143 replies to this topic

[dc-65x]

This project had stalled. I had planned to make a motor I really didn’t want to use because I lacked a critical part.

But, I’ve come up with a solution and built a motor I want, finally! I’ve deleted the previous motor proposal post and here goes my motor build.

I want to build a car based on the one Bob Emott built for Howie Ursaner in the Jan. 1969 MRJ Hinsdale race report. Not built as a clone but rather as if I were reading the race report in 1969 and building my own version:



I consulted with our own good The Dokktor, PdL over this picture and the race reports tech sheet:

Quote

This particular one is a Champion 5001 (Mabuchi FT16BB with one side blank (no hole) can with the aluminum bearing housing……These 5001 came out in 1968 and were first nickel plated, and black in 1969. Not an easy one to find...
Kean used these for a while then switched to the regular black can.

Okie Dokie, I’ve got Champion chrome version so I needed to bang out the crap-O-la ball bearing and put in a good oilite, cut some mongo endbell vents and drill four endbell mounting screw holes. Here’s the stock can on top and the modified one below:



Note the two Mabuchi bearing cups (one mangled) and ball bearings. It was quite, ah, interesting removing them. I’d know what I’d do differently next time!

This flex shaft grinder is a wonderful tool. I used it to drill the endbell mounting holes. It’s so much easier than trying to use a full size pistol drill:



Oh, hey Duffy, lookie here. The old guy can still nail those scribe lines with a punch:



Sorry, apprentice machinist training moment……….Anyway, the Champion DZ magnets and 2-piece shims were too tall to fit in the can (Mabuchi sourced). I ground .015” off the height with a disk sander. Then I lathered up all these pieces plus the magnets…….



……with JB Weld epoxy and stuffed them into the can along with the can bearing, a .525” armature alignment tool and endbell . I made sure there wasn’t any excess epoxy that would LOCK the magnets and shim into the can.

I ended up with nicely aligned bearings and this “magnet sub-assemble” that’s a nice snug “slip fit” into the can:



This step sure isn’t vintage but I’m no master builder from back in the day. A man’s got to know his limitations and this is one of my many:



These magnet hones are slicker than snot. I’ve got a nice .530” magnet bore perfectly aligned with the armature. This makes me happy . The “magnet sub-assemble” can be slipped out of the can and all the magnet dust cleaned up....neato!

Next up, I'll show cutting up that endbell……

[dc-65x]

The "critical part" I said I was in short supply of is the Mura white "unmeltable" endbell. I have a few but I'd like to use them on Mura motors not a hybrid "race motor". I do have some of the later version with the B-motor style brush hardware. REH even sold them until a few years ago. Here's a comparo of the two:



The early style is on top. It's very much like a Mabuchi FT16D endbell but with pent roof brush hoods and made from a high temperature plastic.

The later style on the bottom has been redesigned to take the great B-motor brush hardware. The plastic spring post of the early version is replaced with a screw and brass sleeve. This style of endbell served Mura well into the 90's on their C-can motors.

To make my late style endbell look more like an early one I made a brass "post protector" to hide the late style screw (I ended up not using the fiber washer):



I trimmed as much of the big copper plate off as possible. I also replaced the 36D brush hoods with early 16D hoods. Here's the stock hardware on top and my modified on the bottom:



The plastic part was drilled for comm inspection holes and mill for cooling slots:



The early version on top and my modified late version is on the bottom. I think it looks a little more like the early one and it was a fun project:



Armatures next

[Pablo]

I'm drooling on my keyboard again

[dc-65x]

Hi Pablo. Lookie at these "motor rotors". Time to try one out.......

Here's a selection of Thorp arms. The newest on top:



Again using Steve O's fully indexed Model Racing Journal DVD's it was a snap to come up with these Thorp ads:

12-1968



1-1969



7-1969



1-1970



My earliest on with thick laminations, phenolic wire retainers, fiber end plates and red wire:



This is the one I'm going to use in my motor. It still has the fiber end plates and phenolic wire retainers but with brown wire and .007 laminations:



A still later version. Still clinging to the Phenolic wire retainers but with a green goop coated arm instead of the fiber end plates and .005" laminations:



The last one I have. The phenolic wire retainers are gone and the price is now up to $9.95:



Time to put this whole thing together.......

