286 replies to this topic

[Pablo]

Well thank goodness I asked   I'll remove the bulge.

[Pablo]

Thank goodness the powerplant is done ! What a struggle to do the arm. I gotta get a drill press.

I had 2 problems with arm #2 - the heavy pole was so heavy I couldn't drill enough to make it perfectly balanced, and ran out of room for more holes ! Didn't want to make the same mistake and drill too deep, so I quit while I was ahead.  It's balanced OK but not great.

2. I nicked some winds in one spot and that could cause a failure down the road.  But, it is running right now and I must move on. If it fails later, I'll just change the arm. Runs really cool and sounds fairly smooth.

[Fast Freddie]

What is the deal with older 60s motors having knurled arm shafts on the gear end? It was probably a way to help retain the press on gears but it does screw up the shaft. I pulled one of the Gimble bearing apart trying to get an arm out of a can. The Strombecker hemi and the 150 Cox didn't have this problem.

I also found two different "green comm. end" arms. The one in my Cox 150 had a comm. with open slots like current motors. The other one I removed from a mustard colored can had comm. slots that were filled in with the green plastic. While both are period correct I'm guessing the one with the open slotted comm. is best, right?

[Tex]

I know you're "moving on" to the next step, Pablo, BUT....... if you ever feel like tweaking that arm a little more, perhaps you could ADD a little weight to the other poles to get it balanced(?). How? I dunno.... brush on some extra epoxy(?).

[Pablo]

Already did that. Still slightly heavy on one side.

The real show stopper would be if the arm shorts. It seems to run fine as is.

[Jairus]

You COULD try to balance by adding epoxy.  Just a drop on the light side could help.

[Pablo]

"Already did that. Still slightly heavy on one side." See post # 104 and 105

I gotta move on, 2 more days off and I'm a little burned out on arms for now.

Next time, I'll get a drill press.

[Pablo]

Back to familiar territory

Russkit bracket braced with rod.

This time, bushings will be soldered straight to the holes in the bracket, and custom brass tube spacers used to extend the rear wheels to 3".

For the jig, I'll use .185 tube pieces with .154 aluminum tubes inside. Slathered in ATF, they won't solder up. They will just be there to keep the bracket in place during the build. Bushings will be soldered home as one of the last steps. That way they will be perfectly aligned, and I don't have to worry about them moving around during the build. Rails will attach to the bracket only.

[SlotStox#53]

Can hear your sigh of relief as you get back to bending rod & soldering a Russkit bracket up Pablo Anymore talk of armatures & rewinding could bring you out in a cold sweat !

 

Bracket looks well braced

[Pablo]

I'll be back to arms, Paul, once I get Mr. Drill Press   With a vengeance

Here is my method for aligning the bracket left to right before securing the rear axle works.

Flip the bracket down so the face is over the flag groove.

Then secure and flip back in place. re-check with calipers for perfect side to side alignment.

[Pablo]

Tolerance +/- 3 thou

[SlotStox#53]

Ah yes Mr Drill Press!  Another handy tool for making slot cars , which helps with many different parts of the process! One I will have to look into aswell

Nice lining up of the motor bracket

[Bill from NH]

Will this bracket be for another R&C chassis? Will it be a Can Am car since you already built a coupe & have an F1 in the works?

[Pablo]

Hi Bill   This is going to be an R & C Grand Prix entry. Back in 1966 I guess they called them "Grand Prix".

Now we call them Formula One. I don't understand it. I just solder.

Here is the body:

[dc-65x]

Hi Pablo,

 

Nice bracket! Remember though, the GP cars can only be 2 3/4" in wheel track width.

[Pablo]

Thanks Rick ! You saved me again !

2 3/4 it is.

 

I tried some tube bending experiments.

First is 063 tube with twin pieces of .087 tubes butted up against themselves.

Here was the result:

Next was the same as before, only with .032 wire inside the tube:

Result:

 

[SlotStox#53]

Nice smooth curve you got there Pablo! Amazing difference with that wire inside the tube   Will have to try that with the SS tubing,

[Bill from NH]

In the second picture, the bend looks more uniform. I initially thought the two outside pieces of tubing were butted up againt one another. However, Steve Okeefe's writeup shows them spaced about 3/32" apart. I don't know yet how this spacing would affect the sharpness of a bend.

 

Paul E., what's the dia. of your JDS stainless tubing? In some photos, it looks like .065", yet in others, it looks larger. I'm not too sure how this bending process will work on stainless tubing. It could be too hard & need to be annealed before bending. But try it & see how it works.

[Steve Okeefe]

Paul E.,

 

Bill is 100% correct (Hi, Bill); annealing is how I got the stainless tubing to bend so smoothly, and to the same radius as brass tubing, and with the same bending tools.

 

Nothing wrong with inserting piano wire like pablo did (Hi, Pablo) to prevent the tubing from collapsing or kinking, but if you use a good bending tool it should hardly be necessary!

 

Without annealing, you are going to have an awful time getting that stuff to bend for you at all (but I guess you already know that...)  .

 

Someday I'm going to have to build another chassis using stainless steel tubing, but this time figure out how to do it without annealing or bending the tubing - that way I can capitalize on the hardened material's immense strength, stiffness and light weight.

[Gator Bob]

To avoid the major imbalance  .... Bake the epoxy with the arm standing upright ... let the 'flow' run down into the Kevlar tie.

 

 I used an 'oven' designed to 'cure' fiber optic connectors .... Works perfect but pricy.

 

Like this one --> http://www.specializ...-Oven-4426.aspx#

 

 

Just sayin how I did it.... you could do one at a time in the toaster oven buy standing the arm up in a .5xx drilled metal block or maybe even in an old motor can. The more mass around the stack the more even the heat will be. Toaster oven temp goes (cycles) up and down and not a very consistent, accurate or stable

[SlotStox#53]

Bill, the JDS SS tubing is indeed their .065" size

 

Oh Steve , I have found it can be pesky stuff to try and bend that's for sure!!! The K&S spring bender kit does an amazing job for what it cost, does some nice bends actually , although as noted probably won't bend tight without annealing.

 

 Mr Havlicek bakes his armatures standing up in the easy bake oven ,allowing the epoxy to run down  properly as you say Bob

 

:Update: Just tried the trick of bending the SS tube with the other larger pieces of tube over the top , very easy to bend actually ending up looking exactly as Pablo's first attempt at the brass tubing. Still looks pretty neat in the shiny SS and would probably make a nice looking "strong" chassis .

[Pablo]

Tube bending experiment #3:

.032 wire inside the works.

Twin pieces of 3/32 tubes over the .063 tube, spaced approx. 1/4" apart.

 

That is what I was looking for.

Time to rock n roll

[SlotStox#53]

Awesome! Build on Sir , a tube GP chassis will arise from the Ricks Jig

[Pablo]

I'm going to try something different for main rails. Steve OKeefe pioneered this method of bending 063 tubes using 3/32 tubes over it to produce nice smooth bends. Don Hollingsworth said, back in the day, they shoved wire into the tubes as well. So here is my new experiment. I'm going to leave the wire inside the tubes, and tack solder the ends. The wire can do whatever it wants inside the rails, flex, twist, warp, flop, etc. My extensive experience with .055 wire inside 093 square tubes for IRRA car rails leads me to believe this may result in an "interesting handler".

Step one: Tack wire to one end of the 063 tube.

Note the wire protrudes well beyond the end of the tube to allow for bending and heat.

.032 tube pieces are temporary handholds to bend the 063 tube:

[Pablo]

First bend turned out OK