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Discussion Starter · #1 ·
Thanks to Sealevel for inspiring this project!

If you don't have the money for a real Magnet Marshall, then this DIY project might be for you!

Disclaimer: This project will in no way provide you with the precision and features of the real thing.

Ready to get started? Good! This was a much easier build than my Budget Tire Truer detailed on
another thread by that title.

You will need some supplies. I used a few pieces of scrap plywood, and some 1 x 2 (poplar I think).


And I used some 3/8 x 3 balsa laying around collecting dust.


And a few pieces of hardware.


Of course, to make this all work, you'll need a small cheapy scale. Mine came from Harbor Freight and
measures down to 0.1g and goes up to 500g. Don't spend a lot on the scale, or you should just
save your money for the real thing!


See you next post!

Stan
 

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Discussion Starter · #2 ·
First, let's glue up the bunk. Grab your balsa and CA glue.
Cut your pieces to fit the footprint of the cars you will be
supporting on it.


For me, it will be used exclusively for 1/32 scale cars. The tires of your cars need
to rest on the tops of the bunk.


And there must be a gap in the top to allow for the 'shelf' piece.


The bottom of the bunk will rest on your scale.

When you're done with this part, join me on the next post.

Stan
 

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Discussion Starter · #3 ·
Let's build the base!

I used some wood I already had laying around. You'll need a wide base, a vertical support with a
slot in it, and a horizontal shelf piece.
Here's another pic of the pieces.


I chose to use my table saw to cut the slot or gap into the vertical piece. But you could also
use two smaller individual sticks instead. Just glue or screw them together at the top. Let's drill out the
bottom of our vertical.


I always like to take a few extra seconds to countersink for the screw heads.


Now let's see where we want to mount our piece of metal.


You cannot use brass or aluminum for this, as it must be attracted to a magnet. Instead of a piece
of metal, you could also use a small slice of the type of rails or braid you use on your track
to simulate the actual downforce you get when racing.

Here's how it looks put together. Notice that the horizontal shelf piece has the metal
mounted on it, and has a wood screw with washer that holds it against the vertical support.
You need to be able to adjust it up and down.




We're like, totally done building, dude!

Now, how do we use this thing? See you next post!

Stan
 

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Discussion Starter · #4 ·
Place your scale on the base.


Then the bunk.


You'll need to adjust the height of the shelf. When I set mine so that the metal was
exactly flush with the tops of the bunk, there was so much magnetic downforce that
it exceeded the range of my scale! So I set mine just below flush, like this:


Now that we're set up, let's run a sample.

Just like in 8th grade science class, we have to check the mass of our bunk, so we can
always subtract it out later if needed.

44 grams. This varied slightly (a few 10ths) based on where I set the scale.

The car and bunk together register 139.6 grams.




When we set up the whole stack...


We get a reading of 423.3 grams!


So that means my Scaley NASCAR is pulling 283.7 grams of magnetic downforce!
And the car itself weighs in at only 95.6 grams.

Again, this is only a relative value, useful in comparing various cars and magnets against
one another. You could use a small section of your track type to better simulate
the actual downforce you are experiencing when racing.

Have fun!!!

Stan
 

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David.
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Yes, just use the zero button. Any way, that's allot of pull from the magnet, how fast is the car?
Nice build bye the way.
 

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QUOTE (SSD slotguy @ 27 Nov 2010, 11:58) <{POST_SNAPBACK}>Any way, that's allot of pull from the magnet, how fast is the car?
Nice build bye the way.


+1 on both points.

What does it read if you increase (?) the gap to whatever height the car "really" rides at?

Thanks for sharing! Nice job.

Cheers,
Ian
 

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Greg Gaub
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Excellent work, Stan! As always!
I've seen other DIY marshals using postal/food scales, but they usually entail cutting a chunk out of the scale "table" to insert a piece of steel, so more closely mimic the Magnet Marshal brand product. Those are great, but it can be hard to find a suitable scale, not to mention risk ruining it by cutting it up! Your design should work great with no need to modify the scale itself. Well done!


Yes, magnet marshal scale values are always relative. They will even vary from unit to unit. The idea is to use ONE mashal on the same field of cars. Clubs often have a dedicated magnet marshal that decides if a car meets spec or not. DIY ones like this are great for budget minded clubs and personal users who want an evenly matched IROC set.
 

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WOW !
Kudos to you Stan!
Done in record time, too!

I KNEW you were up to the challenge, but did not think you would have it done this quickly.

Congratulations!


I will have to start thinking about another challenge for you...
But take a few days off, first!

Cheers!
 

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OK, Stan.
Your long weekend is over...

As they used to say in Mission Impossible (the TV original):

"Your next assignment, should you decide to accept it..."

Budget track VACUUM.

I emphasize vacuum since everyone has chipped in Swiffer cars, lint roller attachments, et al including one that had squirrel cages and assorted parts from a computer.

But since my track is in the garage with LOTS of dust (as many others have also commented) I was trying to think of a way to use a mini-vac (like the USB powered computer ones since the old battery powered ones can't be found anymore) to be powered by the track and pulled/pushed by a car.

Trick is the voltage difference between the USB vacuum and the 12V track.
Anyway, it is an OLD saw of mine but if you want another challenge, there is it.

If you need links to work already done, etc. check out my thread at the bottom of this post.
If this does not interest you, that is OK as well. You have already outdone yourself with the last 2 projects.

Thanks again for all the "projects" (track separation for PB, lap counter, budget tire truer, budget mag marshal).

Cheers!


PS The play by play development of your original plastic track layout in its various incarnations was terrific!
 

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David.
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I have one of them vacs, it's not very good so I'm prepared to sacrifice it.
 

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the best track vac ever The ELECTROLUX ERGO RAPIDO 12v rechargable wow this thing SUCKS!!!!! (in a good way) but yes show us your next creation your workmanship is amazing!
 

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ELECTROLUX ERGO RAPIDO 12v ... "This product is no longer available. Continue shopping at Costco."

OK, Mas, where did you get yours? I think it is a bit big to "send around the track" (just like my idea to use an iRobot Roomba got turfed due to its 1:1 size).

But like the idea it uses 12v.

Cheers!
 

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Discussion Starter · #17 ·
One last gasp before I sign off on this thread...
I happened upon a friend's Magnet Marshal at a recent race. So I thought I would attempt to calibrate my gizmo.

I haven't ever used one before, and I see now that even the slightest movement of the same car can create slightly different gram weights. So at best, these sorts of things are relative to the moment and not an absolute standard.

But with that in mind, I adjusted mine ever so slightly to approximate the range of the real MM.

Here's the set up again...


And I tweaked the shelf to read roughly 321 grams, whereas the MM read 318 grams.


Even the actual MM gave different readings on the same car. The gap I ended up with was about 1.04 mm on the caliper, but with the wood construction, even a change in humidity will probably affect the gap.


So I won't set my hot coffee too close!!!
 

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Greg Gaub
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Yep. The littlest things can make a big difference. When we test a car on the MM, we usually turn the tires and test and turn the tires and test a few times, to make sure that the average is within the limit. Still, any way to measure and try to even out a set of cars is better than nothing. Thanks, Stan!
 

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Discussion Starter · #19 ·
By the way Greg, Alan came back through the Phoenix area recently and spent an evening racing with us and telling his stories from all over the planet. He always brings things for us to test drive. This time we demo drove the Scaleauto 1/24 cars with the thin rubber tires. Niiiice! But $$$$! He had an Avant 1/32 LMP with the same type of tires and no magnet... it also was a whole new car!

Stan
 
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