@ All, Hello dear friend Ufopolitics, 

Build strategy for this Mechanical Commutator.
I can help you structure it step by step.
For this project I would not use the traditional molded "duck-tail" commutator method. 

I would build a stationary bolted commutator/distributor:
Copper segments + insulating plates + bolts + brush contact surface.

This is cheaper, easier to repair, and suitable because the commutator is stationary, not a high-RPM motor commutator.
Step-by-step build plan
1. Define the final geometry
Decide first:

• 32 bars total
• inner diameter
• outer diameter
• copper bar width
• insulation gap
• axial height/thickness
• brush contact area

2. Make the insulating carrier
Use:

• G10/FR4 preferred
• Polycarbonate acceptable for prototype

Cut:

• outer circle
• inner bore
• bolt circle
• segment locating marks

3. Machine copper bars
Each copper element needs:

• contact face
• mounting hole
• wire/terminal connection
• insulation gap from neighbors

No duck-tail needed if mechanically bolted.
4. Assemble dry first
Before glue or epoxy:

• mount all 32 copper segments
• check equal spacing
• check concentricity
• verify brush path
• check no segment touches another

5. Add insulation
Between copper bars:

• mica sheet
• G10 spacers
• high-temperature epoxy
• or precision air gaps

6. Bolt and lock
Use:

• insulating washers if bolts are near copper
• thread locker
• brass/stainless hardware
• preferably shoulder bushings if bolts pass close to active conductors

7. Surface finish
After assembly:

• lightly face/true the brush contact surface
• polish copper contact path
• deburr all segment edges

8. Electrical test before operation
Test:

• continuity of each segment
• isolation between adjacent segments
• isolation to frame
• brush overlap from segment to segment

9. Low-voltage test
Start with:

• 3–6 V
• current-limited supply
• slow manual brush movement
• oscilloscope if available

Only then go to 12–24 V.

---

CAD images/files I need from you
To help properly, please send these:
1. Top-view DXF/DWG/PDF
Must show:

• all 32 copper segments
• ID and OD
• segment pitch
• insulation gap
• bolt holes
• brush path

2. Cross-section drawing
Very important. Needs:

• copper thickness
• insulating plate thickness
• bolt stack-up
• washer/spacer arrangement
• brush contact height

3. Exploded assembly view
Showing:

• top plate
• copper segments
• lower plate/ring
• bolts
• spacers
• terminals

4. Brush geometry
Need:

• brush width
• brush thickness
• brush material
• contact pressure method
• overlap width between segments

5. Wiring map
Need:

• segment number 1–32
• which segments are positive
• which are negative
• relation to Group 1–8
• forward/reverse sequence

6. Manufacturing dimensions
Need:

• copper bar thickness
• hole diameters
• bolt size
• insulation gap
• minimum creepage distance
• available tools: lathe, drill press, CNC, hand saw, etc.

---

My recommended next step
Start with a 2D top-view CAD of the final commutator showing:

• 32 segments
• center bore
• outer support ring
• bolt holes
• segment numbers
• brush contact track
• insulation gaps

Once you send that, I can review it and tell you exactly:

• what dimensions look risky
• where shorts may happen
• where mechanical stress is too high
• how to simplify fabrication
• how to make it builder-friendly.

Kind regards, Alex 

Hello All,

Hello dear friend @kampen ,

Ok, so...I really do not want to get involved in giving STRICT Measurements at this point...why?

Because, Anyone that is going to make this Commutator they are going to look for whatever they have 'handy' first...like Brushes, Fasteners, Materials, etc.

So, to keep it "Builder Friendly" I rather -for now- just post here the BASIC INFO related to building it, and the procedure to do it.

I have put together a simple CAD just to show the Basic Structure, only on a TOP VIEW:



On this View I am NOT showing the TOP POM or Base Insulator, just the BOTTOM one.

First thing I would like you all to note: I am using FOUR (4) DOUBLE Commutators Elements that are located at 1-1 and 8_8.
And these Contacts REPEAT on this Sequence TWICE, meaning, we have TWO 1-1 and TWO 8_8.
Or like I mentioned before, these Four DOUBLE Contact Elements are located EXACTLY at 12:00, 6:00, 3:00, and 9:00 O'Clock.

These Four Double Elements will REDUCE the number of Air Gaps to 28, instead of 32.
The TOTAL Number of this Commutator Elements is NOW 28, NOT 32.
It is just that ONE DOUBLE Element run for the Rotary Time of TWO SINGLE Elements, PLUS Including CENTER Gap width.
ALL THESE SOLID COMMUTATOR COPPER BARS ELEMENTS MAKE AN EXCELENT HEATSINK!!!

On my prior post, I cited ALL the Advantages that this new structured commutator will bring along.
But some are very obvious:

• Less Gaps= Less Brush Jump= Smoother Rotation.
• No Gap - on Doble Elements- because simply we do not need these gaps.
• Easier to Build, less Commutator Elements.
• Easier To ALIGN: First Mount ALL Four Double Elements at 90º...from each other's.
• Or say 12 and 6 O'Clock must be exactly at 180º apart.
• As 9 and 3 O´Clock also at 180º apart...
• They will give you the TWO MAIN AXIS (from their exact center line)
• That will give you ALL FOUR QUADRANTS.

