Art & Inspiration FORDILLAC FLATHEAD IN 1/3 SCALE

Thanks, The detail in your work is fascinating. Have you ever thought of doing a full size version? Would it even be possible? Will be watching for this one to run. Do you have a transmission yet? I remember one but thought it was for a different little engine. Thanks for sharing.

 

Wow

 

Next up is the crankshaft. Since I discovered 1144 steel I make all of my crankshafts from this material. It cuts great and the nicest part is there is virtually no warpage, even when making small cranks like the one for my inline 6 cylinder engine.
I chucked up the stock and supported the outboard end with a steady rest to center drill the ends. I then made a short cleanup cut on the O.D. so that I could indicate it true when mounted in the 4 jaw chuck. The other end was supported with the live center. The O.D. was finished for the entire length. I cut the nose of the crank down to .075 larger than the finish diameter so I could mill flats without compromising the finished diameter.
The flywheel end was also cut large enough over finish to also have flats cut on it.
The flats would be for indexing the cranks when cutting the throws.
While the stock was getting the flats milled I roughed out the main bearing areas. It's so much easier to cut the heavy stock with an end mill than trying to plunge with whatever type of cutter in the lathe.

 

All of the mains were cut leaving .006 for the possibility of warpage after the throws are all cut.
The blank was then put back into the mill vise and the first throw area was roughed down leaving .03 stock.
A set of fixture blocks was made from aluminum. The chuck end will fit the large flange that was left on the stock and the tailstock end will fit the crank nose. Each block has a set screw ground flat to accurately locate on the flats that were milled on the blank.

 

The driving fixture block was mounted in the four jaw chuck and indicated. I made up a brass bushing with a .50 hole in it to accommodate the end mill shank for indicating. In this case the offset is .562 which give a total offset of 1.125 so I had to use a mike standard to get the extra 1.00 over my indicator travel. It's very important when making the fixture block to center the hole exactly in the direction opposite the offset. The reason for this is when setting the block in the chuck it needs to be perfectly centered so that you don't get a crooked offset when mounting the blank.
By this I mean you could have the fixture block offset in that direction and still obtain the required shift for the throws but the longitudinal axis would be at an angle and the throws would have a taper.

 

With the fixture block set true the crank stock was mounted and locked in place with the set screw. The tailstock block was slid onto the end of the crank and the live center was put into it, snug enough to support but not tight enough to warp the blank.
At this point I realized that my special tool wasn't long enough to finish the throws so I had to grind another 3/16 from the sides of the tool blank. I then put the lathe into a lower speed range and started cutting. When you start to plunge in with this tool even though the tip is split it will chatter if you go too deep so you have to be patient and take what it will give you.
As you can see it finished up quite nicely.
Three more to go.

 

All the turning is finished, whew!!. Normally when cutting the throws it's necessary to put some packing between the webs that have already been cut but with the size of this crank it cut without any chatter or deflection. The mains are .750 dia. and the throws are .64 dia. These dimensions were scaled from the full sized flathead crank. I finished up the throws then mounted the shaft between centers to finish the mains. I had left about .008 for a cleanup just in case there was any warpage. I didn't measure with an indicator but to the naked eye it ran extremely true prior to cutting. Now I'll have to make a fixture to hold it so I can cut the stock away from the counterweights and drill the oil passages.
gbritnell

 

I finished the holding fixture so I can cut the counterweights and drill the oil passages. I have used the same aluminum plate that I started with. I just keep adding holes.
gbritnell

 

I set the fixture up on the mill and indicated it parallel to the X axis. I found the easiest way to true up the faces to be cut was to use an adjustable parallel set to the height of the two opposite throws. This would eliminate having to indicate every time I had to rotate the crank to cut another counterweight. I could only cut one side of the counterweights at a time because the closest cap would have to be removed for clearance.

 

All of the counterweights were cut. I have a casting of a V-8 crankshaft that I'm using as a model to do the counterweights. Each set of throws has a different amount of material removed.
The sides of the webs near the throws also needed to be cut at 15 degrees so I tilted the mill head and finished those.

 

All the milling is compete on the crank. All that's left to do is drill the oil holes but I'll have to set up the angle table to do that. The holes need to go in at 25 degrees and although my mill head will go over that far there is no provision to crank it, you just loosen the clamp bolts and rotate it. With the motor being up top I don't know how top heavy it is but I'm not going to try and find out.
gbritnell

 

Today's venture was the oil holes. I cleaned the mill table and mounted my angle milling table. I set the angle close with the vernier scale and then indicated across the face to set it square with the X axis.
The reason for this is because it's not an extremely accurate piece of tooling and as you rotate the table it changes the parallelism of the face. With that set I then trigged the needed angle and checked it with the dial indicator.
The fixture plate was then set up and indicated.
I gave myself some layout lines for the centers of the oil holes before mounting to the fixture plate. The centerline was then set by using an edge finder on the O.D. of the crank.

 

The crankpin was brought to TDC by using an adjustable parallel under the 2 crankpins that are at 90 degrees. Picked up the centerline and then drilled with a #2 center drill which gave me an accurate starter hole for the 1/16th drill.
The 1144 steel cut nicely using a new 1/16th drill. I pecked it about every .10 to clear the chips. I also added a touch of cutting oil although as nicely as it cut I doubt it would have been necessary. I just didn't want the chips to gall in the hole.
With the first hole out of the way and the guidelines, speed and feed noted I proceeded to finish the other 3 throws.
The crank was removed after every drilling operation to chamfer the hole where it broke out into the main journal. The fixture blocks are a close fit to the crank and I wanted it to sit flat in the fixture.
The crank was then rotated 180 and all the steps repeated for the other direction.
It turned out to be a much easier operation than I had envisioned. The only other crank that I drilled for oil was for my 302 engine but that was so long ago I didn't remember how that went.
gbritnell

 

Gentlemen,
The crank is finished. I spent the better part of today, burring, filing and polishing but it was completed without incident, oh yes and tweezing little slivers of steel out of my fingers. I set it up on blocks on my photo shooting stand and took picss of it rotated in different positions. On to the connecting rods.
gbritnell

 

Amazing!

 

Amazing!

 

Wow!!!!

 

Really nice work there, GB

 

That is simply beautiful.

 

Pretty incredible work!

 

Gentlemen,
I made a couple of videos of all the parts to date. It just includes everything I have shown here but is a little more interesting to see them live.

 

It's been a long time since posting but I'm making good progress on the engine. The block and internals are all finished except the piston rings.
I didn't have any actual parts to measure from when I started this project so everything was from photos and comparative scaling. I made a pair of Stromberg 97 style carbs and when I sat them on the intake they just looked too small so I upped the scale by 25% and made two more. This time they looked about right. I made a pair of polished helmet style air cleaners for them.

gbritnell

 

Insane

 

Up next are the breather tube, generator and brackets, fan and pulley and the distributor.
Making all the small parts takes as much time as some of the big ones.
gbritnell

 

The distributor will be a Hall trigger type with an electronic ignition. It will be driven off the end of the cam by way of helical gears that I had cut.
gbritnell

 

I'm always stunned by your posts. Amazing skills!! That crank is a work of art!

 

Wow!

 

What do you mill your distributor caps out of?

 

Sir: You are indeed a master machinist.

 

Hi Ebbspeed,
I use black Delrin. It machines nicely and has good electrical properties.