121 replies to this topic

[dc-65x]

I was looking through Steve Okeefe's sub-forum The Independent Scratchbuilder for ideas for my next "inspired by" project when I found this:

 

 

I immediately thought that's it! What a cool looking chassis........of course that's no surprise coming from Bob Emott. He finished second in the big East meets West 1968 California Arco race and his other cars finished third, fourth and sixth in the Pro main. WOW!

 

Here's the link to Steve's thread that has Tony P's pictures and description of the original chassis:

 

Bob Emott's 1968 California Arco Chassis

 

This race was well covered in the November 15, 1968 Model Racing Journal newsletter. In fact that issue is really packed with great pictures and articles so I'll post all eight pages here.

 

Enjoy the read and I'll gather up some parts.  

 

Click on the pictures to enlarge:

 

 

 

 

 

 

 

 

[tonyp]

I’ll be watching this one.

[dc-65x]

Hi Tony  

 

For this "inspired by" build I'll be doing what I did as an avid local slot racer back in 1968. That is, eagerly await the latest newsletter and magazine to see what the "big boys" were building. Then I'd build my own version using their design ideas and the components I liked best or that were available to me at the time.

 

I really like Bob's 2nd place chassis and I might even use some design features from his other 3 Pro Main chassis in this build. His designs were so innovative.  

 

I lived in Southern California at that time so for my motor choice I'm going with a West Coast motor rather than the Eastern Kean Kan motor in Bob's cars. This Mura ad is from November 15, 1968:

 

 

I found some fuzzy pictures of Mura "Playboy Pink" Team Cukras motors and motor kits:

 

 

 

Since I have no NOS Team Cukras motors or motor kits I'll be building mine from the parts I've scrounged. This is better for me anyway as I really enjoy building motors.

 

Here are the end bell components:

 

 

And the parts for the can:

 

 

I'm still deciding on an armature to try and restore back to life............

[Mbloes]

I'm going with a West Coast motor rather than the Eastern Kean Kan motor in Bob's cars.

 

You don't want to go completely hand-built and go with one of those lowered Dynamic cans?

[dc-65x]

Hi Mike,

 

Yes, building one of those low profile motors is on my to do list of cool projects.  But I want to put a mildly "hopped up" Cukras A-can motor in this one.

 

The can is done. New bearing soldered in place and the vent holes chamfered:

 

 

The end bell needs a bit more tweeting.........

 

 

[dc-65x]

The endbell gets a comm inspection/cooling holes:

 

 

The pent roof brush hoods are soldered to the hex brush holders:

 

 

The endbell is drilled and tapped for stainless steel machine screws:

 

 

Done:

 

 

The motor is far enough along to use for my jig motor..............

[dc-65x]

Here's Bob's motor bracket:

 

 

 

I used this Associated piece and modified it as shown on the right:

 

 

The jig motor and motor bracket:

 

[Bill from NH]

Nice start Rick!

[slotbaker]

Nice jig motor.

[dc-65x]

Thanks. The dreaded (for me     ) motor box is next.................

[strummer]

Wow...

 

That is some beautiful and precise workmanship; I can't even begin to imagine...     

 

Mark (also) in Oregon

[dc-65x]

A while back I was conversing.........no, actually whining about making motor boxes to Steve Okeefe. I have a 10 to 1 (or worse) ratio of scrappers to making a good one. Steve took pity on me an did this thread on the subject:

 

The Emott Style Motor Box

 

As a result I have this motor box................

 

 

.............and axle tube for my build:

 

 

Here's how the big Mura A-can fits "good-n-tight" inside it:

 

 

 

The Mura is a bit longer than a Mabuchi based Kean Kan so main rail placement against the motor box might be a bit different. I hope to match it with Bob's chassis as close as I can...........

[Tex]

tough gettin' all them bends just right.... kudos! I've wasted MANY pieces of wire trying to get only TWO bends just right!  lol

[Bill from NH]

Not to confuse the subject, but the two DVDs Steve made & distributed of the old slot car newspaper had short motor box making articles by Mike Steube &  Bryan Warmack. Bryan's article included a "do-it-yourself" bending jig. Neither is as detailed as Steve's article above. Also, one of Tony P's Car Model chassis articles has a 2-piece motor box, which may have a shorter learning curve to make.

[dc-65x]

I have a motor box and axle tube. Before I solder them together I need to figure out the rail placement to correctly locate the motor box side to side.

 

We know Bob's chassis has a 1" wide drop arm. I enlarged a photo of the chassis and measured the width of the drop arm at 2.050". Divide 1 by that 2.050 and I get a multiplier of .476 to use.

 

Measuring the center section width at the same location on the photo I measured the drop arm I have 3.540". 

