Flathead V-8

[Roger B]

Beautiful crankshaft   

I also see in the background that you still use a vernier height gauge rather than a new fangled electronic one 

[steamer]

Daaaamn!!!!


 

[gbritnell]

Hi Roger,
Yes I still use an old vernier type height gauge. Even though the eyes are getting old I can still hit it within .001 and if need be I use a magnifier to check. All of my machining is done with a digital readout so the height gauge is used for reference lines or in combination with a (gasp) surface gauge with a DTI mounted.
The only thing I don't like about the height gauge is the way the scriber mounts. When I learned my trade many years ago all the height gauges had the scribers with the flat side up, that way you could touch your indicator tip to it for checking dimensions. On the Mitutoyo the scriber has the flat side down so you have to go underneath with the indicator. I understand this allow the scriber to go all the way to the bottom but I don't like working that low anyway.
gbritnell

[kvom]

I also use a vernier gauge.  I check its zero using a gauge block.  I'm sure George does as well.

[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.

[gbritnell]

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

[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

[rythmnbls]

Beautiful work on the crankshaft, it seems almost a shame that such nice parts are hidden from view when the engine is completed.

Best regards,

Steve.

[b.lindsey]

What a beautiful piece George. Seems a shame to hide it inside the crankcase   Heck I would make one of those if I could and just put it on the mantle or bookshelf as artwork.

Bill

[Don1966]

Dam! that's a georgeous looking crank. Like Bill said it seems a shame to hide it inside the engine. George just when I think you've done your best you come up with something even better. I like..................

Don

[petertha]

Wow that's nice George.
- re that bifurcated tool you ground up, is the center relief so that it can traverse (ie reduce diameter) across the journal end-to-end manner between the weights? If so, do you save this tool only for the last bit of turning to dimension, or its used right from start?
- I'm guessing the corner radius is for fillet operation between weights. What keeps the connecting rods from migrating into these fillets?
- I was waiting to see you break out some cool lapping tool on journals, but alas no. So what's the finishing recipe to achieve the mirror, final dimension? Wet & dry on sticks or toolmaker stones or...?
- I really like your DTI widget. But I cant tell if the block clamps to the mill spindle cylinder or almost looks like the end mill arbor itself.. or maybe either/or?). Can you elaborate? I'm just looking at making one myself. You have the neatest gadget ideas.

[gbritnell]

Hi Peter,

The width of the tip of the tool is a little bit less than half of whatever the journal width is. This allows the tool to pass over the cut made by the leading edge in both directions. With this crank it wasn't a problem because of the sizes involved but when making a small crank the tip of the tool starts to get quite small although a smaller tool won't have the extra side relief on the cutter. Being as I try to mill away the largest part of the material I use the turning tool for the whole operation.

All full sized cranks have radii in the corners. This is for strength and to minimize stress in the corners. When I make my rods, whether with or without bearing liners I put a matching radius on the edges to allow the rod to run on the corner radius. My rods will have .005 clearance on each side so .005 on the sides and .010 between adjacent rods.

To polish the journals and still keep them parallel and round I have rectangular sticks made from Maple wood onto which I glue various grades of abrasive papers. I use automotive wet/dry papers first and then finish up with crocus cloth. The sticks are made long enough to keep your hands clear of the rotating parts.

If you're referring to the DTI that I used for setting up the offset here's what I did. The flywheel end of the crank should always have a large diameter turned on it whether or not it eventually gets cut down. This allows a wider flat to be cut on it for the set screw to located as squarely as possible. That being said the fixture block requires a large matching bore. I don't like sliding aluminum against aluminum (galling) so I used a piece of brass for the plug. I turned the outside diameter with a little shoulder so it wouldn't get pushed too far into the bore and I bored the center hole for the end mill that you see. In this case it happened to have a .500 shank. I also have tooling dowels which are .0005 larger than the nominal diameter but I try to hit the nominal first and if I go a little over I can still use the tooling dowel. It just so happens I hit the .500 right on the nose the first time.
When setting up the block I took the compound off of the lathe so I had a nice area to clamp my magnetic base to. That way I can use the carriage and cross feed to position the DTI rather than having to push the magnetic base while the magnet is activated. With this particular crank the total travel was greater than the 1.00 indicator would give me so I used the micrometer standard as my extra spacer.
A note of information at this point. When setting up the block for the proper offset you also want to check the other two sides for proper centering to the lathe axis. If you don't you will induce a taper between the chuck and the live center. The first picture shows me checking the block. The second two, checking the offset.  Even worse you could warp the crank because of removing stock with a twisted load applied to it.

I hope this covered what you asked if not ask away.

George

[Mayhugh1]

George,
Your crankshaft is nothing short of magnificent. I'm studying your technique closely as I'll soon be trying to make a similar one for my Merlin. Hope you won't mind a few dumb questions later when I get deep into it. - Terry

[gbritnell]

Hi Terry,
There's no such thing as a dumb question when someone is honestly trying to learn something. It's only dumb when they don't really care but ask anyway.
I'm humbled to have you ask anything after following your radial write-up and build.
Thanks,
George

[Tennessee Whiskey]

George, the crank is stunning, but,  what less have we come to expect from you.  I'm with Bill, I would love to have that crank (and the whole engine ) in individual pieces to display as art.  I had a man try to sell me a Dale Jr. race tire made into a bar table( he knew I was a Ford man) ,  I'd rather have a Britnell made part in my display case anyday.  Looking forward to the handshake at CF

E