[Duffy]

Oo.

Just, Oo.

It don't get better than, Oo.

[dc-65x]

Hi Duffy!

The motor is together and broken in on the power supply. It draws 1 amp at 3 volts. But, it seems to run hot even at that low amp draw. I know the armature spins free as can be and is centered in the magnetic field. It's got a good air gap and the magnets are well charged.

When I told my friend and vintage slot guru Rodney that I was going to use a Thorp arm with their phenolic wire retainers he said, "they run hot". Oh, well.........I'm going to "see it move" anyway and I think it looks "HOT":









Chassis time......

[TSR]

You are not going to paint it black?

[dc-65x]

'TSR', on 05 Jan 2011 - 03:48 AM, said:

You are not going to paint it black?

Ah......well........ah......I sure like chrome.......so shiny.........black......hmmm.........chrome so shiny......black hmm........

To make the motor look like Howie's I'd have to dye the endbell some unknown dark color too

[tonyp]

Black! Black is meaner looking.

[TSR]

Quote

To make the motor look like Howie's I'd have to dye the endbell some unknown dark color too

Probably an endbell from a Mura M444 that were black...

[Steve Deiters]

Those Thorp 26-27 arms with Mike Kondor on the controller were as fast as anything going at the tme. While the Thorp arms did not look as good (nice, tight, straight wraps) as some of the boutique winders of the day like Zimmerman they did have their day in the sun on occasion and were extremely fast as long as the amps were there. I never felt Thorp got as much credit as he should have for the era he served.

[Ron Hershman]

All wires sizes are "REAL" AWG sizes...... LOL...was there anything else? I am sure Mura, Checkpoint and the others were using AWG wire at the time.

Other than Mabuchi motors maybe having "metric" wire on them...did anyone "re use" the Mabuchi wire on the Pro arms of the day?

[Steve Deiters]

I seem to sort of remember a mini controversy of the day when machine wound "rewind' armatures were starting to make their way into the marketplace. The controversy was that the machine wound arms the wire would "stretch" during the winding to assure that it was tight thus reducing the measured gauge of the wire to be something less than 27 or 28 or whatever the stated size of the wire was. I think Thorps' arms may have been hand wound or at least they look that way in the photos which would minimize the stretching...in theory. Was it real? Was it imagined? I don't know if it was or if it really made any difference at the end of the day. A particular make of arm wound turn as fast as it could and that was it. Like most controversies in slot racing it took on a life of its own and lasted for a very brief while then it was gone. Not that it would ever happen today.....a small controversy taking on a life of its own here on the blog!!

[TSR]

Why?

We have plenty of vintage arms at the LASCM and a few Zimmerman, and they don't look so tidy. But they were quite good... I am not so sure that tidiness has much to do with performance as long as it is reasonable and well balanced. The Kean we have as well as plenty of other arms, Pooch, Krum, Steube... are not so tidy either and they were all good!
The tidiest we have from the Classic era are Bob Green's.

[Ben Martinez III]

'Steve Deiters', on 05 Jan 2011 - 4:05 PM, said:

I seem to sort of remember a mini controversy of the day when machine wound "rewind' armatures were starting to make their way into the marketplace. The controversy was that the machine wound arms the wire would "stretch" during the winding to assure that it was tight thus reducing the measured gauge of the wire to be something less than 27 or 28 or whatever the stated size of the wire was. I think Thorps' arms may have been hand wound or at least they look that way in the photos which would minimize the stretching...in theory. Was it real? Was it imagined? I don't know if it was or if it really made any difference at the end of the day. A particular make of arm wound turn as fast as it could and that was it. Like most controversies in slot racing it took on a life of its own and lasted for a very brief while then it was gone. Not that it would ever happen today.....a small controversy taking on a life of its own here on the blog!!

