64 replies to this topic

[proptop]

Things cleaned up nicely...and yes, those are the original type magnets...

The Semi-Can cleaned up good too...I've had some that were rusted in so bad that it seemed like they were almost bonded in...and when I got them out they were so deeply pitted / corroded they distorted badly upon removal...almost crumbled.

 

FWIW there are 2 different thicknesses of the can-in-a-can shim, .007" and .015"

 

Looks like you found a good endbell replacement too...gonna make a real nice motor...the Cukras sticker looks to be in decent condition.

[Pablo]

Hey, you found a new Mura EB!

Mags and shim look great and I like your dammit gizmo. I'm getting excited now

 

From the photo, the springs look kinda stout, but you are there and I'm not.

 

http://rgeoproducts.com/

[dc-65x]

Looking very nice Martin.

 

I know you are an exceptional professional craftsman but, as with any new tool, trying out your new comm lathe on a spare armature might be a good idea. You might have to mess with the tool height. Are you getting a diamond tool?

 

I hesitate to mention this as there was an entire thread dedicated to it with many very strongly held opinions and I don't want to start the debate all over again here........but..........on my finish light pass I put a drop of oil on the comm (Trinity ball bearing oil is what I have handy). Again, experimenting on a spare arm might be a good idea.

 

Maybe I should have PM'd you this......

 

Anyway, here is a link to several period "hop up" articles for all the vintage motor geeks out there (like me ):

 

Motor How-To Articles for the 1969 MCS/USRA Series

[Martin]

Thanks to all, did not know about the can shim thickness, this has to be the thick of the two. I had been saving this end bell for years and did not know when I would use it, so this is the perfect time.

 

I found the comm lathe used, $90 shipped,so I am not sure what it will come with, but yes for sure I will practice first. I have read that article. I will sharpie and play around with light oils. I will read more. Geeks unite

I will have to save my penny's to get a diamond tip. Looks like they are $50 buck ish. 

 

The "dammit" tool helps you not slip, not sure I am getting any twist though? Hardest thing was choosing which tool to cut its head off. So I used a cheepy.

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[John Secchi]

I found the easiest way of getting them off without damaging the paint/can is to grind a slot across the head with a Dremel cut off disc deep enough so i can use a small flat screwdriver, unscrews like a normal screw and if your really tight you can re-use them, or just bin them and use a proper screw!

[oneofwos]

[Martin]

Thanks for that John. I do have a pair of 90 degree wire cutters that grip the head nicely. With a twist and pull they come right out. No problem. I would reuse them only to satisfy the vintage police and even though this is far from mint it would be all stock.  I do have nice small button head screws. So I might say screw it and use those new screws anyway.

 

Pablo. I did measure the brush springs at .020" how does that sound? I will look for alternatives. I kind of settled on these because they fit the post protectors and are silver like stock.

[Pablo]

In comparison, a Champion Light spring mikes at 15 thou. The amount of force is not only a function of wire size, but angle also. This one is about 90 degrees, whereas yours looks about 160 degrees

 

 

I'd start by installing and test a set of light springs first, and gently push on the brushes with toothpicks to see if more force will improve it. You want just enough force to preclude arc jumping. More than that is simply wearing the brushes and comm faster than needed.

 

The springs you have can be bent to provide however much force you decide. Obviously those were installed by someone back in the day that thought he needed lots of it.

 

I'll bet H Man agrees because I graduated Havlicec Theoretical School of Spring Tension Cum Laude

[Martin]

That all makes perfect sense. I will play around with that process.. 

 

I think I have a small spring tension tester, I will take a pic (I have never used it) you can tell me if its of use.

 

Here it is, it is made by Sonic.

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[Bill from NH]

Martin , your tool is a Fiddlestick. John Thorpe was the first to sell them in the early '70s.. The Thorpe had a hook bent into the wire where it exits the top of the brass tube. No two Fiddlesticks will give identical readings due to differences in the internal spring's tension. but they'll all provide relative readings that some don't care to bother with. I always found using them more accurate than bending spring tension by eye. If you want to be anal, you could calculate the readings engraved on your brass tube by using a gram scale. 

[Pablo]

Concur. My thinking with the Fiddlestick is, a good tool for matching tensions in a motor program of exactly the same motor on the same track. In other words, once you find the ultimate tension for a specific motor, make all subsequent motors the same reading. It can be of benefit.

 

As far as there being a Fiddlestick magic setting for a certain motor, no. Just my opinion. I had one and I sold it. If I built motors in batches, I'd have kept it.

[Martin]

Good for comparing spring tensions, that make sense. I will also check other motors springs (on good running motors) I have to get me in the ball park.

[Jairus]

Hey Martin, FYI
Cukras powered slot car goes for $$$.

Get her done.

[Martin]

I was there for that one, but was blown out of the water, I bid $150ish. I thought it would be good to have Pink motor in better condition, I love the blind Champion wheels and the body looked usable too.

 

But not for over $300, yes thank you Jairus, it is incentive to get mine done. I have been practicing with my new comm lathe. When I feel I am ready I will make a clean up cut on the Cukras's comm. Then reassemble and

find a suitable chassis.

 

This auction (same seller,same time) had a Champion Thumbprint in it.  https://www.ebay.com...&orig_cvip=true

[havlicek]

 

 

The amount of force is not only a function of wire size, but angle also

 

Well, if the motor isn't going to be one bazillion percent all-original, there's also the possibility that the number of coils of the brush springs can come into play as well.  Still, I've mostly stopped screwing around with different tensions and mostly just use "lights".

*With a fresh cut on the com, and light springs with regular pre-radiused Big Foots or Gold Dusts (*PLUS making sure the brushes are not bound in the hardware!), most motors will do fine ...at least at first for getting you "in the ballpark".

