Hello all,
My name is Tim Leppert, Iv'e been racing fray style cars for seven years. and been to every fray since 2001.
I thought I would try to get you going on building a fray car from the ground up.
If you have a few tools, and a decent supply of parts, you should be able to build a pretty good fray car.

First things first:
Tools,
You will need a fast way to remove gears. The R.T. gear removal tool is the answer
The R.T. gear press is also a required item. No better gear press made. Don't even bother with any others.
Wheel removal tool.
Good wheel press, Wizard makes a good one, and at a decent price.
Poising tool, You can make your own, just go to H.O. world for the article.
Tech block. Yes you will NEED this, (not just for tech)
Cheap dial calipers, A decent set can found at Harbor freight.
Other stuff after I think about it......

First up, Chassis choice.
You want to find a chassis that is flat on all four corners.
You will need:
Your tech block, two drill blank axles, uncut (about 2" long) and ALL your chassis (stripped of all removable parts)

Simply place the axles thru the rear and front axle holes and place on the tech block so that the ends of the axles are resting on the rails.
press on the corners of the chassis, and find the ones that are touching on all four corners.set these aside(they are very rare)
then begin to rate them based on how far out they are. place them in a line in order of straightness.

Next episode: Gear plates.

I supply specific sought after parts that the FRAY guys need.I am probably the only dealer that will sell the hard to get gearplates,arms and such.Sorry to hijack your thread,just wanted to also help out the newbies and soon to be tuners.
DRAGjet
859-356-1566

In this episode we'll cover two things, Choosing a gearplate and matching it to one of your chassis.

Gearplates:
I will admit to being lazy when it comes to gearplates. If I find one that fits a chassis well, I use it. I don't care if it's a lettered plate or not.
I never try to match a certain plate and chassis by number or letter. I just check the fits that are important to me.

What I look for is:
square topped Idler posts.
rear hole is not too big.
no cuts or grind marks that deam it illegal for the fray.

To prepare for the fitting process, you will need to dissassemble your plates. If you have any plates that read "pattent applied for", keep these gears seperate from the others, they are very early, and usually have better machined geartrains.
As an aside, I do not recommend removing the nine tooth from the shaft, if it's tight, leave it on!

When you have your pile of gearplates, it's time to start checking fits. This is easy, when you get set up.
You will need:
Your tech block,
The 2" long axles you had before
a gearclamp band, (not a tight one!)

Now take you best chassis, grab a plate and assemble it with the band. Install the drill blanks in both the main bearing holes and the cluster gear hole. They will be sticking out the top and the bottom.
Now turn the chassis so that the drill blanks are horizontal. and place it on your tech block the same way we did the axle holes.
They will not touch the same way that the axles holes did. but we are looking for the closest to touching all four as we can get.

Remember that feel and repeat with all the plates you have. When you find the top three or four plates, save them as your top matches and we'll move on to choosing the arm....
in the next installment.

Thanks
Tim Leppert

Choosing the right armature

This is were it gets interesting.
To find your best armature, we have to define "best". My definition is smooth, and fast in the midrange. Lots of folks look for that punchy, rip your throat out armature and all they get is dirty tires. The fact is that you need to difine your driving style and choose arms accordingly.
The other thing to remember is that with the tools available now, you can switch arms faster than rear tires. So if you have a doubt,pull it out. Try another one and see.

OK here goes,
you will need:
1 set of blue and yellow magnets.
1 set of old crappy pickup shoes.(try M/T shoes for this, they don't need springs)
1 set of decent brushes, cleaned and polished.
a power supply at your bench.

Now the trick here is that you have a number of chassis, and a number of plates, now your'e throwing in more stuff like arms.
Try doing one thing at a time and start with the chassis and plate combo you think is your best.
Assemble the shoes and the magnets, then slip in the brushes, and pop in the arm.
Spool 'er up and listen, remember that tone!
Then turn the chassis the other way and run it backwards. it should run faster forwards than backwards. If not, no worries, we can fix that later.
Next,try switching plates. (remember the plate you just tried, you will probably end up with that one) You will hear a difference.When you figure out the the original plate is the best, mark the chassis with the plate # and the plate with the chassis #.
Next thing is to try all those arms and find the one that feels and sounds the best. Set that combo aside.
Now you can grab another chassis and start all over and find the next best combo.