Steve,

I believe the Thorp arms were machine wound, and I agree that they probably didn't get the credit that they deserved. The arms were incredibly consistant and durable. Rarely (very rarely) would there be a bad one, occasionally a great one, and most others above average. Great race arms especially when mains were 40 minute and motor changeouts between heats was not the order of the day

[Ron Hershman]

The Thorp arms ran good because they were balanced really really well out of the package.

[Prof. Fate]

Hi

Rick, check the bushing alignment and try softening the springs to see if that makes them run cooler.

As I said, Bob Green's arms were the first arms I bought that were not my winds. I so admired the work.

I don't remember, somehow the .005 lams, I feel I missed out! grin. As for size. All hand winders develop a "feel". You get used to feeling the change in wire diameter and content/stretch in the wire when doing it by hand. But any tension does stretch and thin the wire. Even machine wound. I have no idea what "true" means here. Any gauge is "plus/minus" around the standard within the tolerances of the machine that made the wire.

Reusing the wire was common back by kids in the early 60s because most didn't even have a radio shack! I did build a few illegal arms to beat an inspector by reusing the wire. But that is a different sort of story.

Fate

[tonyp]

The Thorp stuff ran well at Nutley. We used to sell a ton of them. They ran and lasted longer then the Mura's of that era. The balancing was dead smooth.

[Ron Hershman]

'Prof. Fate', on 05 Jan 2011 - 6:45 PM, said:

I don't remember, somehow the .005 lams, I feel I missed out! grin. As for size. All hand winders develop a "feel". You get used to feeling the change in wire diameter and content/stretch in the wire when doing it by hand. But any tension does stretch and thin the wire. Even machine wound.

I think Champion was the only one to use .005" lams.....Mura did not. So Thorp probably used Champion blanks for awhile before switching to Mura blanks.

As for stretching wire..... it can ONLY be stretched 2/10's of an inch before it breaks.

[tonyp]

2/10's? That is a lot...

[Steve Deiters]

I seem to remember that Thorp designed and built his own balancer. He definitely was the rebalancer of choice here in the midwest for the upper level racers before Parma had a balancer. He was also viewed as others have stated as providing a quality balance that was a step above others that were sourced at the time.

[TSR]

Thorp had his own balancing machine and also balanced many arms including all of Bill Steube.
Thorp also made his own .007", then .005" blanks and sold them to other rewinders.
Gil Gundersen wound all the arms and balanced them from 1970 until Thorp ended his slot car product line.

[Steve Deiters]

'TSR', on 05 Jan 2011 - 8:29 PM, said:

Thorp had his own balancing machine and also balanced many arms including all of Bill Steube.
Thorp also made his own .007", then .005" blanks and sold them to other rewinders.
Gil Gundersen wound all the arms and balanced them from 1970 until Thorp ended his slot car product line.

When did he finally stop armature production?

[Old pink can guy]

I did not have much luck with Thrope motors. Just wer not as fast as the Mura stuff. But did send my Mura's to him after every two races. Com true and balance was better then new. If I remember correctley His wife did most of the winding. The Dok will have to chime in on that. Also Remember Mike Condor Doing very well at a big Race at Speed & sport in the A main and Oting Very well. And a cool guy too!

[dc-65x]

Thanks for all the input . It’s been great to read about everyone’s “Thorp Memories”…..and something else:

'TSR', on 05 Jan 2011 - 03:48 AM, said:

You are not going to paint it black?

'tonyp', on 05 Jan 2011 - 12:25 PM, said:

Black! Black is meaner looking.

'TSR', on 05 Jan 2011 - 2:53 PM, said:

Probably an endbell from a Mura M444 that were black...

“So let it be written….so let it be done”. Yul Brynner



Well, I do my best anyway. I’ve never done the black dye thing before…..