*People familiar with screwing-around with their motors will often have preferences as to what tension and what brand they prefer for their track and application(s).  Springs are a good way to get that final tweak racers prefer...actually, brushes as well.  Both are easy enough to change anyway, but using "regular" brushes and light springs seems to work just fine for delivering a motor...and even fine period with vintage motors.

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*What Pablo said (*and he builds some mighty fine motors!) about adding *light* pressure to the back of the brush with a toothpick while the motor is spinning is a good way to get a handle on what's going on, although things will be different with a motor under load in a car and on a track.  In many cases, the motor will speed up BUT that can mean the brushes just need more time to break-in.  In other cases, the motor will slow down, but you could be exerting more pressure than necessary...so a little testing and intuition can come into play.  If a brush is hung a little, but not enough to prevent the motor from turning, this can help point that out right away because the motor will *suddenly* jump!

[B.C.]

the pink motor in the auction yesterday looked about as good as it could be and not still be in a package.

 

whoever was the lucky buyer, along with the orange picker car that he also won. both were well bought

 

I thought the pink motor would go higher.

 

if it is a thumbprint in the third auction--very very well bought.

[Martin]

Hey John, I mostly look through draws of motor parts I have saved over the years. But I am coming up short when it comes to the small 16d brushes and springs.  Can you recommend a good source for these?

 

Orange picker ( we assume that is what it is ) went for $200+ the Thumbprint went for $150 and the Pink Cukras went for $300+

 

Brian.All the motors looked to be in low mileage condition (as you mention) I am re-calibrating to be able to say well bought? But I did toss my hat in the ring at least on the Thumbprint and the Cukrus but I am glad I still have the almost $700 in my control.

[havlicek]

Hey John, I mostly look through draws of motor parts I have saved over the years. But I am coming up short when it comes to the small 16d brushes and springs.  Can you recommend a good source for these?

 

 

Hi Martin,

     I got a lovely supply of *EXCELLENT quality brushes from Joe Lupo, but they are slightly larger size than the FT16D ones, I think they're actually 26D size, and they also are a perfect fit for the Hong Kong Mabuchi end bells...so maybe they were made for those???  If you include the FJ13UO, there are actually several different sizes of "small" Mabuchi brushes, but no matter, it's VERY easy to size them down with some careful sanding, flipping them over after several strokes to keep them square.  I actually prefer this because I only need to keep one size.  Anyway, I have no idea if Joe has any more, but if he does, they are really good brushes.

As for the springs, I've thrown out so many of them, it's crazy.  I may have a box of assorted ones somewhere, and will look for you, but you would have to match them up in pairs visually.  ***The ones used on the FT36D work best on the FT16D, but are still very light.

[Jaeger Team]

 

Hi Martin,

     I got a lovely supply of *EXCELLENT quality brushes from Joe Lupo, but they are slightly larger size than the FT16D ones, I think they're actually 26D size, and they also are a perfect fit for the Hong Kong Mabuchi end bells...so maybe they were made for those???  If you include the FJ13UO, there are actually several different sizes of "small" Mabuchi brushes, but no matter, it's VERY easy to size them down with some careful sanding, flipping them over after several strokes to keep them square.  I actually prefer this because I only need to keep one size.  Anyway, I have no idea if Joe has any more, but if he does, they are really good brushes.

As for the springs, I've thrown out so many of them, it's crazy.  I may have a box of assorted ones somewhere, and will look for you, but you would have to match them up in pairs visually.  ***The ones used on the FT36D work best on the FT16D, but are still very light.

I tried to contact Joe Lupo (april 2018) in the aim to buy his very interesting brushes, but I never received an answer...

[Martin]

PM sent John, thanks again for all your help. It's all the variations that is a little daunting. I spent hours just trying post projectors that fit the posts and then I had to turn down the flange at the bottom so they looked correct. 

 

I think it comes down to organizing the motor parts I have, into something that makes sense.  Maybe you could just come over,bag and label hundreds of parts, won't  that be fun 

 

Thanks Maurizo for the heads up on Joe Lupo.

[Bill from NH]

Martin, Joe Lupo is a Slotblog member. Anyone should be able to PM him on here.,

[Martin]

Bill,

I think the "Lone wolf" want's to be alone at this time.

 

I did PM him.

[Bill from NH]

Maybe, he did just have his first grandchild.   It's been over a year since I last saw his motor brushes on eBay in 20 pr. & 100 pr. bags. They could be all gone.

[dc-65x]

Professor Motor has 26D brushes which can be lightly sanded to fit 16D brush hoods:

 

Professor Motor Brushes

[havlicek]

Bill,

I think the "Lone wolf" want's to be alone at this time.

 

I did PM him.

 

 

Hi Martin...I got your back 

[TSR]

Since I have to restore quite a lot of older Mura motors with pin tabs, I found that the easiest way to remove them without any damage to the original paint on the can, is to use pliers designed to cut parts from plastic model kit sprues, and  finely grind their jaws even thinner on their bottom side, with a slight angle up on each blade. The blades then go right under the tabs' head, and a gentle twist to the left lifts the tabs with no fuss.

To put the tabs back in, I insert them to get them started and use a precision vise, pushing the tabs by pairs,
Works great for me.

A precision for Jairus: the first generation of the Mura-Cukras motor uses a very dark gray endbell with flat copper brush-holder retainers. The second generation uses a white phenolic plastic endbell with greater heat resistance, and copper pent roof brush-holder retainers. But even far more important: the armature not only has its wires now tied (most of the first gen died when the wires melted their solder and committed suicide), and also welded instead of soldered.
The story of how this took place and why is explained in the "Motors" chapter of the book (really now) in the process of publishing (thank you all for your patience...)

Mura-Cukras first gen:

 

Mura-Cukras second gen: