47 replies to this topic

[TSR]

You forgot one Mabuchi magnet.... the one that had a single retaining clip that the magnets had notches in the center of the inside arc that the clip fit in and retained the magnets in place with the one clip and no clips at the top or bottom of the magnets once inside the can. No 26-D arm is fitting in that set-up as the mags are very thick.

I did not forget, but they had nothing to do with Mura OR Mabuchi, so I did not mention them.
The point was simply that of the full-contour shim, they were used in ALL "A" can motors until the motor was no longer competitive and replaced by the "C", at which point Mura had new thin mags made for their Group-12 large-diameter armatures.

i THINK that those notched mags were at one time marketed by Tradeship, but I have never found a set under their or any packaging, so I can only speculate at this point. I have a few of these but they are "loose" and provenance is not traceable.
There is another mag of the same size that has the notch BEHIND it, and I am still trying to figure that one out...

[Ron Hershman]

i THINK that those notched mags were at one time marketed by Tradeship, but I have never found a set under their or any packaging, so I can only speculate at this point. I have a few of these but they are "loose" and provenance is not traceable.
There is another mag of the same size that has the notch BEHIND it, and I am still trying to figure that one out...

I have a pair of these magnets in a can... I will have to dig it out.... was told by Bob Green they were made for Mabuchi. Tradeship may have packaged them back in the day, but they were used in 16-D motors back then. Mabuchi sold OEM to everyone who wanted to buy back then.

The notch behind the magnet is because that's the way the magnet MFG preferred to make them.... there was only one batch of front notched mags made as there was lots of scrap in the pressing of those magnets.

It the 90's I took some Mura magnets and had the notch cut down the front, but TDK and Hitachi would not make them with the notch in the front due to loss during pressing and production. They were more than happy to do it on the back side.

This is where the P-S SMQ magnets came from and the notch was too big and those magnets never really worked quite right for magnetic reasons.

[TSR]

but they were used in 16-D motors back then.

Ron,
These magnets were not made by Mabuchi. They will not even fit inside a Mabuchi case without modifying it.

[Ron Hershman]

Ron,
These magnets were not made by Mabuchi. They will not even fit inside a Mabuchi case without modifying it.

You are right Mabuchi NEVER made magnets....... they had companies like TDK and Hitachi making the magnets for them and purchasing them OEM for use in their motors.

What can is this????



It says Mabuchi on the "gimble" bearing



What magnets are these with a notch in them??



Looks like the notched magnets fit "just fine" inside the UNMODIFIED Mabuchi can

[Gator Bob]

I think those were used in the later Mabuchis 1970s? with the funky single spring retainer with the U shape at the gimble bushing side. They worked ok but care was needed in assembly to keep the wire from hitting the spring on the bushing end.
Are they Hitachi mags?

[Gator Bob]

magnetically bound up -
Ron please explain this term.

[Ron Hershman]

More 16-D A can dimensions, air gaps, etc.




16-D/A can inside measurements..... Mabuchi, French and Mura

.890" width .603 height..... all three cans measured the same.




The D/A cans with stock Mabuchi magnets

Air gap in all three .560"

Magnet height .585"

Magnet thickness .173"


The D/A cans with the later Mura magnets as used in the D/A can needing the shim

Air gap in all three cans without shim .600"

Magnet height .540"

Magnet thickness .145"

I do not have the "shim" or the can in a can.... if you do measure the thickness and minus from the .600" air gap and you will have the air gap of the mags in the can with the shim in place. So Do the math.

Mura C can

Inside dimensions Width .835" Height .560"

Mura A/C magnet dimensions .540" height .145" thickness

Air gap of the magnets used in both the A/C cans and when placed in the C can .535"



Air gap of "Tradeship" magnets in all three D/A cans .530"

[NSwanberg]

"This was better but still not the "fix"...... then the problem was in the arms and no one ever figured it out until it was years later "

Seems to me I scraped my Christmas money and paper route money together and invested in B can set up and a Mura "Long John" armature. Seems to me it was pretty good for toasting marshmellows.

[Hworth08]

Maybe I missed something but the red/white magnets with the slot look like rather common Tradeship (French) magnets that were avilable in 1966.

The French or Strombecker Hemi mags were the choice till the Arcos came out.

Another magnet from the '60s was a Mabuchi-looking magnet except there was a slot on the back next to the can.