Resuming that we now have:

• Four (4) Double Elements
• Twenty Four (24) Single Elements.

Now, on this CAD, I am showing that each DOUBLE ELEMENT have SIX HOLES:

• Where the TWO HOLES that have a Gold Washer means that it is the PCB Board Mounting Hole [Female Thread] (Closer to the CENTER of Assembly.
• As these Double Elements have their FOUR REAR HOLES to be mounted on POM or Isulation Plate.
• As each SINGLE ELEMENT has ONLY THREE HOLES:
• TWO REAR HOLES for attaching them to POM.
• And the FRONT HOLE [Female Thread] (with Gold Washer), for PCB Mounting.

Please note that this POM Mounting Plate does NOT REACH all the way to the end of ALL ELEMENTS!!
This POM Plates (only the Bottom Plate shown here) serve as:

• ALL Commutator Elements Support.
• And Mounting Support to the Other Commutator Assembly.
• Plus to the End Caps.

ALSO, PLEASE NOTE the VERY INNER DOTTED BLACK CIRCLE:
That CIRCLE is a LATHE CUT LINE...

And I did it JUST TO SHOW the AMOUNT OF METAL TO CUT on LATHE, from SQUARE RECTANGULAR BARS...NOTICE IS ALMOST NOTHING TO BE CUT!!
To make ALL Elements perfectly ROUNDED ENDS.

Now, like I wrote on my previous post:

YOU CAN NOT USE THE POM PLATE TO MAKE LATHE COPPER ELEMENTS CUT!!!
YOU WILL NEED TO MAKE A SPECIFIC FULL METAL PLATE WITH A CENTER SMALLER HOLE.
To mount a SHAFT, OR A THICK BOLT-NUT.
Then use this Shaft-Bolt to mount it on Lathe.

Once you make ONE LATHE MOUNTING PLATE...
It will serve you to perform the Second Commutator Elements Lathe Cut...so, you just need one Mounting Metal Plate.

These Air Gaps -at Commutator- do NOT NEED TO BE FILLED UP with absolutely ANY RESIN!!
The purpose of this Design, is that AIR GAPS are REAL AIR GAPS!!
Not filled up with anything solid in between!

As this will provide MUCH BETTER COOLING AND VENTILATION from Rotor Fins.
Not allowing ANY CARBON DEPOSITS to get in between commutator elements.
PLUS Easier to clean from the Outside with compressed air blowing off...

IMHO, this design, "may look complicated" at first sight...

BUT IT IS NOT!

It is MUCH SIMPLER than the one I am building ...believe me.

AS ANY MACHINE SHOP (does NOT need to be a "Specialist Building Commutators"!!)
IF you show them the Building METHOD, I have described ABOVE.

And of course, you will have to provide YOUR SPEC'S  on even a hand drawing of your SPECIFIC DIMENSIONS.
Plus the thickness of POM or POLYCARBONATE Mounting Plates...I recommend like 1/4 Inch thick or 6.35 mm...where 6 mm would be just fine.

Copper is a very SOFT MATERIAL to Cut, Drill and Thread it...and so are the Polycarbonate Plates...

PLUS THIS DESIGN COULD BE MADE AT SMALLER SCALES...

I will make next time a 3D CAD on MAYA, showing this Design...In order you have a FULL IDEA, how it would look like on 3D

Regards

Ufopolitics

EDIT 1:  About these FOUR DOUBLE ELEMENTS WIDTH:  They will measure the EXACT WIDTH of TWO SINGLE ELEMENTS...PLUS the CENTER GAP ADDED.
Meaning that this way we will prolong the Brush Sweeping Time...
These FOUR POINTS means the END TRAVEL of the Magnetic Field.
And that would INDUCE our END Coils...So, the Field IMPACT TIME would be greater and uninterrupted!!

Hello All,

Ok, so, my job here is to SIMPLIFY the most I can, in order to make your BUILD EASIER and NOT Complicating it with weird measurement materials, not easy to find...

Therefore, here is a TIP to make your Double Elements much easier...and as I wrote on my previous post, these Double Elements consists on TWO SINGLE ELEMENTS Size, PLUS the CENTER AIR GAP (As SOLID FILL, WITH NO GAP):


Then, as above image shows...You could make these Double Elements by:

• Joining Two Single Elements TOGETHER.
• With Copper -or Brass- Laminations -in between- to Fill in Space Gap-
• Clamp-Press them ALL together (with Bench Vise or Hand Visegrip)
• Then Soldering ALL together as ONE PIECE.
• Then File-Sand Surfaces, until you are able to see the Laminations CENTER LINE or SOLDER LINE.

I highly recommend to BUILD ALL YOUR DOUBLE ELEMENTS AS ONE LONG BAR, to then CUT them in LENGTH SIZE EQUALLY.

