64 replies to this topic

[SpeedyNH]

sorry. i withdraw. i wasn't intending to argue or disrupt your thread. 

[Pablo]

Champion endbells are nice, but they don't fit non-Champion motor brackets. The bushing flange is a larger OD which requires hogging out the bracket hole. Easy fix with a Uni-Bit.

 

Tricky part is, the Champion bushing flange protrudes about .055. Most brackets are of .032 thickness.

So you end up with the motor attachment screws digging into the flange instead of snugging the EB up to the bracket face.

 

In the past, I've custom made a "spacer gizmo" to fix this. You don't want to tweak that flange and mess up your arm alignment. This time I marked the area of the flange that is blocking the attachment screws

 

 

Then I Dremel carved those areas enough to "clearance" the flange. Worked out fine. I tested the amp draw of the motor when snugged up tight, and gave it a quick burst of volts just to listen. It is still happy 

 

[Pablo]

WB 3 7/8, GL approx. 3/4, body width 3.0

 

Bracket needed a little bit of tweaking to make true.

Jig block plan: the wheels are a strange OD - .850 - so by using the ".825" holes in my blocks it will give me a little extra clearance over 1/16".

 

In order to make wheel width 3 1/8 using twin steel spacers and allow room for a needle, both duffies were shortened .018

 

 

Next step - bracket bracing and duffy installation 

 

 

[dc-65x]

Hi Pablo  

 

Those shiny rear tires really jumped out at me. I ASSume they are a foam tire coated or dipped in silicone or ?????

[Pablo]

Customer supplied. Some people like them 

 

Building a tongue chunk of 15 rod pieces, to be trimmed .930 X 1.5

 

[Bill from NH]

IIRC, Jim Honeycutt doesn't allow tire goop to be used on his San Antonio track(s), thus the silicone or silicone-coated rears.

[Pablo]

Twin .063 wire main rails. Jig WB and GL set for 3 7/8 and 3/4". Chunk is .930 X 1.4".

Holes in the Dynamic tongue come stock about 1/8 deep - I deepened them to about 1/4".

Tongue needed some carving to allow a full 45 degrees of Jet Flag rotation

 

[Pablo]

Tongue surgery - alignment is critical here in many ways, including some tilt to allow for slope.

I soldered the rods inside the tongue, then tweaked them to lay on the chunk for a "tack n check"

 

 

Once perfectly aligned in all respects, I went wild with the 455 Hakko. A little bit of tilt

 

 

Chunk attached to main rails

 

[Maximo]

There no doubt you have the shop - tools - experience and skills to knock this out of the park!

[Pablo]

On this build, I tried leaving the rear axle tube attachment (in this case, duffies) for much later in the building process.

It lets me get the iron in there to attach the rails much better. So far I like it. Also ensures the bracket face is square, as opposed to relying on the axle/bushing/bracket tube holes for alignment.

 

Another trend I've been experimenting with is using more Koford M333 solder and less 60/40.

Not saying one is better than the other. Just saying, it's much easier to see the transition from when it's wet to when it dries. I'm liking it more and more as I go.

 

Anyway, ISO tube attached to bracket "U" brace. Hinge wire pieces are .055 and spacing between the inner ISO wire and outer rod is, you guessed it, .055    

 

[dc-65x]

Hi Pablo,
 

 Just saying, it's much easier to see the transition from when it's wet to when it dries.

That's really helpful tip for the scratch builder. I first took note of it watching Mike Steube's in his scratch building DVD. You can reheat a joint or solder something else on near a joint and not have everything fall apart by watching the way the solder is behaving.

[Pablo]

1/2" long .055 wire piece rail spacers midway between the axles.

2mm (.078 piano wire) front axle on the jig, ready for 90 degree .055 uprights

 

[Pablo]

The body is kind of "boxy" with straight vertical lines so I concentrated on simple engineering.

Placements of the bite bars, ISO rail connections, pin tubes, weight, etc.

 

 

Keeping in mind I need to tame a potent motor, another rod added to the ISO rails, and five .063 rod outriggers 2 7/8" long

 

 

[Pablo]

Rear and center cross connecting wires for the ISO rails are .039, designed to allow about 5 thou per side wiggle.

Pin tubes trimmed to be slightly longer than Koford "short" pins

 

[Bill from NH]

Rick B., of RGEO, posted today on Facebook that he was getting the parts together to make a few more chassis jigs. If you have any thoughts of purchasing another one, now might be the time to contact Rick. No prices were mentioned, but he did indicate hardware prices had doubled.

[Pablo]

Thanks Bill 

 

These ball bearing mini-wheels are perfect for an ISO Thingie. This is the third car I've built with them.

Ultra-precision - I have to don my geezer goggles to tell if they are spinning or not  

 

With O-rings installed, they mike at .685 (17.4mm) OD. Sans O-rings, .625".

Math says a .621 OD jig wheel will make the front end clear .032".

By setting the fronts at ground zero without the O-rings, she will clear about .030".

 

Bore is 2mm (.0785) so I use a piece of tinned .078 piano wire for an axle.

I prefer that over a hard 2mm axle for several reasons.

 

I took great care to protect the precious wheels with masking tape.

As soon as I tack a set of .055 uprights to the axle, they will come off ASAP  

 

[Pablo]

.055 and .047 uprights secure the axle. Probably overbuilt 

 

.039 wire piece across the chunk and a piece of .032 control the ISO. A hair of movement is all it takes to make the magic work

 

[Pablo]

BB's in duffies attached to the REHCO. .032 upper brace added

 

[Pablo]

One more set of braces to buttress the duffies. They snake underneath and solder to the ISO tube

 

 

All aligned in the jig, ready for hanging the outriggers

 

[Pablo]

Outriggers, bite bars, and down stops done. Inner front wheel retainers in place, axle pre-trimmed to size.

Axle ends tinned with acid so the outer retainers can be soldered on after tumbling with paste flux, not acid

 

 

Into the tumbler tonight 

[Pablo]

 

 

 

[Pablo]

 

 

[bluecars]

Looks great Pablo. Would you please explain to us mere mortals what duffies are.

[Pablo]

Look at the custom machined brass bushing/ball bearing holder gizmos that fit the REHCO bracket perfectly in post #28.

They are named "duffies" after the maker Duffy, RIP.

[NSwanberg]

Shiny!