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Discussion Starter · #1 ·
like to find better and easier ways to do things.Im by no means a cheap skate,but I like to find cheaper ways to do things as well.This cost me around 3 bucks total.

One of the things I have been kicking around in my skull was a way build a simple tool to balance t jet arms.Watch makers poising tools are expensive,and over kill as well.I read a "how to" on one of the HO sites on how to do it.Good concept,but I felt there were way too many variables involved.And frommy experience,too many variables means just that many more ways something can go wrong.

And being that an arm balancer must be somewhat of a precision tool,that just wouldnt do.

So I kicked it around down here in the dungeon on and off for the last few weeks.I was off today,so I made it my top project of the day.

Its amazingly simple tomake,and works amazingly well to boot.I did a gray lam copper wire tjet arm before,and without even really trying,I balanced it and noticed a big improvement in RPM,s when I ran it ina test chassis on my bench.

So,here's how I did it.And again,I LOVE this camera the wife bought me.

Ok.First up the materials.




Two brand new virgin utility knife bladesThe squarish piece of metal was in my junk box.I think it goes into the bottom of one of the slats from a set of vertical blinds we had over the patio door to keep it hanging straight.A piece of brass would work just as well,as long as you check it for trueness.
The four rectangular pieces of metal are keys for a shaft.I got them in the nut and bolt section of the local hardware store.They are quite true,all at almost dead exact .250.
Years ago,when I was in tech school,I took machine shop and metalurgy.We had a lot of stuff donated to the school by Curtiss Wright,stuff that was used to build planes during WW2.
The teacher showed us a wooden box once,of things that were(I think,it was 25 years ago)called "jo blocks".
They were pieces of some kind of hardened metal,the size of dominos.They were dead on EXACT sizes,used for calibrating machinary.
I thought of those today,and these shaft keys were the best I could come up with.

Ok next,securing the first blade to the metal.

My work bench is a stainless steel restaurant work table.I have it adjusted with the adjusters on the legs to be dead perfect level.
So I put my blade on the middle of the metal plate,held up on each side by two of the keys,like this:





Ok,next step.
Fasten both sides of the blade to the plate with a hot glue gun.Blob it on good,but be careful not to get any on the keys:



End part one


Mike
 

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Discussion Starter · #2 ·
Part two

Aaaaaaaaaaaaaaaaaaand onward to the next step,attaching the other blade.
Two of the keys will be used to make sure the blades are exactly the same distance from each other as well as level to the plate.
Place the other blade on the plate like this on the plate,with two keys between each blade,and two holding the unfastened one in place.




Again a liberal dose of hot glue.Fasten the blade first,let it set,remove the keys,and hit it again with the hot glue to secure it all around.

Now take one of the two keys out of the center.CAREFULLY drip hot glue betwee the two blades.With one hand,press the two blades tight to the center key,with the other hand,use something to smooth the glue down to the center key.
Any excess that you get on the blades can easily be scraped off with a small exacto blade.





Ok,after cleaning it up a bit,this is what I got as far as level and true.I had to shim the one side of the plate on the table with a piece of paper.No biggie:



And here it is,done,with an arm on it:



Put the arm on,roll it a few times,note which lam keeps dropping to the bottom,Dremel off some material,repeat.

Besides the old gray lam I mentioned earlier,I also did an old JL one I had in my box.No vibration,and increased RPMs.
Its cheap,simple,and it works!!!!!!

So I thought Id share that with you guys.I tried to explain it best I can.I explain things better in person then with the written word,so feel free to ask any questions.
 

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These actually do work, used a similar device for years not only for arms but wheels and tires too. I use a file instead of a dremel, I tend to get a little grind crazy. Good job.
 

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You did great job!....novices like myself greatly appreciate it...

I've been playing with cars for years...hell...decades....never raced with a group...

Any tuning tips you can share are great...I need to learn how to tune, repair, and bebuild my cars...all makes of them...from pancakes to super mags...

I just got an invite from a local gentlemen to come check out their group...he found me here...They have been racing in the Toledo area for years...and have 9 active tracks...the yearly 8 hour endurance race is on the 7th...and I have been invited to attend the practice session on new years day...They run mag cars which is fine...as I love them all...and depending on the tech requirements...I have a couple stockers I would be comfortable driving...

I dont mind being a rookie...I do mind not having a decent car to field...

I'm hoping to get some hands on help...and if I am welcome to join the group...it will spur me to bring my modular track idea to fruation...

I really have to keep the tyco stuff I have for now...but I'm going to do perminate modular sections that can be assembled into different tracks....kinda like my temp christmass layout...

There are many people who lurk here and never post...just shy I guess...or afraid to look like novices...but I'm sure I speak for a few of them in offering thanks that you long timers share your tuning tips...

I'm often afraid to even attempt to disassemble a chassis for fear it will never run again...while you guys rip them apart for kicks....slap them back together...and run the crap out of them...

To many of us...tuning is a mystic art..akin to freemasonry....we get the concept....but the practice is beyond us...

Thank you SIR! :thumbsup:
 

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Discussion Starter · #7 ·
sethndaddy said:
when you say "take some material off with the dremel" what material are you talking about?
Off of the lamination.The metal that is next to the solder tabs,that comes in different colors.Green,gray,blue,red,etc.

Its pea soup green on the JL arm.

Good question tho,I'll try to post a pic today to better explain.

Roadrnr: LOL!!!!! It wont win any beauty contests.But better safe then sorry.

Mike
 

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Mike get yourself some cheap bubble levels,i salvage them from little string line levels i get at the dollar store,and glue them right to the plate.
I glued my razor blades to a piece of glass,glued the glass to a chunk of 2X4,used some 1/4 receiver nuts in the bottom of the 2X4,screwed short 1/4" bolts into the reciever nuts,and with the little bubble levels glued to the glass surface,i can level the razor blades anywhere
Excellent post Mike
Rick
 

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Just to add some more,when i did mine,i used key stock like Mike did and 2 part 5 min epoxy,but i put a big old speaker magnet under the piece of glass to help lock eveything into place ,then used a dab of epoxy on the corners of the razor blades,the magnet held everything in place while the epoxy set-up.
After the corners were set-up,i removed the magnet and keystock,and finished gluing them into place
 

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Im new to T-Jets, just bought my first one today actually. How many RPM's does the average new stock TJet arm spin off the track w/out a load? Im wondering how much of an accelleration increase this would result in. Very nice write up though, I planned to do something similar as well!

P.S. Have you tried one of these out since you balanced one just to note the performance gains/losses?
 

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Discussion Starter · #12 ·
Hornet said:
Just to add some more,when i did mine,i used key stock like Mike did and 2 part 5 min epoxy,but i put a big old speaker magnet under the piece of glass to help lock eveything into place ,then used a dab of epoxy on the corners of the razor blades,the magnet held everything in place while the epoxy set-up.
After the corners were set-up,i removed the magnet and keystock,and finished gluing them into place
Real quick,I'll post more later.Just walked in from work............

Rick,I had it all figured out how to do it with magnets,that was how I did my first one.
Only one problem,the mags magnetized the blades.It caused the arm to not roll straight.

Mike
 
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