This way ALL your Double Elements would be Identical in WIDTH., plus you minimize Labor Time, as going One By One...

Therefore, ALL Copper Materials You will need are:

• SAME SIZE Rectangular Copper Bars, as for SINGLE ELEMENTS SIZE (For TWO Commutators, or 64 Small Elements)
• LAMINATED Copper Sheets, (same as Bars Lengths) Just enough to Build your FOUR Double Elements Air Gaps fill.
• Cut Lamination into strips to size (I recommend to cut them a bit bigger than bars).
• Then after soldered together, you will file/sand them to EVEN-SMOOTH SURFACES.

Now,  related to the AIR GAPS, between ALL ELEMENTS, I consider they should be between 0.5 Minimal to 1.0 mm Max.

Again, these Spec's DEPENDS/VARY based on the Brushes WIDTH You have available:

• If Your Brushes are WIDER (Say 1 1/2 size of One Single Element) then your Air Gaps could be a bit wider than 1.0 mm (1.5 mm Max)
• If Your Brushes are SMALLER in WIDTH than a SINGLE ELEMENT WIDTH, then YOU DO need to KEEP Air Gap on the MINIMAL GAP (0.5 mm)

The IDEAL SETUP, would be that Brushes are Wider than a Single Element Width.  In order that TRANSITIONS between Sequential Group Coils are smoother Timing wise.

Regards to All.

Ufopolitics

EDIT 1: These Fill in Laminations could also be made out of BRASS...As Brass SOLDERS perfectly well with Copper. (And of course you make & prep all these Double Bars BEFORE Lathe Cutting)
HOWEVER, If you have Both Options, I RATHER USE-SAME COPPER MATERIAL as ALL Elements.

Reply to Ufopolitics Message # 822

This new drawing is actually one of the most useful construction details Ufopolitics has posted so far.
After studying it, I would modify my earlier recommendation.
What Ufopolitics is proposing
He is not machining a special "double-width" copper bar.
Instead he is creating the double element from:
Single Bar
+
Gap Filler Lamination
+
Single Bar

Then:
Clamp
→
Solder
→
Machine Flat
→
Cut To Length

Result:
[Single][Filled Gap][Single]

becomes one solid copper assembly.
That is actually a very practical shop method.

---

Why this is smart
Suppose:
Single element width:
6.0 mm

Normal gap:
1.0 mm

Then double element width becomes:
6 + 1 + 6

= 13 mm

Exactly what he wants:
Single
+
Gap
+
Single

with no center interruption.

---

What I would do
Step 1
Buy only ONE copper bar size.
Example:
C110 Copper Flat Bar

6 mm thick
6 mm wide
1 meter long

(or whatever final dimensions become)
No custom machining.

---

Step 2
Cut ALL singles from same stock.
Example:
24 singles

per commutator.

---

Step 3
Create long double-element stock
Instead of making 4 doubles individually:
Build:
Bar
+
Copper Strip
+
Bar

full length.
Clamp.
Silver solder.
Then cut.
Exactly as Ufopolitics suggests.
This guarantees:

• identical width
• identical geometry
• less labor

---

One improvement I would add
I would use:
Silver-bearing solder

instead of ordinary tin solder.
Example:
Sn96Ag4

or
45% silver brazing alloy

because:

• higher strength
• better conductivity
• survives brush heating better

---

Most important hidden feature
Many people miss this.
The double elements are NOT there merely to simplify construction.
They deliberately create:
Longer brush dwell time

at:
1-1
8-8
1-1
8-8

positions.
Meaning:
Brush stays longer
Field stays longer
End coil interaction lasts longer

This is an electrical timing feature.
Not just a mechanical feature.

---

Air-gap recommendation
I agree with Ufopolitics.
For a prototype:
0.5 mm

minimum
1.0 mm

preferred
1.5 mm

only if brush width allows.

---

Brush width rule
This is extremely important.
The brush should be:
Wider than one element

but
Narrower than:
Element + Gap + Element

Otherwise timing changes.
For example:
If:
Element = 6 mm
Gap = 1 mm

Then:
Brush ≈ 7–8 mm

would be ideal.

---

My overall assessment
This laminated-double-element idea is:
✅ Cheap
✅ Easy to fabricate
✅ Uses standard copper stock
✅ Produces identical double elements
✅ Preserves the intended commutation timing
✅ Eliminates the need for special copper extrusion
If I were building this commutator myself, this is exactly the route I would take rather than trying to machine custom double-width bars from scratch.
The next drawing we should produce is probably an exploded assembly drawing showing:

• Bottom POM plate
• Single copper elements
• Double laminated elements
• Mounting screws
• PCB attachment points
• Top clamping plate
• Brush position and width

That would finally be close to a machine-shop-ready build package.

Kind regards, Alex

I am working on the next drawing producing an exploded assembly drawing showing:

• Bottom POM plate
• Single copper elements
• Double laminated elements
• Mounting screws
• PCB attachment points
• Top clamping plate
• Brush position and width