Million Dollar Skunksworks Kirkham

[David Kirkham]

Don,

Thanks for the tip! I'll post more pics soon.

David

[David Kirkham]

Gents,

And now for the push to have this baby driving by Thursday (our track day)!

David

[David Kirkham]

We were thrown a HUGE curve ball this past week. We have a CNC tube bender and we needed some 3/4 tooling to make the body tubes for our ride. The supplier kept putting us off and putting us off and putting us off... Finally, I told Sandwich to tell the guy either it showed up this week or we were going to make it ourselves. He laughed and said it was too complicated for us to make and that it would take us way longer than the 5 extra weeks he was quoting us...



Telling me I can't do something is a "no-no" around here. Waiting on this car is NOT an option.

Truthfully, the part is pretty hard as the tolerances are very tight. To complicate matters further, 17-4 SHRINKS in heat treat, so you have to make the part over sized on the bearing surfaces and then "guess (educated guess from our long experience with 17-4). Sandwich was busy so it fell to me to baby sit the part. It took 3 passes to hit the tolerance. As you can imagine, it makes you sweat when you are moving the lathe wear offsets by 0.0005" at a time to make sure you hit it just right.

The bending tool posed a particular problem as the radius we needed is actually smaller than the axle shaft the bending dies normally sit on. Solution? Cut the die groove right into the axle!

Everyone told us we couldn't do it (I hate it when people say that; I even told my guys in Poland I was going to fire the next worker who told me "niemozliwe" (not possible).

So, here is is the tool, 3 DAYS later. Engineered, lathed, milled, ready for heat treat.

[David Kirkham]

The part was a real pain as we had to mill in a flat spot to keep the incoming tube straight as it is being bent. The flat spot is critically positioned tangent to the radius of the groove. If you miss, you put ugly "bite" marks in the tube and we don't like ugly!

So, Sandwich milled an exact female of the tool to hold it exactly in place. That way, there is NO way X Y Z or A can move.

[David Kirkham]

Here is the part with the milled out area and the insert installed--perfect fit--no tool marks from this baby!

[David Kirkham]

Here is the die that actually goes on top of the axle I just showed you. This die is for the "roll bending" or "push bending" of the 3/4 body tubes. Roll bending is really cool. If you have never seen it, you will not believe it. When we get it up and running, I will post a YouTube of it. We made this out of 4340 and man is it a pig to machine.

[David Kirkham]

Here is another shot of one of our lathes. It is a pretty big HL-30. We can spin around 30 inches on it I think--never had a reason to try something that big, however. We use big lathes because you have to have the power to hog on the nasty materials we use like 4340 and 17-4 stainless. It is a 30 horsepower lathe. For reference, home lathes are 1-5 hp. Most manual lathes in machine shops are 2-5 hp. Of course, there are lathes out there to turn battle ship barrels...who knows how many hp they have!

[David Kirkham]

Gents,

I will start posting this week's pictures now. We are still working in the car here (waiting for the Kirkham Homecoming crowd to come back). Post will be sporatic throughout the evening. Stay tuned for the fun

This is the throttle pedal. Notice the kink in it. It has to clear the steering column. The pedal matches the brake and clutch pedal.

[David Kirkham]

This is a shot of the prototype gas tank (just to make sure everything fits). The tank for the car will be polished to a mirror finish. The tank is stainless (about anything we make that is not aluminum we make out of stainless--just say no to rust).

[David Kirkham]

This is a picture of the steering intermediate shaft support. The angle on the steering column shafts is so high, we had to use a Borgeson double jointed u-joint. When you use those floppy monsters, you MUST use another support in the system to keep everything rigid. It just barely clears the #5 head tube.

[David Kirkham]

Speaking of head tubes and exhaust...the customer wanted the exhaust to run out the back...complete custom job here.

[David Kirkham]

We used 2 inch radius bends on the entire system (except the collectors). We had to keep everything as tight as possible.

[David Kirkham]

I was up late last night and so I just posted a lot of pictures without captions. I am going right now to caption the pictures so you may want to look back over the past page or two.

Thanks for looking and thanks for the comments and emails!

David

[David Kirkham]

Another week has come and gone. This, however, is a very special week...stay tuned.

Here are some pics of the parts as they came out of the mills.

[David Kirkham]

Here you can see the sway bar pivot.