80 replies to this topic

[HarV Wallbanger III]

Well, if that's the fuse, lets rewind boys! I have a bunch of experience with round brushes running rewound G+ arms in HO for drags.

[Prof. Fate]

Hi,

A follow-on story: Another local "Jim Young" back in the '60s had a small custom slot car company called "24th Creations" making pro cars for the area. These days, he keeps his hand in by racing some 1/32 and managing the local Kingleman on Saturdays so that the owner has a day off!

When I got the Kemtron cleaned up, I took it by the track for Jim to play with. So, there he is out trundling around the track (at that time a Hillclimb) and he had a big tear running down his face. "See how nice these things were? It is sort of sad that the cars got smaller and faster, because these were just neat!"

Fate

[boxerdog]

So, Barney, talk to us about round brushes and flimsy coil springs, please! I can't see those things carrying much current in their present form.

[HarV Wallbanger III]

The short story... Our HO club were using the stiffest springs BSRT made at the time for drag racing G+ cars. I talked to Gary Beadle and those were as stout as he made because they were made for road racing with milder arms.

I taught the guys how to rewind and we started rewinds with 34 ga. then 32 ga. wire and they were fast but we wanted more. Our club did drag and road racing once a month as the local hobby shop owner rented the Grange Hall for us.

I had a larger range of wire but the springs would just collapse (like a "fuse", remember the fuse statement). We could not get 31/30 and 29 wire to work at all. One of the guy's dad owned a junkyard and he had seen small springs in lock tumblers from glove boxes and doors, etc. So he and I went through everything we could take apart until we found springs that would fit the diameter of the brush tubes. We then had springs that would not act like a fuse... all we did is cut them down to get enough spring pressure to run big wire arms....without pushing the tubes out of the chassis. Then something else became the "fuse" like gears, tires, and wheels! We would show up with a handful of rewinds and blow through the comms racing. The guy at the hobby shop loved us because we would buy more arms and keep the best for road racing and rewind the new arms that did not make the cut.

I have not got into these Kentron/KTM springs yet but if the springs are that weak you just have to find a coil spring made from larger wire. I do have a listing for springs now days and think we could find what's needed.

Oh and our 29 wire G+ arms looked like they were wound with coat hanger and we put as many coils as we could on them to try to mild them out a little.
Yes, they wore out the comms fast as 2-3 runs but they were stinkin' fast! We even raced MagnaTraction cars with the PC comms and they would trash the comms in 1-2 passes. If I remember right the largest wire we could get to run on them was 31 wire???

I would think that if these Kemtrons were too hot they would suffer from not enough magnet and not have much brakes. You don't get something for nuttin' so I will not go too wild at first as we want to run them on a road track. It was at this time Team CORT started as I lived on Orange St. and called my HO track California Orange Raceway.

[Hworth08]

The 1/24 motor builders might have been and are taking a short cut on motor brushes. The faster 1/64 cars have used very nice externally-adjustable brush tubes for years. Very simple to adjust brush pressure with an allen wrench.

[HarV Wallbanger III]

When the G+ came out it had just brush tubes. With the rewinds we used, even an adjustable brush would still not be enough to run #29 ga. arms without starting with stiffer springs but it sure would have made it easier if we would have had them in the '70s.

What we really needed was shunted brushes! We will not be shoving anything near high current on these old Kemtrons for road racing. We will just need a little stronger spring and that will be easy enough to do.

I think the brushes will be the next fuse. If they will take just a little more pressure without crumbling we will be able to use them.

[Gator Bob]

That motor looks wonderful.

Well, it is not a KTM/Kemtron but Barney and all the Legends got my dead stock DC-706 Pittman - Dynamic chassis Proxy car going 8.80s with 45 year old tires on the King at BP.

Building an all NOS KTM-powered Kemtron SW Chassis car now just for fun!!!

Never ran the padlocks back in the day. I started out with inline Atlas open frame factory green wire rewinds with the ball bearings on the home set and went straight to 36Ds when the local commercial tracks opened.

I love train motor slot cars.

[Prof. Fate]

Hi,

Starting with the Atlas, then the Hemi, what I did was take two or three springs and wind them together to fit inside the tube to up the pressure and reduce the "fuse" effect.

Fate

[dc-65x]

For the front half of the chassis I'm going old school. Kemtron offered these pieces to make a chassis and drop arm:



The tubes are 5/32" in diameter and look a bit big on a Kemtron. They look fine on a Pittman 85 but I decided to make my own form 1/8" tube. First, mark the tube where you're going to squish it and get it straight in the vise with a square if you want to be neat....Pete:



A little center punch and pistol drill action is next...