Next installment:
brushes and brush tensioners.
:woohoo:

..

Next installment:
brushes and brush tensioners.
:woohoo:[/QUOTE]

WHEN? :thumbsup:

Great step by step. Thanks! :dude:

Next installment is in the works guys!
You will need:
your chassis, arms, brushes, and an AM radio!

Really

:wave:

Great thread Tim! :thumbsup:

Based on your experience with these cars and the processes you describe, I bet this is second nature to you now, but if you had a video camera and taped some of these steps, I know a newbie such as me would watch it!

Waiting with baited breath!!!

lol- I use the radio too! Cant wait for the next exciting episode.

You know... I'm not trying to be funny here but would someone PLEASE explain what the heck a fray car is? No really, I'm not kidding. I've heard alot about these but what's so great about this car that I can't get with my SG+ or like a wizzard or something?

What does it look like? Is this based on something else? Does it cost an arm and a leg to make? I paid $40 or something like that for a wizzard awhile ago and I thought that was a bit high so any insight here would be helpful.

Thanks,
Xence

A fray car is a T-jet with an independent front end at 1 5/16" in width, typically a drill blank of 1 5/16" is used for a rear axle and silicone over sponge tires are used. The arm can be trued and balanced and each pole must not ohm lower than 16.0 on average. Resin bodies are used that have been lightened and lowered, also the newest thing is to use CNC'd gears as they are perfectly centered and straight and enables you to not have to go through dozens of stock gears to find the perfect fit. I'm sure more will add but that is the basics of it.

If $40 is a lot to you, don't bother with this car type, or much else that goes beyond stock for that matter.

The great thing about these cars is that they are not blindingly fast, but they are a heck of a lot of fun to drive.

I'm not against spending more than $40 but I would need a place to race this little devil. As it is now I can't say that I know a place here in ct. that races. I know there was a group of guys out here somewhere but I know they were at least an hour away. Normally I wouldn't mind this but I drive an hour each way to work every day. I really would rather not drive even more than I already do. I'm not deadset against it I would just rather not.

check out this website, and look at the section where the bodies are sold. it shows lots of examples of fray cars.

http://www.moonstonebodies.com/modern_car_bodies.html

also check out the fray (the race)

http://howorld.fsmra.com/archives/fray/fray/pgfrayst.html

yes, you could spend less and go faster, but for me fray cars are suich a kick because they are really tweaked for maximum performance. a big block chevy or ford in stock trim will blow away a tricked out VW bug, but tricked out VWs are still cool. at least ot me :)

if you have any experience with stock tjets, its frankly amazing how fast a really well built fray car is compared to stock tjets

They're open wheel sedans :)

Fast, yeah, but too silly looking for my tastes. Should either get the wheels back under the body or widen the bodies to cover them.

The tuning tips apply very well to the T-Jet chassis in general and are worth trying for sure.

Most of the TJet races I've been to also run a round of stock TJet races, so the stock form bodies and chassis are still represented. The Fray/VHORS style cars really grow on you once you realize just how much fun and fast they really are. I see them as really tricked out TJet Race Cars that would probably be something between a super stock and a modified in 1:1 racing. Since they are Real Race Cars the aesthetic concerns are allowed to take a backseat to the performance ones. I'm totally cool with their looks and even more so when racers trick them out with nice paint and decals.

I agree with twolff that they are really sorta odd looking. Now having said this I am NOT against doing this sort of thing even if the car costs me $100. I don't want to spend $100 a week on a car but if I jump into it and I end up with a few of these devils that I can race with .... so be it. I'm cool.

I get back to the forementioned problem, and I'm working on fixing this now, of a nearby place to race. I've got another post going as well on 12'x4' track. Hopefully this will come to fruition and then maybe I can get some people over now and then and possibly even get to a place where we race these fray cars.

Yes, these cars are kind of silly looking, but you're really missing out on a great driving experience if you're basing them solely on appearance. The fray car is the most fun thing in my race case, bar none.

Holy Crap!
You guys are taking over my thread!
L.O.L.

But Really,
I'm working on the next installment as we speak.

Holy Crap!
You guys are taking over my thread!
L.O.L.

But Really,
I'm working on the next installment as we speak.

