Dead-On Alignment

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Dead-On Alignment

Post by TurtlePowered »

If wheels do not run true, left to right, is it even possible to achieve dead-on alignment?
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Stan Pope
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Re: Dead-On Alignment

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TurtlePowered wrote:If wheels do not run true, left to right, is it even possible to achieve dead-on alignment?
Rolling the wheels individually on the slightly inclined test surface is the first step in my alignment process. If the wheels do not roll straight individually, then my process will probably not converge.
Stan
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Da Graphite Kid
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Re: Dead-On Alignment

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Stan, what sort of "test surface" are we talking about here?
What type of material and preparation?
What is the length?
How high do you raise one end?
What do you use to ensure that the wheel is straight to begin the test?

I was thinking of using a 4 foot long section of 3/4" MDF (medium density fiberboard) since this stuff is so flat (and because I can't find any straight lumber). The dinner table is off limits after giving it a fine dusting of graphite a few years back... :oops: ... and I thought we had taken enough precautions by covering it with plastic! I could add a couple of snap-line chaulk marks as guide lines that the wheel would have to keep between and to use as visual references. To make sure the wheel starts straight, I'm thinking of ripping another piece of MDF as a guide with the thickness reduced on side that is contacting the inside edge of wheel under hub. Than I could use another piece of MDF on the edge of that to make sure the guide piece is straight with the edge of the test surface. All testing would, of course, be done after all wheel preparations where completed.

What can I say, we don't have our derby restrictions - I mean rules - yet so I can't start building a car yet. Besides, I've got a chopped up sheet of the MDF laying around that my wife has accused me of buying when I didn't need it! :roll:

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Re: Dead-On Alignment

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I'm thinking about using a piece of parque flooring that is around 4' long or the leaf of our kitchen table. The parque I could mark up since I just found that. The leaf my wife would probably shoot me if it use permanent marker on.
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Da Graphite Kid
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Re: Dead-On Alignment

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I'm thinking about using a piece of parque flooring that is around 4' long or the leaf of our kitchen table. The parque I could mark up since I just found that. The leaf my wife would probably shoot me if it use permanent marker on.
...or banish you to your workshop! :lol:

Wait, that isn't a bad thing now is it? :o I've got seven derby kits, tools, sandpaper and paint out there. All I need is some food and water and I'm set! :wink:


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Stan Pope
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Re: Dead-On Alignment

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Da Graphite Kid wrote:Stan, what sort of "test surface" are we talking about here?
What type of material and preparation?
What is the length?
How high do you raise one end?
What do you use to ensure that the wheel is straight to begin the test?
My "test surface": Kitchen table made of maple, I think.

Preparation: Wipe away all peanut butter, jelly, butter, and anything else that nearly blind Mama might have missed. Feel with flat of hand for anything that the cleanup might have missed. Wipe wheel treads with a soft clean cloth. Wash the wheels in mild detergent, rinse and dry if you tried rolling them on the table before you wiped off the peanut butter.

Length: Typical kitchen table width ... 40"? This runs with the grain of the wood, and has some join lines that are a handy reference.

How high: I have some small wedges cut from 2X4 that I slip under the legs to level the table end-to-end and raise one side around a half inch. (It is a pure joy to see a car smoothly accelerate down that slope!)

How straight to begin with: Don't worry... you should be able to tell if it rolls in an arc (because of conical tread) or if it wobbles side to side (because of tread irregularities) as it rolls. Retest "wobble" results to make sure that it is the wheel and not the table. A speck of dust or a bread crumb can cause significant wobble. Now, a "straight line" is just an "arc with infinite radius". Don't worry about arcs of large radius. If you can see the wheel curve in its path across the table, then rework or replace it.

After an alignment session, I use a cloth with a small amount of mineral spirits to clean off the table top. This is excellent for removing graphite traces. Then, wash the table top with mild detergent to remove traces of mineral spirits. Mama should be happy then.
Stan
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Re: Dead-On Alignment

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TurtlePowered wrote:I'm thinking about using a piece of parque flooring that is around 4' long or the leaf of our kitchen table. The parque I could mark up since I just found that. The leaf my wife would probably shoot me if it use permanent marker on.
"Qualify" your test surfaces by repeated tests. If one wheel rolls inconsistently then there may be a problem of surface inconsistency. If several wheels roll consistently, but not in a straight line, then you may have deformation (e.g. sag) in the surface.
Stan
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Re: Dead-On Alignment

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Stan Pope wrote:
TurtlePowered wrote:I'm thinking about using a piece of parque flooring that is around 4' long or the leaf of our kitchen table. The parque I could mark up since I just found that. The leaf my wife would probably shoot me if it use permanent marker on.
"Qualify" your test surfaces by repeated tests. If one wheel rolls inconsistently then there may be a problem of surface inconsistency. If several wheels roll consistently, but not in a straight line, then you may have deformation (e.g. sag) in the surface.
How far should a wheel be able to travel without major detours?
2' x 1" off mark?
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Re: Dead-On Alignment

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Stan,
Thanks for the info on your test set-up. I guess I was thinking of rolling the wheels too fast! :oops: Rolling the wheels on a small incline would be better to show if they will roll straight or not. Rolling them at a fast pace may not allow you to see any wobble.

As for mineral spirits to clean the table with: I think I'll just stick with my MDF. If I mess it up, s'okay. If I mess the table up, like TurtlePowered: I may be shot (table was a gift from her sister)!

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Re: Dead-On Alignment

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Da Graphite Kid wrote:Stan,
Thanks for the info on your test set-up. I guess I was thinking of rolling the wheels too fast! :oops: Rolling the wheels on a small incline would be better to show if they will roll straight or not. Rolling them at a fast pace may not allow you to see any wobble.

Da Graphite Kid
Yes, the gentle slope causes actions to take place in slow motion!
TurtlePowered wrote:How far should a wheel be able to travel without major detours? 2' x 1" off mark?
I think you want better than that. The reason is that the alignment method depends on observing a wheel deflection of less than 1/8" in about a foot of travel, and being able to attribute that deflection to axle orientation rather than wheel or work surface defects.
Stan
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Re: Dead-On Alignment

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We use a 4 foot long, 1 foot wide white laminated shelving board to check alignment. I installed 2 tee nuts at one end and a single tee nut at the other. I run long screws through the tee nuts to create a 3 point contact with the floor. I permanently marked the surface with multiple lines the full length. The screws provide fine adjustment side to side and also adjusts the slope angle. I check level by rolling a ball bearing down the surface and adjust until it runs straight with the lines.
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Re: Dead-On Alignment

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ExtremePWD wrote:We use a 4 foot long, 1 foot wide white laminated shelving board to check alignment. I installed 2 tee nuts at one end and a single tee nut at the other. I run long screws through the tee nuts to create a 3 point contact with the floor. I permanently marked the surface with multiple lines the full length. The screws provide fine adjustment side to side and also adjusts the slope angle. I check level by rolling a ball bearing down the surface and adjust until it runs straight with the lines.
That is an excellent alternative for a kitchen table! Probably easier to adjust for level, too! Nice work. :)

When you set up, how much slope to you use?
Stan
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Re: Dead-On Alignment

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The normal setup is about 1" rise for the 48" run which is approximately 1.2 degrees. It seems to work pretty well for alignment checks.
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