... followed by some chassis building bits from Kemtron and Speedway:



Here the pieces are all laid out to show what's what:



Everything jigged up in my Rick's Jig:



Here's my Rick's Jig with the chassis parts and motor removed showing all the alignment pins in place. This jig really makes scratch building FUN!



The finished chassis all cleaned up. Top view:



Bottom view:



Wheels and tires next...

[Horsepower]

Is there a drop arm limiter?

[Gator Bob]

My slot car career started the day I put my Kemtron X501 motor into a Kemtron sidewinder kit chassis that I assembled in our oven. I took it to Polks Hobbies in NY and entered the Thursday night race and began a winning streak that night that lasted years. That car made Lou Del Rosario quit racing at Polks and start his own raceway in Elmsford.

Howie,

Good thing you built that car and drove Lou to open Elmsford. Could you imaging the state of the hobby; Lou held it together thru the dark ages.

[HarV Wallbanger III]

Beautiful, Rick! (Even yer dang chassis jig is clean enough to eat on!)

[dc-65x]

Is there a drop arm limiter?

Hi Gary,

Yes, I installed one after I polished the chassis. That way I could pivot the arm out of the way. But, you got me thinking... that hurt a bit but I did it anyway . I'm going to look through the old magazines and see how often drop arm down stops were used in the "pre-Mabuchi" days .

Hey Barney, I'm going to give my Rick's Jig a good cleaning and see if she can be even more purdy . A clean chassis jig is a happy chassis jig .

[Gator Bob]

The Kemtron Dealer Parts kit is wonderful!

[bradblohm]

Hey Rick,

Look on this link. It contains a picture of Shelby's Maserati 450S and looks like your body to me.

Hope this helps,

Brad

[don.siegel]

Excellent, Brad - I had a little trouble making it past that second photo (Carroll, too), but once I saw that 450S I think you found the right body, well... the other right body!

Don

[Horsepower]

[size="4"]
Hi Gary,

Yes, I installed one after I polished the chassis. That way I could pivot the arm out of the way. But, you got me thinking... that hurt a bit but I did it anyway . I'm going to look through the old magazines and see how often drop arm down stops were used in the "pre-Mabuchi" days .

I think the limiter is a good idea but in the days of the Kemtron, all I ever remember seeing was guys using the guide shoe wires to limit drop. Not really the greatest solution but at the time, that's all there was.

[tonyp]

lead wires made the best drop arm down stops and were the most used style.

[Jairus]

That's what I thought Rick was doing when he showed that first chassis pic. But after post #38, I am not not so sure...

[Horsepower]

Never argue with the best because you will always come out second.

[dc-65x]

BAZOOKA!










LOOK AT THEM PIPES! Bazookas indeed! Whatever livery this car ends up with it's going to get a pair of Bazookas for sure .

Speaking of the livery, thanks for all the posts and PM's with help

But first wheels and tires. The article above says to use 16" front wheels and 17" rears. The 16" and 17" are tire sizes, or the diameter of the tires bead. The actual wheel diameter is about 1 1/2" bigger than that.

I needed 18 1/2" rear and 17 1/2" front wheels or a scale .770" rear and 730" front. I ended up with these:



Those are some giant Riggen threaded rears with 40mm "German" tires and Revell threaded front wheels and tires. The axle nuts are Cox flanged and the gears are Weldun 64P.

To true these threaded wheels and tires I made another mod to my Hudy tire grinder. It's now a dedicated 1/8" axle machine. The modified threaded axle I bought for the metric Hudy bearings just didn't run true enough. Here are the modified Hudy parts:



The pulley was reamed out to 1/8", the straightest vintage threaded axle I could find modified and some vintage Hobby House bearing cups with 1/4" X 1/8" ball bearings fit the Hudy perfectly:



Time to screw the whole car together.......and make some BAZOOKAS!

[Edo]

.....and make some BAZOOKAS!

BAZOOKAS?
Plural?
You mean you're making more than one car?

[dc-65x]

Hi Edo,

The race fans of 1957 named the 450S "Bazooka" because of them pipes!. WWII was only 12 years in the past and they remembered the Allies tank killer and bunker buster, the Bazooka:







They don't look exactly like a real Bazooka but you get the idea .I'm working on making them pipes! now .

But first, here's the finished roller:





The bottom view shows the drop arm stops:



For a pickup I'm using the OLD Dynamic guide. It's big, ugly and was used quite a bit. I'm using "hairy braid" on mine:



K&B wire wheel inserts. Big ones in the back......



.....and smaller in front:



Onward to Bazooka Land........

[tonyp]

Damn' I thought we were talking about bazooms.... Beautiful job as always Rick.

[dc-65x]

Damn' I thought we were talking about bazooms....