LOL Tim!

We're just staying tuned in and filling your thread with "unholy crap" while waiting for the next exciting episode. :thumbsup:

Just a bunch of squirmy kids during intermission. :p

OK Here we go:
You will need:
The radio (AM and tuned to no station)

A power supply rated for 18-20 volts. Pluged in to the same recepticle as the radio.

Your parts and pieces

a small, sharp pointed probe, or toothpick

a set of sharp pointed tweezers.

some Wizzard brand brushes (do not scrimp on these. They are the ONLY brushes I use)
polish faces on a peice of paper setting on a hard, flat surface.

OK
Find That good chassis, throw on some shoes and let's get to it!

First, make SHURE you know which direction your power supply is running. and were to place magnets for proper rotation. the best way to do this is to take a car you know runs in the proper direction and test the supply.
the arm should rotate clockwise when all is right.
THIS IS IMPORTANT!!!!!!!!

Now that we have that done, let's start testing.
Grab that good plate, an arm and brushes, assemble with clamp
spool it up and remember the tone. Then turn the chassis around and spool it it up backwards, you should sound better forwards than backwards.

Don't change anything yet.

We want to "seat" the brushes.
We do this by getting the arm running and pressing the brushes against the com, GENTLY.
Try to stand up the chassis and get it running and use the toothpick to do this. Press in the center of the valley of the brush tensioner. You should feel the brush directly thru your fingers.
you will hear the revs go down a little,then release and repeat. don't allow the arm to stall when you do this. This should gain some revs for you.

The next thing to listen for is spinning brushes.This is something you don't want.If you have a good solid tone, your good.
if it sounds like you are slightly changing the position of your controller, you have a brush spinning.
To stop this you will need to scratch an "X" in the bottom of your brushes. then reseat. this should correct the problem.

Now we get to the good stuff.
If your arm spins faster in the proper direction (clockwise) skip this next step.
If your arm spins faster anti clockwise, then we need to correct it.

Remove the arm but not the brushes. Align your chassis so that you are looking from the back to the front, you should be looking at the front brush.
The right side should be higher than the left. To do this, remove the brush and grab the "v" with your tweezers from the side you want to be higher.
GENTLY tweek it up, and replace the brush and inspect.
this is a very delicate adjustment so go slow.
Simply turn the chassis around and repeat for the back brush. Try to get them looking the same.

When this is done to your liking, we will move on to adjusting tension. There are many ways to do this, and I will not get into all of them here.This is my favorite method,
Remove the arm and brushes. Looking from the top, place the toothpick in the valley of the tensioner and gently push up. this will bend the spring at the root of the "v"not back by the rivet. Do this a little at a time, checking your progress with the brush.


But try this test first.

Turn on the radio, turn the station selector to a spot were there is no signal.
Now spool up your chassis. You will hear the static change. This is a poor man's ocilloscope. It will let you know how efficient your little motor is running. As you play with the brushes, adjusting and changing, you will find that the static will get louder and softer, depending on your adjustments.
The quieter you can get the signal, the better your arm will perform.
You will also find that certain arms are quieter than others in that chassis.

Avoid over adjusting the brush tensioners. they are very delicate. if you get into trouble and bend one the wrong way, you can save some of them by making a little lasoo out of dental floss and pulling it back.

Never try to add tension with the chassis assembled. always remove the arm and brushes.

When you have it close, start changing out arms, looking for the one that sounds good.

Good luck! :wave:

Next installment:
blueprinting the geartrain.

One silly question Afxgns, do you put the "X" on the brush towards the tensioner or towards the arm? I did this only one time cause I read about it somewhere else and I believe I put it towards the tensioner to keep it from spinning? Is this right? One thing I noticed was the car ran slower but I didn't do all the tweaking you mentioned!! Now will have to go back and do it right!! Great freakin' thread you got going here Afxgns!!!!!!!!!! Keep it coming!!

Oh, could you give a quick explanation on why you "X" the brush and its benefits!! Pleeeeeeeeeeease!!
Thanks,
Tom

The X is put in the brush and placed down towards the holder and away from the arm. This way the brush is seated in the groove and won't spin when the arms spins across it. If the brush spins you will lose power and thus lose speed. Sometimes with the Wizzard brushes since they are really tall you may see a bit of slow down because you now have too much tension on the arm, sanding them down lower will reduce that tension and it should speed back up.

