141 replies to this topic

[Mopar Rob]

With my Can-Am / GTC fleet just about ready for the Sano, I decided to build some JD chassis.

Building a JD sports and JD F1 for Ramcat Larry, one F1 for Bill ( does my machine work ) and the last F1 is mine.

All I can say I would rather build just about any Retro chassis other than these. One of the hardest builds ever. I haven't figured out how to keep all the rods from falling over on top of each other before using the jigs clamp? Worse yet was trying to figure out where I wanted the brass rods to go? Normally I would have used ACad, but was scolded by PM that you don't CAD JD chassis

Next will be adding the pin tubes to the F1's and make and bend the drop arms.

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[Duffy]

(Rob & I have been PM'ing over this, a little, and I'll share the safe stuf:)

Awwww Rob, I sympathize! But I dropped out of Slots at the very eve of this technology, and it was a great place to dip back in when I surfaced last May.

As far as keeping the rods in place--well, what's the best analogy? "Herding Cats" or the scene in Alice where they're playing Quoits with flamingos? Depending on which jig you have, the solid crossclamp with a layer of door insulation underneath will hold everything well enough. You just tighten up to SNUG and then, when all's right, clamp down and start tacking. Anything moves, you adjust.
It's building WITHOUT the comfort of preprogrammed precision. But, if you free yourself from the dependence on fancy tooling, you'll be amazed at how much your HANDS really know.

You will be kinking drop arms sometime next week, if the bridge don't wash out.

Duffy The Scolder

[Mopar Rob]

Depending on which jig you have, the solid crossclamp with a layer of door insulation underneath will hold everything well enough. You just tighten up to SNUG and then, when all's right, clamp down and start tacking. Anything moves, you adjust.


It's building WITHOUT the comfort of preprogrammed precision. But, if you free yourself from the dependence on fancy tooling, you'll be amazed at how much your HANDS really know.

The clamp does hold it down very nice, but you have to put all the rods in before using the clamp. That's when they fall over.


I do like my crutch

[68Caddy]

Cad or not Rob, those are some cool chassis. Are you going to post more pic's?


Nesta

[Mopar Rob]

Are you going to post more pic's?

Nesta

When I build some more of it.


Here is a picture of the bottom. I like the way the rails look at the back of the chassis. Looks like a waterfall or Art Deco. Don't know if it make a difference how the rails are layed out or spaced so I just did what I thought looked cool?

Started making one tongue and using Rick's widget's

Maybe a little more surfing the web and then back to the workshop

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[Duffy]

A caution: what you're showing as TOP may be intended as bottom. I'd want the big flange keeping the guide leveled. --Duf

[Mopar Rob]

The guide is upside down. I haven't soldered the widget in yet, so I didn't want it to fall out

[Craig]

Boy howdy, does that CAD drawing make a good backdrop Rob!

[Mopar Rob]

I just grab whatever drawing is handy. Figure it looks better than using a paper towel or something similiar?


Your drawing was handy since that's what I was going to build next until sidetracked by these JD chassis.

[68Caddy]

Good one Rob.


Nesta

[Richie]

GREAT LOOKING WORK Rob!!!! Keep us posted, I want to build an F1 for myself to play with, gotta get a motor bracket, and body still So many projects, so little motivation LOL!

-Richie

[Mopar Rob]

I used the JK JD bracket and and maybe a WRP? I liked the JK, just wished it was about .030 wider.

[Rick]

Rob, once the first rail is laid in straight, they are easy to build. I built two for the Palooza.

I have an order for a few "bundle of rods" laying here now. It's tougher to bend it all up than it is to solder it all up. LOL Looks like you did a real fine job.

[Pablo]

how to keep all the rods from falling over on top of each other

??? I don't get it. Can't you just secure it with a small piece of masking tape, then tack solder it ?
Or hold it in place and tack it ?

Those clamps scare me...as soon as you remove the clamp, the piece goes "sproing".
Rods should lay relaxed, not under duress....same as retro

[MSwiss]

That's tony p's first rule of chassing building.
No clamping.
He just hold rails down with his fingers.

I've tried it and it can be done.
You have to be quick but once you have one end tacked in,
you tack in the opposite end.
You can then go back and forth and get a good joint just being careful
there is always somewhere along the joint where the solder isn't molten.

It's also a lot easier holding down an .047 rail vs. an .063.

[MantaRay]

FWIW..........I have found that Making/Bending and correctly fitting the drop arm is the most time consuming part of the process.........build on

[One_Track_Mind]

Hi Rob,
I feel your pain in building the JD cars,as I've only built one of the F1's it was by far the hardest lesson learned in bending all the brass evenly.

Great Job!...keep us informed of the development process.

[tonyp]

They are a pain to build. They take as long as a can-am to do.

[Hworth08]

Those clamps scare me...as soon as you remove the clamp, the piece goes "sproing".
Rods should lay relaxed, not under duress....same as retro

I always felt it best to have the rails as Pablo states, relaxed.

The modern jigs allow for nice frames. When we used the extremely popular Russkit jig you had to blueprint the JIG and then build most of the frame. A Russkit jig wasn't wide enough to hold the wide multi-rod frames so a builder installed the last rod out of the jig.

But the Russkit jig sure was better than graph paper! No telling the number of folks that Mike Morrissey taught to build through the magazine articles.

[4laneron]

Here's how I start my jail door builds, I use a center-peice the same width as the motot bracket. This gives you something to build off, I start off the front axle tube I don't use clamps just my fingers.

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[Ramcatlarry]

WHERE did I put my CERAMIC toothpicks (for spacers)????

[Jairus]

Hey Rob, nice work! I might have to build one now....

[gascarnut]

I guess we all have a technique of some sort for these frames.

I bend all the main rails at once, but I solder them in one at a time, so I don't have to worry about alignment. As long as the jig is holding the bracket and the front axle tube in the right spot, this works fine.

Having a bending jig makes this part of the job much easier - I use the jig that's in the middle of my Backtrack jig, but I build on my Rick jig so I can insert pins in the holes to manage the rails spacing.

The drop arms are the real pain IMO. I have made a separate jig just for building them. I will take a photo over the weekend as I am building some JD cars right now.

[Mopar Rob]

Dennis:


I also bent all the rails at one time. I use the Backtrack bender. Seemed real simple.



I just set my jig for my desired wheelbase and put in the axles with tubes suspended by the jig wheels. If I wanted the rals to be outside to outside the tubes I took the measurement, set the bender and bent them. If I wanted the rails inside the tubes I took the measurement and subtracted .125, set my bender and bent them. Like I said real easy with some simple math and a good tool.


Maybe I'll take some photos when I make the drop arms. My plan in my mind it doesn't seem like it will be any harder

[gascarnut]

Dennis:


I also bent all the rails at one time. I use the Backtrack bender. Seemed real simple.



I just set my jig for my desired wheelbase and put in the axles with tubes suspended by the jig wheels. If I wanted the rals to be outside to outside the tubes I took the measurement, set the bender and bent them. If I wanted the rails inside the tubes I took the measurement and subtracted .125, set my bender and bent them. Like I said real easy with some simple math and a good tool.


Maybe I'll take some photos when I make the drop arms. My plan in my mind it doesn't seem like it will be any harder

Rob,

I don't do inside-to-inside or outside-to-outside. I do all the rails outside-to-inside so they all are bent to one length, except the very inner set which I bend up inside the motor bracket. That way, I can set the Backtrack bender once.