Emk Update

[Art Anderson]

Finally, some more progress to report on the 1904 Knox truck. I've shown the engine before, but have been struggling with the front axle assembly since the end of September. I had one all built, just needed a bit of touch up on the mill, and I got one end caught in the roller & wedge tightening system that milling vises use for accuracy, crushing it beyond fixing.

So, after a month or so of cooling off from that, I started over, built the axle beam itself in nothing flat, then on to the spindles. At first, I figured I could simply fabricate the spindles from K&S brass tubing, a combination of square (for the inner ends, round for the outer section that carries the wheel, but in practice, just too small for silver soldering, given the limited stuff I had to make a suitable soldering fixture. That took a couple of weeks, then off for a couple of weeks, onto other things, then Thanksgiving week. Finally, I figured out the setups needed on my mill to accomplish the spindles, in solid brass, that worked!

Here's the basic axle components. The axle itself is 1/8" square brass tubing, with 3/32" round tube to make the "yokes" which capture the kingpins and the spindles themselves. The reinforcing web was made with a strip of 1/32" x 1/4" K&S brass strip, soldered into slots cut into each end of the axle beam itself. After that was done, the ends of the axle beam were "fishmouthed" on the mill, and the round tube silver soldered into place. Finally, a 3/32" end mill was used to mill out the slot in each yoke to accept the inner end of a spindle. 3/32" holes were drilled across the face of the axle beam to accept the round plugs that make up the spring perches (the springs are cantilever style, the ends of the main leaves trapped in a slotted perch, and these had to be spaced exactly the width of the frame rails.

Next up was to make a pair of steering arms, and the tie rod. Note that one steering arm is longer than the other--this one will be on the right hand side of the axle, the added length to acommodate the drag link, which goes across the axle, from the steering column. The steering arms are 1/16" square brass tubing, with a bit of 1/32" rod inside, to provide a locating pin for mounting to the inner part of the spindle. Ordinary straight pins were used for pivots, worked like a charm. I hit a snag though, with the kingpins! I had figured on using 1/32" brass rod for the kingpins, with bits of 1/16" tubing at top and bottom to provide "plugs" in the yoke to hold them, BUT I misread things, used a .035" drill for drilling the kingpin holes in the spindles--SLOPPPY!!!!!. So what to do? I sure didn't want to have to remake those spindles, so I took a quick shortcut, knowing that gap filling CA glue can be used as a filler--so, I simply filled the kingpin holes in the spindles with some CA, hit it with the kicker, and let it set up. Then, I mounted the spindles each in the mill, and used a proper 1/32" drill bit to drill out the CA to the proper diameter--IT WORKED! YAY!!!!

The last step was to make the round spring perch plugs, install them, and slot the back sides of them on the mill for holding the ends of the springs. Simple 3/32" brass rod, drilled on one end for hex bolt head detail, then silver-soldered into place, cleaned up with a wire brush on the Dremel, then clamp in the mill, slot the backs of the plugs. Completed axle assembly (and perhaps the most complex part of this project, engine included:

So, now it's on to the next part of this "over the top" model car project--the rear axle and chain driveline. Stay tuned!

Art

Edited January 10, 2010 by Art Anderson

[Matt LeBlanc]

WOW!!!!

[Jon Cole]

OMG. That's all I can say!

[PatRedmond]

Superb !

[Foxer]

I didn't realize you had "lost" the first axle in September ..what a bummer. This one SURE looks good, though!

[charlie8575]

Wow. I'm looking forward to March, that's for sure!

Charlie Larkin