Does Sequence of Polishing Operations Matter?

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Stan Pope
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Does Sequence of Polishing Operations Matter?

Post by Stan Pope » Fri Feb 15, 2013 2:17 pm

Suppose that I polish an axle by stepping from 64 micron (assuming that the axle finish is already no more than 120 micron) to 32 micron to 16 micron to 8 micron to 4 micron to 2 micron, and I do each step sufficient to accomplish the rated finish, for instance, 15 seconds each. Then I start in the reverse direction, using 4 micron paper to 8 micron to 16 micron, etc., for the same durations.

Are the two 16 micron finishes the same "roughness?"

My intuition say "Yes, but..." So, I'm looking for some input from real world experience.

==============

Why bother, you say? To avoid "grinding down" the bores during some tests of axle finishes. If I test between polishings as the finish grows finer, I expect that the impact on the test wheel bore will be more drastic than if I test between polishings as the finish grows coarser.


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Re: Does Sequence of Polishing Operations Matter?

Post by Speedster » Fri Feb 15, 2013 5:08 pm

Here is what I was planning to do. I have a 3 wheel rail rider that runs fairly consistent in Lane 1 of my track. I planned on using Max V's 4094 axles, new 1.8 gram wheels, and change just the axles in the back wheels. If I remove the DFW I fear it would introduce too many variables. Start out running bare axles on wheels with Hob-E-Lube. Bare axles then polished with Brasso. Each pair of the following axles would now be prepared using the previous step. The steps are as follows: 400 grit wet, 1500 grit wet, 3000 grit wet, 3000 grit wet followed with Brasso. I would now have 6 separate pair of axles. After running the car with the axles treated with only Brasso, I would then start with the axles treated with Brasso and a 3000 grit sanding and work toward the 400 grit. Max-V's axle measures .087 to start. The axle diameters would each be measured. This should cause the least damage to the bores. Comments?



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Re: Does Sequence of Polishing Operations Matter?

Post by sporty » Fri Feb 15, 2013 5:18 pm

A good chance you will ruin the wheel bores. I recommend not using a 1.8 gram costly set of wheels.

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Re: Does Sequence of Polishing Operations Matter?

Post by Speedster » Fri Feb 15, 2013 5:35 pm

I thought perhaps a high quality wheel would be the most sensitive to change. I have a feeling the times are not going to change much. If we are dealing with thousandths of a second I think I won't be able to determine that it was caused by sanding of the axle. The car will run to the hundredth, usually, but seldom to the thousandth. It'll be fun even if it ends up not proving anything.



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Re: Does Sequence of Polishing Operations Matter?

Post by sporty » Fri Feb 15, 2013 5:52 pm

I have done testing kind of like this 3 or 4 years ago. You will find out there will be a bigger time differance than you can imagine. esp with starting with a raw axle. but you also have to do about 9 to 12 runs, to get real data.

The bigger question that I had to ask, was after I kept using the same wheels. was the pre exsisting damage that happened prior to the more prepped axle, effect the times and the further testing ? to not give accurate testing.

I felt the answer was yes and I would recommend trying to have 4 sets or more wheels, with the same bore size, stock bsa wheels, instead of using 1 set of wheels, because of the damage that happens from the first phaze of the testing of a un prepped axle is severe in my mind.

Just something to ponder.

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Re: Does Sequence of Polishing Operations Matter?

Post by Speedster » Fri Feb 15, 2013 7:32 pm

That's a good point. There are so many variables. Instead of doing all the different grits, why not do the extremes. I will polish 3 axles with Brasso and stop. Sporty, how about if I send you 3 axles and you prepare them your way and detail on DT what you did to them. I have a 3 1/2 oz. tungsten canopy. I will cut a simple wedge and make the total weight, with wheels and axles, 5 oz. I'll run the car, as a straight runner, down the track 10 times for each set. I'll set the CM at 1", or whatever you think will give us the best test. I will use your axles in the 1st 10 runs. The diameter on my set should remain at .087. I'm eager to learn what the diameter on your prepared axles will be. Thoughts ?



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Re: Does Sequence of Polishing Operations Matter?

Post by sporty » Fri Feb 15, 2013 8:00 pm

I'll think about it, My days of doing stuff is really at end. and my way of polishing axles., well I had not planned on buying stuff. I think I have just enough left over to polish for the cars for mid america.

So my priorities right now, are to completing that task. and then after that. If I have anything left over to do some. I can look at it then. how does that sound ?


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Re: Does Sequence of Polishing Operations Matter?

Post by Speedster » Sat Feb 16, 2013 3:38 am

Sounds Good.
Cheers,
Bill



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Re: Does Sequence of Polishing Operations Matter?

Post by Stan Pope » Sat Feb 16, 2013 1:34 pm

Please don't forget the original question:
Stan Pope wrote:Suppose that I polish an axle by stepping from 64 micron (assuming that the axle finish is already no more than 120 micron) to 32 micron to 16 micron to 8 micron to 4 micron to 2 micron, and I do each step sufficient to accomplish the rated finish, for instance, 15 seconds each. Then I start in the reverse direction, using 4 micron paper to 8 micron to 16 micron, etc., for the same durations.