[Ron Hershman]

Are they Hitachi mags?

No one knows for sure Bob...... TDK and Hitachi were the two biggest makers and suppliers of "small arc" magnets in the 60's to Mabuchi and still are today.

[Ron Hershman]

magnetically bound up -
Ron please explain this term.

This happens when the field strength is too strong for a particular armature wind. The field is so strong that while the motor may run, the arm is actually "slowed" down in the field reducing RPM's and torque.

Here is a modern example of being "magnetically" bound up..........

The new Pro-Slot "hard" Neo motors/magnets. While good for drag racing, the magnets are too strong for road racing as the motors get very hot. Remove material from the cans and this helps reduce the magnetic field in the motor allowing the arm to have more RPM's and more torque while running a bit cooler, but not cool enough.

But in some motors removing metal in the cans can have the opposite effect as well by making the field too weak causing excessive heat.

Like a current FK motor with the poly neo mags........ they usually run a bit faster once they get warmer......this is because the magnets when cool are too strong for the arm and as the motor is ran the magnets get hot and weaker "unbinding" the arm giving more RPM's and faster lap times.

Most racing these motors have observed this many times.

[Gator Bob]

Perfect explanation Ron. Thanks.

[Ron Hershman]

I think those were used in the later Mabuchis 1970s? with the funky single spring retainer with the U shape at the gimble bushing side. They worked ok but care was needed in assembly to keep the wire from hitting the spring on the bushing end.
Are they Hitachi mags?

I can also tell you this..... in the 90's when I went to TDK to have a magnet made with the slot down the center, TDK wolud not make it....maybe from their "experience" in making these magnets one time in the 60's????

They could have very well been made at TDK for Mabuchi in the 60's or any other company at the time.

[TSR]

Looks like the notched magnets fit "just fine" inside the UNMODIFIED Mabuchi can.

No, they do not. In order to make them fit, the indentations on top of the can have to be flattened, and I hardly see a production line of little Japanese ladies doing that. The stock Mabuchi magnets have an indentation on top and bottom to clear these indentations.
If anything, these magnets MAY be from Johnson in Hong Kong, but I have no way to know at this time.

The D/A cans with stock Mabuchi magnets

Ron, these as shown are NOT stock Mabuchi magnets.

[Ron Hershman]

Ron, these as shown are NOT stock Mabuchi magnets.

Well they came out of a unopened Mabuchi 16-D motor.

You need to get out a set and give us the measurements ASAP

[TSR]

Yes I will, sometimes today. Ron, I understand that you may not have all the proper parts on hand because these things are now pretty old and not too many are still truly original.
I have on hand unopened samples of every single Mabuchi FT16 sized motor since 1963 and will walk you though it.
The "can in a can" shim is reported on the 1967 Mura catalog as M141, "Semi-can" and M600, "Semi-can with Magnum 88 magnets". This a full 8 months before the Mura M-400 series of new motors with the "30-thou" can came out.

In the same catalog, the rewound Mabuchi FT16DBB (the nickel plated can with oval hole and aluminum bearing housing) is described as "M244, new Magnum 880 Ultra Hi performance ball bearing motor w/NEW Semi-can magnetic shield. Endbell output (60 day warranty). Available in 25 sgl or 29-28 dbl.

Mura NEVER intended to use their new can, the one with the Tradeship tooling, without that semi-can.

[Ron Hershman]

Mura NEVER intended to use their new can, the one with the Tradeship tooling, without that semi-can.

Agree..... the newer style magnets ( thinner and shorter ) never fit the can correctly. Plain and simple.

[TSR]

OK, I made all the measurement, took plenty of pics, and the winner is...
Let me sort out the mess first!

[Gator Bob]

Mura soup de jour.

[TSR]

I am going to open a new thread for this.

[TSR]

This is an old thread and I did not see the last postings, but those mags (see post # 29) were made for and marketed by Tradeship, not Mabuchi. They were designed, as so many products were, to fit inside the Mabuchi FT16 and FT16D cans as an upgrade. They were supposed to have better material and it is likely possible because I found a set of these mags inside a genuine early Steube motor during its reconditioning.

 

So just because someone finds something inside a Mabuchi motor that is not standard, does not mean that it was made or marketed by Mabuchi.

[Old pink can guy]

Sorry I that it was agreat motor untill I tired it.

[Gator Bob]

I am going to open a new thread for this.

 

Link please ...