Marty has it right,
Put the "X" on the side towards the tensioner.
If the brush is spinning, the acceleration is inconsistent. But the main reason is your braking the alost gone. Also, the brush will actually wear the tensioner in two, if you let it.

The X is put in the brush and placed down towards the holder and away from the arm. This way the brush is seated in the groove and won't spin when the arms spins across it. If the brush spins you will lose power and thus lose speed. Sometimes with the Wizzard brushes since they are really tall you may see a bit of slow down because you now have too much tension on the arm, sanding them down lower will reduce that tension and it should speed back up.

Thanks Marty, much appreciated!! :thumbsup:
Tom

Marty has it right,
Put the "X" on the side towards the tensioner.
If the brush is spinning, the acceleration is inconsistent. But the main reason is your braking the alost gone. Also, the brush will actually wear the tensioner in two, if you let it.

Ditto to you Tim!! :thumbsup: KEEP IT COMING!!
Tom

P.S. Tim...Kinda lost translation of this.."But the main reason is your braking the alost gone" :confused: :)


Question...How do you put multiply "Quotes" into a reply :confused:

Fat finger Freddy stikes again!

There are lots of reasons NOT to have brushes spinnig.
But the main reason is, how much braking you loose.
Traditionally, Fray cars don't run a brake wire. So all your braking has to come from the car. Either the geartrain or the brushes.
With the advent of the RT gears, your brush settup is even more important.

I Hope that covers it.

Now we get to the good stuff.
If your arm spins faster in the proper direction (clockwise) skip this next step.
If your arm spins faster anti clockwise, then we need to correct it.

Remove the arm but not the brushes. Align your chassis so that you are looking from the back to the front, you should be looking at the front brush.
The right side should be higher than the left. To do this, remove the brush and grab the "v" with your tweezers from the side you want to be higher.
GENTLY tweek it up, and replace the brush and inspect.
this is a very delicate adjustment so go slow.
Simply turn the chassis around and repeat for the back brush. Try to get them looking the same.
Interesting! What is the reasoning behind this? And whatever the reasoning, wouldn't it just work temporarily, until the brushes wear a bit?

Yes your brushes will wear some, as they are a NWI (normal wear item).
The idea is to optimize performance in the correct direction of rotation within the brush wear limit.

It's another leg of the current path. Chattering carbons rob performance... Carbons that are tighter than tree bark kill armatures!

Like shoe tuning, it's a fine line that you have to sneak up on. Too much comm tension, and your asking for heat problems and excessive wear to the comm plates ...too loose and yer dogging the track with the potential for arcing damage on the comm plates.

A comm set up thats too tight is generally exhibits twitchy handling (off throttle skidding) and heat problems. A too loose setup is usually gutless often exhibiting erratic track manners or surging.

My rule of thumb is if you run a few laps and the arm pinion burns yer thumb it's too tight! LOL. sizzle....

Probably one of the most important and often overlooked step in the process is the "no load" break in period of your comm setup. This is where you should watch for "heat build up/no coast" (tight) or the "arcy/chattery" (loose) scenarios. Just do it!

Note: Every one has their own setup gadgets. For test poking the brush springs while radio tuning I use a sharp "cocktail" toothpick. For a brush spring adjusting tool a pocket screw driver that has been ground to fit the brush spring contour affords good control. I also use the toothpick as a tension removal tool from the topside should I over tease the brush spring.

If your new to process and worried about it, try it out on a clunker chassis first to get the feel of it. As Tim stated, GENTLY does it.

Thanks, Bill. But actually, the part I'm asking about is where afxgns says to make the right side of the brush higher than the left. Why, and how does it help the arm perform better when it's spinning clockwise?

I think you're getting confused by the fact that as you look from the rear of the chassis, you are seeing the FRONT brush.
The trick is to get the trailing edge hitting first. As the arm is set into place, the preasure will flatten out the brush.

I think I understand what you're saying to do; put more pressure on the trailing edge of the brush if the arm runs faster when spinning counter-clockwise.

What I'm trying to understand is why? What is the theory behind putting more pressure on the trailing edge of the brush? Why does this correct the problem? :confused:


Thanks for the great thread!

