Article written by Big Jim Greenemeyer

How the serrators cut - First, serrations are made up of peaks and valleys but since it's only the peaks that touch the comm (if the valley touches the comm, there are no serrations left) this is what we concern ourselves with.

Second, I'm listing the serrations on the different cutters and brushes by the number of serrations per inch measured from peak-to-peak.

Also, I found that the "stack" of serrations on a brush can start in a peak or a valley The only brushes I found that start with the peaks were the T#4500's and the T#4455. Nothing strange there-they are the same compound. The only difference is the standup vs. laydown comfiguration. The number of serrations per inch indicate how "fine" or "coarse" the serrations are but not how many are necessarily on each brush.

Since the dictionarys don't list the word "Serrater" we can make history here. Do we spell the tool that makes serrations a "Serrater" or "Serrator" . I'm not an English teacher but I say "Serrator", just looks better. If anyone out there knows any contradictory rule in English that says it would be proper to spell it the other way, let me know.

So whipping out a magnifier and a steel machinist scale I did some measuring. Here are the results.

SPI = Serrations Per Inch.

PROMATCH SERRATOR TOOL: 36 SPI
INTEGY SERRATOR TOOL: 32 spi (Same as the P-94 brush).
TRINITY SERRATOR TOOL: 40 SPI (but much shallower than the others).
TRINITY #4499 Brush: 44 SPI
TRINITY #4500 Brush: 56 SPI
TRINITY #4455 Brush: 56 SPI
TRINITY #4383E (P-94) 32 SPI (Matches Integy tool).
TRINITY #4380E (P-94) 32 SPI
TRINITY #4383 brush: 56 SPI
REEDY #767 Brush: 56 SPI
Putnam Pro "green": 44 SPI
Putnam Pro "red" : 44 SPI
Putnam Pro "blue" : 56 SPI

I couldn't figure a way to accurately measure serration depth. The Integy and ProMatch serrator tools "look" to be about the same.

What if any difference there is in a "fine" or "coarse" serration as far as power output, I'm not sure yet. But it is general thought that a finer serration is easier on the comm.

This motor tip is from Big Jim Greenemeyer.

hank..i didnt see the racetech surater tool..where does that fit in?

Another one I'de like to see is the fussy brush system

Hank is there any difference in Comm wear and power output if the serations are
with the comm rotation, or at a diagonal

Greater performance from straight serrations-:thumbsup:
The diagonal serrations actually wear out quicker as well due to them being much shallower than a straight serrated brush.

what about comm wear? Wouldn't the shallow serations seat faster then?,Wouldn't the diagonal provide a even surface wear compared straight and groves on comm.

I've never seen a cross seration brush.

The main point of the serrations is to transfer power to the comm without the extra "drag" from the extra surface area. The brush with serrations has a faster "brake-in time" and also does not require as heavy a spring to do the same job, as a full brush. So, it is easier on the comm, but still produces the same or better results. Also, as a bonus, it produces more RPM's, because of less drag (friction).
Kevin

I've never seen a cross seration brush.


Then you havent seen my idea of a brush cutting jig,

Trinity makes a cross serrated brush.. there is also some cutters out there that have a cross serrate slot on them..