Are the two 16 micron finishes the same "roughness?"

My intuition say "Yes, but..." So, I'm looking for some input from real world experience.


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Re: Does Sequence of Polishing Operations Matter?

Post by sporty » Sat Feb 16, 2013 2:57 pm

Stan Pope wrote:Please don't forget the original question:
Stan Pope wrote:Suppose that I polish an axle by stepping from 64 micron (assuming that the axle finish is already no more than 120 micron) to 32 micron to 16 micron to 8 micron to 4 micron to 2 micron, and I do each step sufficient to accomplish the rated finish, for instance, 15 seconds each. Then I start in the reverse direction, using 4 micron paper to 8 micron to 16 micron, etc., for the same durations.

Are the two 16 micron finishes the same "roughness?"

My intuition say "Yes, but..." So, I'm looking for some input from real world experience.


Well for me, I was too confused to understand, what you were trying to compare, two different types of sand paper rated the same ? Or were you asking, if you skipped steps in the polishing, buy jumping around with a greater range of sand paper grits. would your surface still be the same ? as if you had not ???

because then you say, if you reversed the polishing process and started at 4micron to 8 micron to 16 micron.

when you said reverse, I typically understand that to mean you are now going to start with the lowest micron and work you're way upto 16 micron ?

I was not smart enough to understand what you were doing or trying to do, So i didnt bother replying.

and Like I have said, what kind of sand paper are you using ? and what is the other type ?


Someone with a micro scope would have to the one to answer those questions, If you have one, then that would be the key to answering your question.



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Re: Does Sequence of Polishing Operations Matter?

Post by *5 J's* » Sat Feb 16, 2013 9:39 pm

I take the question as - if you started with a 120 micron finish axle then polished using 64 micron, then 32, then 16 then, 8, then 4, then fininshing with 2 micron. Now take that axle polished to 2 micron and "scratch it up" with 4 micron, then 8, then finishing with 16 micron. Would the axle this axle "scratched" to 16 micron- have the same finish as the axle when it was being polished and just finished polishing at 16 micron.

Intuition tells me that if you spent sufficient time to get to "terminal" finish with each grit (polishing and "scratching") then yes,they would be the same.



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Re: Does Sequence of Polishing Operations Matter?

Post by Speedster » Sun Feb 17, 2013 1:21 am

I think the 16 Micron "roughness" would be the same. FS recommended in a previous Topic the axle test be conducted starting from a finished axle and that makes a lot of sense. I agree, starting from Fine to Coarse would have to be easier on the bores.

I think the 16 Micron "roughness" would be the same -- but the axle wouldn't. To reach 16 Microns the 2nd time you have gone through 16, 8, 4, 2 once and then 4, 8, 16 a second time. If you sand your axles down to 2 microns and install them in the car you might have a faster car at that point. If you do a test where you have sanded the axles twice the car might run slower among the grits not because of the coarseness of the axle but because you are consistently reducing the diameter of the axle.
If the intent is to see if a car will go faster with sanded and polished axles I think a good test would be to run a polished (Brasso) un-sanded axle against a polished (Brasso) and sanded axle. Run the polished and sanded axle first if it's felt it would do less damage to the bore.



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Re: Does Sequence of Polishing Operations Matter?

Post by Stan Pope » Sun Feb 17, 2013 2:20 am

Thanks, guys! You're telling me that I'm not overlooking anything stupid and that it is probably worth spending time on an initial test of concept.

A reason for making several comparisons along the smoothness scale is to avoid the mistake of assuming a relationship is linear. In the arena of graphite lubrication for PWD, there are two (at least) schools of thought. One says "The smoother the better!" The other says, "There is a point (around xxxx grit) at which performance peaks. Then performance declines as you go past that point."

Then there are some additional dimensions of performance over an above "How fast will it go?" One such is duration, e.g., "What is the best average time over 10 runs?"


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Re: Does Sequence of Polishing Operations Matter?

Post by loren.phillips » Sun Feb 17, 2013 8:25 am

Do these 2 schools of thought (the smoother the better vs. performance peaks at xxx grit) also apply to oil lubrication?
I can see how "performance peaks at xxx grit" applies to graphite. It is a solid that can be "worked" into micofractures. But for oil, I have assumed that "the smoother the better".



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Re: Does Sequence of Polishing Operations Matter?

Post by chromegsx » Sun Feb 17, 2013 11:03 am

Stan,

While I don't think many have "real" world experience with what your asking...(nor do I).... You will likely get lots of opinions mostly geared toward "X" grit = "X" grit, what difference does it make which direction it is accomplished? Wish I had a better microscope than a toy as I would go test this and snap pics for side by side comparison. But I can't help but think that there has to be a difference (you're getting the same point two different ways), although in my mind it should be very insignificant for the path you appear to be heading down. And results from either direction would be very interesting to see.



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