I'm relatively sure DC current is directional from - to +

so follow the current path across yer comm

Flip over your chassis and follow with a pencil, the current flows from the rails to the comm in one direction or the other dependant on track polarity.

Consider the looser side, whichever side that may be, like a current leak. If the leak is pre-winding (intake side) based on the current direction flow; then the arm cant do it's full potential of work. Ya got "current interuptus"

If the current leak is post winding (the exhaust side of the comm) then the arm poles get a better charge and she spins up faster, albeit it not quite optimum. AKA"current constipatus"

It is important to note that whatever the polarity, the trailing brush must operate within its proper tension range for current to escape the comm thus completing the circuit and optimizing performance potential. Often an after break-in recheck will indicate that a slight touch is required on one spring or the other. Be certain you re-install the brushes in their correct "broken in position" after final tweaks. Once you've established your comm setup ...leave it be...replace brushes to correct performance drop off due to normal brush wear instead of chronically re-tweaking your set up.

It all depends on which way the electrons are driving across the comm.

You're pretty handy to have around Bill.
What a great explanation of the concept.

I think it is a very nice thing for you to give these tips,way to go!!
DRAGjet

I think it is a very nice thing for you to give these tips,way to go!!
DRAGjet

Yeah Tim's letting the cat out of the bag...snicker...but "I" didnt cough up any secret Dragula tips under penalty of unga bunga! :p

...cuz really I'm not nice...actually very naughty...just ask Santa. He says I'm very likely to re-offend. :thumbsup:

Dunno if my line of comm blarney is kosher er not. Never gave the "why" a moment of thought until yesterday. I was hoping someone with a full compliment of braincells like "AFX Too" would chime in. Thus providing some proper electrical theory and bailing our butts out.

Just a caveman here..."Ugh... lil car no go! ... me squeeze brushes...makum car go faster!"

"Uh oh!..squeezum too tight and burn finger...me invent fire!" :woohoo:

There very helpful to the new tuner,and the old guys who need a fresh spin on things they might not have picked up.Drag cars are a totally different tune though,more brush pressure good..uga buga!!
DRAGjet

I have yet to find an original t-jet chassis that I can get too much brush tension with.

Tuff ones, AFX, JLs all can be over tensioned. But I would LOVE to get more tension from my Jets.

As you all will see in the next installment, when you get a really good set of gears, you need to stop the thing. And brushes do that real good.

Thanks for the compliments

Bill Hall said:
Flip over your chassis and follow with a pencil, the current flows from the rails to the comm in one direction or the other dependant on track polarity.

Consider the looser side, whichever side that may be, like a current leak. If the leak is pre-winding (intake side) based on the current direction flow; then the arm cant do it's full potential of work. Ya got "current interuptus"

If the current leak is post winding (the exhaust side of the comm) then the arm poles get a better charge and she spins up faster, albeit it not quite optimum. AKA"current constipatus"

It is important to note that whatever the polarity, the trailing brush must operate within its proper tension range for current to escape the comm thus completing the circuit and optimizing performance potential.
OK, I get all that, but I'm still confused.

Let me try again:
Why would I want a single commutator brush to have more pressure on one side of the brush than the other? Bill talks of the trailing brush, but Tim was speaking of each brush having more pressure on its trailing edge. Intiuitively, it makes sense to have equal pressure across the entire surface of the brush for best performance (assuming the overall pressure is right). Tim's suggestion seems counterintuitive, which is why I'd really like to understand.

Sorry if I'm beating a dead horse or wearing out my welcome,
but everyone else seems to get it but me! :(

Thanks for your patience. :)

Tim
Have you tired HO world brushes or Dennis Ruthfords 2mm brush they are pretty tall.

I get the most tension with out tweakin the "V" bend at the brush is to take a sewing needle and with chassis up side down and VERY carefully ,slide the sewing needle under the right side of the brush spring right next to rivet lift up to were the sping is out of the brush hole about 1/8" and with you finger nail press down on the brush sping. This tightens the spring buy the rivet giveing you a much more aggressive tweak and pulling up on the right side of the spring( with chassis upside down looking down at the bottom) will give you side tweak to spring that Tim was talking about so the comm gaps don't hag up on hard edge of brush with rotataion of the comm.Once this is done right you should have the end of the Brush spring ( before the "V" bend starts) touching the chassis and the "V" bend should be sticking through the brush hole.