 

3.540 X .476 = 1.685 or super close to 1 11/16" wide center section. 

 

 

This is only a close (hopefully) approximation because when the photo was taken the camera was never perfectly parallel to the chassis. That's why I measured the photo at the same location for both measurements.

 

My Rick's Jig has pin hole spacing for 1 5/8" and 1 3/4". I'd have to use short pieces of 3/32" and 1/8" sloppy fitting tube to get my rail spacing. 

 

Gizmos are the answer!      I machined some new ones. 1/8" brass rod with precision reamed 1/16" dowel pin holes:

 

 

Here they are in the jig and holding my outer frame rails in the right location:

 

 

The two most important solder joints done. Now I can get on with the rest of the chassis:

 

 

You know, I spent days moving parts around trying to get things to look like the picture of Bob's chassis. I think I'm finally close.

 

But the Pros of the period could make a chassis like this on a motel room coffee table at 3 AM that could win in the main. I find that amazing.   

[Bill from NH]

The old pros didn't have today's versatile chassis jigs either. It's feels nice to have a lathe, when one is needed. 

[Steve Okeefe]

Looking real good Rick! 

 

I spent a lot of time scaling photos too, and also had to take the problem of parallax into account.  Even if the camera is only slightly off-center, it really skews the scaled dimensions.

 

Here's an alternate method to cross-check your calculations (you might think of it as a "reality-check"): If we presume the drop arm is one inch wide, count the number of rails (I see four on each side; total eight 1/16" rails), plus the spaces between the rails (I see two 1/16" and two 1/32").

 

How do I know those spaces are 1/16" and 1/32"?  I don't, but aside from careful observation, I can make an educated guess.  If the pro builder is thrashing this together on a motel coffee table at 3am, he's likely to use what he has on hand to space the rails evenly.  That would be 1/16" rod and .032" piano wire.

 

Anyway, add up the dimensions of all the rails and spaces, add it to the width of the drop arm, and what do you get?  One and 11/16 inches presumptive size.

 

Those Gizmos are quite clever; I will have to make some too.

[tonyp]

You guys are way over thinking this. Lol.


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[dc-65x]

You're right Tony   Bob could have built dozens of chassis in the time I've been staring at this one.  

 

You're right too Steve. Great minds think alike.........or something like that.  

 

Looking at Bob's chassis there are 4 rails on each side and a large and small space on either side of the second rail:

 

 

 

 

The 1 11/6" rail spacing I decided on will give me a "large" and "small" spacing shown in the picture. Subtracting out the 1" drop arm and the eight 1/16" rails I'm left with 3/32" of space per side.

 

As Tony said I'm probably over thinking this and I wouldn't be surprised if Bob used his calibrated eyeball to set that rail spacing. But I'll be using the "gizmos" on the inside of the outer rails to set up that 1/16" and 1/32" (or large and small) spacing. 

 

I'm making the rails up now with pictures of the gizmos working their magic to follow...............

[Mbloes]

 

 

The 1 11/6" rail spacing I decided on will give me a "large" and "small" spacing shown in the picture. ...........

 

Totally no offense, Rick, but I'm gonna go out on a limb and say that Bob's intent was to probably make everything symmetrical and that maybe in the heat of battle it just came out a little off.

 

I would go with symmetry on both sides.

[dc-65x]

That could be Mike. But one of the things that caught my eye with this chassis was the unique rail spacing. So regardless of how the spacing came about I'm going to replicate it simply because....I like it. 

 

That said, I remember my senior machinist mentor could read a 6" machinist scale (a finely graduated ruler) to .005". Tony P. once told me he could place parts to be soldered on a chassis to within .005" by eye. I wouldn't be surprised if Bob Emott could do the same.

[Pablo]

He who dies with the most gizmos wins 

[dc-65x]

Time to put those "gizmos" to work. I've got the rails, front axle tube and uprights, plumber and drop arm hinge tubes ready to go:

 

 

The gizmos and other locating pins set up in the jig:

 

 

Cranking up the Ungar iron..............

[Eddie Fleming]

Cranking up the Unger.

 

 That's kind of like "release the Kraken" 

[dc-65x]

OK Eddie...........here goes!  

 

 

Here's the jig setup for the first (inner) rails. All those clamps are not forcing misshapen parts down flat.

They are holding perfectly flat parts in place so they absolutely will not shift when I'm busy soldering:

 

 

A clamp is shifted to attach the outside rails which are aligned by the inner and outer gizmos:

 

 

The piano wire rail is bumped up to the inner gizmos and soldered in place;

 

 

The final rail is bumped up against the outer rails for soldering:

 

 

The drop arm hinge tube helps tie everything together until I add the motor box bracing:

 

 

And finally the setup to install the front axle and plumber hinge tube:

 

 

Here's the partially complete center section after initial cleanup:

 

 

Next up is the motor bracket install and motor box bracing...........