joints milled in, but that had problems with the square cornered holes. For this set I am trying drilling and inserting brass rods to form the tenons, so I can use round holes throughout. The rods, most likely 1/4" diameter, will be loctited and pinned.

[Roger B]

I'm still following in the background    So many fine pieces and lots of swarf     

[cnr6400]

Just remember, if you use baling wire for an assembly, the rusty and kinked used kind is stronger and grips best.............one of these days LocLoose will probably offer it in fluid form for $732.45 a 5 mL bottle. 

The jig work looks great Chris! 

[crueby]

Here is the fixture plate with the angled piece attached, showing how it sits on the mill table and bolts to the t-slot

Easier to see what its doing when its turned around - the side rail that is at the top is now level. If the angle bar is on the other side, the opposite rail will be level. This will be used when drilling the pin holes to fasten the parts, and also for drilling/milling operations to attach all the other little brackets that go on the side rails later. Much more consistant and held more secure than trying to level it in the mill vise.

It also works when the fixture is laid down flat on the mill table - the angled bar rests against the side of the mill table, and gets the angle correct horizontally. I did have to temporarily remove the table lock to get it to fit.


With the fixture down flat, and a blank for the middle rail clamped in place, the angle can be milled on the end by running the mill table left/right for the cut, and moved in for depth of cut.


And the real test for whether it all works - turned the trimmed end of the middle rail around, and it seats up nice and snug against the side rail. 
The rails all have a little bit of a radiused corner, so it looks like there is a small gap but there is not. After assembly, the frames will be trimmed down on the wide faces to final thickness, and that radius will go away.


The same sort of operations will be done on the top of the side rails where they meet the upper crossbar, but there the fixture will be set square to the mill table. For drilling the ends of the side rails, the fixture will be stood upright - the mill column does have enough height for that (checked several times! )

Looks like the fixture is going to work out well - very happy with that!   

[RReid]

That fixture looks like a really clever and effective solution to more than one problem. Nice work!

[crueby]

Thanks Ron,  it's the big brother of the one I came up with for the lower frames, those didn't connect at the top/middle like these, so the jig was only for one side for those.

[ddmckee54]

I of course can't speak from personal experience, but I've been told that Bondo and paint covers many sins things.  (You know, Bondo and paint makes me the welder I ain't.)

Since you're painting everything anyway, those small gaps would be a perfect application.

Don