Now if you have to much right to left on the brush spring you can easily be fixed by useing that tooth pick and press very sightly on the brush spring by the rivet

You must remember the copper on these chassis are very thin and everything described above, are very delicate and aggressive steps take care and go slow

Yes I've tried the needle method. It does work pretty good. But I hav'nt treid any HOW brushes and I didn't even know Dennis had brushes. I'll need to hit him up.

Why would I want a single commutator brush to have more pressure on one side of the brush than the other?

You are correct that the ideal situation is to maintain a uniform and correct pressure across the entire brush surface. This will reduce excess brush friction and sparking, the two things that kill brushes and sap motor performance.

The brushes in pancake motored slot cars have a precarious mechanical balance that affects their mechanical and electrical performance. The fact that the brushes are not firmly seated in their holders creates a number of problems. First, when the comm is moving the friction between the comm and brush wants to move the brush sideways. Second, if the brush is not sitting perfectly flat and evenly supported across the entire range of lateral movement, the friction between the comm and brush will tend to tip the brush on its side, and third, the angular force applied by the commutator at the friction point between the comm and brush makes the brush want to spin in its socket. All of these things move the brush around and create added friction,. Once the brush starts moving around the brush pressure is affected and this can cause additional sparking.

Ideally, motor brushes are broken in at a specific contact point on the comm and assume a shape and form an interface that maximizes the wear characteristics of the brushes and performance of the motor. With inline motors this behavior is obvious because the brushes develop a concave shape to better mate with the comm. With pancake motors you want the same exact break-in thing to occur, and you want to form a perfect interface between the comm and the brushes. Stabilizing the brushes is essential. If the brushes move around they are never broken in and if they spark the comm-brush interface (or film) is destroyed, creating more friction, more heat, and even greater brush wear. It's a cascading failure effect.

That being said, all adjustments made to the brush springs and/or brushes are made to counteract those three natural tendencies: lateral movement, tipping, and spinning. Using a brush that better fills the socket, like JB's, reduces lateral movement. Preloading the brush spring on one side can help offset the tipping tendency. Notching the brushes can help counteract brush spinning. Finally, once you get things as stable as possible, don't hesitate to use break-in your brushes for a few minutes before the start of a big race and after you have taken the car apart. And keep track of which brush goes in which socket.

Afxtoo - Thanks for addressing my question with your excellent post.

Preloading the brush spring on one side can help offset the tipping tendency.
So Tim runs the arm in reverse to determine whether preloading is necessary? From your explanation, it would seem as though some preloading might always be beneficial.

Tim
Have you tired HO world brushes or Dennis Ruthfords 2mm brush they are pretty tall.

Does Dennis have a website. The only tall motor brushes I have seen were Umphi's Tall Boys out of Germany

Roger Corrie

Yes Dennis's web site is http://thepitbox.4t.com/ and HO world's web site is http://www.howorld.net/

Hey guys,
I'm home for a few days and I'll be getting to the next installment in short order.
Give me the skinny on what your problems have been in the previous segments. Too long, too short, wrong info, what gives?

Tim

Hey Tim, they have all been excellent. Maybe at the end, you could do a repost of them all at the beginning of a new thread, I think we've all mixed this up a bit by posting so much throughout.

Thanks!

Tim
I think tips are very informative and VERY helpful the only way it could be better is if it was in video so we could see what you are doing too. I really appreciate all the help you have given me with the tips and one on one build tech.
Travis

Tim
I think tips are very informative and VERY helpful the only way it could be better is if it was in video so we could see what you are doing too. I really appreciate all the help you have given me with the tips and one on one build tech.
Travis
I trying now to get some pics together for the next segment. That will have to do for now.

Hey Tim,

Thanx for the huge effort putting this all together!

Hey Tim,

Thanx for the huge effort putting this all together!

You're more than welcome.
While I'm doing this Project, we're trying to put together a fray team. We've lost Three guys since the last Fray, so we need to find some good drivers fast.
If anyone is interested, try my e-mail:
leppertsinkc@sbcglobal.net

Tim
Captain
Independence Fray team